ANSC 3400 Exam 1
What do you know about "gizzard teeth"?
- gizzard glands secrete koilin - koilin rods form the "gizzard teeth" that are horizontal and branched
What characteristics of the jejunum make it the place where the majority of nutrient digestion/absorption occur?
- longest villi = more microvilli (brush border) = more glycocalyx = more surface area for digestion and absorption to occur than any other part of the small intestine
How would you distinguish the "requirements" and "allowances" for vitamins?
- requirements: usually close to minimum levels required to prevent deficiency signs - allowances: total levels fed to compensate for factors affecting the need
If we know the body's H2O content, we can estimate the body fat, protein, and ash contents because:
...
To estimate the requirement, we have to know the needs for _____. (5 things)
1. Maintenance 2. Growth 3. Reproduction 4. Lactation 5. Work
What are the four phases of gastric development in ruminant species?
1. Newborn Phase 2. Preruminant Phase 3. Transitional Phase 4. Preweaning and Postweaning Phases
The primary end products of rumen fermentation are "short-chain" VFAs. Why?
1. because C skeletons cannot be completely oxidized to CO2 in absence of O2 2. also, e-transport systems do not function - thus low ATP production 3. VFAs are the primary energy source for the host
What is unique about horses in terms of "prehension"?
1. prehension agents include teeth, upper lips, and tongue, but the sensitive, mobile lips during feeding from a amanager 2. during grazing, the lips are drawn back to allow the incisor teeth to sever the grass at its base 3. mastication on only one side of the mouth at a time
Why is it important to have ideas on interactions of minerals (2 reasons)
1. prevent bad interactions 2. prevent secondary deficiencies
Essential Minerals
1. withdrawal from body induces same response across species 2. deficiency accompanied by biochemical change 3. its addition reverses or prevents abnormalities
What area of the stomach is the secretory portion?
Fundic/Gastric region
secretion is affected by:
H2O content amount of food in mouth
What can we say about microbes in the cecum and colon in terms of satisfying the pig's needs for energy, protein, and vitamins?
It is the sight of nutrient retrieval remained in digesta before excretion. It has a high microbial population, which contributes VFA, but young pigs cannot utilize VFA and cannot utilize microbial protein.
What is Maintenance? How is it measured? Why do we need energy/nutrients for this? If needs not met, what could happen?
It is the state in which there is neither gain or loss of a nutrient by the body; the energy and nutrients needed to support vital functions. Measured by basal metabolism (measure heat production) Need energy for respiration, circulation, maintenance of muscular activity and production of internal secretions If not satisfied, fasting catabolism will occur (breakdown of body tissues
Why would it be important for us to have some ideas on the interactions involving minerals?
It's important for us to have some ideas on interactions because they may be synergistic or agonistic and could result in an accidental deficiency or toxicity. We also need to know how much of the minerals are actually being absorbed so we know how much minerals to put in a diet.
What is the most important aspect of nutrition?
Knowing the requirements. to find these requirements we need to know the value of the feedstuff and energy. Most important factor to determine value of feedstuff is digestibility
Acidosis
Lactic acid accumulation in the rumen and in the blood if animals are overfed with, or are abruptly switched to grain or other readily fermented carbohydrates. Can be lethal
Why do chickens have a poor sense of smell?
Oriented towards other purposes such as orientation and direction
horses and ruminants can both synthesize:
SOME B vitamins however not as extensive as ruminants
What is the reason for the statement: 1 disadvantage associated with having the rumen would be inefficient utilization of "some" carbs and proteins
Whatever is left/escaped fermentation will be utilized poorly because of insufficient digestible enzymes in host
Nutrition
all the processes whereby food and oxygen are presented to and utilized by living cells, and waste products are eliminated
What is the most important factor when determining the nutritional value of feedstuffs/diets?
digestibility
5 words to describe nutrition
food, cells, Oxygen, and waste
Instead of just memorizing, we can define "nutrition" using our own words if we can remember 4 terms, which are:
food, cells, oxygen, waste
"Gastrin" is the focal point of controlling the activity of the stomach, and _____ & _____ are responsible for regulating the gastrin secretion
histamine and secretin
Why do we need energy/nutrients for "lactation"?
mammary growth, biosynthesis of milk components
Factors effecting digestion to excretion
needs, digestibility/ availability, processing, animals, environment
Is fattening or finishing animals part of growth? Explain.
no because true growth is the increase in proteins, minerals, and water not fat!. In practice, a considerable amount of fattening is an integral part of growing animals for meat
Why is the "fasting metabolism" value not sufficient to satisfy the maintenance need?
perhaps, influenced by heat increment from ingested feed, energy to consume feed, normal activity, group size, body composition, environmental temperatures
_____ is the only VFA that can be used for gluconeogenesis.
propionate
Define "Allowance"
satisfying the "entire" population; fixed or available amount
What is most important aspect of nutrition?
satisfying the energy and nutrient needs or establishing the requirements
Factors effecting procurement
sight, smell, experiences
Obviously, the major difference between "fat soluble and water soluble" vitamins is solubility, but there is one additional major difference between the two
storage, fat soluble is stored, water soluble is excreted
As we mentioned, "laying hens and lactating sows" do not mobilize a lot of Ca and P from bones, which can lead to leg problems. To prevent/alleviate such problems, it is important for them to ___________ before the laying or lactation period.
store more Ca/P, maybe supplement feed
Why can't "true absorption" be determined by a balance study?
the feces contain some minerals
Bilot's Spot and Glaucoma are cause by _____.
vitamin D deficiency
1 disadvantage of having a rumen would be inefficient utilization of carbs and protein because:
whatever remains/escaped from ruminal fermentaton is utilized poorly because of insufficien digestible enzymes in host
What are some basic differences among various species in the GI system?
• Pigs: Similar to the human GI tract (monogastric) • Poultry: Have no true stomach and a short small intestine; have a crop, proventriculus and a gizzard. Two ceca. The cloaca is the opening that empties both the urinary and digestive systems' waste. • Horses: Have a small upper GI tract, and a huge lower GI tract • Cattle: large upper GI tract (Reticulum, Rumen, Omasum, Abomasum)
Perhaps, we can say that "fat-soluble" vitamins are mostly involved in the regulation of _____(1)_________, whereas "water-soluble" vitamins are mostly involved in ____(2)________.
(1) bodily functions, such as eyesight (Vit A) or bone densities (Vit D) (2) enzymatic functions
Uric acid is associated with poultry bc they do excrete the N end product as uric acid. The breakdown of ______ can also produce uric acid (why we have small amount of uric acid in our urine)
(answer NOT urea or protein) - keep looking
How would you describe the utilization of carbohydrates by rumen microbes? (Carbohydrates to VFA and gases):
): utilize cellulose; oxidation of VFA via the TCA cycle and conversion of propionate to glucose, then oxidize glucose. Cellulose Hemicellulose Starch Sugars Pectins Glucose Pyruvate Lactate Acetate Formate H2 Propionate Butyrate CO2--> CH4
Balance test may be a good way to estimate mineral requirements because the balance would be a reflection of a dietary concentration or intake of mineral in question
+/- balance instead false
Describe the Newborn Phase.
- 0-24 hr - forestomach is not functional at birth and represents a small proportion of the total stomach - contains no microbes
Describe the Preruminant Phase.
- 1-3 wk - principle food is milk - nursing leads to greater saliva secretion, which contains an enzyme to aid in hydrolysis of milk lipids - reticular groove closes, allowing the bypass of the ruminoreticulum straight to the omasum and abomasum
Describe the Transitional Phase.
- 3-8 wk - animal starts to ingest progressively larger quantities of roughage, which stimulates the development of the salivary glands and the ruminoreticulum - ruminoreticulum starts acquiring microbes - starts producing VFA and gas - this period is critical for establishing the ruminoreticulum
Describe the fate of propionate.
- 30% is metabolized by the forestomach wall to lactic acid - almost completely removed by liver - converted to oxaloacetate and used in Krebs cycle or together with lactic acid, converted to glucose, which is either released into circulation or stored as glycogen in liver
What can be said about horses' small intestine? Any consequences?
- 30% total digestive tract volume and main site of both digestion and absorption - no gallbladder (no direct bile secretion to duodenum) - fast flow rate - easy to overwhelm digestive capacity of stomach and SI b/c of limited volume - designed to digest carbs and proteins in grains in upper gut (feed 2-4 times/day for safer, more efficient digestion)
What can be said about horses' large intestine/cecum-colon?
- 50-60% total digestive tract volume - site for microbial digestion/fermentation (similar to microbial pop. in ruminants) - bacterial breakdown of cellulose and other carbs to produce VFA and bacterial synthesis of B vitamins and protein (some absorption of VFA from cecum)
Describe the Preweaning and Postweaning Phases.
- 8 wk-adulthood - the preweaning phase coincides with the natural decline in lactation - reticular groove becomes erratic and absent in older animals unless they are being fed milk regularly - start resembling characteristics of adult animals
What is meant by the phrase, "the duodenum is primarily a mixing site for digesta"? Is that true for all nutrients?
- The digesta is mixed with various enzymes secreted by the pancreas as well as bile from the liver (stored in the gallbladder). - Yes?
What are some factors that contributed greatly to the progress made in "mineral nutrition" since the 1920's and 1930's?
- advances in chemistry & physiology enabled scientists to initiate mineral studies - synthetic diets: useful in identifying individual macro and microelements (use pure sources of energy like CH2O, lipids, protein, and all mineral of interest) - interrelationships observed between chemical composition of organisms and earths crust were useful in understanding the importance of minerals
What is the primary function of the "crop" in chickens? Can they survive without it? What is it?
- an esophageal "out-pocketing" - main function: food storage site - not essential for well-being or maximal performance of the bird unless feed is severely restricted
What are some of the limitations in the microbial "protein synthesis"?
- available energy and NH3
What should we remember about the brush border area of the small intestine?
- brush boarder enzymes located at brush border - enzymes are integral part of the membrane at the brush border (not secreted but "shed" into lumen) - made up of the microvilli
What should we remember about the glycocalyx of the small intestine?
- can be found at the apical portion of microvilli - provides additional surface for absorption and contains enzymes
How would you describe the utilization of carbs by rumen microbes?
- carbs are utilized by the ruminant microorganisms, very little glucose is absorbed by ruminants - VFA account for 70% or more of animal's energy needs: oxidation of VFA in TCA cycle => conversion of propionate to glucose => oxidation of glucose
What is unique about the horse stomach in comparison with other nonruminant species? What are the consequences associated with these differences?
- compared to others, horses have a small stomach (10% of volume of digestive tract) - does not have as extensive muscular movement activity and ingesta tends to arrange itself in layers (reason for being prone to greater digestive disorders) - fast flow rate - when stomach remains empty, excess gas produced can cause rupture of the stomach ("continuous" consumption is optimum)
General characteristics of "water-soluble vitamins"
- contain N, S, or Co, along with, C, H, and O - no appreciable storage - excess is excreted in urine and generally non-toxic
Satisfying vitamin needs in pigs, poultry, and other non-ruminant species.
- depends on diet - intestinal synthesis of B vitamins is low relative to ruminants - habitually practice coprophagy
Why is the balance test not a good way to determine mineral requirements?
- errors at each step or incorrect estimates can all add up - is complicated, laborious, and requires a high accuracy from collection to analysis
What can we say about microbes in the cecum and colon in terms of satisfying the pig's needs energy, protein, and vitamins?
- fairly high in the microbial population - microbes produce volatile fatty acids (VFAs can be absorbed, may be an important source of energy) - may be important in obtaining B and K vitamins via coprophagy - synthesis of amino acids have littel/no value to pigs
What would be some significance/importance of non-protein nitrogen utilization by microbes?
- fermentative microbes can use urea to synthesize protein - ruminants can be fed urea as an inexpensive supplement - secrete urea formed during protein metabolism into saliva, which flows into the rumen and serves as another nitrogen source for the microbes
What should we remember about the villi of the small intestine?
- finger-like projections extending into lumen of the small intestine - covered in microvilli (form brush border) - increase surface area - longest in jejunum - very active area with rapid turnover of cells
Elaborate on this statement, "the small intestine is the only site where simple sugars and amino acids can be absorbed in all animals".
