Principles of Animal Nutrition Test 3

Fatty acid degradation

1. Energy from fat stores 2. Fats are broken down in: a. Muscle, connective tissue, liver, kidney, adipose 3. Triglyceride + tissue lipase = glycerol + fatty acid 4. Liver, heart, resting skeletal muscle rely heavily on fatty acid oxidation 5. Lipids are transported in blood by chylomicrons 6. Chylomicron = TG, cholesterol, phospholipid, protein 7. TG glycerol + fatty acid 8. Glycerol liver Glucose Kreb's cycle

The tally

1. Energy release a. 1 NADH/pyruvate = 3 ATP 2. Kreb's cycle a. 3 NADH = 9 ATP b. 1 GTP = 1 ATP c. 1 FADH2 = 2 ATP d. Per turn of Kreb's cycle, 12 ATP are produced 3. Total net ATP/pyruvate = 15 ATP 4. 2 moles of pyruvate per 1 mole glucose 5. The final tally a. Glycolysis + Kreb's = 8 ATP + 6 ATP + 24 ATP = 38 ATP

Wintering pregnant cattle, Human obesity, Hibernating animals

Practical conditions where we may feed for weight loss? "fasting"

Fat Digestion: horse

a. No gall bladder, constant secretion of bile b. Digested and absorbed in the S.I.

Ruminant Digestion: small intestine

a. Similar to that for non-ruminant b. CHO digestion i. Starch—amylase-->maltose -Maltase glucose ii. Sucrose ----sucrase--> glucose + fructose iii. Lactose ---- Lactase -->glucose + galactose c. Hindgut fermentation i. Similar to rumen ii. Undigested CHO and NFE 1. Starch/cellulose - MCO, Amylase, Cellulase glucose ---MCO-VFA's

Stomach: horse

a. Small in relation to total tract b. Not as muscular as in other species c. Tends to lead to greater digestive disturbances d. Should be fed in small meals, more than 1x per day e. HCL, Pepsin, Mucin

Carbohydrate digestion: horse

a. Soluble - wheat, oats, corn, barley i. Digestion in S.I. - amylase, disaccharides (lactase, etc) b. Fibrous - cellulose i. L.I. - MCO fermentation ii. VFA's produced, absorbed, utilized as energy iii. Less efficient than ruminant due to faster passage rate

Normal blood glucose levels

a. Species - Blood glucose level i. Non ruminant - 70 - 120 mg/dL ii. Cattle - 40 - 6- (mg/dL) iii. Birds - 120+ (mg/dL) iv. Man - 80-120 (mg/dL) v. Reptiles - 20 (mg/dL)

The ruminant fermentation cycle

a. Starch and cellulose -------MCO, Cellulose, Amylase---C6H12O6 b. C6H12O6 ---MCO 2 acetic acids + CO2 + CH4 2. a. Green plants (637 kcal photoenergy) b. Plant consumed by ruminant c. MCO digest and fermentation rearranges glucose molecule to yield VFA's d. Metabolism yields energy and waste products

Lipid Hormonal control

a. Insulin i. Increases fat storage b. Epinephrine i. Decreases fat storage c. Cortisol i. Decreases fat storage d. Glucagon i. Decreases fat storage e. Growth hormone i. Decreases fat storage

Colic

a. Is a potentially fatal syndrome, manifested by mild to sever abdominal pain and depression. "Any gastrointestinal condition that causes pain" b. Many causes: gut contraction and or dehydration i. Too much or too rapid grain consumption ii. Stoppage of intestinal flow c. Other causes: i. Parasites, gas production, and improper husbandry d. Symptoms: i. Pawing, kicking at belly, abnormal postures

Lipid digestion

a. Stomach i. Churning of stomach creates small fat droplets ii. Pyloric sphincter meters fat droplets to small intestine b. Small intestine i. Key player: Bile salts and lipase ii. Bile 1. Produced by liver 2. Stored in gall bladder (except horses) 3. Secreted into duodenum 4. Major actions: a. Emulsification of fat b. Arrange triglycerides for hydrolysis by lipase iii. Lipase 1. Cleaves fatty acid from glycerol backbone

Lipid Body storage

a. Storage as triglycerides in body i. Occurs in all tissues ii. Adipose tissue is a special fat tissue adipocyte

