Animal Nutrition Exam 3 babes
Are aldehydes or ketones the most easily oxidized?
Aldehydes are most easily oxidized. They contain an extra hydrogen atom instead of carbon to carbon bond.
What enzyme is necessary for cellulose digestion? What bond does it attack and split? Where does it come from? Where does the digestion occur in the digestive tract?
Cellulase is necessary for cellulose digestion. It can break/hydrolyze the glucose-4-beta-glucoside linkage of cellulose. Comes from microflora of rumen and cecum/colon. Rumen or large intestine via microorganisms.
What is cellulose? Where is it found? To what extent? What is its constituent monosaccharide? How is it different from starch?
Cellulose - the most abundant substance in the plant kingdom - It represents about 50% of the dry matter of all vegetation - The single most abundant organic compound in the world - The major structural component of cell walls in plants ... Function in plant is to form the plant skeleton ... The fiber or stiff, hard portions of the plant found in the stem leaves and roots - Composed of D-glucose in beta-1,4 linkage - A large polymer (3000-5000 glucose units) and is insoluble in water - Digestion of cellulose ... It is not hydrolyzed by any mammalian enzymes but microorganisms do have a cellulase
What is the composition of CHO on a molecular weight basis?
Chemical composition (by percent molecular weight) of carbohydrates is: C (40%), H (7%), and O (53%). In feed, carbohydrates occupy 80% of diet on a weight basis.
What is the efficiency of the conversion of the free energy of the oxidation of glucose?
Conversion of free energy of the oxidation of glucose has an efficiency of 40-65%
What is the form of most of the energy in plants?
Form of most energy in plants is available largely as carbohydrates→ only with a small fraction of calories as fat ... Mono-, di-, and polysaccharides, including starch, and a mixture of other complex carbohydrates, including cellulose and lignin (which resist hydrolysis by digestive enzymes)
Which is the only hexose of any importance found in nature that is a ketone?
Fructose is the only hexose of any importance found in nature that is a ketone. The rest are aldehydes.
How are the hexoses important to nutrition?
Hexoses are a very large and very important part of carbohydrate nutrition because they are the most abundant carbohydrate found in nature. They are important in 2 ways: 1. Food components (in their polymerized forms they make up a major portion of the animal and human diet - ex. Starch, cellulose) 2. Metabolism: serve as both fuel and intermediates in metabolic pathways
Are hulls digestible? How much lignin is in them?
Hulls are highly digestible (60-80%) with only 2-3% lignin.
Why is glucose such an important sugar in animal nutrition?
Important to metabolism for 2 important reasons: 1. Major CHO used for energy at the cellular level (All digested dietary CHO are converted into glucose (metabolic essential)) 2. Major circulating CHO in blood
Can mammals digest cellulose and lignin on their own?
No they resist hydrolysis by digestive enzymes elaborated by the host animals. They need a microbial populations in their rumen/cecum/colon/ large intestine to help digest these complex carbohydrates
Does the body require carbohydrates in the diet? Why do we eat so much of it then?
No, but virtually all natural food sources contain some carbohydrate which is why we eat so much of it.
What are the most important factors in determining the physical and chemical properties of a triglyceride?
Major factors that determine the physical and chemical properties of individual fatty acids are the chain length and degree of unsaturation of the individual fatty acids making up the triglyceride -Triglycerides composed of saturated fatty acids with a chain length of 10 or more carbons are solid at room temperature - those with less than 10 carbons are usually liquid -Triglycerides containing mostly unsaturated fatty acids are liquids at room temperature -Triglycerides whose composition is only long-chain saturated fatty acids are solids -Several constants are used commonly to characterize the chemical properties of fats
What is the function of CHO in the diet?
Major function of CHO is a source of dietary energy. In plants, CHO can be involved in tissue synthesis, energy reserves, energy transformations, and structural support.
Compare the molecular weight of polysaccharides to monosaccharides.
Polysaccharides are polymers of simple sugars with 10 or more glycose units. The molecular weight of Polysaccharides is high. Several thousand monosaccharides can be bonded together to form a polysaccharide
What is the primary source of galactose?
Primary source of galactose is milk. Galactose is a component of milk sugar and its derivatives are found in the brain and nervous tissue. It is used by all species except poultry, which lacks lactase (without lactase, no breakdown of galactose).