- for cecal digestors, simple sugars are absorbed by the SI, but for ruminants, only a small portion of simple sugars are absorbed by the SI; the others are fermented to VFA in the forestomach - in cecal digestors, protein is lost in SI before it reaches the fermenting vat (no amino acids), but for ruminants, microbes that flow into stomach and SI are digested and absorbed as amino acids
Effects of superalimentation or "force-feeding"
- force-fed animals had a faster growth rate than animals who were not force-fed - just means that the amount a food an animal wants to eat may be different than the maximum that they can eat
Compare pigs and poultry in terms of sight and smell?
- fowl and pig have both rod and cone cells, thus they can see "color" - birds have poor sense of smell, so they depends mostly on acute eye sight in seeking food, whereas pigs are completely opposite
Satisfying vitamin needs in ruminants
- grazing animal probably deficient in A and possibly E - diet and biosynthesis may be adequate to synthesize B vitamins - may need supplementation - inadequate synthesis of B vitamins if under stress
What would be the focal point of gastric secretion?
- hormone called "gastrin" - "histamine" is responsible for the secretion/stimulation of gastric secretions and "secretin" also regulates "gastrin"
What is unique about the esophagus of a horse?
- horses seldom vomit; have only one-way peristaltic movement or because of the marked tonus of the lower esophageal sphincter (holds food in) - Horses are the only domestic species in which acute gastric dilation can occur to the point of rupture of the stomach wall
Elaborate on why microbial populations can be affected by the type of diets and pH.
- if pH drops to about 5.5, protozoal populations become markedly depressed because of acid intolerance - more drastic lowering of rumen pH, as can occur with grain overload, can destroy many species and have serious consequences to the animal
Why do we say that saliva may have some special importance in ruminant species? In dogs?
- in ruminants, saliva contains no enzymes, but has additional importance: provides N, P, Na for rumen microbes; also highly buffered for maintaining pH balance in rumen - dogs (and other carnivores) don't have enzymes in saliva, salivary reflex conditioned by the sight of food, salivary secretion has the special function of evaporative cooling
General characteristics of "fat-soluble vitamins"
- involved in regulation of metabolism of structural units - consist of only C, H, and O - stored in liver or adipose tissues - tissue accumulation can reach toxic levels
Satisfying vitamin needs in horses.
- lack of info - most likely deficient in A and E (D if kept in confinement) - uncertainty and use of confinement systems leads owners to supplement - KEY: provide good quality hay
What is the importance of lactate and ammonia produced in the rumen as a result of fermentation?
- lactic acid is produced during the degredation of starch and is used by secondary bacteria to produce propionate; lactic acid is a strong acid that causes the pH of the rumen to fall rapidly - ammonia arises from the deamination of dietary proteins, non-protein nitrogen sources, and urea derived from saliva and across the forestomach wall; NH3 is usually incorporated into microbial protein; if it can't be absorbed, it causes the pH of the rumen to rise
What are some similarities/differences between ruminants and cecal digestors?
- main difference: location of fermentation vat - both are able to digest and extract energy from cellulose - ruminants can utilize protein from fermentative microbes and cecal digestors cannot - cecal digestors can utilize dietary hexose sources directly and ruminants cannot
Why are minerals so important for our bodies?
- minerals serve as stable insoluble compounds in bone tissues - maintaining ionic equilibrium - maintaining osmotic pressure - maintaining acid-base balance
Describe the fate of butyrate.
- most butyrate is metabolized/oxidized to ketone body - the remainder is carried to the liver and metabolized similarly, thus absorbed butyrate appears in the general circulation almost entirely as beta-hydroxybutyrate
How would you describe the absorption of VFA? Does the status of papillae affect VFA absorption?
- most of the VFA produced are absorbed across the forestomach wall - absorption is higher when the pH in the rumen is lower and when the chain length increases - yes
How is "mineral metabolism" different than most other nutrients?
- once dissolved or activated by enzymes, then minerals become assimilable or utilizable - minerals are excreted extensively into the GI tract => blood - minerals aren't broken down
Define "Vitamin"
- organic substance - present in small amount - components of enzymes - derived by intrinsic biosynthesis (cannot be synthesized by animals and must be obtained from the diet)
What is the reticular groove? Why is it important
- passage that allows milk to bypass ruminoreticulum and flow directly through the relaxed omasum to the abomasum - important because it allows the milk to bypass the rumen and avoid being digested by microbes
Can a typical "corn-soy" diet for nonruminant species supply all the necessary vitamins? Minerals?
- pigs and chickens (non-ruminants) need to be supplemented and horses and other ruminants need good quality hay - only satisfies few elements, horses and ruminants need forages/roughages high in minerals and non-ruminants need to be supplemented
How could we describe protein and/or N utilization by rumen microbes?
- protein nitrogen sources and non-protein nitrogen sources provide the rumen with nitrogen, as well as endogenous nitrogen from saliva and rumen wall - microbes cleave the peptide bonds of amino acids and release the amino acids, which are then deaminated - the NH3, carbon skeleton, and energy are left to be used by the microbes to synthesize their own amino acids
What are some fundamental differences in the taste apparatus of pigs and chickens?
- taste buds are located throughout the oral cavity, particularly on tongue in pigs, whereas they are restricted to or located on the back of mouth in birds - sense of taste may be associated more with "aversion" rather than "preference" in poultry
What is the primary reason for the anaerobic environment of the rumen and the the primary end products being mostly short-chain VFA?
- the environment of the rumen has to be anaerobic to support the microbes (bacteria and protozoa) that ferment starches to VFA - fermentation end products are mostly short-chain VFA simply because C skeletons cannot be fully oxidized to CO2 in the absence of oxygen
What particular reasons cause chickens to have a poor sense of smell?
- their sense of smell may be oriented toward other purposes; ex: other than feed detection and/or evaluation such as ascertaining "'orientation and direction" - another possibility is the lack of mastication
How do poultry satisfy nutritional needs with a stomach, per se?
- use the crop for storage, and proventriculus and gizzard for gastric digestion - proventriculus provides HCl and pepsinogen - gizzard is a site for grinding and gastric digestion
apparent digestibility
. Apparent digestibility does not consider metabolic fecal nutrient.
"____" is fine, fiber-rich polysaccharides, which can be found on the surface of microvilli - perhaps acting as barrier between microvilli and digesta?
...
What are the two sets of glands in the small intestine that are responsible for secretions? What are their primary functions?
1. Brunner's Glands - protect duodenum from stomach acid, provides optimum pH for enzymes 2. Crypts of Leiberkuhn - secretion of mucus and various enzymes
What are the two strategies evolved for "professional fermentors"?
1. Cranial fermentors: (cattle, deer, sheep) - have large, multi-compartment section between the esophagus and true stomach; forestomach can house complex ecosystem that supports fermentation 2. Caudal fermentors aka cecal digestors: (horses and rabbits) - complex and exceptionally large large intestine, where fermentation takes place
You can estimate the maintenance energy needed by determining the BMR, which can be done by measuring heat production. What is heat production?
1. Fasting catabolism: deny feed - the nutrients needed to support activities (maintenance, circulation, etc) must come from the breakdown of body tissues. 2. By eliminating all potential factors that may increase heat production, the minimum E expenditure compatible with the maintenance of life is BMR 3. Heat production is heat generated by bodily processes (metabolism of nutrients)
Steps of Nutrition
1. Procurement 2. Ingestion 3. Digestion 4. Absorption 5. Assimilation 6. Metabolic functions and resulting metabolites 7. Excretion
What are some pancreatic hormones and their functions?
1. Somatostatin - coordinate GI tract activities and regulate rate of energy intake (short--term regulation) 2. Insulin - glycogenic, antigluconeogenic, antilipolytic, and antiketotic activities (hormone of "energy storage") 3. Glucagon - glycogenolytic, gluconeogenic, lipolytic, and ketogenic activities (hormone of "energy release") 4. Pancreatic Polypeptide - function not well-known; inhibits pancreatic secretions and relaxes gallbaldder
What are some major advantages associated with microbial fermentation in the reticulorumen?
1. allows digestion and then absorption of fermentation products that are of value to the host before the acidic abomasum 2. change poor quality protein to "good-quality" microbial proteins 3. selective retention (cud chewing) of coarse particles extends fermentation time and allows for further mechanical breakdown during rumenation 4. release of fermentation gas from the system by eructation 5. toxic substances in the diet may be attacked by the microbes before being presented to the small intestine
What are some criteria that can be used to describe "true" hormones?
1. can be isolated pure 2. effects have been studied 3. action demonstrated under physiological conditions
What are some of the gases produced in the rumen? What are the consequences of the gases being produced?
1. carbon dioxide 2. methane - pollution issue, elimination of methane waste-product represents the loss of about 8% of the total digestibility of the diet 3. hydrogen sulfide - potentially toxic gas, even in small amounts 4. hydrogen 5. oxygen
What would happen if the needs for "reproduction" were not met?
1. during growth: delayed sexual maturity, reduced fertility, reduced sperm production 2. during pregnancy: may lead to permanent damage, death of the fetus in utero, or the birth of a weak animal 3. after parturition: nutrient concentrations in the colostrum are reduced, milk production declines, and survival of the young is much less likely
What are the best approaches for determining mineral requirements?
1. for macroelements - practical feeding trials (analysis of organs and tissues) 2. for microelements - analysis of organs, tissues and whole body
What 3 things does a biological dose-response curve show?
1. gross deficiency/excess 2. marginal 3. optimal
What is a fistula?
1. lid surgically attached to rumen - to study mineral metabolism (able to determine what happens at specific location) 2. useful in studying effect/fxn of minerals on microflora of digestive tract
What is the significance/importance of pH changes throughout the GI system?
1. low pH in the stomach prevents multiplication of ingested bacteria (except lactobacilli) 2, digestive enzymes have a fairly narrow range of optimum pH; too low or too high will decrease the hydrolysis or activity of enzymes
What is pellagra?
1. means rough skin, seen around neck 2. SEVERE deficiency the 4 Ds: dermatitis, diarrhea, dimensia, death
Define "Requirement"
1. minimum amount of concentration needed 2. amount of nutrients needed to satisfy the "average" population
What are the three types of stomach cells responsible for gastric secretions?
1. neck cells: secrete mucus 2. parietal cells: secretes HCl and exchange Na+ with H+ 3. chief cells: responsible for the secretion of enzymes, electrolytes, and water
What is unique about cattle in terms of "prehension"?
1. no upper incisors and only an upper dental pad and lower incisors 2. lips have limited movement, thus tongue is main prehensive organ 3. tongue is long, rough, and mobile 4. chew on only one side of jaw
What are some differences between pigs and chickens in terms of digestive physiology?
1. pigs born of litters, chickens hatched from eggs 2. proportionally, feathers make up more body weight on chickens than hair does on pigs 3. pigs have an immature digestive system at birth, chicks have full complement of digestive enzymes at hatching 4. Chicks have a different digestive tract/process.
Describe the compartments of stomach in ruminant species.
1. reticulum - spherical and esophagus enters at cardia 2. rumen - divided into dorsal and ventral sacs 3. omasum - a kidney-shaped structure and consists of many leaves, which enhance the internal surface area/volume ratio of the omasum 4. abomasum - consists of fundic, body, and pyloric regions
What are the three major disadvantages associated with having microbes in the rumen?
1. ruminants spend a large part of its day chewing 2. need complicated mechanisms to keep the fermentation vat running efficiently 3. pathways of intermediary metabolism must be geared toward the use of the peculiar end products of fermentation
What are the major functions of the pancreas?
1. supplying enzymes to SI for starch, protein, and fat digestion 2. secretion of water, bicarbonate and others into duodenum 3. supplying hormones to manipulate nutrient metabolism on a moment-to-moment basis
What are some of the major contributions of microbes on microbial fermentation to the host animal?
1. synthesis of high quality proteins in the form of microbial bodies 2. synthesis of protein from non-protein nitrogen sources 3. synthesis of B vitamins
Do horses have advantage of both ruminants and nonruminants? Also, horses have propensity to have lots of digestive problems - why do todays horses develop so many nutritional problems? anything to alleviate problem?
