Pigs are non-ruminants

• Single stomach• Eat feed low in fiber• Humans are also

non-ruminants

• 1. Mouth• 2. Esophagus• 3. Stomach• 4. Small Intestine• 5. 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

Glandular regions of

simple stomach

Cardiac

FundicPyloric

Glandular regions of equine, porcine and ruminant stomachs

• Cardiac, fundic and pyloric gland regions are glandular

• Esophageal regions (“E”) are non-glandular epithelium

Cardiac gland region

(cardiac mucosa)

Cardiac

FundicPyloric

Fundic gland

region

• Mucous neck cells

• Parietal cells• Chief cells

Cardiac

FundicPyloric

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)

Pyloric gland

region

• Mucous secreting cells

• G cells

Cardiac

FundicPyloric

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

Substances that stimulate HCl secretion by parietal cell

• Gastrin• Acetylcholine• Histamine

– Histamine secreted by ECL cells in gastric mucosa

Gastrin may interact with either receptor

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 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

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

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