1. Pigs are non-ruminants

2. Definition of a non-ruminant
Single stomach
Eat feed low in fiber
Humans are also non-ruminants

3. Parts of the digestive tract
1. Mouth
2. Esophagus
3. Stomach
4. Small Intestine
5. Large Intestine

4. What does the digestive system do?
Breaks down feedstuffs into …..
simple chemical parts…..
so the pig can absorb…..
and utilize them .

5. What does the mouth do in digestion?
Breaks down feed stuffs by chewing
Adds saliva to help in digestion

6. What does the esophagus do?
Muscles contract to move the food down to the stomach

7. What does the stomach do?
Adds digestive juices to break down food

8. What does the small intestine do?

9. The small intestine….
Mixes secretions
Absorbs nutrients

10. What does the large intestine do?
Storage and formation of feces
Absorption of water
Secretion and reabsorption of electrolytes

11. Digestive System of a Pig

12. Non-ruminant Abomasum- true stomach depends on digestive enzymes
pepsin, rennin, trypsin, chymotrypsin, HCL
Needs
energy (fat and CHO), protein (a.a.), minerals (Ca:P 1.2:1 to 1.5:1), vitamins, water, antibiotics and other additives

13. Swine Gastrointestinal Physiology
11/04

14. Digestive secretions: saliva
Functions of saliva in non-ruminants:
Lubricates food to facilitate swallowing
Contains antibodies and lysozyme
Some amylase in saliva of swine and rats, but much less than in humans
Functions of saliva in ruminants:
Maintains fluid consistency of rumen
Slightly alkaline; helps neutralize acids formed by fermentation
May help prevent frothing in rumen

15. Gastric pits in gastric mucosa
Gastric pits are openings to ducts into which gastric glands empty their secretions

16. Exocrine gland
Any gland that directs its secretions through a duct into a compartment that is contiguous with the exterior of the body

17. Glandular regions of simple stomach
Cardiac
Fundic
Pyloric

18. Glandular regions of equine, porcine and ruminant stomachs
Cardiac, fundic and pyloric gland regions are glandular
Esophageal regions (“E”) are non-glandular epithelium

19. Cardiac gland region (cardiac mucosa)
Fundic
Pyloric

20. Fundic gland region Mucous neck cells Parietal cells Chief cells
Cardiac
Mucous neck cells
Parietal cells
Chief cells
Fundic
Pyloric

21. Fundic gland region Mucous neck cells secrete mucus
Parietal cells secrete:
HCl
Intrinsic factor (not in cats); necessary for absorption of Vitamin B12

22. Fundic gland region Chief cells secrete pepsinogen
HCl converts pepsinogen into pepsin
Pepsin is a proteolytic enzyme (breaks down proteins into peptides)

23. Pyloric gland region Mucous secreting cells G cells Pyloric Cardiac
Fundic
Pyloric

24. Pyloric gland region
G cells are endocrine gland cells – secrete the endocrine hormone, gastrin
Endocrine cells secrete hormones into the bloodstream – travel to a distant part of the body where they produce an effect on another cell type

25. Substances that stimulate HCl secretion by parietal cell
Gastrin may interact with either receptor
Gastrin
Acetylcholine
Histamine
Histamine secreted by ECL cells in gastric mucosa

26. Rennin Enzyme secreted by abomasal mucosa of young ruminant
Acts to coagulate milk protein, which facilitates its digestion

27. Hormone secretions of small intestine: cholecystokinin
Site of secretion
Stimuli for secretion
Actions
Primarily duodenal mucosa
Chyme with a:
High amino acid concentration
High fatty acid concentration
Low pH
Inhibits gastric emptying
↑ secretion of pancreatic enzymes and HCO3-
Stimulates gall bladder contractions

28. Hormone secretions of the small intestine: secretin
Site of secretion
Stimuli for secretion
Actions
Duodenal mucosa
Chyme with a:
Low pH
High fatty acid concentration
↓ HCl production in stomach
↑ pancreatic HCO3- secretion
↑ biliary HCO3- secretion

29. Exocrine pancreatic secretions
Liquid rich in HCO3-
Pancreatic digestive enzymes
Both are secreted into duodenum

30. Pancreatic digestive enzymes
Pancreatic proteolytic enzymes (pancreatic proteases) are secreted as proenzymes (zymogens)

31. Activation of pancreatic proteases in small intestine
CCK stimulates duodenal mucosal cells to produce enteropeptidase
Proelastase
Elastase

32. Absorption of amino acids from small intestine