What factors can affect the rate of digestion of starch?
Rate of digestion of starch in preparation for absorption affected by: - Particle size - Nature of the starch (amylase and amylopectin content) - Interactions of starch with protein and fat - Presence of antinutrients like phytate, tannins, saponins, and enzyme inhibitors
Which pentose is found in every living animal cell?
Ribose is found in every living cell - it's a component of ATP, ADP, riboflavin, and RNA.
Ketosis: What animals are affected and when?
Ruminants are especially affected when there is limited glucose absorption during periods of great glucose demand (i.e. lactation or pregnancy). In dariy cattle, ketosis has been linked with metabolic vitamin B12 deficiency. Sheep are often affected by ketosis when pregnant and if it gets too bad, they may lose the baby. Swine and other nonruminants experience ketosis when underfed.
Describe the importance of gluconeogenesis to ruminants.
Ruminants constantly depend on gluconeogenesis for metabolic needs - depend on acetate instead of glucose as a major product of digestion. In ruminants, glucose is converted in the rumen and rarely ever directly uptaken by the small intestines.
What is the empirical formula for simple carbohydrates? Complex carbohydrates?
Simple carbohydrates have the empirical formula of CnH(2n-2)O(n-1). Complex carbohydrates have the structure of CnH(n-2)O(n-1).
What does leaf:stem ratio of a forage tell us?
The higher the number the better ...Can also be used to compare two forages ...The higher ratios are usually better
Are both amylose and amylopectin digested by the same enzymes?
Yes generally the digestive enzymes secreted by animals can hydrolyze both
What are the CHO fractions found in the leaf? Why are they there?
most forage nutrients are found in the leaf -Fiber - moderate quantities -Monosaccharides - high photosynthesis end products are found in leaves and thus we would expect to find most monosaccharides here -Starch - none
What is glycogen? What is its purpose in the body? What is glycogenesis? Glycogenolysis?
-Starchlike compound -Can be hydrolyzed rapidly back to glucose -Allows blood glucose level to be maintained within narrow range -Conversion of circulating blood glucose to glycogen (glycogenesis) and by reconversion to glucose by glycogenolysis when BG declines Glycogenesis → formation of glycogen from glucose requiring 2 ATP for every glucose; glucose molecules are added to form the long chain of glycogen Glycogenolysis → breakdown of glycogen to form glucose
What is ATP? What is oxidative phosphorylation? What is the significance of oxidative phosphorylation to the body biochemical processes?
1. Adenosine triphosphate which two are required for glucose to glycogen conversion 2. Phosphorus uptake by ADP (adenosine diphosphate) to form ATP is called oxidative phosphorylation 3. The process is the driving force for many biochemical processes, including absorption of nutrients from the gi tract, synthesis of proteins, nucleic acids, fats, and carbohydrates.
Explain the difference in the two types of starch. Are they digested with similar efficiency? What are the similarities and differences in them?
1. Amylose will generally be 25-30% of all starch in most plants - Soluble in hot water - Straight chains of D-glucose - a-1,4 linkage in chemical bond - Amylose exists in a helix 2. Amylopectin will usually amount to 70-75% of all starch in most plants - Insoluble in water - Branched chain D-glucose - Linkage is a-1,4 linked with a-1,6 cross linkage - Phosphorus is found in amylopectin at the rate of 1 part per 400 glycose units - Molecular weight - 1,000,000 or more - one of the largest in nature - The branched chain structure provides multiple sites for enzymes to attach. Perhaps makes it more digestible Both are amylose and amylopectin occur as glucose polymers link via glucose-1-4-alpha glucoside linkage Hydrolysis of starch in amylose and amylopectin to glucose is similar. The digestive enzymes used by the animals are generally able to hydrolyze both efficiently *Amylopectin is typically in higher quantity when comparing ratios of content in feed
What does lignin do for plants? Where is it found in plants? What is it associated with? How does a plant's age affect lignin content? How does it affect digestibility?
1. Associated with cellulose it affects the bioavailability of the cellulose and hemicellulose for microbial use and in this way affects the nutritive value of a plant material for animals. In plant cell walls in combination with cellulose/hemicellulose -Lignin is found in the woody part of plants 2. Lignification increases with plant age and in mature trees lignin is the chief structural component 3. It decreases digestibility hence why veggies and cereals are low in lignin while grass and legumes are higher (less digestible)
What is the significance of the citric acid cycle in terms of energy to the animal? The Embden-Meyerhof glycolytic pathway?
