Animal Nutrition.pptx

Animal Nutrition 1  Animal Nutrition I. Nutrients II. Digestion Forms III. Mammalian Digestive System IV. Particle Feeding V. Bulk Feeding VI. Group Feeding 2  Learning Objectives 1. Explain the dietary value of macronutrients 2....

Animal Nutrition 1  Animal Nutrition I. Nutrients II. Digestion Forms III. Mammalian Digestive System IV. Particle Feeding V. Bulk Feeding VI. Group Feeding 2  Learning Objectives 1. Explain the dietary value of macronutrients 2. Explain the importance of essential nutrients 3. Evaluate the benefits of intracellular and extracellular digestion 4. Compare the structural differences between gastrovascular cavities and complete digestive tracts 5. List the primary structures of the mammalian system 3  Learning Objectives 6. Compare and contrast the enzymatic digestion in the stomach and the small intestine 7. Explain the optimal foraging theorem 8. Describe absorption in the large intestine 9. Compare the forms of particle feeding 10. Describe the strategies for bulk 4  Animal Nutrition I.A Macronutrients. These include carbohydrates, lipids, and proteins. The elements that make up these nutrients are mostly C, H, O, N. Carbohydrates provide immediate energy but fats have more energy / gram. 5 I.B Essential nutrients are those the animal body cannot synthesize and include a) Essential amino acids b) Essential fatty acids c) Vitamins d) Minerals The role of these substances is activation of enzymes, metabolism, and building of other cells and body structures 6 7 C. Undernutrition Undernutrition results when a diet does not provide enough chemical energy An undernourished individual will – Use up stored fat and carbohydrates – Break down its own proteins – Lose muscle mass – Suffer protein deficiency of the brain – Die or suffer irreversible damage 8  JiTT Question Essential amino acids are A. all of the amino acids required to make proteins. B. those that cannot be made in the body. C. obtained only by eating plants. D. obtained only by eating animals. 9  II. Digestion Forms A. Stages of Feeding 1. Ingestion: taking in food 2. Digestion: breaking food into small pieces for absorption 3. Absorption: nutrient uptake by cells 4. Elimination: expulsion of undigested material 10 B. Intracellular Digestion 1. In intracellular digestion, food particles are engulfed by phagocytosis 2. Food vacuoles, containing food, fuse with lysosomes containing hydrolytic enzymes 11 C. Extracellular digestion: the breakdown of food particles outside of cells 1. It occurs in compartments that are continuous with the outside of the animal’s body 2. Animals with simple body plans have a gastrovascular cavity that functions in both digestion and distribution of nutrients 12 3. More complex animals have a digestive tube with two openings, a mouth and an anus 4. This digestive tube is called a complete digestive tract or an alimentary canal 5. It can have specialized regions that carry out digestion and absorption in a stepwise fashion 13  JiTT Question A “complete digestive tract” differs from a gastrovascular cavity in that only the complete tract A. permits extracellular digestion. B. uses its surface area for nutrient absorption. C. has specialized compartments. D. allows elimination of undigested wastes. 14  III. Mammalian Digestive System A. Mammalian Digestion 1. The mammalian digestive system consists of an alimentary canal and accessory glands that secrete digestive juices through ducts 2. Mammalian accessory glands are the salivary glands, the pancreas, the liver, and the gallbladder 15 3. The first stage of digestion is mechanical and takes place in the oral cavity 4. Salivary glands deliver saliva to lubricate food 5. Teeth chew food into smaller particles that are exposed to salivary amylase, initiating breakdown of glucose polymers 6. Saliva also contains mucus, a viscous mixture of water, salts, cells, and glycoproteins 16 7. The tongue shapes food into a bolus and provides help with swallowing 8. The throat, or pharynx, is the junction that opens to both the esophagus and the trachea 9. The esophagus conducts food from the pharynx down to the stomach by peristalsis 10. Swallowing causes the epiglottis to block entry to the trachea, and the bolus is guided by the larynx, the upper part of the respiratory tract 17  JiTT Question In humans, the first opportunity for ingested food to undergo enzymatic hydrolysis is in the A. mouth. B. stomach. C. small intestine. D. large intestine. 18 B. Digestion in the Stomach 1. Gastric juice has a low pH of about 2, which kills bacteria and denatures proteins 2. Gastric juice is made up of hydrochloric acid (HCl) and pepsin 3. Pepsin is a protease, or protein-digesting enzyme, that cleaves proteins into smaller peptides 19 4. Parietal cells secrete hydrogen and chloride ions separately into the lumen (cavity) of the stomach 5. Chief cells secrete inactive pepsinogen, which is activated to pepsin when mixed with hydrochloric acid in the stomach 6. Mucus protects the stomach lining from gastric juice 20 7. Coordinated contraction and relaxation of stomach muscle churn the stomach’s contents Sphincters prevent chyme from entering the esophagus and regulate its entry into the small intestine 21  JiTT Question Stomach acid A. splits polypeptides into amino acids. B. splits fats into fatty acids and glycerol. C. activates pepsinogen into pepsin. D. initiates the development of stomach ulcers. 22 C. Digestion in the Small Intestine The small intestine is the longest section of the alimentary canal It is the major organ of digestion and absorption The first portion of the small intestine is the duodenum, where chyme from the stomach mixes with digestive juices from the pancreas, liver, gallbladder, and the small intestine itself 23  The pancreas produces proteases trypsin and chymotrypsin that are activated in the lumen of the duodenum Its solution is alkaline and neutralizes the acidic chyme In the small intestine, bile aids in digestion and absorption of fats Bile is made in the liver and stored in the gallbladder Bile also destroys nonfunctional red blood cells 24  The epithelial lining of the duodenum produces several digestive enzymes Enzymatic digestion is completed as peristalsis moves the chyme and digestive juices along the small intestine Most digestion occurs in the duodenum; the jejunum and ileum function mainly in absorption of nutrients and water 25  Villi epithelial cells absorb fatty acids and monoglycerides and recombine them into triglycerides These fats are coated with phospholipids, cholesterol, and proteins to form water-soluble chylomicrons Chylomicrons are transported into a lacteal, a lymphatic vessel in each villus Lymphatic vessels deliver chylomicron-containing lymph to large veins that return blood to the heart 26 27  JiTT Question A fatty acid absorbed into an intestinal cell A. is hydrolyzed to smaller fragments. B. becomes part of a chylomicron. C. is bound to bile salts. D. exits the cell to directly enter the blood. 28  Optimality Models A. The optimal foraging theorem predicts that animals will choose prey that provides the highest energy gain with the smallest energy investment: Ej > Sj + Pj Factors: Ej: energy gained by eating item “j” Sj: energy spent searching for item “j” Pj: energy spent pursuing item “j” B. Prey models predict what type of prey an animal should try to catch. 1. Animals that often encounter easy to catch prey (E>S+P) and consume it become generalists. Example: House Sparrows. 2. Some animals may easily find prey but not eat it because it is too hard to catch or ingest (E