Ruminant protein, CHO, and fat digestion

Question 1

What type of bacteria are there in the rumen?

Answer 1

amylolytic, cellulolytic, and lactate utilizing

Question 2

What do amylolytic bacteria do?

Answer 2

produce amylase and turn starch into glucose

Question 3

What are the major end products that amylolytic bacteria make?

Answer 3

lactic acid and propionate

Question 4

What pH do amylolytic bacteria tolerate?

Answer 4

5-5.7

Question 5

What do cellulolytic bacteria do?

Answer 5

break beta linkages in cellulose and hemicellulose to create clucose and xyloses

Question 6

What is the major end product that cellulolytic bacteria make?

Answer 6

acetate, propionate and butyrate

Question 7

What pH do cellulolytic bacteria prefer?

Answer 7

pH above 6

Question 8

What do lactate utilizing bacteria do?

Answer 8

use lactic acid as a main energy source and protect the rumen from the lactate made by amylolytic bacteria

Question 9

How many kcals do cows get from alpha-linked starch and sugar?

Answer 9

2.2-2.4 kcal/g of sugar because their bacteria take some of the energy

Question 10

How many kcals do horses get from starch and sugars?

Answer 10

4 kcal/g

Question 11

How many kcals do cows get from cellulose and hemicellulose?

Answer 11

2.8-3

Question 12

How many kcals do horse get from cellulose/hemicellulose?

Answer 12

2.5-2.7

Question 13

What layers are between the unstirred water layer in the rumen and the lamina propria?

Answer 13

S. corneum, S. granulosum, S. spinosum, S. basale

Question 14

What is the rumen fluid pH?

Answer 14

6.5

Question 15

What is the unstirred water layer pH?

Answer 15

5.8

Question 16

Why is the pH of the unstirred water layer lower than the pH of the rumen fluid?

Answer 16

because the epithelial cells absorb Na from the fluid making the pH lower

Question 17

What type of epithelium is in the rumen?

Answer 17

stratified squamous epithelium

Question 18

How do things cross the apical membrane of the stratum granulosum?

Answer 18

non-ionic diffusion

Question 19

How do things get from layer to layer to reach the stratum basale cells?

Answer 19

they use gap junctions

Question 20

How do things cross the basolateral membrane of the stratum basale cells to enter the blood vessels in the lamina propria?

Answer 20

they use non-ionic diffusion

Question 21

What is pKa?

Answer 21

the pH at which 50% of a weak acid will be in the dissociated form and 50% will be in the undissociated form

Question 22

At pH 4.76 what will acetic acid exist as?

Answer 22

50% acetate and 50% Hacetate

Question 23

At pH 5.76 what will acetic acid exist as?

Answer 23

90% acetate and 10% Hacetate

Question 24

At pH 6.76 what will acetic acid exist as?

Answer 24

99% acetate and 1% Hacetate

Question 25

What is the rumen pH normally?

Answer 25

6-6.5

Question 26

What form will volatile fatty acids be in the rumen?

Answer 26

dissociated form

Question 27

What does the lower pH of the unstirred water layer promote?

Answer 27

more VFA absorption

Question 28

What happens to proteins in the rumen?

Answer 28

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

Question 29

What happens to the proteins in bacteria when they die?

Answer 29

the ruminant utilizes it when it reaches the small intestine - microbial protein

Question 30

What is rumen undegradable protein?

Answer 30

protein fed to ruminant that will escape microbial destruction

Question 31

__________ + ___________ = Metabolizable protein for ruminant

Answer 31

microbial protein, rumen undegradable protein

Question 32

What does rumen undegradable protein do?

Answer 32

delivers amino acids to the small intestine

Question 33

What influences the degradability of diet protein?

Answer 33

the amino acid content (S-S bonds and folding) and amount of heating (the more heating the more undegradable)

Question 34

What percentage of microbial protein do bacteria contribute?

Answer 34

85-90%

Question 35

What percentage of microbial protein do protozoa contribute?

Answer 35

10-15%

Question 36

What are the sources of nitrogen for rumen microbes?

Answer 36

NPN from feeds, de-aminatino of rumen degradable protein, urea recycling through rumen wall and salivary secretions

Question 37

What does microbial protein depend on?

Answer 37

amount of organic matter actually fermented, availibility of N at tume that organic matter is fermented

Question 38

Why feed fat to ruminants?

Answer 38

lipids efficiently form adipose and milk fat and can be utilized by muscle as energy source for long term exercise

Question 39

What is another reason to feed fat that is not applicable to ruminants?

Answer 39

it is to increase palatability

Question 40

Why can fats be bad for ruminants?

Answer 40

they can be toxic to bacteria that degrade structural CHO

Question 41

What can bacteria do to unsaturated fats?

Answer 41

bio-hydrogenate them to make them less toxic but also create compounds that depress milk fat and has other health implications

Question 42

Why would you want to feed fully saturated fats or fatty acids?

Answer 42

the problem with biohydrogenation is circumvented and they can improve energy balance to the cow

Question 43

What can be fed to a ruminant to get fatty acids through the rumen?

Answer 43

Calcium salts