1. Citric acid cycle is the metabolism of acetyl-CoA which is the final common energy pathway for carbohydrate, fat, and carbon skeletons of amino acids. ATP, CO2, and water are created. 2. Embden-Meyerhof glycolytic pathway (glycolysis) is where most of the metabolism of glucose 6 phosphate occurs to ultimately form pyruvate. 3. Both of these are significant because they form the basis for understanding energy metabolism in animals
Describe the difference in a saturated and an unsaturated fatty acid.
1. Saturated fatty acids are organic compounds that contain only single bonds between carbon atoms 2. Unsaturated fatty acids are organic compounds that contain one or more double bonds between their carbon atoms. 3. The double bonds of an unsaturated fatty acid are very reactive. This means that unsaturated fatty acids are less stable than saturated fatty acids.
Classify the lipids of importance in nutrition.
1. Simple lipids - esters of fatty acids with various alcohols Fats, oils, waxes Fats and oils are esters of fatty acids with glycerol - waxes are esters of fatty acids with alcohols other than glycerol Fats and oils make up the largest fraction of lipids in most material. They have a high energy value (9.45 kcal/gram compared to 4.1 for carbohydrates) 2. Compound lipids - esters of fatty acids but also contain groups in addition to fatty acids and alcohols Phospholipids, glycolipids, and lipoproteins are the 3 major types Phospholipids (phosphatides) contain phosphoric acid and N Glycolipids contain carbohydrates and sometimes nitrogen Lipoproteins are lipids that have a protein moiety 3. Derived lipids are substances derived from the previous groups by hydrolysis Includes fatty acids, glycerol, and other alcohols 4. Sterols are lipids with complex phenanthrene-type ring structures 5. Terpenes have isoprene-type structure
What are the three major groups of microorganisms found in the rumen? Which is largest in microbial mass?
1. Small bacteria (selenomonads, Oscillospira flagellates) Largest 2. Ciliated protozoa (entodinia, dasytricha + diplodinia, Isotricha + Epidinia) 3. fungi
Name the important tests for classifying physical characteristics of lipids.
1. Triglycerides composed of a chain of 10 or more saturated fatty acids will be solid at room temperature. Any triglyceride less than 10 carbons will usually be liquid. 2. Triglycerides containing mostly unsaturated fatty acids are liquids at room temperature. Triglycerides whose composition is only long-chain saturated fatty acids are solids. Several constants commonly used to characterize chemical properties of fats: 1. Saponification number: number of milligrams of KOH required for the saponification (hydrolysis) of 1 g of fat Saponification number of a low molecular weight fat (Short-chain fatty acids) is large and becomes smaller as the molecular weight of the fat increases Saponification number gives a measure of the average chain length of the three fatty acids in the fat 2. Reichert-Meissl (RM) number: number of mL of 0.1N KOH solution required to neutralize the volatile water-soluble fatty acids (short chain) obtained by hydrolysis of 5 g of fat Beef tallow and other high molecular weight fats contain practically no volatile acids and therefore have RM numbers near zero, but butter contains a higher proportion of volatile acids and has a RM number of 17 to 35 3. Iodine number: number of grams of iodine that can be added to the unsaturated bonds in 100 g of fat Iodine number is a measure of the degree of hydrogenation (saturation) of fatty acids in fat Completely saturated fat (like tristearin) has an iodine number of zero Liquid fat (like linseed oil) has an iodine number of 175-202
Are CHO found in the body of mammals?
Animals have few body carbohydrates, with less than 1% because after all daily energy needs are met, the rest of the carbohydrates consumed are converted to fat because it weighs less per calorie, gives 2.25 as much energy and is more efficient for storage.
Are VFAs useful for swine?
Amounts absorbed from large intestine of nonruminant are less certain, but may be as much as 30% of the digestible energy in swine
Describe the two types of carbohydrate classification.
Based on number of carbon atoms per molecule of carbohydrate (i.e. pentoses with 5 C) Based on number of molecules of sugar in the compound (i.e. disaccharides with 2 sugar molecules)
What do cellulose and hemicellulose do?
Being relatively insoluble they are most important in providing structural support for living plants
How important is diabetes in domestic animals? Ketosis?