MCO fermentation: horse

much like ruminant ii. Produce VFA's absorbed through cecum and colon 1. Acetate 2. Propionate 3. Butyrate

Storage

of fat soluble vitamins and cholesterol derived substances a. Storage of ADEK is ~~ 30-90 day

Composition of triglycerides

tends to be similar to the ones consumed, except for ruminant a. Ex. Swine fed unsaturated fatty acids will deposit unsaturated fatty acids (soft pork)

Digestion

- breakdown of large molecules to simpler, smaller chemical compounds that can be absorbed

Absorption

- set of processes that result in passage of small molecules from lumen of gut through cells of G.I. tract to bloodstream

Glycogenolysis

1. Description: Breakdown of glycogen a. Glucagon - increases ______________, increase blood glucose

Glycogenesis

1. Description: process of "making glycogen" a. Muscle and liver b. Happens immediately following a meal c. Hormone involved: insulin

Relative efficiency of VFA production

1. 1 Glucose 2 Acetic Acids + CO2 + CH4 = 62% 2. 1 Glucose 1 Butyric acid + 2 CO2 = 78% 3. 1 Glucose 2 Propionic acids + 2 H2O = 109%

Energetic efficiency of glucose oxidation

1. 1 mole of glucose = 673 kcal/mole 2. ATP = 7.3 kcal/mole a. (7.3 x 38 = 277 kcal/mole of glucose) / 673 kcal/mole =42% 3. where does the remaining 58% go?? a. Heat and CO2

Lipid classification

1. 2 types a. saturated - single bonds b. Unsaturated - double bonds

Metabolism of VFA's - all animals

1. Acetate a. Enters Kreb's cycle via Acetyl-CoA 2. Butyrate a. Converted to ketone, then converted to Acetyl-CoA 3. Propionate a. Enters Kreb cycle via succinyl-CoA b. Also converted to pyruvate and back to Glucose

CHO digestion in the horse

1. Combination of non-ruminant and ruminant 2. Small intestine a. Amylase b. Sucrase, lactase, maltase, 1,6-isomaltase 3. Hindgut fermentation a. Similar to rumen fermentation i. Starch/cellulose -MCO, Amylase, Cellulase Glucose---MCO VFA's

Fasting to improve health

1. Complete fasting caused the following losses of body weight (compared to initial BW): a. 12.6% after 14 days (n = 11) b. 13.4% after 18 days (n=10) c. 15.6% after 20 days (n = 9) d. 20.1% after 29 days (n = 6) e. 20.6% after 30 days (n = 5) f. 21.5 after 31 days (n-2), and g. 25.3% after 40 days (n=1)

What proteins are catabolized

1. Concept of protein turnover a. Do not have storage of proteins as we have for fat b. Rapidly turning over protein i. GI tract ii. Liver iii. Muscle 2. If protein of body tissues is mobilized, and deaminated to provide energy, urea is formed a. Sulfur (S) creation also occurs after catabolism of sulfur amino acids 3. Thin individuals lose twice as much body N per unit of body weigt during a fast compared to obese individuals a. [N losses occur when protein is fed in excess of needs, and the same effect occurs with an imbalance of amino acids.] 4. Obese mammals that hibernate preferentially metabolize fat and conserve lean 5. The bear is especially adept at conserving lean by re-absorbing N and electrolytes from the bladder. 6. Other species are not as efficient at conserving lean weight at a particular level of fatness as the bear 7. One explanation is that humans have greater percentage of body weight represented as brain tissue compared to animals, and the demand of the brain for glucose increases the need for glucogenesis (the generation of glucose from other compounds). a. The author of a review concluded, "low protein diets are inefficient and even hazardous" 8. The amount of protein metabolized depends upon: a. The duration of the fast b. The amount of glycogen stored when the fast is initiated c. The carryover effect of consumption of excessive protein (meat for example) prior to the fast that results in more excretion of urea in urine during the fast 9. Urea is released into the blood and is removed from the blood by the kidneys and excreted 10. In ruminant species N is recycled by removal from blood by salivary glands for presentation to the ruminal microorganisms 11. After an overnight fast there is release of fatty acids, glucose from liver (or possibly muscle) glycogen, and amino acids from protein tissues. 12. Initially tissues around the intestinal tract provide nutrients and probably represent much of the quick weight loss during dieting. 13. The critical nutrient is glucose, since the brain tissue demand apparently depletes the free glucose pool of the body in about 2 hours. a. The body must provide glucose to prevent loss of consciousness and neurological damage. 14. Liver gluconeogenesis is continuous (even when fed) making glucose from lactate, glycerol and amino acids 15. A fast longer than 2 to 3 days removes all the glycogen from the liver and about one-half of the muscle glycogen. 16. Once exhausted of glycogen, the liver produces more of the ketones that characterize a prolonged fast. 17. Acetone is volatile, and produces a "sweet" odor of the breath. It is also excreted in urine 18. Most farm animals can lose BW 19. Yet, at certain early stages of growth of a young animal the eventual mature BW will be permanently stunted. 20. Older animals will compensate after periods of limited feed availability by more rapid growth after adequate feed is provided - and may even overtake controls that were fed routinely

