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• Single stomach • Eat feed low in fiber • Humans are also non-ruminants • • • • • 1. 2. 3. 4. 5. Mouth Esophagus Stomach Small Intestine Large Intestine • Breaks down feedstuffs into ….. • simple chemical parts….. • so the pig can absorb….. • and utilize them . • Breaks down feed stuffs by chewing • Adds saliva to help in digestion • Muscles contract to move the food down to the stomach • Adds digestive juices to break down food The small intestine…. • Mixes secretions • Absorbs nutrients • Storage and formation of feces • Absorption of water • Secretion and reabsorption of electrolytes 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 Swine Gastrointestinal Physiology 11/04 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 Gastric pits in gastric mucosa • Gastric pits are openings to ducts into which gastric glands empty their secretions Exocrine gland • Any gland that directs its secretions through a duct into a compartment that is contiguous with the exterior of the body Cardiac Pyloric Fundic Glandular regions of simple stomach Glandular regions of equine, porcine and ruminant stomachs • Cardiac, fundic and pyloric gland regions are glandular • Esophageal regions (“E”) are nonglandular epithelium Cardiac Pyloric Fundic Cardiac gland region (cardiac mucosa) Cardiac Pyloric Fundic Fundic gland region • Mucous neck cells • Parietal cells • Chief cells Fundic gland region • Mucous neck cells secrete mucus • Parietal cells secrete: – HCl – Intrinsic factor (not in cats); necessary for absorption of Vitamin B12 Fundic gland region • Chief cells secrete pepsinogen – HCl converts pepsinogen into pepsin – Pepsin is a proteolytic enzyme (breaks down proteins into peptides) Cardiac Pyloric Fundic Pyloric gland region • Mucous secreting cells • G cells 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 Gastrin may interact with either receptor Substances that stimulate HCl secretion by parietal cell • Gastrin • Acetylcholine • Histamine – Histamine secreted by ECL cells in gastric mucosa Rennin • Enzyme secreted by abomasal mucosa of young ruminant – Acts to coagulate milk protein, which facilitates its digestion Hormone secretions of small intestine: cholecystokinin Site of secretion Stimuli for secretion Primarily duodenal mucosa •Inhibits gastric Chyme with a: emptying •High amino •↑ secretion of acid pancreatic enzymes concentration and HCO3•High fatty acid •Stimulates gall concentration bladder contractions •Low pH Actions Hormone secretions of the small intestine: secretin Site of secretion Stimuli for secretion Actions Duodenal mucosa •↓ HCl production in stomach •↑ pancreatic HCO3- secretion •↑ biliary HCO3secretion Chyme with a: •Low pH •High fatty acid concentration Exocrine pancreatic secretions • Liquid rich in HCO3• Pancreatic digestive enzymes • Both are secreted into duodenum Pancreatic digestive enzymes • Pancreatic proteolytic enzymes (pancreatic proteases) are secreted as proenzymes (zymogens) Activation of pancreatic proteases in small intestine • CCK stimulates duodenal mucosal cells to produce enteropeptidase Proelastase Elastase Absorption of amino acids from small intestine