Animal nutrition

1. Animal nutrition Chapter 41

3. Function • 1. Digestion • 2. Absorption of nutrients/water • Energy • Growth • 3. Elimination

4. 1 2 3 4 Mechanicaldigestion INGESTION Chemicaldigestion(enzymatichydrolysis) DIGESTION Nutrientmoleculesenterbody cells ABSORPTION Undigestedmaterial ELIMINATION

5. Heterotrophs

6. Intracellular digestion

7. Extracellular digestion

8. Extracellular digestion

10. Fig. 41-9 Crop Gizzard Intestine Esophagus Pharynx Anus Mouth Typhlosole Lumen of intestine (a) Earthworm Foregut Midgut Hindgut Esophagus Rectum Anus Crop Mouth Gastric cecae (b) Grasshopper Stomach Gizzard Intestine Mouth Esophagus Crop Anus (c) Bird

11. Digestive system

12. General structure • Gastrointestinal tract (tube) • Mucosa: inner layer (epithelial) • Submucosa: connective • Muscularis: 2 layers of muscle • Serosa: outer layer (connective) • Plexues: nerves located in the submucosa

13. Digestive organs • Mouth • Pharynx • Esophagus • Stomach • Small intestine (duodenum, jejunum, ileum) • Large intestine (cecum, ascending colon, transverse colon, descending colon, sigmoid, rectum, anus)

14. Digestive organs • Accessory organs • Liver • Gallbladder • Pancreas

15. Digestion • Mouth • Teeth • Gizzard (in birds to help grind food) • Salivary glands • Secrete saliva • Amylase (enzyme to breakdown starch)

16. Mouth

17. Salivary glands

18. Digestion • Chew or mastication • Tongue pushes food • Pharynx • Epiglottis closes • Esophagus

19. Pharynx

20. Esophagus • Esophagus • Muscular tube • Connects pharynx to stomach • Peristalsis: • Rhythmic movement of muscle contractions • Moves food along • Esophageal sphincter: • End of esophagus keeps food in stomach

21. Stomach • Mucosa lining (epithelial) • Parietal cells • Secrete H + Cl ions • Chief cells • Secrete pepsinogen • Pepsinogen is converted to pepsin • Digests proteins

22. Stomach • Gastric juices: • HCl, pepsinogen & mucus pH=2 • Chyme: • Mixture of partially digested food

23. Stomach

24. Stomach

25. Small intestine • Chyme • Leaves stomach via pyloric sphincter • Duodenum • Digestive enzymes from pancreas • Bile from liver & gallbladder • Most digestion occurs in the duodenum & jejunum

26. Intestines

27. Small intestine

28. Small intestines • Villi along intestine epithelium • Microvilli • “brush border” • Aids in absorption • Secretes enzymes • Break disaccharides (sucrose, lactose)

29. Small intestine

30. Accessory organs

31. Accessory organs • Pancreas • Secretes fluids via pancreatic duct • Exocrine system • Trypsin & chymotrypsin (proteases) • Amylase (starch) • Lipase (fats) • Bicarbonate (neutralizes HCl) • Endocrine (insulin and glucagon)

32. Accessory organs • Liver • Secretes bile • Contains bile pigments & bile salts • Bile pigments are waste from break down of RBC • Eliminated

33. Accessory organs • Bile salts • Emulsify the fats • Bile made in liver • Stored in gall bladder • Released when eat fatty meal • Gallstones can block release

34. Smallintestines • Monosaccharides, aa are transported to the blood capillaries • Hepatic portal vein • Liver • Heart • Transported to body

35. Smallintestines • Fatty acids & monoglycerides • Villi • Triglycerides • Chylomicrons: (triglyceride & protein coat) • Lymph system

36. Fig. 41-15b Microvilli (brushborder) at apical(lumenal) surface Lumen Bloodcapillaries Epithelialcells Basal surface Epithelial cells Lacteal Lymphvessel Villi Key Nutrientabsorption

37. Fig. 41-16 Triglycerides Lumenof small intestine Fatty acids Monoglycerides Epithelialcell Triglycerides Phospholipids,cholesterol,and proteins Chylomicron Lacteal

38. Carbohydrate digestion Protein digestion Nucleic acid digestion Fat digestion Oral cavity,pharynx,esophagus Disaccharides Polysaccharides (starch, glycogen) (sucrose, lactose) Salivary amylase Smaller polysaccharides,maltose Stomach Proteins Pepsin Small polypeptides Essential nutrients Lumen ofsmall intes-tine DNA, RNA Fat globules Polypeptides Polysaccharides Pancreatic amylases Pancreatic trypsin andchymotrypsin Pancreatic nucleases Bile salts Maltose and otherdisaccharides Fat droplets Nucleotides Smallerpolypeptides Pancreatic lipase Pancreatic carboxypeptidase Glycerol, fattyacids, monoglycerides Amino acids Epitheliumof smallintestine(brushborder) Small peptides Nucleotidases Nucleosides Disaccharidases Dipeptidases, carboxypeptidase,and aminopeptidase Nucleosidasesandphosphatases Nitrogenous bases,sugars, phosphates Monosaccharides Amino acids

39. Large intestines • Absorbs water • Absorbs vitamin K • Concentrates wastes • E. coli • Feces • Cloaca • Combines feces & urine wastes in some animals

40. Large intestine

41. Large intestine

42. Veins to heart Hepatic portal vein Lymphatic system Liver Absorbedwater Absorbed food(except lipids) Mouth Stomach Lipids Esophagus Small intestine Anus Secretionsfromsalivaryglands Secretionsfromgastricglands Secretions from liver Rectum Largeintestine Secretions from pancreas

43. Food • BMR • Basal metabolic rate • Obesity • Heart disease, diabetes, stroke • Anorexia, Bulimia

44. Essential nutrients • Essential aa • Minerals • Vitamins • A, B-complex, C, D, E, K • Scurvy, rickets, pernicious anemia, bleeding

46. Abnormalities • Ulcers • H. pylori • Bacteria • Treated with antibiotics • Reflux: • Gastric juices go backwards to esophagus

47. Hiatal hernia

48. Pyloric Stenosis

49. Colon Cancer

50. Jaundice