Gluconeogenesis

1. Description: "making glucose" from non-CHO sources 2. Liver and kidney 3. Essentially the reverse of glycolysis 4. Very important in ruminant a. Very little glucose is absorbed b. Propionate converted to glucose

Lipid digestion in ruminants

1. Diets can be grain or forage 2. Lipid contents of grains (seeds) mainly triglycerides 3. 4. Lipid content of stems and leaves mainly galactolipids a. Galactolipid Glycerol + galactose + FFA b. Glycerol and galactose VFA 5. Fatty acids derived from rumen travel as FFA or MCO cell walls to stomach and S.I. for digestion and absorption

CHO metabolism

1. Digestion Absorption Metabolism 2. CHO metabolism includes all rxn's that CHO undergo a. Metabolism is complex b. It is an essential linked series of chemical reactions for living cells

Fasting energy metabolism

1. Fasting heat metabolism, or basal metabolic rate (BMR), is defined a. The amount of heat produced per unit of time by a person (or animal) resting in a comfortable temperature, after the energetic effect of consuming food has dissipated

The rate of weight loss is roughly a function of the energy deficit

1. Fasting results in losses of about 0.5 kg/day in the obese and about 0.35 kg/day in the non-obese

General categories of feeding requirements

1. Fasting/feeding for negative energy balance 2. Maintenance 3. Growth 4. Reproduction/egg laying 5. Work

Fatty Acid Metabolism

1. Fatty acids are produced from acetyl CoA 2. Sources of acetyl CoA: a. CHO b. Protein c. VFA's d. Degraded Fats 3. Tissues a. Liver, kidney, brain, lungs, mammary gland 4. Location of synthesis: cytosol 5. Synthesis: a. Fats are made of two carbons at a time b. Process continues until fatty acid is 16 C long c. Enzyme: fatty acid synthase 6. Control of fatty acid synthesis: a. Excess energy (glucose, protein, fat) increases fat synthesis b. Deficient energy decrease in fat synthesis

Ruminal Digestion

1. First step is ruminal digestion of CHO 2. Fructose, cellulose, hemicellulose, starch, mono and disaccharides, and pentose's are all converted to glucose

Gastric lipase

1. Found in stomach 2. Not very active in mature animals (<30%) 3. Is function in young animals a. Acid lipase b. Secreted from chief cells c. 50% of lipase activity in the neonatal animal d. Does not require bile e. Neonate - whale has 40 to 50% fat in milk

CHO metabolism continued

1. Fuel sources a. Glucose, galactose, and fructose - glycolysis b. Fats and Proteins - Kreb's cycle 2. Glucose and the struggle for energy a. Body requires constant supply of glucose 3. Normal blood glucose levels a. Species - Blood glucose level i. Non ruminant - 70 - 120 mg/dL ii. Cattle - 40 - 6- (mg/dL) iii. Birds - 120+ (mg/dL) iv. Man - 80-120 (mg/dL) v. Reptiles - 20 (mg/dL) 4. Regulation of blood glucose level a. Blood glucose levels are highly regulated in mammals b. Liver and pancreas both control glucose levels c. Insulin from pancreas i. Increases storage of uptake of glucose by cells ii. Stimulate formation of glycogen by liver d. Glucagon from pancreas i. Increase conversion of amino acids to glucose ii. Stimulate conversion of amino acids to glucose e. Glucocorticoids - increase blood glucose i. Stimulate growth/metabolism f. Epinephrine - increase blood glucose 5. Muscle and liver glycogen a. Muscle - .5-1% of weight is glycogen b. Liver - 20% of weight is glycogen

Why do we study metabolism?