1. the horse is a hind-gut fermenter - so may have advantages of both - in terms of satisfying the protein/AA and vitamin needs, also the utilization of fiber 2. Advantages of both are: can utilize cellulose like ruminants and can use fermentable nutrients directly like other nonruminants 3. will ferment cellulose and others to volatile fatty acids 4. How to alleviate - digestive system can be easily overwhelmed because of its size, and can develop stomach problems (stomach rupture etc) Regularity of feeding might be crucial (frequent, smaller meals), reduce carb overload of the cecum (promote gut homeostasis), and maximize contribution of forage (adequate fiber intake)
What would be the main differences between a typical digestion study and an "indicator method"?
1. the indicator used as a marker is not absorbed in the GI tract, not losing any. 2. much easier: no need to keep track of feed intake and fecal output, no total collection, no metabolism stall
What are some similarities between pigs and chickens in terms of digestive physiology?
1. they are nonruminants, thus they have a less "meaningful" symbiotic relationship with microorganisms along the GI system vs ruminants 2. need amino acids, not protein per se (protein is supplied but the amino acids come from the microbes) 3. limited ability to utilize fibrous components of diet 4. diets consist predominantly of grains and soybean meal => more susceptible to mineral/vitamin deficiencies 5. raised in confinement 6. fast growing and efficient in feed conversion
For most species, esophagus is simply a passageway for feed but it does have some implications/importance in horses and chickens because:
1.It prevents vomiting and belching in horses, which can lead to gas buildup in the stomach - 1 way cardio/esophageal sphincter 2. In chickens, mucus glands in upper esophagus moisten bolus then uses peristaltic action to move bolus to and from crop
Can a typical "corn-soy diet" for non-ruminant species supply all the necessary vitamins?
A corn-soy diet is good for supplying amino acids and energy, but not good at supplying vitamins, so the animal must be supplemented with vitamins.
Ketosis
A generic term for any condition in which ketone bodies (acetone and acetoacetate) are readily detectable in the body fluids and the expired breath. Formed in the liver mitochondria
Why can poultry not utilize fiber efficiently?
Access to the cecum is restricted. VFA in poultry is only about 2-3%.
What would be some advantages and disadvantages of using radioactive indicators in studying mineral metabolism?
Advantages of using radioactive indicators are that they make it possible to study the exchange between digestive tract and blood, incorporation of minerals into tissues and magnitude of reserves as well as the transplacental passage. Disadvantages of using them are the interpretations of results are often very difficult.
Major differences between 2 methods? Why do we say apparent? Why can't we just say digestibility? Why is digestibility the most important factor?
Apparent digestibility does not consider endogenous nutrients in feces. Actual digestibility does. Digestibility determines exactly what nutrients and foodstuffs are available to be utilized, absorbed, etc.
Ammonia Toxicity
Arises most commonly when excessive amounts of urea are fed, especially at the time of low amylolytic fermentation. Occurs because VFA production rate is much lower, thus, less substrate for protein synthesis so less microbial protein synthesis occurs.
What are some of the limitations of microbial protein synthesis?
Available energy and NH3. For diets containing urea, may need sulfur, and branched-chain C-skeletons.
Why is a balance test not a good way to determine the mineral requirement?
Balance studies are not good to use for minerals because they are most commonly used for macromolecules, they are complicated and laborious and require a high accuracy from collection to analysis. The balance of minerals is affected by many factors and minerals can be lost through the skin. So a balance study has limited value in estimating an accurate requirement.
In the small intestine, 2 sets of glands are primarily responsible for the secretion of viscous alkalkine mucus and intestinal enzymes, respectively
Brener's glands and crypts of Lieberkuhns
In the small intestine, 2 sets of glands, " ____ & ____ ," are primarily responsible for the secretion of viscous alkaline mucus and intestinal enzymes, respectively
Brunner's glands (duodenum) and crypts of Lieberkuhn (intestine)
In the small intestine, 2 sets of glands, ___________ & __________, are primary responsible for most of the secretions.
Brunner's glands and Crypts of Lieberkun
Is there anything unique about brush border enzymes like lactase, sucrose, and peptidases compared with pancreatic enzymes?
Brush boarder enzymes are located at the brush boarder of the intestinal villi and shed into the lumen as opposed to pancreatic that enter via the pancreatic duct.
How do we usually satisfy the vitamin requirements of horses and ruminants species?
Can ingest enough by grazing, not much need for supplements except under extenuating circumstances. Horses.Lack of information.Most likely to be deficient in A and E (and D if kept in confinement).Deficiency of B and K is less likely than other nonruminants.Uncertainty and use of confinement systems means that owners are more likely to supplement! Ruminants.Grazing animals may be low in A and possibly E.Diet and biosynthesis are usually adequate to meet B vitamin requirements (because of ruminal flora).May need supplementation under some conditions.Feeding a complete B vitamin mixture to cattle entering a feedlot can lead to decreased stress and increased gain, and fed to feedlot calves can decrease morbidity.Inadequate synthesis of B vitamins under stress is likely!
What do we mean by ammonia toxicity?
Causes by using an excess amount of NPN. It is caused by an excess in the blood, overloads the livers ability to detox, ruminant pH increase, and causes the rumen function to shut down, and then causes ammonia toxicity. Can cause an animal to die from ½ hour to 2 ½ hours/ treatment is to empty the rumen or stab open the rumen.
What is unique about poultry red blood cells?
Chickens have ½ red blood cells from other animals so they metabolize things faster because their heart rate is faster. They have a lower oxygen capacity.
In terms of satisfying the nutritional needs of their young, are there any differences between chickens and mammals?
Chickens must consume large amounts of Ca for egg production (mammals do not need such a high amount of Ca)
Why are the "red blood cells" of poultry unique?
Chicks have a higher metabolic, respiration and heart rate due to the relatively fewer number of red blood cells.
What deficiency causes wasting disease?
Cobalt def. on lush pasture in ruminants - just skin and bone
What are some differences between ruminants and cecal digesters?
Differences between ruminants and cecal digesters: ruminants can efficiently digest and extract energy from cellulose and can utilize the protein from fermentative microbes. Hindgut fermenters can efficiently digest and extract energy from cellulose and can utilize dietary hexose sources directly (sugars).
What is the most important factor in establishing nutritional value of feedstuffs/ diets?
Digestibility
What is meant by apparent digestibility?
Doesn't consider the metabolic fecal nutrient means the portion of feedstuff nutrients the animal uses
Conclusions or inferences from the data set?
Energy from barley is most digested in the rectum and cloaca. Protein is digested mainly at the rectum and cloaca as well. Nonruminants rely heavily on hindgut fermentation and digestion for protein and energy in barley. Very little digestion of proteins and energy of barley takes place in the duodenum( energy) a substantial amount of energy digestion takes place in the ileum. As well as the duodenum and ileum for digestion of protein in barley making up worthy portions.
Why can't carbohydrates that escaped the rumen microbial fermentation not be utilized efficiently by the host?
Escaped glucose (carbohydrates) is utilized poorly in ruminants because of insufficient digestive enzyme in the host
When using urea, we should supplement ruminant diets with sulfur and branched chain C skeletons because those are usually the most limiting factors for microbial protein synthesis
False
The entrance to ceca, which are the main fermentation site, is somewhat restricted and that might be one of the reasons that young pigs cannot really utilize fiber efficiciently
False large intestine
Throughout history people had to deal with many serious defiicnecies or disorders and we no know that some of these can be caused by vitamin deficiencies. Pellagra by thiamin and beriberi for niacin
False, deficiency of niacin causes Beriberi and deficiency of niacin causes Pellagra
Pigs like humans have a propensity to become obese partly because they are very responsive to the action of glucagon and not really responsive to action of insulin
False, very responsive to insulin
If we can give some drugs based on the metabolic body weight, we may end up with overdosing animals thus it would be better fro us to do that based on absolute body weight.
False. exact opposite metabolic is safer than absolute
One of the reasons that chickens have a relatively high heart rate might be their erythrocytes thier white blod cells seem to be less than half that of many mammals
False: leukocytes
In general ntirite does not have much of adverse effects on nonruminant animals but bacteria in water can convert it to nitrate which can form methemoglobin thus reducing the oxygen carrying capacity
False: nitrites are bad news bears
As we mentioned we can say a nonessential amion acid without any problem but we should not say a nonessential mineral because all minerals are metabolically essential.
False; both should be stated as being essential, some may not be dietarily essential, but are, nonetheless still essential.
Pepsin an endopeptidase is mostly responsible for pancreatic digestion of protein and it has 2 pH optima, 2 and 3.5, and it is not really active if the pH is greater than 4
False; gastric digestion
A double exchange mechanism? Well it refers to active absorption of Na and Cl which involves cation exchange between Cl and bicarbonate on one side and anion exchange between Na and hydrogen on the other side
False; got anions and cations mixed up
Senses such as sight, smell, touch, and taste seem to play some roles in seeking or finding food/feed. For instance the olfactory system seems to be importatn for poultry birds simply because they cannot masticate or don't have heated mouth
False; vision is far more important in chickens
Why is a fasting metabolism not a sufficient value to satisfy the maintenance need of animals?
Fasting metabolism value is not sufficient enough to meet maintenance needs because during fasting the nutrients needed to support body activities must come from the breakdown of body tissues. Typically will break down from fat or bones to obtain minerals
What can you make out of the biological nutrient dose-response curve?
For the gross deficiency or toxicity, we have enough knowledge to prevent it. The marginal deficiency region, humans don't show many signs because they are usually only deficient in one nutrient, so it is hard to tell. The optimal region, that is where the body should be in terms of good nutrition. It is affected by many factors such as interactions, environment, genetics, and sex
What is the effect of superalimentation of force-feeding?
Forced-feed pigs gain much more weight then the controlled group. The more feed they consume, the more they will gain. Feed intake is the key for the overall productivity of food producing animals. It takes a few days before the forced-feed animals surpass the control group animals.
What do we mean by Bloat
Gas fills the rumen and it must be eliminated. Newly arrived forages sit in the middle of the rumen where grain sinks to the bottom. If the animal cannot fart or burp it will build up the gases and get bloat. In order to get rid of the bloat, you can give the animal mineral oil to help pass the stuff in the rumen to let the gas out. If that does not work or is an emergency, need to puncture the rumen.
Bloat
Gases cannot escape the animal because eructation-inhibition reflex is initiated. The buildup of pressure can interfere with movement of the diaphragm and circulation and cause death.
What is the focal point of gastric secretion?
Gastrin is the focal point of controlling gastric secretions. Gastrin is regulated by Histamine, which is responsible for secretion and Secretin. Gastrin is responsible for the secretion of acid, water, electrolytes, enzymes, etc. It is made of a family of polypeptide hormones.
is fine fiber rich polysaccharides, which can be found on the surface of microvilli and it's perhaps, acting as a barrier between microvilli and digesta
Glycocalyx
"Fattening or finishing" is integral part of commercial production but is not part of "growth" because:
Growth is characterized by increase in proteins, minerals, and water -- not fat
Why is HCl necessary for protein digestion?
HCl denatures proteins, activates pepsin from pepsinogen, and provides the optimal pH for pepsin to work
How to increase heat production if or when necessary?
Have animal consume feed or get active
There seems to be a relationship between an animals size and lifespan. How would you explain this relationship?
Higher metabolism (smaller species) = shorter life span because of increased heart rate.
What would be some consequences of differences in the metabolic rate?
Higher metabolism = shorter life span. Faster metabolic rate: burn calories/energy more efficiently. Slower: store more calories as fat (can lead to obesity).
What did we mean by horses being hindgut fermenters?
Horses have advantages of both non-ruminants and ruminants. They have lots of microbes in the hindgut. The microbes help ferment carbohydrates and cellulose into volatile fatty acids (VFA). The microbes also synthesize a lot of vitamins and proteins/ amino acids. Horses can use cellulose like ruminants and can utilize nutrients directly after being digested like non-ruminants.
Does the horse have "advantages" of both ruminant and nonruminant species? Elaborate.
Horses have the advantages of both ruminants and nonruminants; the fermentation in the hind gut resembles that of ruminant species, meaning that they are able to use cellulose/ fiber in the same way that ruminants can, but also can absorb other nutrients directly like non-ruminant species (don't have to go through microbes in the rumen).
It is commonly assumed that microbial proteins or bodies of microbes are high quality proteins, do you agree or disagree?