Both are connected primarily with faulty carbohydrate metabolism. Diabetes does occur in domestic animals but its importance is unknown unlike with humans where it affects people of all ages. Ketosis, on the other hand, appears to be more of a problem for domestic animals
Explain why there is very little carbohydrate found in the body of a living animal.
Carbohydrate only make up very little of the body as animal cells do not have an effective way to store carbohydrates. Once digested, carbohydrates are either used for energy, or they can be stored as glycogen (often in the liver). However, the limit for glycogen storage is very low, meaning that only small amounts of glucose (from digested carbohydrates) will be stored as glycogen. Once the energy requirements and glycogen storage limit is met, there is nowhere for excess carbohydrates to be stored. Therefore, the body converts excess carbohydrates/glucose to fat as animal bodies can store energy in the form of fat. Fat is thought to be the prefered method of storage (over carbohydrate) as it contains 2.25 times as much energy by weight, therefore it is the more efficient storage method.
What carbohydrates can the carbohydrate splitting enzymes (carbohydrases) break down to monosaccharides and which ones can they not break down?
Carbohydrate-splitting enzymes (carbohydrases) are effective in hydrolyzing most complex carbohydrates to monosaccharides except for those with a glucose-4-beta-glucoside linkage (i.e. in cellulose)
What are the two major sources of energy for the animal body? Which is provided in greatest quantity in the diets of food-producing animals?
Carbohydrates and lipids. Lipid content is usually less than 5% in the diets so carbohydrates take majority
Speculate on the practical problems associated with excluding carbohydrates from the diet. (There is no biochemistry in the correct answer to this question. Think about a practical, cost effective diet for animals as you answer this question).
Carbohydrates exist in practically every animal's diet, and they are readily available. Most feeds are plant-based, and much of plant material is made of carbohydrates. Carbohydrates can make up to 85% of the dry weight of forages, thus are very difficult to not include in diets. While there is no clear evidence that carbohydrates are dietary essential, they do provide a large percentage of the dietary energy for an animal. Therefore, since carbohydrates provide energy and have no clear negative impact, there is no reason to exclude them from a diet. Additionally, exclusion of carbohydrates would mean the the feedstuff would have to have energy provided from another source (either fats or proteins). And because most feedstuffs can only have a certain percentage of fat without problems, that would mean that more protein would be necessary. Protein-rich feed is much more expensive. Thus, excluding carbohydrates from the diet would be very costly.
What portion of the dry matter of forages is CHO?
Carbohydrates form 70% of dry weight of forages and an even higher percentage in seeds (up to 85%).
Explain how the deficiency of specific disacharidases can affect animals.
Deficiency of specific disaccharidases in the GI tract results in serious gastrointestinal upsets. In addition young animals feed too much sucrose (not developed sucrase) can result in severe diarrhea and death
What are dextrins?
Dextrins are breakdown products in the gut ...Result from digestion or hydrolysis or heat action on starch ...Contain 3-8 glucose units
What comprises the largest fraction of lipids in most materials? Make some statement about the energy content of these lipids.
Fats and oils make up largest fraction of lipids in most materials. They have a high energy value (9.45 kcal/gram) as compared to carbohydrates (4.1).
Name the lipids of greatest importance in nutrition.
Fatty acids, glycerol, mono-, di-, and triglycerides, and phospholipids
What are the CHO fractions found in the stem? Why?
Fiber - large concentrations of structural carbohydrates Monosaccharides - small amounts should be found as sugar being transported from leaves to seeds Starch - none
What are the carbohydrate fractions found in the seed?
Fiber - some because of the hull or seedcoat Not much Monosaccharides - some, but not much, would be found as precursors of starch Starch - large concentrations are found as would be expected - the plant stores it there to nourish the seedlings
What is gluconeogenesis? What is its purpose? What does it mean to be glucogenic? Ketogenic? Does this mean that excess amino acids could be used for energy? Which of the amino acids are glucogenic?