1. Generally, how do we use knowledge of metabolism to feed animals 2. How do we integrate out knowledge of the metabolism of fats, carbohydrates and protein to feed animals as well as ourselves? 3. What's available - composition of feeds and foods 4. What animal, what person: information such as species, age, stage of growth, rate of growth 5. Nutrient requirements

Glycolysis process

1. Glucose, a six carbon molecule, enters the cytosol which is anaerobic and is oxidized to 2 pyruvate molecules yielding 2 ATP and 2 NADH molecules. 2. Each pyruvate is then transported into the mitochondria which is an aerobic environment and is converted to 2 acetyl-CoA which yields 2 NADH molecules. 3. One Acetyl-CoA enters the Kreb cycle at a time. For each turn of the Kreb's cycle one Acetyl-CoA yields 3 NADH, FADH2, and 1 GTP 4. NADH and FADH2 enter oxidative phosphorylation. NADH yields 3 ATP and FADH2 yields 2 ATP. Ox/Phos regenerates NAD and FAD for glycolysis and Kreb's cycle 5. Thus, 10 NADH from one mole of glucose yields 30 ATP, plus 2 FADH2 yields 4 ATP, plus 4 ATP/GTP = 38 ATP.

Human and non-ruminant animals

1. Lactase deficient = lactose intolerant a. Genetic correlation b. Results in accumulation of gas and diarrhea 2. Raffinose flatus a. Trisaccharide in beans not hydrolyzed by mammals b. Readily hydrolyzed by MCO c. MCO degradation results in large production of CO2 3. Diabetes mellitus a. Cells can't absorb glucose due to lack of insulin b. Blood glucose levels increase and spill over into urine 4. Pentosuria a. Excretion of pentose in urine

Summary of fasting

1. Little carbohydrate storage in tissues 2. Animals mobilize fat - no net synthesis of carbohydrate from fat 3. Animal mobilizes protein - protein can be catabolized to meet critical carbohydrate needs

Tissue composition

1. Muscle a. H2O -75% b. CP -21% c. Lipid -2-3% d. Ash - 1% 2. Bone a. H2O - 37-38% b. CP - 18-20% c. Lipid - 17-20% d. Ash - 25% 3. Fat a. Lipid -90% b. H2O -8% c. Ash/CHO -2% d. CP - negligible 4. Skin a. H2O - 80% b. CP - 20% c. Ash - negligible d. Lipid - negligible

Glycolysis

1. Oxidation of glucose to 2 pyruvate 2. Glycolysis a. Uses two ATP initially b. Generate: c. 2 NADH d. 4 ATP 3. Produce two pyruvates/glucose a. Net yield = 2 ATP, 2 NADH 4. This is the glycolysis scheme you are expected to know 5. -page 11 notes 6. The tally a. Energy release i. 2 ATP - yields 2 ATP ii. 2 NADH - yields 6 ATP b. Net ATP is 8 ATP 7. NADH a. Nicotinamide adenine dinucleotide b. Electron transport yields 3 ATP/NADH 8. FADH2 a. Flavin adenine dinucleotide b. Electro transport yield 2 ATP/FADH2

Pancreatic lipase

1. Primary fat digestion enzyme 2. Secreted with pancreatic juice 3. Secreted in an inactive form 4. Activated by Ca in lumen of S.I.