I agree in the case of ruminants because they flow into the stomach and small intestine where they are digested and absorbed as amino acids and small peptides. I disagree for horses because the fermentation vat of the horse is behind the small intestine, all microbial protein is lost.
Why do we say saliva may have some special importance in ruminant species and dogs?
In dogs, saliva contains no enzymes. Salivary secretion in dogs also has the function of evaporative cooling and gets rid of excess body heat. In ruminants the production of saliva is continuous but greater while eating and ruminating. Can reach 12 gallons a day in cattle. Contains no enzymes but provides N, P, and Na for microbes. It is highly buffered which helps maintain the proper pH for the microbes.
What is the main differences between a typical digestion study and an indicator method?
Indicator method: uses a marker that is not digestible or absorbable such as lignin or insoluble ash Apparent digestibilty: can be obtained by measuring concentration of marker in the feed vs. feces; do not need to measure feed intake or feces output
What do we mean by back and forth peristalsis in poultry small intestine?
It increases retention time, which increases the efficiency of digestion and absorption.
What is Growth? How is it measured? Why do we need energy/nutrients for this? If needs not met, what could happen?
It is a correlated increase in mass of the body in definite intervals of time, in a way characteristics of the species Fat accretion in the reserve tissues Determines the total feed requirement Not grow or die
What do we mean about ketosis?
It is an increase in acetoacetate, beta hydroxybutyrate and acetone. It is the primary problem in dairy cows. Causes hypoglycemia (lack of glucose/ energy), mobilize fatty acids and glycerol from fat storage, increase in acetyl-CoA, liver cannot handle the increase in acetyl-CoA because not enough energy (oxyloacetate), convert to keytone bodies, and decrease in feed intake and decrease in milk production.
Is there anything unique about the esophagus of horses?
It is difficult for horses to expel gases and cannot vomit so it is dangerous that things cannot go back up the esophagus.
What is Lactation? Why do we need energy/nutrients for this? If needs not met, what could happen?
It is milk secretion An increase in nutrient density during late stages of gestation result in an increase in mammary growth and milk yields Mineral deficiencies can result in weakened skeletal system; high producing animals may have to rely on body reserves to produce milk
What is Reproduction? If needs not met, what could happen?
It is the act of creating life iv. Before Breeding: sterility, low fertility, silent estrus, or failure to establish or maintain pregnancy During Growth: delayed sexual maturity in both sexes; under and over feeding of energy can result in reduced fertility; under- nutrition decreases the number and vigor of the sperm and may cause cessation of spermatogenesis During Pregnancy: females who are severely undernourished during development becomes pregnant, the drain of her body by the developing young may result in permanent damage, death of the fetus in utero, or the birth of a weak animal. If deficiency is severe, may result in resorption of the fetus, absorption, malformed young, birth of dead, weak, or undersized young... just like ones severely undernourished during growth.
What do we mean by heat production and why is it important?
It is the energy that is not converted to do work is released in the form of heat; used to maintain a constant body temp
Compared with other non-ruminant species, is there anything unique with a horse's stomach?
It is very slow compared to other species, about 30% slower. The passage rate is very fast though. Food tends to arrange itself in layers, which contributes to digestive disorders. When the stomach is empty, has can accumulate and cause colic and bloat. In order to help prevent bloat and colic, it is better to feed horses small meals when it comes to grains and sweet feeds. It is best that they are fed two to three times a day with grains and sweet feeds. Grasses and hay they can be feed less or graze throughout the day.
What do we mean by acidosis
Lactic acid concentration. Rapid fermentation, increase in lactic acid by lactobacillus sp., decrease pH, more lactic acid, further decrease in pH, increase in osmolality of the rumen, dehydration and circulatory collapse. MAJOR PROBLEM!
What did we say about the Ca status or need and potential problems in laying hens and lactating sows?
Laying hens mobilize large amounts of Ca, and are susceptible to leg problems (can be true to a lesser extent for lactating sows).
What are some of the major microbial contributions of microbes or microbial fermentation to the host animal?
Major contributions of microbes and microbial fermentation to host animal: synthesis of high quality protein in the form of microbial bodies (bacteria and protozoa, which can be digested and absorbed by the host animal)(animals need certain amino acids, which their cells cannot synthesize, "indispensible amino acids" - fermentative microbes can synthesis and provide them to their host); synthesis of protein from non-protein nitrogen sources (fermentative microbes can utilize urea to synthesize protein as an example)(in some situations ruminants are fed urea as an inexpensive dietary supplement) (they also secrete urea formed during protein metabolism into saliva, which flows into the rumen and serves as another nitrogen source for the microbes); synthesis of B vitamins (mammals can synthesize only a few B vitamins and require dietary sources of others) (fermentative microbes an synthesize all the B vitamins and deficiencies are rarely encountered in some animals)
Why do many minerals have a low absorption rate?
Many minerals have a low absorption rate because the minerals are excreted into the GI tract and they are excreted so the body doesn't absorb most of the minerals that are ingested; turn into salts
How/ why are microbial populations affected by the type of diets and pH on an animal?
Microbial populations can be affected by type of diets and pH because diet affects substrate availability and rumen pH is typically between 6 and 7 but may fall if large amounts of soluble carbohydrate are consumed; I pH drops to 5.5 protozoal populations become markedly depressed because of acid intolerance.
b. describe fate or pathway of each of those VFA (acetate, proprionate, butylate)
Most carbohydrates are converted to the VFAs: acetate, butyrate and propionate, with a significant increase in the proportion of propionic acid when starch-rich concentrates are fed. Butyric acid - most are metabolized to ketone bodies Propionic acid - 30% metabolized by the forestomach wall to lactic acid, the remainder removed by the liverAcetate (most abundant) - small amount metabolized to CO2, can be taken up by most body tissues to form acetyl Co-A for use in the citric acid cycle (to make ATP)
Explain the nutritional status and priority of pregnant females.
Most crucial in last trimester of pregnancy. Only a small portion of nutritional value supports fetus growth, majority is for increased bodily functions during pregnancy. If there are moderate deficiency the fetus will take priority over dam's tissue needs so the body will divert minerals and tissue to maintain the fetus. It too severe fetus will be aborted
How should we describe protein and Nitrogen utilization by rumen microbes? How about NPN?
NPN eaten mixes with urea in saliva and moves to rumen to make ammonia. Overflow of NH3 goes to liver where it is turned into urea and excreted in urine. Ammonia in rumen mixes with keto acids and bacteria (after gaining energy from CHO (in form of fats and proteins)) turn them into microbial proteins that, if not absorbed will be excreted in feces. Protein eaten escapes microbial digestion and gets excreted (40%), or turns into amino acids (60%) that will either turn straight into ammonia or into keto acids before turning into ammonia. NPN usually means urea.
Many minerals can easily form salts or other insoluble complexes, thus the absorption rate for these elements is generally very low. Exceptions?
Na, K, Cl
Many minerals can easily form salts or other insoluble complexes, thus the absorption rate for those elements is generally very low. Exceptions?
Na, K, Cl, and a few others
The Fundic or gastric area is the major secretory portion of the stomach. What are the three types of cells responsible for the gastric secretions?
Neck cells are responsible for mucus secretions. Parietal cells are responsible for acid secretions- HCl denatures protein, activates pepsin, and provides the optimal pH. Chief cells are responsible for enzyme secretions.
Can you use essential/ nonessential to describe amino acids, minerals, and vitamins?
No, especially for amino acids. Should use dietary essential or non-essential nutrients
Is fattening or finishing animals part of growth?
No, it is only for increasing market value because you are adding only fat, which isn't necessary for animal growth. Growth is development of muscles not fat
What do we mean by the essential mineral element typically shows a normal distribution?
Normal distribution means relatively constant among individuals in various species.
Dispensable Nutrients
Nutrients that can be synthesized from other substances in sufficient quantity to meet the bodies needs
As we mentioned, today's horses seem to have a lot of digestive problems such as colic, rupture, and laminitis. Why would you think today's horses are so prone to developing so many problems? Is there anything we can do to avoid/alleviate such problems? Yes, they definitely have some problems, but at the same time, the possible cause of those problems can be advantageous for horses (...having ruminant-like digestion?)!? Well, can we really say that horses have advantages of both "ruminant and nonruminant" species?
Originally, horses evolved as grazers, leading to a smaller stomach which is not suited to consumed large amounts of concentrated feed at a time. If they do, problems such as colic, rupture, and laminitis will arise. This can be prevented by smaller, more frequent meals. Horses are hindgut fermenters, meaning some materials of feedstuff, like glucose, can be broken down in the stomach will the more difficult materials to break down, like cellulose, can be processed by microbes in the cecum. Thus, they can take advantages of carbs, vitamins, and other nutrients in the forages that the stomach cannot breakdown.
Describe utilization of carbs by rumen microbes. describe how major products are formed. metabolism of protein and nitrogen in ruminant species?
Pentoses can contribute to energ; Ribose can by sytnhesized and occurs in ATP, ADP, etc. Hexoses-Glucose primary energy source, end product of starch digestion, galactose converted to glucose in liver, Tri tetra pent rafinose, stachyose, verbascose, is microbially fermented which can produce lots of H and Co2 gas, soy protein products have limited fermentation potenial. Starch limited digestion. Cellulose hydrolyzed by microorganisms only microbes. hemicellulose more easily utilized than cellulose because of less H bonding. Fermentation of fibers mostly hemicellulose. Digestibility of protein is 85% and is similar to milk and lean meat. Nitrogen At tissue level - Metabolic pathways similar 2. Can synthesize dispensable AA 3. Cannot synthesize indispensable AA Essential AA must be provided from digestive tract 4. Tissue proteins constantly undergoing turnover 5. AA not stored 6. Constant supply of AA required Microbial population has profound effect on AA reaching S.I. a. AA profile at S.I. different from diet Up--grades low quality dietary protein Down--grades high quality dietary protein b. Enables ruminants to use NPN efficiently Ruminants can be productive without a source of dietary true protein c. Animal can survive on low amounts of diet no AA balance most feeds contain more RDP than RUP lack of optimal ruminal fermentation when replacement with too much RUP lack of AA uniformity in by product feeds with high RUP
Taste apparatus is present in both pigs and chickens but there seems to be some fundamental difference between the two species. Why?
Pigs can taste and so can poultry, but in pigs the taste is more important then in poultry. Pigs seem to like sweet feeds, where poultry will eat anything without much consideration. Chicken use taste to avoid bad or dangerous feeds.
Usually include most vitamins in a pig or poultry diet much more than the requirement. What is the rational for so much vitamins?
Pigs&poultry are confined so need more supplementation, give more vitamins to meet needs (influenced by many factors*) It is common to provide much more of the vitamin to satisfy the needs of the animal than is actually required; the rationale for this is that most vitamins are pretty cheap to buy in supplement form, and the amount spent counterbalances the risk of having a deficiency. Depends on the diet to a greater extent compared to ruminants. Intestinal synthesis of B vitamins (but past the point of absorption-coprophagy gives an increased amount of absorption of B vitamins synthesized in the intestines).
Are there any factors that influence the status of villi and microvilli?
Present in the lumen of small intestine. The villi are longest in the jujenum. In a very active area with rapid turnover of cells
Steps involved in nutrition
Procurement --> Ingestion --> Digestion --> Absorption--> Assimilation --> Metabolic functions --> Excretion.
What do we mean by professional fermenters?
Professional fermenters are cranial (foregut - ruminants) and caudal (hindgut - cecal digesters) fermenters. Caudal are similar to humans in stomach and small intestine but have a large complex large intestine with a large cecum and colon. Cranial have multi-compartmented section of the digestive tract between esophagus and true stomach. The forestomach houses a complex ecosystem that supports fermentation.
What are some of the factors that contributed to the process made in mineral nutrition?
Progress can be attributed to advances in chemistry and physiology, synthetic diets used to identify macro and micro elements, and interrelationships observed between chemical composition of organisms and Earth's crust were useful in understanding the importance of minerals
What does it mean that the duodenum is the primary site for mixing of digesta and is it true for all nutrients?
Responsible for secretion of viscous and alkaline substances which protect the intestinal wall from acidic gastric contents.