Gluconeogenesis is the formation of glucose by body tissues (liver, kidneys) from noncarbohydrate metabolites (including lipids and amino acids). This process gives a net increase in glucose. 1. Through the process of gluconeogenesis, glucogenic compounds are metabolized and give rise to a net increase in glucose a.Examples being all nonessential amino acids and some essential amino acids such as arginine, histidine, valine, methionine, cystine, threonine, tryptophan) are glucogenic 2. Some amino acids (isoleucine, lysine, phenylalanine, and tyrosine) are both glucogenic and ketogenic meaning that they give rise to glucose and acetone or other ketones. Leucine is strictly ketogenic 3. Yes amino acids not used for protein synthesis enter the general pool of metabolites that provide energy for normal body maintenance and productive functions
What is the ultimate source of energy for most animal cells?
Glucose - Basic unit is made available to animal cells either by ingestion of glucose or its precursors by the animal or by conversion from other metabolites ... Carbon skeletons of these substances and of products of fat metabolism provide the energy for maintaining normal life processes
What are the only monosaccharides that occur to any extent in free form in nature?
Glucose and fructose are the only monosaccharides that occur to any extent in free form in nature.
Name some common CHO.
Glucose, fructose, ribose (5C), pentoses, hexoses, sucrose, cellulose, glycogen, starch, gums, sugars, polyhydroxyl aldehydes and ketones.
How is glycerol classified?
Glycerol is a derived lipid (substance derived from previous groups by hydrolysis)
What is glycogen? Where is it found? To what extent? What is its constituent monosaccharides?
Glycogen (animal starch) and is CHO storage in the body - Resembles starch in some ways - Found in liver and muscles ... Can be 10% of the wet weight of the liver. In most species, it will be 2-8%. It is water soluble. After 24 hours of fasting the liver glycogen with 0 for most species - It yields glucose as its only end product of hydrolysis so it is a pure polymer of glucose
What happens when ingestion of carbohydrates exceeds current needs? Note to student: Just about here the text gets too detailed for our purposes. Read though this but don't get bogged down in detail. It is important to understand the significance of these pathways however so be able to answer the following study question.
Glycogen storage is limited therefore when ingestion of carbohydrates exceeds current needs for glycogen formation, glucose is converted to fat. Glucose is broken down to pyruvate for fat synthesis
Describe the difference in cell wall contents between a pasture and a dormant pasture and a hay and a silage. Explain.
Grains are 60-80% starch, which is 80-90% digestible - they are thus generally less than 15% cell wall Forages vary depending on maturity more than anything else Green pasture: 35-45% cell wall percent, 4-6% lignin Dormant pasture: 60-80% cell wall, 6-12% lignin Hay: 40-60% cell wall, 4-8% lignin Silage: 40-60% cell wall, 4-8% lignin Hulls (seedcoats) are 60-80% cell wall - they are highly digestible - 60-80% and only 2-3% lignin
Why discuss lignin in the lesson with carbohydrates?
Has much to do with whether or not other carbohydrates are useful energy sources. It is not a CARBOHYDRATE but it affects the digestibility of CHO fractions. Also provides structural support especially in aging plants. Any fiber fraction will have lignin associated with it in the plant
Define hemicellulose.
Hemicellulose is a complex polymer that is a mixture of carbohydrates containing primarily pentosans. -"Hemicelluloses are defined as components of plants that are insoluble in boiling water, soluble in dilute alkali and readily degraded by dilute acid". Mammals do not manufacture enzymes to digest hemicelluloses but microorganisms can - Small portion of hemicelluloses are degraded by the acidic conditions of the stomach making them partially digestible
Ketosis: How can it be prevented? (Please answer each individual portion of this question in an easy-to-read format.)
In pregnant ewes, we know ketosis is partly caused by reduced stomach capacity due to increased uterine size limiting feed intake. Perhaps by increasing the number of daily feedings, this can reduce the chance that these pregnant ewes are not getting enough food (which would cause ketosis). There is also evidence that, in cows, administration of supplementary niacin may prevent ketosis. In dariy cattle, ketosis has been linked with metabolic vitamin B12 deficiency. So perhaps, with more research, there could be prevention of ketosis with relation to vitamin B12 administration.
Where are most monosaccharides absorbed?
In the small intestine → The upper and proximal absorption of the small intestine i.e duodenum and jejunum have the largest capacity for absorption
What is the polymer of fructose?
Inulin is the polymer of fructose (found in many plants in the form of mannans).
What is a glycose unit?
It is a generic descriptor for monosaccharides
What is the importance of glycerol to nutrition?
It is the alcohol component of all triglycerides common in animal and plant tissues. It is also a component of phosphatides-lecithin, cephalin, and sphingomyelin All neutral fats and some other lipids contain the trihydric sugar alcohol glycerol
Ketosis: How can it be treated?