Lipid forms

1. Simple lipids a. Makes up the largest % of lipids b. Fats, oils, waxes c. Butyric acid, 4 c - caproic acid, 10C

What about Fat

1. Storage 2. Mobilization

The effect of fasting on the spirits of the faster varies with the individual

1. Usually there is a loss of buoyancy of spirit 2. A decreased desire to work 3. A decrease in the actual power of working

Metabolism of VFA's

1. VFA's - ruminants a. 1^0 energy source: little glucose absorbed b. used as energy 2. Absorption of VFA's a. 1^0 through rumen wall - passive diffusion b. Very fast, enters blood stream quickly c. Feed - increase blood VFA's within minutes

Weight loss is exponential with time, so the declining rate of loss is proportional to BW

1. This makes sense since body tissues are the only source of energy available

Lipids

1. Wide variety of sizes and shapes 2. Have one thing in common a. Water insoluble b. Hydrophilic loves water c. Hydrophobic hates water 3. Energy density a. One gram fat = 9.45 kcals gross energy b. One gram CHO = 4.2 kcals gross energy c. Fat has 2.25 times more energy d. Related to the ratio of O:H in molecule

Complete fasting caused

1. pulse rate to decline during the early days of fasting, but began increasing slightly, but consistently, after day 16 2. Blood pressure to peak on the 3rd day, then generally declined until day 17, and finally stabilized throughout the remainder of the 31 - day fast.

Lactase deficient

= lactose intolerant a. Genetic correlation b. Results in accumulation of gas and diarrhea

Vitamin digestion: horse

A. Past the site of primary absorption

Electron transport and oxidative phosphorylation

Page 12 notes

Kreb's cycle

Page 12 notes

Metabolism

The sum of the processes of chemical changes in living cells by which energy and nutrients are provided for vital processes and activities and new materials are assimilated

Proteins, carbohydrates, fats and lipids

What do humans or animals eat when fasting?

Chylomicron

a small fat globule composed of protein, phospholipid, cholesterol and lipid

Carbohydrate digestion of non-ruminant: NFE

a. %NFE = %DM - (%EE + %CP + %ash + %CF b. where: NFE = nitrogen free extract i. DM = dry matter ii. EE = ether extract or crude lipd iii. CP = crude protein iv. CF = crude fiber

Energy tally: Beta oxidation

a. 16 C fatty acid = 8 acetyl CoA x 12 ATP = 96 ATP i. = from beta oxidation ii. (7 NADH, 7 FADH2) = 35 ATP iii. 96 + 35 = 131 ATP 2. Glucose = glycolysis and Kreb's cycle = 38 ATP 3. 131/38 = 3.44 more ATP for 16 C fatty acid (palmitate)

Capacity of organs: horse

a. Esophagus: 4-5 feet b. Stomach: 8-19 quarts c. Small intestine: 70 feet and 68 quarts d. Large colon: 10-12 feet and 86 quarts e. Cecum: 4 feet and 28-36 quarts f. Small colon: 10-12 feet and 16 quarts g. Rectum is 1 foot

Beta oxidation of fatty acid

a. Beta oxidation is stepwise removal of 2 C from fatty acids i. Removes 1 mole of acetate (2 C) as acetyl CoA b. Steps repeat until fat is completely broken down i. Palmitic acid (16C) 8 acetyl CoA ii. Stearic acid (18C) 9 acetyl CoA iii. 19C fatty acid 8 acetyl CoA + 1 Propionyl CoA c. Fatty acids are degraded to acetyl CoA d. Acetyl CoA can then enter the kreb cycle e. Location: mitochondria

Regulation of blood glucose level

a. Blood glucose levels are highly regulated in mammals b. Liver and pancreas both control glucose levels c. Insulin from pancreas i. Increases storage of uptake of glucose by cells ii. Stimulate formation of glycogen by liver d. Glucagon from pancreas i. Increase conversion of amino acids to glucose ii. Stimulate conversion of amino acids to glucose e. Glucocorticoids - increase blood glucose i. Stimulate growth/metabolism f. Epinephrine - increase blood glucose

Carbohydrate digestion of non-ruminant: Absorption

a. Brush border i. Passive diffusion 1. High to low [C] gradient 2. No energy 3. No carrier protein ii. Active transport 1. Occurs only for monosaccharides 2. Couples with Na transport out of cell 3. Competition among sugars for carrier system b. Relative rates of absorption i. Active transport 1. Galactose>> glucose ii. Passive diffusion 1. Fructose>> Mannose>> Xylose>> Arabinose

Dynamic state of lipid in body

a. Catabolism- breakdown of lipids b. Anabolism- synthesis of lipids

Large intestine: horse

a. Cecum b. Large colon c. Small colon d. Rectum e. MCO inhabit cecum and large colon i. MCO fermentation much like ruminant ii. Produce VFA's absorbed through cecum and colon 1. Acetate 2. Propionate 3. Butyrate