We talked about utilization of carbohydrates by rumen microbes & we discussed the fate of major fermentation products (VFAs). Describe a. utilization of carbohydrates by rumen microbes (or describe how major products of rumen fermentation are formed)
Rumen microbes can ferment starch and other carbohydrates, such as cellulose Because most carbs are utilized by ruminant microorganisms, very little glucose can be absorbed by ruminants. VFA account for 70% or more of the animal's energy needs: -oxidation of VFA during TCA cycle -Conversion of propionate to glucose, then oxidation of glucose. Flow chart: cellulose, hemicellulose, starch, mono&disaccharides, pectins->glucose->pyruvate->acetate & lactate(->proprionate)
What do we mean by ruminants/ruminant species?
Ruminants are animals that ruminate which means they regurgitate food and chew it more to break it down and repeat this process. Spend about 8 hours a day doing this.
What do we mean by "ruminant/ruminant species"?
Ruminants are named so because they ruminate, or chew cud. They have a stomach that consist of a non-secretory forestomach and a secretory stomach (abomasum).
Talked about utilization of carbohydrates and protein by rumen microbes. Describe metabolism of protein or nitrogen in the rumen.
Ruminants eat protein from feed as well as nonprotein nitrogen (NPN) in the form of urea. Microbial enzymes degrade protein: proteases/peptidases cleave peptide bonds and release AA, AA deaminated by microbes, and release NH3 and the carbon skeleton, Microorganisms use NH3, the carbon skeleton, and energy to synthesize their own amino acids. Formation of NH3 is very rapid and very few amino acids are left in the rumen. Protein leaving the rumen: Microbial bodies and escape protein ("bypass" protein-not degradable by the rumen) Proteins enter the abomasum/small intestine and are digested by proteolytic enzymes similar to those in nonruminants
Why is the body fat and milk fat of ruminant species more saturated than other species?
Ruminants have a higher ratio of saturated to unsaturated fatty acids than nonruminants because of the intraruminal hydrogenation of unsaturated fatty acids.
What characteristics of ruminant animals are different than monogastric (nonruminant) animals?
Ruminants have four stomach compartments-a nonsecretory forestomach and a secretory stomach compartment.
The _____ is the only site where simple sugars and amino acids can be absorbed in all animals
Small Intestine
As animals get smaller their basal metabolic rate gets increased. How do the animals cope with the increase?
Small animals cope with high metabolism by increasing respiratory rate due to need for more oxygen that cannot be satisfied with more blood.
It seems that a sodium deficiency can result in inefficient use of carbohydrates, proteins, and even some vitamins, such as Thiamin and Vitamin C. Why?
Sodium plays in important role in active transport of nutrients
What are some of the major advantages associated with microbial fermementation in the reticulorumen?
Some major advantages associated with microbial fermentation in reticulorumen are it allows digestion and then absorption of fermentation products that are of value to the host (microbial cells, VFAs, and B vitamins); it changes poor quality protein /N compounds to good quality microbial protein; selective retention of coarse particles extends fermentation time and allows for other mechanical breakdown during rumination (cud chewing); release of fermentation gas (mostly CO2 and CH4) form the system by eructation(burping); toxic substances in the diet may be attacked by the microbes before being presented in the small intestine.
Are protozoa important for ruminant species?
Some protozoa are important but they are far less numerous than bacteria. The most important ones are anaerobic ciliates that are differentiated on the basis of morphology. Protozoa utilize the same set of substrates as bacteria; different populations show distinctive substrate preferences; many utilize simple sugars and some store ingested carbohydrates and glycogen; many species consume bacteria (help with bacterial overgrowth)
What is the main difference between "fat soluble" and "water soluble" vitamins?
Storage fat-soluble vitamins are stored in the liver or adipose tissue (Vitamin A,D,E,K) - can serve as reserves H2O-soluble vitamins have no appreciable storage - must be supplied continuously in the diet
Why are minerals so important for our bodies?
Take part in many functions of the body such as structural (bones), homeostasis, acid- base balance, cell membranes, enzyme systems, hormones, and microflora
What is the best approach to study the mineral requirements?
The best approach to studying macro mineral requirement would be a practical feeding trial. Analyze the tissues and organs to analyze the minerals. Don't have to slaughter the animal. For a micro mineral test, you don't see a response with a feed study, so you should slaughter the animal and analyze the organs, tissues, metabolites, etc.
Elaborate on this statement, "microbial proteins or bodies of microbes and high quality proteins."
The bodies of microbes can be a source of high quality protein because fermentation allows utilization of the protein in the microbes (only in ruminants)
Why can't poultry utilize fiber efficiently?
The colon acts more to convey ileal and cecal digesta rather than active fermentation and absorption
What are some consequences of the horses' large intestine/ cecum-colon?
The diameter of different segments of the large colon varies and the arrangement includes several flexures where the colon turns back onto itself; this makes it susceptible to turning back on itself and other digestive upsets when the flow is abnormal.
We determined energy and protein digestibility of corn in pigs and chickens at 3 different sites. What conclusions or interferences can we make by simply looking at this data set: Energy: duodenum= -7.3% corn, ileum=65.8%, rectum/cloaca=78.4%; protein: duodenum=20.1%, ileum=74.6%, rectum/cloaca=81.7%
The duodenum is the mixing site for most nutrients w/ water, buffers, and enzymes (after the stomach which is important in enzymes for protein digestion). The jejunum is where most absorption of nutrients takes place; btwn the duodenum and ileum. After the ileum, some more nutrients may be digested by fermentation in the cecum and the rest would be absorbed by the time it sets to the rectum/cloaca
Why can't carbohydrates that escaped rumen microbial fermentation be utilized efficiently by the host?
The host cannot utilize carbohydrates that escape rumen microbial fermentation efficiently because in order to be utilized, the carbohydrates must be fermented into VFAs. There is no enzyme in vertebrates that can hydrolyze cellulose, and only microbes can synthesize those enzymes.
Why is there a relationship between the size of animals and life span?
The larger the animal the harder it may be to satisfy metabolic needs so the larger the animal the shorter the lifespan.
What are the major functions of the pancreas?
The major functions are supplying enzymes to the small intestine for starch, protein and fat digestion, secreting water, bicarbonate and others into the duodenum to change the pH, supply hormones to manipulate nutrient metabolism on a moment-to-moment basis which is important for controlling metabolism.
It seems that the need for "vitamins" has increased in recent years. Why would you think that is? Also, we usually include some vitamins much more than requirement, i.e., 2 to 3 times or even more! What would you think the rationale or reasons behind such a practice? Does the discussion we had on the difference between the "requirement and allowance" have anything to do with such a practice? Finally, how do we satisfy the vitamin requirements or "nonruminant species" and "horses and ruminant species"?
The need for vitamins has increased because of changes in farming practices. For example, increased confinement of animals causes greater stress levels, subsequently making a greater need for vitamins. Also, an increase in grain-soy diets leads to less vitamin rich food sources, which need to be restored via feed. Feeding on sole requirement measures would be on an individual animal's basis, since requirement is the amount needed to satisfy the average animal's needs, so feeding based on allowance may be a better option, since allowance compensates for factors affecting the entire population. Vitamin requirements can differ between nonruminants and horses and ruminants because animals with microflora in their gastrointestinal tract, such as horses and ruminants, have the ability to synthesize all B vitamins, whereas nonruminants cannot produce their own B vitamins. (and feed differences)
What are the primary functions of the crop in chickens? Can chickens survive without a crop?
The primary function of the crop is for food storage and for microbial digestion. It can supplement some saliva and help move the bolus to the crop. Organic acid in the crop helps start digestion and helps kill bad microbes that might have been ingested. Chickens can survive without a crop as long as they have a consistent feeding schedule and don't over eat at once.
What do you think about the statement "the SI is the only site where simple sugar and amino acids can be absorbed in all animals"?
The small intestine is the only site where simple sugar and amino acids can be absorbed in all animals - not true because in horses they are absorbed via the SI and circulation but in ruminants very little glucose is absorbed in general and what is, is absorbed in the forestomach.
What do we mean by "back and forth peristalsis" in poultry's small intestine?
The small intestine of poultry is relatively short, but the absorptive effectiveness is increased by back and forth peristalsis. This keeps the digesta in the small intestine longer, which increases absorption.
We've determined energy and protein digestibility of corn in pigs and chickens at the 3 different sites (...the same values for pigs and chickens? Could happen?!) Well, based on our discussions in the class, what kind of "conclusions or inferences" can we make by simply looking at this particular data set...if we don't have any other information, that is?
The stomach contains many digestive enzymes (ex: pepsin) that breakdown protein, and this may be why there is a larger amount of absorbed proteins vs carbs in the duodenum. The jejunum would be next, and this is where most of the nutrients are absorbed, so by the time you get to the ileum, you see a huge gap of absorbed carbohydrates and proteins. Next would be the cecum/colon area, and though this is primarily for water absorption, you will get some carbs and proteins getting absorbed, giving the final percentage in the rectum/cloaca. Any microbes in ileum may contribute to VFAs, but no protein absorption.
Why is protein synthesis so costly and why is amino acid balance so important for protein synthesis?
The theoretical min protein requirement for growth is the amount actually stored in the body, but this is far below the actual requirement because of wastage in digestion and metabolism. Amino acid proportions needed would not change regardless of the rate of growth, thus an appropriate amino acid balance in the diet is important for efficient and optimum protein nutrition.
What is important of the villi or microvilli, brush boarder area, glycocalxy, and some intestinal enzymes in the stomach?
The villi undergo constant turnover and the number and size of the villi change due to which area the villi is in, the nature of the diet, and the amount of food. The villi increase the surface area of the intestines. The brush boarder area contains lots of enzymes that are shed into the lumen. The glycocalyx is the fine polysaccharides rich in fiber. The jejunum digests and absorbs most of the nutrients in the small intestine.
How can we determine digestibility using a typical digestion study?
There are three ways: o Feed an animal a certain diet and add markers in the diet, feed the diet at a constant rate, and collect all the feces to see and determine the left over nutrients in the feces. The markers will tell you where to start and end in the testing of the nutrients in the feces. o Use metabolism or digestion stalls where the animal is confined for collection of the feces uncontaminated by urine. o Fecal collection bags can be used to collect feces into the bag while an animal is grazing on pasture. o For all three studies, typically use males because easier to collect feces without urine, but there could be a difference between males and females.
What can we say about the horses small intestine and large intestine/ cecum-colon?
There is a better relationship here then in the small intestine in terms of relationship with microbes. When fermentation goes up, gas production goes up and that can cause bloat and colic. Bacteria breakdown of cellulose and other carbohydrates produce VFA. It can also cause problems because stomach capacity is small and the passage rate becomes slow.
As the size of animals gets smaller, the metabolic rate increases tremendously. How do animals cope with such an increase in their metabolic rate?
There is a tremendous increase in the metabolic rate as the animal size gets smaller (i.e. the mouse's metabolism is MUCH higher than an elephant's). To compensate, the smaller animals must supply greater amounts of oxygen and nutrients. The heart is only about 5% of body weight in most species, so the smaller the animal is, the faster its heart must beat to keep up.
How would you describe of vitamins?
They are organic compounds that are found in natural foods, but distant from carbohydrates, fats, proteins, minerals and water. They are found in small amounts. Essential for development of normal tissues, health, growth and maintenance. They can result in specific diseases or syndromes when absent from the diet or not properly absorbed or utilized. They cannot be synthesized and must be obtained from the diet exclusively. They can catalyze reactions.
What is the primary factor controlling those pancreatic hormones?
They are regulated by plasma glucose, which is dependent on energy status.
What did we say about the Ca, P, and Vit. D status and potential problems in laying hens and lactating sows?
They contain a lot of Ca, P, and vit. D during the laying/lactating process in order to absorb Ca into the bones before lactating or laying eggs. If not enough Ca or P in the body, then the minerals will be taken out of the bones and given to the eggs or pigs. If not enough Ca then egg shells may become thin and can lose the chicks inside.
Why do today's horses have a lot of digestive problems?
They have a lot of problems because their digestive systems have evolved to utilize forages and their systems cannot digest and utilize grains or concentrate. It is easy to overwhelm their digestive tracts and there is not much digestion or absorptions. The solution is to feed grains and concentrates in small amounts, around 2 to 3 times a day to help.
Since poultry don't really have a stomach, how do they satisfy their nutritional needs?