Ketosis can be treated by focusing on restoring normal blood glucose concentrations. IV glucose and oral propylene glycol adminstration are common. Additionally, hormones like ACTH (adrenaocorticotropic hormone) and adrenal corticoid hormone can be given to help improve the situation.
Describe in detail what ketosis is and why is occurs.
Ketosis is when an excess of ketones accumulates in the body (and eventually even the urine) due to a problem with lipid or carbohydrate metabolism. Common ketones that build up include acetone, acetoacetate, and beta-hydroxybutyrate. Ketosis is often seen with hypoglycemia, elevated mobilization of adipose tissue lipids, increased production of ketones, and/or lipemia. It often occurs due to starvation or underfeeding and often partnered with the onset of a greater energy need (like pregnancy or lactation). If the body does not have enough carbohydrates, it must use fat (ketones) for energy. It can also happen if carbohydrate metabolism pathways are somehow compromised.
Where is lignin in the plant? Describe lignin's digestibility.
Lignin is found in the cell walls of plants, helps with structure and increases as plants age. Very indigestible itself, lignin combines with cellulose, hemicellulose, and protein chemically and reduces their digestibility. Neither mammalian enzymes nor anaerobic bacterial enzymes can split the bond. But aerobic organisms and fungi can break the bond and degrade it. Strong alkali can also break bond but leaves lignin intact.
Define lipids.
Lipids are organic compounds that are relatively insoluble in water, but relatively soluble in organic solvents Introduction - lipids are not polymers composed of one particular kind of building block, like carbohydrates or proteins ... instead, 'lipid' is a collective term for a wide variety of substances varying from simple, short-chain fatty acids to large, very complex molecules. They are heterogeneous compounds not always chemically related. 3 things in common: 1. Water insoluble, but are soluble in organic solvents such as benzene, chloroform, and acetone 2. Actually or potentially fatty acid esters 3. Utilized by living organisms
How much monosaccharide is absorbed in the ileum and stomach? Large intestine?
Lower ileum absorbs fewer monosaccharides than the upper small intestine (duodenum and jejunum). The stomach and large intestine absorb little if any sugars.
What is the average percent elemental composition of lipids?
Make up - elemental composition of lipids by % moleculare weight on average: 77% Carbon 12% Hydrogen 11% Oxygen
Who(what)producesVFAs?
Microbes in rumen doing anaerobic fermentation.
Why doesn't the fat in milk separate immediately after the cow is milked?
Milk has lecithin in it naturally and this is why it takes several hours for the cream in milk to separate. The lecithin slows down the separation. Thus, milk is a temporary emulsion
Compare sweetness levels of sucrose to fructose and maltose.
Most to least sweet: Saccharine (40,000) Aspartame (18,000) Fructose (173) Sucrose (100) Glucose (74) Maltose (33) Lactose (16) *So, fructose>sucrose>maltose
In healthy animals, what is the absorption rate of soluble carbohydrates? Does it vary significantly from one source to another?
Normal absorption of soluble carbohydrates often exceeds 90% - similar for a wide variety of carbohydrate sources
Are all plants good sources of dietary CHO?
Not all plants are good dietary carbohydrate sources. Not all forms of carbohydrates are digested by all animals. (Must consider species and type of carbohydrate in diet.)
Which carbohydrates can be absorbed from the gut?
Only monosaccharides can be absorbed from the GI tract, except in newborn animals capable of absorbing larger molecules.
What is pectin? How is it used in the plant?
Pectin is a complex polysaccharide similar to hemicellulose *Pectin helps with cell wall structure by covalently linking hemicellulose and then hydrogen bonds to cellulose microfibrils. - Digestibility - depends on microbes (of questionable value to monogastrics); studies show that much of it is digested, even by humans ... the microorganisms must find it a readily fermentable fraction for this to be true - Diarrhea preventative - great water holding capacity and is often given as a diarrhea medication in humans and young animals - Feed products - beet pulp is high in pectin ... often given to cattle at shows Stays in ruminoreticular area and expands with water Makes the animal look as if it has great capacity (spring of rib) Used a good deal in dairy rations A desirable fiber fraction for balancing the dairy ration
Define a phospholipid, a glycolipid, and a lipoprotein.