Diabetes mellitus

a. Cells can't absorb glucose due to lack of insulin b. Blood glucose levels increase and spill over into urine

Protein digestion: horse

a. Digested in stomach and S.I. b. MCO protein produced in hindgut i. Cannot be digested or absorbed

Carbohydrate digestion of non-ruminant: Intestines

a. Duodenal lumen i. Pancreas 1. Pancreatic juice - NaHCO3 2. Presence of CHO in lumen stimulates amylase release ii. Amylase action 1. Hydrolyzes a-1, 4 linkages a. Amylose maltose b. Amylopectin Maltose + Isomaltose (dextrin) 2. Amylase hydrolysis of starch results in: a. Starch b. Maltose c. Isomaltose (dextrin) d. Glucose 3. CHO not hydrolyzed by amylase: a. Cellulose b. Hemicellulose c. Lactose d. Sucrose e. Maltose b. Duodenal mucosal cells i. Further digestion of CHO ii. Responsible for final hydrolysis of CHO iii. Enzymes found in brush border of duodenum iv. Brush-border enzymes include: v. Lactose ----lactase--> glucose + galactose vi. Sucrose ----sucrase--> glucose + fructose vii. Maltose----maltase--> glucose + glucose viii. Isomaltose---- Isomaltase--> glucose + glucose c. Jejunum and ileum i. Hydrolysis decreases ii. Absorption d. Cecum and colon i. Residues of digestion 1. Crude fiber 2. Undigested NFE ii. Fermentation iii. Absorption of water and VFA's

Metabolism of CHO provides:

a. Energy source i. Glucose catabolism yields ATP 1. ATP = Adenosine Triphosphate 2. Provides metabolic fuel ii. Heat is given off iii. Red blood cells and brain use glucose extensively b. Short term energy source i. Glucose c. Long-term energy storage i. CHO serve as precursors to fatty acids (fat) ii. Glycogen (in muscle and liver) d. Amino acid precursor i. Amino group added to C skeleton provided by CHO

Fat storage vs. Fat catabolism

a. Energy surplus b. Times of surplus c. Glucose, protein, and fat } fat storage d. Energy is deficient i. Fat storage energy

Dietary fat

a. Excellent source of energy b. Sometimes too good

Pentosuria

a. Excretion of pentose in urine

Lipids as a carrier for absorption

a. Fat-soluble vitamins from gut b. In blood as lipo-protein complexes i. Cholesterol - HDL, LDL ii. Sex hormones iii. Fat-soluble vitamins - A, D, E, K

3 systems of major importance in CHO metabolism

a. Glycolysis i. Anaerobic - No O2 ii. Occurs in cytosol - all enzymes present in cyt b. Kreb's cycle (TCA) i. Aerobic - need O2 ii. Occurs in mitochondria c. Oxidative Phosphorylation i. Aerobic- needs )2 ii. Occurs in mitochondria d. Purpose of these cycles: i. Oxidize glucose and generate ATP and other metabolically active compounds for animal metabolism

Essential fatty acids

a. Linoleic (18 C, 2 double bonds) b. Linolenic (18 C, 3 double bonds) c. Arachidonic (20 C, 4 double bonds) i. Can not be produced by animals ii. Precursors of a number of unsaturated fatty acids d. Linolenic Arachidonic Prostaglandins

Major enzyme in lipid digestion, absorption, and transportation

a. Lipase b. Two forms i. Gastric lipase 1. Found in stomach 2. Not very active in mature animals (<30%) 3. Is function in young animals a. Acid lipase b. Secreted from chief cells c. 50% of lipase activity in the neonatal animal d. Does not require bile e. Neonate - whale has 40 to 50% fat in milk ii. Pancreatic lipase 1. Primary fat digestion enzyme 2. Secreted with pancreatic juice 3. Secreted in an inactive form 4. Activated by Ca in lumen of S.I.