They use the crop for storage and proventriculus and gizzard for gastric digestion. The proventriculus is another storage sight. It has microbes in it to help with fermenting carbohydrates. The gizzard is very efficient for grinding feed. Gizzard teeth are in the lumen of the proventriculus. On the hard layer there are Koilin rods which are protein-polysaccharide complex. They are horizontal and branched and protruding from the surface. One the muscular layer, there are glands responsible for soft and hard secretions termed koilin, which becomes koilin rods.
Why do gastrointestinal hormones exhibit overlapping activities?
This occurs due to a survival method years ago, where if one hormone did not work, another would be able to work the same... that's why multiple hormones due similar things.
What are some criteria to describe true hormones?
To be a true hormone it must be isolate hormone, have its effects study, and its action demonstrated under normal or physiological conditions. Some examples are gastrin, GIP, VIP, Sacretin, and cholecystorin.
What is the significance/importance of pH changes throughout the gastrointestinal system?
To control ingested microbes, providing the optimal pH for enzymes, and can also change to dictate a certain type of reaction to take place in the GI tract. pH increases as you go from the stomach to cecum to colon. As digestion moves from the stomach to the small intestine, no pepsin is available and no longer active.
As we mentioned usually an essential mineral shows a normal distribution the concentration of a particular mineral would be relatively consistent in tissues and organs of individuals even among various species
True
Body fat of ruminants tend to be more saturated because microbes can saturate 70-90% of unsaturated fatty acids in the rumen which can be incorporated into their body directly
True
Importance of bacteria for ruminants? They are playing a very important role in rumen fermentation and also they are controlling the population of protozoa by consuming those bugs as a source of nutrients
True
Papillae in the reticulum and rumen are more like villi and microvilli of the small intestine, and they are increasing the surface area for absorption of eg. VFA
True
Some proteins can be converted to VFA by microbes and those are a very important source of energy for microbes but not for the host
True
Under practical conditions, the amount ofr energy needed to balance fasting metabolism is not enough for maintenance simply because we have to consider heat increment when consuming feed energy needed to consume feed and support normal activity
True
Water is the most important factor
True
What are the gizzard teeth? Well they are uniquely associated with the fowl and contain protein polysaccharide complexes known as koilin or koilin rods
True
When we consider the process of protein synthesis we have to remember that all 20 AA must be available in adequate amounts simulataneously and also there would be many mistaekes in the process thus increasing energy expenditure greatly
True
our discussion was on rumen fermentation of proteins but because of how proteins are fermented we concluded that for the host the most important end products are VFA
True
Why did we mention that the true absorption of minerals couldn't be determined by a balance study?
True absorption cannot be determined by a balance study because most of the mineral value will be excreted.
Unlike pigs, chickens may be able to utilize some non protein nitrogen because their ceca and colon seem to be capable of absorbing some amino acids
True.
When we're discussing rumen fermentation of "dietary protein", we concluded that "the most important products of rumen fermentation for the host are volatile fatty acids (VFA)!" Well, how did we end up with drawing that conclusion? We thought we were talking about dietary protein, not carbohydrates! Obviously, you would have to describe "how microbes utilize dietary protein and N" in your response. Also, we did talk about "microbial proteins". Well, how would you feel about the efficiency of utilization of "some dietary protein" for the host?
VFAs are used by the host when they are oxidized in the citric acid cycle to convert propionate to glucose and subsequently oxidize glucose. Dietary proteins are broken down by microbes to produce VFAs. Microbes utilize nitrogen by degrading ingested protein to NH3, C-skeleton, and then use that energy to synthesize its own amino acids.
Describe the fate or pathway of each of these VFAs?
VFAs provide 70% of ruminants needs. Acetate utilized minimally in the liver, and is oxidized throughout most of the body to generate ATP. Another important use of acetate is as the major source of acetyl CoA for synthesis of lipids. Proprionic acid is almost completely removed from portal blood by the liver. Within the liver, proprionate serves as a major substrate for gluconeogenesis, which is absolutely critical to the ruminant because almost no glucose reaches the small intestine for absorption. Butyric acid, most of which comes out of the rumen as the ketone beta-hydroxybutyric acid, is oxidized in many tissues for energy production.
What do we mean by villi, microvilli, brush border, and glycocalyx?
Villiµvilli are in the small intestine&increase surface area for more absorption. BB secretes enzymes that terminate carb(+?) digestion. Glycocalyx fiber rich polysaccharides on microvilli (important in cell recognition)
what is deficient in animal with scurvy?
Vitamin C
What are the consequences of chickens poorly developed lymphatic systems?
With a poor lymphatic system, chickens cannot break down long chain fatty acids. Because they cannot break them down into usable elements, they have adapted and are now able to absorb long chain fatty acids directly.
In satisfying vitamin needs, is it common to provide much more than the requirements?
Yes it is common to provide extra vitamins in a diet. There are many factors to consider that determine if it is a good practice or not, example the cost, the environment- nitrogen/phosphorus production are factors.
Minerals in the future may be classified as essential. Agree or disagree?
Yes, all mineral are essential to some extent
Do horses really have advantages of both ruminants and nonruminants? Why do today's horses develop so many nutirtional problems is there any way to avoid or alleviate?
Yes, they have an active flora of bacteria similar to ruminants, allowing them to utilize proteins that would otherwise be lost and produce VFAs like propionate, butyrate, acetate. have advantage of nonruminants in that do not have rumen which cuts down on time needed to ruminate digest, has the efficiency of ruminants without sacrificing time. Horses develop so many problems due to the fact that their stomachs were designede to digest carbs and proteins in upper gut (very little) and consume mostly grass diets. Designed to eat several small meals instead of a large one. To help: feed 3-4 times a day, do not overhwelm stomach, allow mainly grazing with concentrate to make up the difference not as a mainstay.
What is "growth"?
a correlated increase in the mass of the body in definite intervals of time in a way characteristic of the species; characterized primarily by an increase in protein, minerals, and water
Why would minerals in the future be classified as "essential" elements?
a deficiency consistently results in an impairment of the function from optimal to sub-optimal
How can we determine "digestibility" using a typical digestion study?
a digestion study involves feeding an animal a given amount of feed or at a constant rate laced with a marker and that has had proximate analysis run. Then feces is collected and another proximate analysis is run. The difference is the apparent digestible portion of the feed/feed ingredient
Describe the fate of acetate.
a small amount metabolized to CO2, which can be taken up by the body tissues to form acetyl-CoA for use in the citric acid cycle to make ATP
What are some of the similarities between pigs and poultry?
a. Are non-ruminants, thus less meaningful symbiotic relationships with microorganisms along the gastrointestinal system vs ruminants b. Need amino acids, not protein per se c. Have limited ability to utilize fibrous components of the diet d. Diets consist predominantly of grains and soybean meal in the modern production system, more susceptible to mineral and/ or vitamin deficiencies e. Are raised in confinement facilities in the modern production system f. Are relatively fast growing and efficient in conversion of feed to body tissues
As ingesta or digesta move through the gastrointestinal tract, there are some changes in pH, which would be important for:
adjusting for different microbes which have different optimal pH ranges
Why do we need energy/nutrients for "reproduction"?
although there are no substances needed by the reproductive organs, which are not needed by the tissues, the metabolic pathways followed by some of the nutrients provided by the blood stream may differ from others
Allowance
amount/concentration of energy of nutrient needed to satisfy the average population vs. satisfying the entire population; given but not needed
Obviously, insulin and glucagon are very important for energy metabolism seems to be the major factor controlling their secretion
and plasma glucose
When we're talking about digestibility, we used the term "apparent" digestibility! Why didn't we say just "digestibility or true digestibility?"
apparent digestibility does not account for the endogenous losses - states basically that not all ingested food is absorbed. true digestibility accounts for endogenous losses
We did mention that the best way to prevent leg problems in laying hens and sows will be to build up Ca and P in their bones before lactation
b/c Ca and P in bones will be mobilized whether or not it is in diet, so defiicnecies can and will resutl in others
As we mentioned it seems taht a sodium deficiency can result in inefficient use of carbs, protein, and even some vitamins, such as thiamin and vit. c
because Na is essential for absorption, passive transport, and assisting in utilizaiton
What is the reasons for providing so many vitamins? Does discussion on requirement vs allowance relevant? define first. how do we satisfy the vitamin requiremnets of nonruminants and horses?
because the electrolyte balance effects performance and even though there are the main vitamins and minerals even the less obvious vitamins can cause deficiencies imbalances, drops in performance because vitamins determine absorption and utilzation.
Why is the fasting metabolism value not sufficient to satisfy the maintenance need?
because the fasting metabolism is measured when the animal is doing nothing and is under optimal conditions, thus, not depicting a realistic requirement. Energy in fasting metabolism is not sufficient because at heat increments from ingested feed, energy to consume feed, normal activity, group size, body comp, temp, etc
As we mentioned, the primary end products of rumen fermentation are short chain volatile fatty acids or VFA acetate, propionate and butyrate
because they create what are the beginning products for citric acid cycle, glycolysis, and carbon nitrogen, etc.
In terms of satisfying the nutritional needs of their young, what are the differences between chickens and mammals?
birds produce eggs, which contain sufficient nutrients for the embryo to develop outside of the body and no special food is required after hatching
What is the primary factor controlling pancreatic hormones? (specifically insulin and glucagon)
blood glucose levels
We mentioned that we can estimate the maintenance energy need by determining the basal metabolic rate, which can be done by measuring heat production which is
can be measured by respiration calorimeter. related to body size, body weight related to body metaboism, energy expended in fasting animal
What are the consequences of chickens having a poorly developed lymphatic system?
cannot absorb long-chain fatty acids
What are some of the consequences of differences in metabolic rate?
change in energy levels, body composition, and death by overdose
How can "heat production" be increased?
changing ingested feed, energy to consume feed, normal activity, group size, body composition, environmental temperatures, etc.
Explain the phrase, "mineral metabolism is in a dynamic state."
continuous turnover
What do we mean by mineral metabolism is in a dynamic state?
continuous turnover in an animal's body
In practice, fattening or fnishing is an integral part of growing animals for commercial meat production, but strictly speaking is not a part of growth because
correlated increase in mass of the body in definite intervals of time, in a characteristic way of the species is growth
What does gross deficiency/excess of nutrients cause?
deficiency/toxicity = death
"Apparent" Digestibility
digestibility determined not considering the nutrients from non feed sources or metabolic fecal nutrients found in feces
When we think about the "maintenance" need for protein of N, some very obvious and important terms would pop into our head such as ____________.
endogenous nitrogen metabolism - the minimum essential N catabolism associated with the maintenace of the vital processes of the body
What is "heat production"?
energy expanded in the fasting animal; can provide useful basis of reference for other phases of energy metabolism
What is the difference between "brush border enzymes" compared to pancreatic enzymes is:
enzymes are integral parts of membrane at brush border (of intestinal villi) not secreted but SHED into the lumen
Why is the utilization of carbs by rumen microbes important?
especially important in utilization of fiber; no enzyme in vertebrate animals that allows for the breakdown of cellulose, however microbes do have that ability
It seems that pigs do have "preference" for a certain feedstuff, but a sense of taste for poultry may be associated more with __________ rather than preference.
exclusion
Factors that affect Procurement
eye sight, smell, experience...