Phospholipid: a heterogeneous group of compounds classified together because they have ester phosphorus present ... contain phosphoric acid and N Glycolipids contain carbohydrates and sometime nitrogen Lipoproteins are lipids that have a protein moiety (part protein).
Define phospholipids, identify where they are found, and state what they do. What do lecithins do?
Phospholipids are a heterogeneous group of compounds classified together because they have ester phosphorus present. On hydrolysis they yield fatty acids, phosphoric acid, and usually glycerol and a nitrogenous base ..Occur in every living cell - major component of membranes (cell walls and internal cell bodies) ...They form stable complexes with lipids, carbohydrates, and proteins to help with cell organization ..Other functions: mitochondrial enzyme systems and lipid transport because of their emulsifying properties Ex. is lecithin (keeps oils and water together)
What process creates CHO?
Photosynthesis produces CHO in plants via chlorophyll in chloroplasts. This process forms glucose from CO2 and H2O.
What is the difference in alpha and beta glucose? What are the implications of this difference?
Position of H and OH groups on the #1 carbon determines i the compound is in the alpha form or beta form - Alpha form (a) is the precursor to of maltose, starch, and glycogen - Beta form (b) is precursor of cellobiose and cellulose - Digestibility: no mammalian enzyme to digest B-linked glucose - this is why the animal must have microorganisms that do make such an enzyme ... there are mammalian enzymes to digest a-linked glucose molecules
Are VFAs easy to absorb? From where?
Readily absorbed from the rumen → less certain about amount absorbed from large intestine
How might recombinant DNA technology assist in improving fiber digestion?
Recombinant DNA (gene-splicing) techniques are being applied in carbohydrate nutrition by cloning cellulase genes from microorganisms ... Changing microbial activities in GI tract may be applied in this way to enhance breakdown of holocellulose (lignin bond) to increase cellulose use
What is starch? Where is it found? What are the similarities and differences in the two types of starch?
Starch is the reserve energy material of most plants - it is concentrated in the tubers, rhizomes, seeds, and fruits... when fruits ripen, there is a conversion of starch to sugars that accounts for the sweetening. There are 2 kinds of starch: 1. Amylose will generally be 25-30% of all starch in most plants - Soluble in hot water - Straight chains of D-glucose - a-1,4 linkage in chemical bond - Amylose exists in a helix 2. Amylopectin will usually amount to 70-75% of all starch in most plants - Insoluble in water - Branched chain D-glucose - Linkage is a-1,4 linked with a-1,6 cross linkage - Phosphorus is found in amylopectin at the rate of 1 part per 400 glycose units - Molecular weight - 1,000,000 or more - one of the largest in nature - The branched chain structure provides multiple sites for enzymes to attach. Perhaps makes it more digestible
What are extensins and why are they of little value to animals?
Structural components of plants also contain proteins (extensin), which are generally of low bioavailability owing to their inaccessibility to proteolytic enzymes
What are the monosaccharides in sucrose? Maltose? Cellobiose? Lactose?
Sucrose is one D-glucose and one D-fructose. Maltose is 2 molecules of a D-glucose in a-1,4 linkage. Cellobiose is 2 glucose molecules in beta-1,4 linkage. Lactose is a-D-glucose and a-D-galactose.
In fiber digestion, what is the unique place of the termite?
Termites have enzymes to break down lignin.
Why is the setting of seed such an important time to consider in forage harvesting?
The amount of lignin escalates around the time of the setting of seed. Thus, many forages are harvested during the period when they are beginning to to bloom or slightly before
What are the chemical elements and their ratio in CHO?
The chemical elements in carbohydrates are carbon, hydrogen, and oxygen at the ratio of 1:2:1. Chemical composition (by percent molecular weight) of carbohydrates is: C (40%), H (7%), and O (53%).
What do rumen microorganisms do with fiber carbohydrates?
The microbial population in the rumen contain species that elaborate enzymes capable of hydrolyzing cellulose present in plant cell walls which are seen in stems, leaves and the outer bran layer of seeds.
What VFA are primarily produced by anaerobic fermentation of carbohydrates? What does the animal use these for? Can pigs use VFA?
