18/04/2023 Dr. Nelson Duchi D., PhD.

FISOLOGÍA DE LA DIGESTION EN MAMÍFEROS

Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

Basic Functional Anatomy of the Digestive System

– Monogastrics –

18/04/2023 Dr. Nelson Duchi D., PhD.

Digestive Tract - Pig

Esophagus

Stomach

Liver Pancreas

Duodenum

Small intestine (jejunum, ileum)

Cecum

Colon

Rectum

18/04/2023 Dr. Nelson Duchi D., PhD.

Organs of the Digestive System– Monogastrics –

Mouth►Mechanical breakdown of foodstuffs by chewing (reduces

particle size, increases surface area for action of enzymes).

►Saliva added as a lubricant and, in some species, contains amylase to begin starch digestion.

Esophagus►Tube connecting the mouth to the

stomach.

18/04/2023 Dr. Nelson Duchi D., PhD.

Organs of the Digestive System– Monogastrics –

Stomach►Enzymatic digestion of proteins begins.

►Foodstuffs reduced to liquid form.

Liver►Center of metabolic activity in the body.

►Major role in digestive process is to provide bile salts to small intestine (needed for digestion and absorption of fats).

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

Organs of the Digestive System– Monogastrics –

Pancreas►Provides a potent mixture of digestive enzymes to the

small intestine to help in digestion of fats, carbohydrates, and proteins.

Small Intestine►3 sections – duodenum, jejunum, ileum

►Site of final stages of chemical enzymatic digestion.

►Where almost all nutrients are absorbed.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

Organs of the Digestive System– Monogastrics –

Large Intestine►3 sections – cecum, colon, rectum

►Site of water absorption from G.I. tract.

►Bacterial fermentation occurs (production and absorption of volatile fatty acids).Somewhat limited in monogastrics

►Feces formed.

18/04/2023 Dr. Nelson Duchi D., PhD.

Digestive Process - MonogastricsProteins Fats Starch

MOUTH

STOMACH

SMALL INTESTINE

Peptides

proteases

Amino acids

peptidases

Fatty acids

bile salts lipases

Maltose

amylase

Glucose

amylase maltase

= main site of absorption

18/04/2023 Dr. Nelson Duchi D., PhD.

Digestive Tract - Poultry

Esophagus

Crop

Proventriculus

Gizzard Liver

Gall bladder

Cecum

Cloaca

Large intestine

Small intestine (jejunum, ileum)

Pancreas

Duodenum

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

Organs of the Digestive System– Monogastrics –

Specialized Organs in Poultry Beak

►No lips, no teeth, and no chewing.

Crop►Out-pocketing of the esophagus that provides storage for

consumed food.

►Foodstuffs moistened and softened (little if any digestion).

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

Organs of the Digestive System– Monogastrics –

Specialized Organs in Poultry (continued)

Proventriculus►Glandular stomach where the first significant

amount of digestive juices are added. Gizzard

►A muscular organ used to grind and break up food.

►May contain grit (small stones) eaten by animal.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

18/04/2023 Dr. Nelson Duchi D., PhD.

Organs of the Digestive System– Monogastrics –

Specialized Organs in Poultry (continued) Cloaca

►Common chamber into which the digestive, urinary, and reproductive tracts open.

When fecal material is excreted, the cloaca folds back at the vent allowing the rectal opening of the large intestine to push out, closing the reproductive tract opening.

18/04/2023 Dr. Nelson Duchi D., PhD.

Specialized Poultry Organs

Proventriculus

GizzardCrop

Cloaca

18/04/2023 Dr. Nelson Duchi D., PhD.

Basic Functional Anatomy of the Digestive System

– Hind Gut Fermentors –

18/04/2023 Dr. Nelson Duchi D., PhD.

Digestive Tract - Horse

Esophagus

Stomach

Duodenum

Small intestineCecum

Large colon

Small colon

Rectum

18/04/2023 Dr. Nelson Duchi D., PhD.

Organs of the Digestive System– Hind Gut Fermentors –

Mouth, esophagus, stomach, liver, pancreas, gall bladder, and small intestine have similar functions as compared to monogastrics.

Large Intestine►Major difference between monogastrics and hind gut

fermentors is the large intestine

►Large intestine is exceptionally large and complex compared to monogastrics and ruminants.

18/04/2023 Dr. Nelson Duchi D., PhD.

Organs of the Digestive System– Hind Gut Fermentors –

The large intestine of hind gut fermentors is analogous to the rumen in ruminants.►Large, anaerobic fermentation vat.

►Microbes digest structural carbohydrates (cellulose, hemicellulose) and soluble carbohydrates that escape digestion in small intestine to VFA’s.VFA’s absorbed from large intestine and utilized by the animal.

►Microbial protein produced in large intestine is wasted (only very limited absorption from large intestine).

18/04/2023 Dr. Nelson Duchi D., PhD.

Digestive Process – Hind Gut FermentorsProteins Fats Starch

MOUTH

STOMACH

SMALL INTESTINE

LARGE INTESTINE

Peptides

proteases

Amino acids

peptidases

Fatty acids

bile salts lipases

Maltose

amylase

Glucose

amylase maltase

Cellulose Hemicellulose

VFA’s

= microbial action = main site of absorption

VFA’s