Carbohydrate digestion of non-ruminant: Stomach

a. Low pH - denatures amylase b. Acid moistens CHO and disrupts H-bonds c. No CHO digesting enzymes

Carbohydrate digestion of non-ruminant: Mouth

a. Mastication b. Saliva i. Moistens feed and disrupts structure c. Salivary amylase i. a-1, 4 linkages 1. some hydrolysis in humans 2. little effect in pigs

Lipid production in mammary tissue

a. Monogastric animals i. Milk fat primarily derived from glucose b. Ruminant animals i. Milk fat primarily derived from acetate (VFA) ii. Presents unique challenge for ruminant nutritionists 1. Propionate increases efficiency 2. Acetate increases milk fat

Small intestine: horse

a. Much the same as in other species i. Duodenum ii. Jejunum iii. Ileum b. Pancreatic secretions, brush border secretions c. One exception = i. Continuous secretion of bile from liver into S.I.

Muscle and liver glycogen

a. Muscle - .5-1% of weight is glycogen b. Liver - 20% of weight is glycogen

Esophagus: Horse

a. One way peristaltic movement b. Strong cardiac sphincter

Lipids as a source of energy

a. Oxidation of fat yields CO2 + H2O + energy b. 2.25 times more than CHO c. As far as cost, it can be cheap i. Cheap substitute for CHO

Functions of lipids

a. Oxidation to CO2 for ATP b. Glycolipids, phospholipids c. Lung alveolar integrity d. Prostaglandin, sex hormones, adrenal hormones e. Energy

Founder

a. Problem with too much or too fast eating can cause acidosis and production of endotoxins b. Most common cause: i. Excess soluble CHO in grain or lush pastures c. Leads to laminitis (inflammation of the laminae)

Body fat

a. Serves as the major storage form of energy in the body b. No net synthesis of glucose from fat

Anabolism

a. The constructive part of metabolism involving synthesis i. H+ + OH- H2O

Catabolism

a. The destructive part of metabolism involving the release of energy and breakdown of complex materials i. H2O H+ + OH-

Raffinose flatus

a. Trisaccharide in beans not hydrolyzed by mammals b. Readily hydrolyzed by MCO c. MCO degradation results in large production of CO2

Mouth: horse

a. Upper and lower incisors - mastication b. Mobile lip c. Saliva i. Parotid ii. Sublingual iii. Submaxillary iv. No enzyme present, lubrication of food

Fat intake

associated with heart disease a. Cholesterol plaques in arteries b. Causes a narrowing of the arteries i. HDL - high density lipoprotein not much lipid ii. LDL - Low density lipoprotein lipid iii. VLDL - Very low density lipoprotein high iv. High levels of LDL and VLDL assoc. with heart disease

Carbohydrate digestion of non-ruminant: Duodenal mucosal cells

i. Further digestion of CHO ii. Responsible for final hydrolysis of CHO iii. Enzymes found in brush border of duodenum iv. Brush-border enzymes include: v. Lactose ----lactase glucose + galactose vi. Sucrose ----sucrase glucose + fructose vii. Maltose----maltase glucose + glucose viii. Isomaltose---- Isomaltase glucose + glucose

Carbohydrate digestion of non-ruminant: jejunum and ileum

i. Hydrolysis decreases ii. Absorption

Carbohydrate digestion of non-ruminant: Duodenal lumen

i. Pancreas 1. Pancreatic juice - NaHCO3 2. Presence of CHO in lumen stimulates amylase release ii. Amylase action 1. Hydrolyzes a-1, 4 linkages a. Amylose maltose b. Amylopectin Maltose + Isomaltose (dextrin) 2. Amylase hydrolysis of starch results in: a. Starch b. Maltose c. Isomaltose (dextrin) d. Glucose 3. CHO not hydrolyzed by amylase: a. Cellulose b. Hemicellulose c. Lactose d. Sucrose e. Maltose

Carbohydrate digestion of non-ruminant: Cecum and colon

i. Residues of digestion 1. Crude fiber 2. Undigested NFE ii. Fermentation iii. Absorption of water and VFA's

Ruminant Hindgut fermentation

i. Similar to rumen ii. Undigested CHO and NFE 1. Starch/cellulose - MCO, Amylase, Cellulase glucose ---MCO-VFA's

Foregut: horse

makes up 38.5% of gut a. Consists of stomach and small intestine

Hind gut: horse

makes up 61.5% of gut a. Consists of cecum, large colon, and small colon

VFA synthesis by MCO in rumen

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