Ruminant protein, CHO, and fat digestion Flashcards
What type of bacteria are there in the rumen?
amylolytic, cellulolytic, and lactate utilizing
What do amylolytic bacteria do?
produce amylase and turn starch into glucose
What are the major end products that amylolytic bacteria make?
lactic acid and propionate
What pH do amylolytic bacteria tolerate?
5-5.7
What do cellulolytic bacteria do?
break beta linkages in cellulose and hemicellulose to create clucose and xyloses
What is the major end product that cellulolytic bacteria make?
acetate, propionate and butyrate
What pH do cellulolytic bacteria prefer?
pH above 6
What do lactate utilizing bacteria do?
use lactic acid as a main energy source and protect the rumen from the lactate made by amylolytic bacteria
How many kcals do cows get from alpha-linked starch and sugar?
2.2-2.4 kcal/g of sugar because their bacteria take some of the energy
How many kcals do horses get from starch and sugars?
4 kcal/g
How many kcals do cows get from cellulose and hemicellulose?
2.8-3
How many kcals do horse get from cellulose/hemicellulose?
2.5-2.7
What layers are between the unstirred water layer in the rumen and the lamina propria?
S. corneum, S. granulosum, S. spinosum, S. basale
What is the rumen fluid pH?
6.5
What is the unstirred water layer pH?
5.8
Why is the pH of the unstirred water layer lower than the pH of the rumen fluid?
because the epithelial cells absorb Na from the fluid making the pH lower
What type of epithelium is in the rumen?
stratified squamous epithelium
How do things cross the apical membrane of the stratum granulosum?
non-ionic diffusion
How do things get from layer to layer to reach the stratum basale cells?
they use gap junctions
How do things cross the basolateral membrane of the stratum basale cells to enter the blood vessels in the lamina propria?
they use non-ionic diffusion
What is pKa?
the pH at which 50% of a weak acid will be in the dissociated form and 50% will be in the undissociated form
At pH 4.76 what will acetic acid exist as?
50% acetate and 50% Hacetate
At pH 5.76 what will acetic acid exist as?
90% acetate and 10% Hacetate
At pH 6.76 what will acetic acid exist as?
99% acetate and 1% Hacetate
What is the rumen pH normally?
6-6.5
What form will volatile fatty acids be in the rumen?
dissociated form
What does the lower pH of the unstirred water layer promote?
more VFA absorption
What happens to proteins in the rumen?
they will most likely be degradedto ammonia and carbon skeltons by the rumen bacteria or the bacteria may use the AA for their own benefit
What happens to the proteins in bacteria when they die?
the ruminant utilizes it when it reaches the small intestine - microbial protein
What is rumen undegradable protein?
protein fed to ruminant that will escape microbial destruction
__________ + ___________ = Metabolizable protein for ruminant
microbial protein, rumen undegradable protein
What does rumen undegradable protein do?
delivers amino acids to the small intestine
What influences the degradability of diet protein?
the amino acid content (S-S bonds and folding) and amount of heating (the more heating the more undegradable)
What percentage of microbial protein do bacteria contribute?
85-90%
What percentage of microbial protein do protozoa contribute?
10-15%
What are the sources of nitrogen for rumen microbes?
NPN from feeds, de-aminatino of rumen degradable protein, urea recycling through rumen wall and salivary secretions
What does microbial protein depend on?
amount of organic matter actually fermented, availibility of N at tume that organic matter is fermented
Why feed fat to ruminants?
lipids efficiently form adipose and milk fat and can be utilized by muscle as energy source for long term exercise
What is another reason to feed fat that is not applicable to ruminants?
it is to increase palatability
Why can fats be bad for ruminants?
they can be toxic to bacteria that degrade structural CHO
What can bacteria do to unsaturated fats?
bio-hydrogenate them to make them less toxic but also create compounds that depress milk fat and has other health implications
Why would you want to feed fully saturated fats or fatty acids?
the problem with biohydrogenation is circumvented and they can improve energy balance to the cow
What can be fed to a ruminant to get fatty acids through the rumen?
Calcium salts
