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22 Cards in this Set
- Front
- Back
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What is digestion broken down into ? |
Physical breakdown-mastication, grinding, chewing -chemical hydrolysis -acid hydrolysis -enzymatic breakdown |
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What are factors affecting digestibility? |
1.rate of passage -level of feed intake -feed frequency, particle size, feed source 2.age (teeth and enzymes) 3.disease or parasites 4.nutrient excess or deficiency |
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What happens during mechanical particle size reduction? |
most animal feed ingrediants undergo some sort of physical particle size reduction, which increases surface area and allows for greater interaction with enzymes and microbes |
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What is acid hydrolysis? |
stomach-low pH 2-3 -more importantly it provides optimal pH for enzyme activity (pepsin and trypsin) |
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What is ezymatic hydrolysis? |
based on the structure of the substrate it will be specific for one enzyme -lock and key concept |
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What happens with carbs, lipids and proteins during enzymatic hydrolysis? |
carbs- polysaccarides to monosaccarides lipids- triglycerides to fatty acids and glycerol (broken down, absorbed and metabolized) proteins-peptides to amino acids |
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What happens during carbohydrate digestion in non-ruminants? |
1. begins in mouth with salivary amylase 2. continues in small intestine with pancreatic amylase 3. finished by maltase, sucrose and lactase -break down alpha 1-4 bonds |
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What happens in carbohydrate digestion in ruminants? |
1. no salivary amylase 2. bacterial cellulase and hemicellulase break down beta 1-4 bonds between glucose molecules in cellulose and hemicellulose 3. starch is broken down in rumen as well 4. remaining starch is broken down in small intestine *rely on microbes for breakdown |
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What are the end-products of carb digestion in ruminants and non-ruminants? |
non-ruminants: glucose ruminants: VFA's -high fiber promotes acetate -high starch: proprionate |
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What happens in fat digestion in monogastrics? |
consume triglycerides-FFA glycerol/ micell-absorption into lymphatic system-chylomicrons |
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What happens during fat digestion in ruminants? |
Triglycerides-broken down by microbes in rumen-if glycerol-VFA's if FFA-deposited as saturated fatty acids *unsaturated fatty acid gets saturated by rumen microbes |
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What are growth trials? |
evaluate animal performance fed graded levels of a nutrient or ingrediant Typically evaluate: ADG, ADFI, and F/G Other Criteria: Digestibility, body composition, milk production, reproductive performance, blood metabolites |
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What is digestion? |
measure of the amount of nutrients that go in and those coming out |
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What is the digestion coefficient? |
measures the difference between what is consumed and what is secreted (Weight of feed x nutr in feed)-(weight of feces x nutr in feces) / weight of feed x nutrition in feed |
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What is total digestibility? |
difference between intake and excretion -relatively simple -fairly precise -does not take into account losses/gains from fermentation, sloughed cells, and enzymes |
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What is illeal digestibility? |
difference between intake and excretion but collected at the end of small intestine -requires a cannula inserted into wall of small intestine -more precise because it bypasses microbial fermentation in large intestine |
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What is true digestibility? |
identical to illeal digestibility but also takes into account nutrients from digestive enzymes and slough intestinal cells |
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What is absorption? |
getting nutrients across cell membranes into cells for metabolism Depends on: -size of molecule, chemical properties, site of absorption |
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What is passive transport? |
no energy required |
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What is active transport? |
energy is used. -movement of molecules up the concentration gradient Energy ATP: powers a pump that directly moves nutrients across the membrane |
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What is diffusion? |
type of passive transport -movement of molecules from a region of high concentrations to low concentrations without expenditure of energy |
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What is facilitated diffusion? |
type of passive transport -similar to diffusion but involves a specific carrier compound -no energy required |
