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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.
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.
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.
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.
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.
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.
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