The primary VFAs that are produced are acetic, propionic, and butyric acids. These provide a large proportion of total energy supply. Even in pigs, whose ability to use cellulose is less than ruminants → some energy required for maintenance can be provided by VFA produced by microbes in large intestine
If you could genetically engineer a more efficient system of carbohydrate digestion for the ruminant, what would you try to make the new system accomplish? (Think about inefficiencies and places where there is waste as you answer this question.)
The whole ruminant stomach system mainly revolves around being able to digest and use fibrous carbohydrates like cellulose. Currently, ruminants have microorganisms living in the rumen that contain enzymes like cellulase and are able to digest and use fibrous carbohydrates that the ruminant's own enzymes cannot. Thus, the ruminant has to provide these microorganisms the perfect environment and to wait for these microorganisms to digest these fibrous carbohydrates. This process takes time and is not the most efficient. The most efficient was for this to work would be for the ruminant themselves to be able to make enzymes, like cellulase. By making enzymes like cellulase, the ruminant would no longer need microorganisms (or even a rumen) as enzymes in the small intestine could break down fibrous carbohydrates like cellulose and then the ruminant could directly use that for energy. Because ruminants rely on microorganisms to digest carbohydrates, often acetate is produced as an end product instead of glucose. This is less efficient as gluconeogenesis is then required in order for the ruminant to make acetate a useable form, and that requires energy. As mentioned prior, if ruminants has enzymes like cellulase to digest these carbohydrates for themselves, this would be a much more efficient process. However, being able to add a cellulase gene to the cattle genome via CRISPR is not happening in the future anytime soon, so until then, to make ruminant carbohydrate digestion more efficient, it is important to minimize sucrose as ruminants like cattle do not produce very much sucrase (necessary to digest sucrose). Additionally, because ruminants do have microorganisms that hydrolzye cellulose, it is okay to put cellulose containing carbohydrates in ruminant feed. Another way to make carbohydrate digestion more efficient in ruminants time-wise is to speed up the growth of the microorganisms in rumen are increase their production of enzymes like cellulase. This would result in faster fibrous carbohydrate breakdown.
What happens to monosaccharides other than glucose once they are absorbed?
They can be converted to glucose by reactions in the liver and then stored as glycogen
The Van Soest NDF system is of great importance as an index of dietary energy value of feedstuffs. Briefly describe the fractions the NDF system breaks forages into. How digestible is each? Note to student: it may be helpful to refer back to the discussion on the topic found in lesson 3 and to look at text Figure 3.1
This method is used to determine the digestibility/dietary energy values of the components of a feed such as a forage. Uses a detergent to extract lipids, sugars, organic acids, and other water-soluble material, pectin, etc. These products are typically cell contents and are more soluble. The non-soluble neutral detergent insoluble fiber NDIF contains major cell wall components such as cellulose, hemicellulose, and lignin. Ruminants have an easier time digesting components of NDIF then nonruminants. Fibrous portions of plants (stems, leaves, seed coats) are high in cellulose.
Describe in detail what ketosis is and why it occurs. What animals does it affect and when?
This syndrome involves excess of ketones (acetone, acetoacetate, and B-hydroxybutyrate) accumulating in body tissues because of a disorder in carbohydrate or lipid metabolism Common in cattle at the peak of lactation and in sheep in late pregnancy. Also occurs in swine and other nonruminants during starvation or chronic under feeding, often at the onset of a sudden new energy demand such as at the beginning of lactation Symptoms such as hypoglycemia, depleted liver glycogen, elevated mobilization of adipose tissue lipids, increased production of ketones, and lipemia.
What is the primary function of carbohydrates in animal nutrition?
To serve as a source of energy for normal life processes.
What is starch's job?
To serve as an energy reserve in roots, tubers, and seeds. Not very soluble
How much total energy is released in the conversion of glucose to carbon dioxide and water?
Total energy released in conversion of glucose to CO2 and H2O is 673 Kcal/mol
How is blood sugar controlled in the body? What is hyperglycemia? Hypoglycemia?
Under endocrine control with hormones glucagon and insulin from the pancreas playing an important role in maintaining normal blood glucose concentrations. 1. Hyperglycemia is when their blood glucose levels are too high which can occur after a carbohydrate meal and insulin acts to pull these carbohydrates out of the blood 2. Hypoglycemia is when blood glucose levels are too low and glucagon acts on glycogen to break it down, produce glucose, and put glucose back into the blood.
Where do ruminants consuming all-forage diets obtain most of their energy?
VFAs