T/F: "nonessential amino acid" is okay, but "nonessential mineral" is not okay because all the minerals are essential, metabolically
false
True or false: Although most carbohydrates would be fermented by rumen microbes, a small amount of carbohydrates can escape microbial fermentation. And, those carbohydrates can be digested by the host animal's digestive enzymes and absorbed efficiently.
false
True or false: As we mentioned, we should not say "non-essential amino acids" because, metabolically, all amino acids are essential! Similarly, we should not say "non-essential minerals" for the same reasons.
false
True or false: Horses use their tongue extensively in consuming feed, whereas cattle seem to use their lips extensively. Chickens? They don't seem to have a good prehension mechanism in consuming their feed?!
false
True or false: It seems that water-soluble vitamin deficiency signs are directly related to the function of the vitamin, but it is difficult for us to relate signs of fat-soluble vitamin deficiency to some specific functions.
false
True or false: Perhaps, the main advantage of using radioactive indicator to study mineral metabolism is that we can increase the dietary content or physiological concentration of the element above the normal so that we can study its effect much more easily.
false
True or false: Pigs, like humans, have a propensity to become "obese" partly because they are very responsive to the action of glucagon and not really responsive to the action of insulin.
false
True or false: The amount of protein or nitrogen estimated by "fasting metabolism" is not sufficient for maintenance because, under practical conditions, we have to consider heat production from ingested feed, energy needed to consume feed, support normal activity, etc.
false
True or false: To estimate the "energy needs for maintenance", we have to consider endogenous urinary nitrogen, metabolic fecal nitrogen, and growth of hair, nails, etc.
false
True or false: Two long ceca are the primary fermentation site in pugs, but the entrance to the ceca is somewhat restricted. That's why young pigs cannot really utilize fibrous feed efficiently.
false
True or false: When we're using urea as a protein supplement, we should also supplement ruminant diets with sulfur and branched-chain C-skeletons simply because those are usually limiting factors in microbial protein synthesis.
false
What is the primary difference between fat--soluble and water-soluble vitamins?
fat-soluble vitamins can be stored and water-soluble vitamins cannot be stored
It seems that the chicken's "lymphatic system" is poorly developed, which is important because, unlike other species, they cannot absorb ____________ through the lymphatic system.
fatty acids (long-chain)
It seems that the chicken's lymphatic system is poorly developed, so they would have to use other means to absorb ____.
fatty acids via a portal system
It seems that the chicken's lymphatic system is poorly developed thus they would have to use other means to absorb
fatty acids/fats
What would be the best way to feed our horses in terms of "meal frequency"?
feed small portions 2-4 times per day
Factors effecting ingestion
flavor, palatability, size, texture, temperature
Factors that affect Ingestion
flavor, palatibility, size/texture, temperature...
In practice, "fattening or finishing" is an integral part of growing animals for commercial meat production, but strictly speaking, it is not part of growth because:
growth consists only of protein, water, and minerals, NOT fat
What type of food can affect metabolic rate? Can we rely on the thermogenic effect of food?
high protein diets burn up to 25% calories (increasing metabolic rate); No because food only represents 5-10% of metabolic rate
We mentioned that if we know the body water content we can estimate the body fat, protein, and ash contents because
if we know one component water is a major one it is easy to calculate others, water determines digestion and absorption of nutrients that determine body composition
What is the main difference between a typical digestion study and an indicator method?
in typical digestion studies you must measure input&ouput thus using collection bags or metabolism crates to collect feces. Indicator method, use an indigestible marker, only need to collect a small amount of feces.Typical digestion study measures intake of nutrients-nutrients in feces and give a percentage of apparent digestability. A typical digestion study involves: 1.Running a proximate analysis of feed/feed ingredient.2.Feeding an animal a given amount of feed, or feeding at a constant rate.3.Collecting feces from given amount by use of a marker or collecting feces at a given time on a constant rate of feeding.4.Running a proximate analysis of feces. 5.The difference is the apparent digestible portion of the feed/feed ingredient. Indicator method uses an indigestible method element/compound; don't have to change nutrient intake at all.method involves the use of an inert reference substance as an indicator (less time consuming/laborious than the traditional type of study). By determining the ratio of the concentration of the reference substance to that of a given nutrient in the feed and the same ratio in the feces resulting from the feed, the apparent digestibility of the nutrient can be obtained without measuring either the feed intake or feces output
Two important functions of "pancreas?" Although we should not ignore others such as secretion of _______________, the primary functions seem to be supplying enzymes and some hormones.
insulin and digestive enzymes
Why would it be important for us to have some ideas on "interactions" involving minerals?
interacting minerals may be synergistic/antagonistic to each other prevent undesirable interactions and avoid secondary deficiencies
What would be some disadvantages of using radioactive indicators in studying mineral metabolism?
interpretation of results is often very difficult
Anemia
iron deficiency
We mentioned that the "balance test" may not be a good method to use in estimating the mineral requirement. Do you remember why?
it is complicated, laborious, and requires a high accuracy from collection to analysis. The balance of minerals is affected by many factors (environmental, physiological conditions, etc.)
"Gizzard teeth" are uniquely associated with the fowl and consisted of a protein-polysaccharide rod complex known as __________, which can form the rod that can protrude through the lining of the luminal surface.
koilin
Osteomalacia
lack of Ca
Osteoporosis
lack of Ca
Goiter
lack of iodine
Wasting Disease
lack of vitamin B12
Scurvy
lack of vitamin C
Downer Sow Syndrome
lack of vitamin D and Ca
White Muscle Disease
lack of vitamin E and can also be caused by too much selenium
Rickett's or bow legs
lack of vitamine D, Ca, and P
Parakeratosis
lack of zinc
Best way to prevent leg problems in laying hens/lactating sows would be to build up "Ca and P" in their bones before laying/lactating. Why?
laying eggs and lactating draw major amount of Ca and P from bones - to prevent, add more to diet as to build up stores that will be mobilized
When we're talking about the requirement, we mentioned "maintenance" and "basal metabolic rate", which can be estimated by measuring "heat production". What do we mean by these three terms? Also, as animals get smaller, we see a tremendous increase in the "metabolic rate", and there seems to be a relationship between the metabolic rate and "longevity"! Well, how do animals cope with such an increase in their metabolic rate, and what would be the basis for the relationship between the metabolic rate and longevity?
maintenance - the state of the body when it is not growing or producing, and it still supports vital functions basal metabolic rate - used to measure maintenance energy needs, heat production during fasting, minimum energy expenditure compatible with maintenance of life heat production - energy expended in the fasting animal as size of animal decreases, the metabolic rate increases, thus decreasing longevity of the animal due to wear/tear. a faster metabolic rate leads to an increase of calories burned, thus more calories will be needed because there's no storage as body reserves
How do we measure "growth"?
maximum size and development are fixed by heredity and nutrition is an essential factor determining whether the genetic potential will be reached
As we mentioned, animals may be "marginally" deficient or excess in some nutrient, such as a vitamin, but, often, we may not realize that at all simply because __________.
may not show symptoms
It is rather important for us to have some ideas on "interactions" of minerals for a couple of reasons, which are:
minerals are synergistic (work together) or antagonistic (work against each other) and may have those interactions in the GI tract or cell itself
It seems that we can induce _____ in laying hens by feeding a "no salt" diet because a deficiency of salt can result in reduced/no fee intake
molting
It seems that we can induce _______-in laying hens by feeding a no salt diet because a deficiency of salt can result in reduced or no feed intake
molting
Why do many minerals have a very low absorption rate?
most minerals, with the exception of Na, Cl, and K, form salts and other compounds, thus they are relatively insoluble and not readily absorbed
Why is it a common practice to provide animals with more than the necessary amounts of vitamins?
most vitamins are relatively cheap to buy in supplement form, the cost of supplements counterbalances the risk of having a deficiency
Factors that affect Digestion through Excretion
needs, digestibility/availability, processing, animals' size/age, environment, etc
What is unique about chickens in terms of "prehension"?
no teeth and swallow their food whole
Can we us the terms "essential/ non-essential" for amino acids?
no, because there are 20 essential to life amino acids but 9 of them are dispensable
Is fattening or finishing animals part of growth?
no. it is a part of growth in practice, but technically growth only involves an increase in the structural tissues such as muscle, bone, and organs(proteins, minerals, &water). Not fatty tissues. Fattening refers to actually depositing fat which requires energy storage
We did talk about brush border enzymes such as lactase sucrase and peptidases just briefly. One unique aspect of those intestinal enzymes compared with, let's say pancreatic enzymes is
not secreted, but shed into the lumen, the jejunum also digests and absorbs most nutrietns
What are the three major disadvantages of having microbes in the rumen?
o 1. Wasteful use of protein (some protein is better then others. High quality protein lose carbon skeletons and NH3). o 2. Inefficient use of some CH2O. Lose CH20 (sugars, starch, etc.) rapidly and completely to VFA. o 3. Loss of energy to methane. 8-10% of potential energy is loss to methane.
Describe the four compartments of ruminant species.
o 1st compartment is the reticulum. Looks like honeycomb and has lots of papillae. Primary site of fermentation. o 2nd compartment is the rumen. Has lots of papillae which increase the surface area. Extensive capillary system. Another primary site of fermentation. About 80% of the stomach. o 3rd compartment is the Omasum. Monitors digestions of the igesta/digesta/ 1/3 of the stomach. o 4th is the abomasum which is the true stomach.
What is some the vitamin deficiency disease that plagued the world for a long time?
o Beriberi is the earliest document deficiency disorder and recognized in China. It causes a swelling of the legs. o Iemir Deficiency affects sheep and it causes their head to be bent backwards. o Polyneuritis is found in chickens and it is muscle paralysis and retraction of head. o Poloencephalomalcia- thiamin deficiency in cows. Causes dullness, blindness, circling, and head pressing. o Pellagra is a Niacin deficiency that causes dermatitis, diarrhea, dementia, and death... the 4 D's. 20,000 deaths in early 1900's. Common among corn eating populations... corn low in niacin. o Biotin deficiency in turkey. Cutaneous system is affected. Footpad lesions in pigs. In horses, it affects the walls of the hoofs and causes' crumbling's of the edges of the hoof.
What are two sets of glands in the small intestine that are responsible for secretions? What are their primary functions?
o Brunner's glands or duodenal glands: These glands help protect the duodenum and create the optimal pH balance and lubricates. o Crypts of Lieverkuhn or intestinal glands: These glands secrete mucus and various enzymes such as maltose, sucrose, and peptidase. These glands are located in the epithelial lining of the intestines.
What are some of the main differences among various species in their gastrointestinal system?
o Chickens: Have two cecum, a small intestine that is not very efficient, does not have a true stomach but does have a crop, proventriculus, and a gizzard o Pigs: Have one cecum and one true stomach. o Horses: Have a large cecum (hindgut) with a large colon and intestine. The front portion is not very efficient. o Cattle: Have a four-chambered stomach, but overall one stomach. Have a rumen.
Are there any differences for supplying vitamins for different types of animals?
o Chickens: They require Methyamine amino acid for their feathers. It is a fast limiting agent. Vit. B o Pigs: Young pigs cannot utilize a corn-soy diet right away so they must be supplemented at birth with milk. Vit. B o Horses: Vit. A, E, and D, but these requirements can be met with high-quality, sun-cured hay. o Ruminants: Grazing animals may be deficient in Vit. A and maybe E. Under stress or high productivity, may need thiamin and niacin. They can synthesize own Vit. B but B supplementation reduces stress and increases grains. o Non-Ruminants: Vit. B and K.
What are some characteristics of "fat-soluble" and "water-soluble" vitamins?
o Fat Soluble: involved mostly in regulation of metabolism of structural units- eyes, bones, etc. Digested with fats and require fat for absorption and transport. Stored in the liver. Toxicity of Vit. A and Vit. D is possible but not likely. Mostly consists of C, N and O. o Water-soluble: Mostly concentrated with the release of transfer of energy. Mostly consists of C, N, and O, but also contains N, S or Co. Associated with the fluid compartments of the body. Must be supplied continuously in the diet, except for B12. If excess, it is excreted in the urine.
What are some of the pancreatic hormones and their functions
o Insulin: an energy storage hormone. When there is too much energy, insulin is released to decrease it. o Glucagen: an energy release hormone. When energy is low, glucagen is released.
What are some of the differences between pigs and poultry?
o Pigs: Pigs are delivered in a litter. Pigs have hair. Pigs have an immature digestive system at birth and need milk at birth. Lactating pigs are susceptible to leg problems due to Ca loss. o Chickens: Chickens hatch from eggs. Chickens have feathers (5-7% of their body weight). Chicks have a complete digestive system at birth so they can eat corn and soybean meal. Chickens have a greater metabolic rate, respiration rate, and heart rate. Laying hens mobilize large amounts of Ca, which makes them susceptible to leg problems. Have a different digestive tract and process than pigs.
