Animal digestion

Benefits of microbial Fermentation

• Volatile Fatty acids: Energy source

• Microbial Fermentation: Essential amino Acids

• Vitamins B & K

• Gases: CO2, CH4, H2S

• Heat

Final Products of Digestion

• Maltose → Glucose + glucose

• Sucrose → Glucose + Fructose

• Lactose → Glucose + Galactose

• Proteins → Amino acids

• Fats → fatty acids + glycerol

Digestive enzymes in stomach and small intestine

stomach:

• Pepsin → protein breakdown

• Renin → Milk digestion in small animals

• Gastric lipase → fats

Small intestine:

• Intestinal Peptides

• Intestinal Maltase

• Lactase

• Sucrase

Ideal Rummen Conditions

• Ph~ 6-7

• Constant food supply

• Anaerobic environment

Avian vs Swine

Avian has:

• Crop → food storage

• Gizzard → mechanical breakdown

• Ceca → Fermentation

Accessory organs and their functions

• Salivary glands → lubrication and secretion of saliva

• Pancreas → Secretes Pancreatic juice, buffer and enzymes (e,g, Lipase, amylase, protease)

• Liver → Produces bile

• Gallbladder → Stores bile

Organs and their roles in the GIT

• Stomach → Protein digestion, acid digestion (HCl, pepsin)

• Small intestine → Nutrient absorption

• Large Intestine → Water absorption and microbial fermentation

Which body functions does NE for maintenance support?

• Muscular work

• Metabolism

• Body tissue

• Stable body temperature

• Organ function

• Immune system

Net Energy usage animals

• Maintenance

• Growth

• Lactation/egg production

• Reproduction

• Work

3 major animal trials to measure Feed Utilization

• Feeding trial → Give animals food, collect their poop, and check what nutrients they didn’t absorb.

• Digestion trial → Measure how much of the food is actually digested and used by the animal.

• Metabolism trial → more detailed test that also checks urine and hair loss to see how much the body retains. A balance trial compares intake vs. excretion to find net retention.

Formula for energy

• GE - Fecal Energy = DE

• DE - Urine/gasses = ME

• ME - Heat Increment = NE

• NEp= NE- NEm

Dogs formula:

• ME = 130 kcal x BW^0.75

• BWkg= (BW/2.2)

• Food amount= (ME / ME in food)