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Nutrition and Digestive Physiology. Dr. Mickey A. Latour Purdue University West Lafayette, IN 47907. Livestock Feeding. How is a ration balanced?. Pearson Square. Pearson Square. Soybean Meal = 3 parts Barley = 28 parts Total Parts = 31 Soybean Meal = 3/31 or 10% Barley = 28/31 or 90%
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Nutrition and Digestive Physiology Dr. Mickey A. Latour Purdue University West Lafayette, IN 47907
Pearson Square • Soybean Meal = 3 parts • Barley = 28 parts • Total Parts = 31 • Soybean Meal = 3/31 or 10% • Barley = 28/31 or 90% • If mixing a ton (2000#) SBM = 200#, Barley = 1800#
Digestion • Overview of digestion • Overview of the enzymatic, hormone and cellular processing of nutrients • How do animals utilize the nutrients they consume and furthermore, is the process different between animals?
Digestion • There are four steps in digestion:
What is a Ruminant? • Animals with more than one stomach compartment
Why don’t cattle need as much B vitamins? • Microorganisms in the stomach of the cow make their own B vitamins
NonRuminants • Foragers: Horse, rabbit • NonForagers: pig, poultry
Digestive System • Large complex molecules broken down into simpler molecules
Digestion (Nonruminant) • Swine, Poultry, Fish and to some extent young calves and lambs are functionally nonruminants until the accessory stomach compartments develop (several months). Food---Mouth-Esophagus-Stomach--Small Intestine---Large Intestine- Rectum---Anus
Digestion • Food/Mouth: A) The food is considered a “bolus” and the act of putting food in the mouth is called “prehension”. B) Mouth is where chewing occurs to increase the surface area of food which aids in the digestion process.
Digestion • Stomach (Gastric 3 phases) A) Small amounts of pepsinogen are released and the stomach become acidified through the hormone gastrin. Three phases of Gastric secretion
The Stomach Figure 24.12b
Stomach Lining Figure 24.13c, d
Digestion • Small Intestine - Once food enters the small intestine a number of hormones are stimulated: - Hormones a. Secretin----stimulates pancreas to release enzymes b. Gastric inhibitory peptide
Small Intestine • Important digestive and absorptive functions • Secretions and buffers provided by pancreas, liver, gall bladder • Three subdivisions: • Duodenum • Jejunum • Ileum • Ileocecal sphincter • Transition between small and large intestine
Intestinal Wall Figure 24.17b, c
Intestinal Wall Figure 24.17d, e
Functions of the Large Intestine • Reabsorb water and compact material into feces
The Gallbladder • Hollow, pear-shaped organ • Stores, modifies and concentrates bile
Gallbladder Figure 24.21a, b
Digestion • Bile acids do two things: 1) Emulsify fat into small particles and targeted for absorption 2) A means for excretion of waste products (i.e., biliruben)
Digestion • Large Intestine: a) Active absorption of electrolytes and water
Horse & Rabbit • Ruminant digestive differences
Digestion in Horse and Rabbit • Not classified as a ruminant or nonruminant: • Digestion and absorption is somewhat similar to nonruminant’s • through the small intestine. • The real difference exist in the large intestine (cecum, large colon, • small colon, rectum, and anus) where they can store 35 gallons • of ingested food. This volume size coupled with time provides • an excellent site for bacterial action and the liberation of nutrients.
Digestion • Ruminant (Cattle, Sheep, Goat): Very important, since they convert grasses material into products.
Digestion • Mature ruminant has 4 functional stomach compartments: • 1) Rumen • 2) Reticulum • Rumen is the largest segment and provides a near ideal environment • for microorganisms. The organisms in turn provide the following: a) convert large amounts of starch and cellulose to volatile fatty acids b) convert both protein and nonprotein nitrogen into amino acids c) synthesize Vitamin K, and all B complexes
Digestion • Reticulum is the site of fermentation of ingested materials and • commonly referred to as the “honeycomb” where there is great • filtering of ingested materials between the rumen and omasum.
The Pancreas • Pancreatic duct penetrates duodenal wall • Endocrine functions • Insulin • Exocrine functions • Majority of pancreatic secretions
The Liver • Performs metabolic and hematological regulation and produces bile • Histological organization
Anatomy of the Liver Figure 24.19b, c
Liver lobule is the basic functional unit of the liver • Hepatocytes form irregular plates arranged in spoke-like fashion • Bile canal carry bile to bile ductules • Bile ductules lead to portal areas
Liver Histology Figure 24.20a, b