In terms of prehension mechanism, is there anything unique about pigs, chickens, horses, or cattle?
o Pigs: Use a snout for rooting and digging for food, lips for prehension, and cheeks to aid in mastication and mixing. They have teeth that help with grazing, biting, and chewing. Mixes food with saliva to help with swallowing. o Chickens: Have no teeth and swallow their food whole. Their beaks are made of hard tissues so there is little oral manipulation of food. Have a hard time eating large particles. If there is a problem with the beak, the efficiency goes down, feed intake goes down, and performance goes down. Debeaking is a process that needs to be done carefully. Trimming the beak down is a better process for protecting the beak while preventing fighting with beaks. o Horses: Uses teeth, upper lip, and tongue. They use both lateral and vertical movements of the jaws to shred plants. The upper jaw is wider then the lower jaw so can only chew on one side at a time. o Cattle: Have no upper incisors and only an upper dental pad and lower incisors. Uses the tongue a lot and cuts grass by movement of the head. Lips have limited movement. Can chew only on one side at a time.
In terms of sight and smell, what are the differences between poultry and pigs?
o Poultry: Chickens can see the color green better so they preform better with green feed. Have better vision than pigs. They can distinguish particle size, so if their vision goes down, then their feed intake goes down and they performance goes down. They have a poor sense of smell so they rely on sight. o Pigs: Pigs have poor eyesight. They eyes start rooting to protect the eyes. They rely on smell because they cannot see well.
How would you explain the nutritional status of a pregnant female?
only a relatively small portion of the total nutrient requirements are used for fetal tissue growth, indicating that the increases in other bodily functions associated with pregnancy; the metabolic rate of pregnant female is, thus the needs are higher
What is our primary objective in terms of satisfying nutritional needs of animal/humans?
optimize performance
Insulin and Glucagon are very important for energy metabolism and ______ seems the be the major factor controlling their secretion.
plasma glucose
We all know something about insulin and glucagon, but we should not forget "____________", which can control the action of insulin and glucagon!
plasma glucose
What would be some advantages of using radioactive indicators in studying mineral metabolism?
possible to study the exchange between the digestive tract and blood, the incorporation of minerals into tissues, the magnitude of reserves, and transplacental passage
For most species, esophagus is simply a passage way for feed, but it does have some implications or importance in horses and chickens because
presence of strong esophageal sphincter in horses so they can't vomit and crop in poultry have enzymes that help with digestion
Why do many gastrointestinal hormones exhibit overlapping activities?
probably as an adaptation/survival mechanism
Why is protein synthesis so costly and why is amino acid balance so important for protein synthesis?
protein wastage in digestion and metabolism; amino acid proportions needed would not change regardless of the rate of growth
Uric acid is usually associated with poultry because they do not excrete the N end product as uric acid but the breakdown of _________can also produce uric acid. That's why we have a small amount of uric acid in urine
purines, peptides, protein/nitrogen, body cells, and food you eat **
What region of the stomach is responsible for the secretion of gastrin?
pyloric region
As we all know, microbes can produce a lot of gases, and one of the well-known disorders in cattle and others is "bloat!" Well, why do they develop such a condition?
rapid release of soluble proteins from the degradation of the forage and rapid production of gas by the microbes
What is "prehension"?
refers to seizing and conveying of food to the mouth
Having ____ is very important for young ruminants because milk can flow directly into the omasum and abomasum, which results in better utilization of milk
reticular groove
Having is very important for young ruminants because milk can flow directly into the omasum and abomasum which results in better utilization of milk
reticular groove
We did mention that one disadvantage associated with having the rumen would be an inefficient utilization of some carbohydrates and protein because
rumination takes a long time to utilize because of the amount of time it takes. some proteins are also better quality sometimes glucose is easier to utilize
Gastrin is the focal point of controlling the activity of the stomach and are responsible for regulating the gastrin secretion
secretin and histamine
We mentioned that many minerals can easily form salts or insoluble complexes, and their absorption rate is rather low! Exceptions are "Na, Cl, and K!" We also mentioned another mineral with a greater absorption rate, which was:
selenium
What can we "take home" from a biological dose-response curve?
shows the relationship between functionality and nutrient concentration/intake
Regardless of the species, most of digestion and absorption of nutrients take place in the _____.
small intestine
How would you explain the relationship between body size and life span?
smaller species have a shorter life expectancy due to an increased heart rate and metabolism
What do we mean by "professional fermenters"?
species of animals that have a section of the digestive tract devoted to housing microbial populations
Explain the phrase, "the essential mineral element typically shows a normal distribution".
suggests the existence of internal control mechanisms
Why do we need energy/nutrients for "maintenance"?
support of vital body process, which are essential for life
What is berriberri?
swelling of legs - a THIAMIN deficiency
It is important for us to have some ideas on interactions of minerals for two reasons
synergistic working together or antagonistic against each other
To determine the nutritional value of feedstuffs/diets, what is the most important factor? Why?
the actual value of ingested nutrients depends on many factors, the first and most important being "digestibility". b/c if an animal cannot digest a particular nutrient, they cannot utilize it
Unlike pigs, chickens do not have a true "stomach!" Well, then, how do they accomplish the initial digestion of feedstuff/feed?
the crop stores feed that gets sent to the proventriculus that contains HCl and pepsinogen that begins breakdown and the gizzard mechanically breaks down food
What do we mean by "heat production"? And is there any importance or significance to it?
the measure of energy expenditure of the fasting animal after eliminating all potential factors that may increase heat prdctn. Measured with calorimeter & is basal metabolic rate.Heat is produced when energy/nutrients are converted to work-it is not an efficient process and some is wasted as heat. This heat is necessary to maintain a constant body temperature
Requirement
the minimum amount of concentration of energy or nutrient need to prevent a deficiency
Basal Metabolism (basal metabolic rate)
the minimum energy expenditure compatible with the maintenance of life
Basal metabolism
the minimum energy expenditure compatible with the maintenance of life can be obtained and such a minimum value
What is "maintenance"?
the state in which there is neither gain or loss of a nutrient by the body
Explain how the type of food can affect the metabolic rate and if it is a reliable method to determine the thermogenic effect of food for ex weight loss.
the total thermogenic effect of food represents only about 5 to 10% of total energy expenditure in the human body
"Brush border enzymes," such as lactase, sucrase, and peptidases, are a bit different from, let's say, pancreatic enzymes simply because:
they are shed instead of secreted by the small intestine
Elaborate on the statement, "today's horses have a lot of digestive problems."
they evolved to eat grass, but we feed a lot of grains and concentrates; horses should spend 10-12 hours per day grazing and prefer small frequent meals.
Why are horses described as "hindgut fermenters"?
they have microbes in the hindgut (cecum) that ferment cellulose to volatile fatty acids, as well as supplying vitamins and amino acids. They can then absorb these nutrients and utilize them.
Why are protozoa important to ruminant species?
they primarily ciliate and many utilize simple sugars and some store ingested carbohydrates as glycogen; protozoa can also consume bacteria to prevent bacterial overgrowth.
Dispensable (Non-Essential) Nutrients
those that can be synthesized from other substances in sufficient quantity to meet its needs
Indispensable (Essential) Nutrients
those that cannot be synthesized by the body from other substances, or those that cannot be synthesized fast enough to meet its needs
Indispensable Nutrients
those that cannot be synthesized by the body from other substances, or those that cannot be synthesized fast enough to meet the bodies needs; MUST BE SUPPLIED IN DIET
If we don't satisfy the needs for "maintenance", then what would/could happen?
tissue breakdown
Nutrition
to nourish; all processes whereby food and oxygen are presented to and utilized by living cells and waste products are eliminated.
True or false: "Ketosis" can be caused by inadequate oxaloacetate to utilize excess acetyl-CoA in the citric acid cycle. Unutilized acetyl-CoA would be, then, converted to ketone bodies, and excess ketone bodies can result in ketosis!
true
True or false: "Senses" such as sight, smell, and taste seem to play some roles in finding food/feed. For instance, the "olfactory" system seems to be very important for pigs, whereas the "vision" seems to be very important for poultry/birds.
true
True or false: As we mentioned, usually, an "essential mineral element" shows a normal distribution, i.e., the concentration would be relatively constant among individuals, tissues, and or organs in various species.
true
True or false: Chickens have poorly developed sense of smell, and, perhaps, no mastication and having unheated mouth may have something to do with less olfactory detection.
true
True or false: Gastrin (...actually, a family of polypeptides) is the focal point of controlling gastric secretion, and it is controlled by 2 factors, histamine and secretin.
true
True or false: If we give some drug based on body weight, we may end up with overdosing animals; thus, it would be important for us to do that based on the metabolic body weight, such as body weight^0.75.
true
True or false: It seems that some species have capacity to produce some acid at the upper portion of the gastrointestinal tract, and it might be beneficial in controlling potentially harmful ingested microorganisms...because microbes are very sensitive to changes in pH.
true
True or false: It's amazing that each milliliter of the rumen content may contain 10 to 50 billion bacteria, 1 million protozoa, and various numbers of yeast and fungi!
true
True or false: Liver is important for the utilization of nutrients, and it is involved in, among the others, the synthesis of urea, fatty acids, and proteins and the storage of glycogen, vitamins, and others. But, it is mostly associated with the maintenance in mature or adult animals.
true
True or false: Regardless of species, the majority of nutrients are digested and absorbed at the upper portion of the small intestine, e.g., at the jejunum, even though some nutrients can be absorbed at the lower part of the gastrointestinal system, such as vitamin B12 at the ileum.
true
True or false: Throughout history, people had to deal with many serious diseases or disorders, and we now know that some of those can be caused by the "deficiency" of some vitamins. Examples? "Scurvy" by deficiency of vitamin C and "pellagra" by deficiency of niacin!
true
True or false: When we consider the process of "protein synthesis", we would have to remember that all 20 amino acids must be available in adequate amounts simultaneously, and also there would be many "mistakes" in the process, thus, increasing the energy expenditure greatly.
true
Describe the fate of VFAs (acetate, butyrate, and proprionate) and what is importance of glucose?
utilize carbohydrates to make glucose. Glycolysis occurs to turn glucose into pyruvate.
Why do we need energy/nutrients for "growth"?
various nutrients are needed for growth, but the need for energy is by far the largest and primarily determines the total feed required
Because of its involvement in just about every aspect of nutrition of animals, what is perhaps the most important factor in the utilization of feed ex. From ingestion of feed to exretion of waste products?
water
What is most important factor in nutrition?
water
6 basic nutrients
water, carbs, lipids, proteins, vitamins, and minerals
Elaborate on how "todays horses have a lot of digestive problems"
we have to be careful not to overload the horse's system; must ensure adequate fiber intake and feed small, frequent meals. Horses are susceptible to excessive gas production, colic, stomach rupture, and laminitis. Horses seldom vomit because they have only one-way peristaltic movement, and because of the marked tone of the lower esophageal sphincter (actually keeps the food down, unlike in humans where it can open back up for emesis) Horses are the only domestic species in which acute gastric dilation can occur to the point of rupture of the stomach wall. Stomach 10% of the volume of the digestive tract (much smaller than other species) Not as extensive muscular movement and ingesta tends to arrange itself in layers Flow rate is relatively fast-large meals pass more quickly than feed eaten continuously in small amounts When the stomach remains empty, the excess gas produced can cause rupture of the stomach, so it is very important to feed small frequent meals to horses. Horses today have a lot of digestive problems; they evolved to eat grass, but we feed a lot of grains and concentrates. Horses should spend 10-12 hours per day grazing and prefer small frequent meals. Within 2-4 hours, undigested and unabsorbed ingesta get to the cecum and colon-easy to overwhelm the digestive capacity of the stomach and small intestine because of the limited capacity/volume.Designed to digest carbs and proteins in the upper gut, thus it is important to feed small amounts 2-4 times per day. The diameter of different segments of the large colon varies and the arrangement includes several flexures where the colon turns back onto itself; this makes it susceptible to turning back on itself and other digestive upsets when the flow is abnormal.
Can we us the terms "essential/ non-essential" for minerals?
yes
Does the discussion we had on requirement vs. allowance have anything to do with giving more vitamins
yes. The requirement is the amount needed to maintain proper function/prevent deficiency signs. Allowance: total levels fed to compensate for factors affecting the need.
Do horses really have advantages of both ruminant species and other nonruminant species? Elaborate.
yes; digest carbs&proteins in uppergut.the fermentation in the hind gut resembles that of ruminant species, meaning that they are able to convert cellulose/fiber into VFA in cecum in the same way that ruminants can, but also can absorb fermentable nutrients directly like non-ruminant species (don't have to go through microbes in the rumen).
