Tim's protein digestion

Question 1

Rumen Environment (CO2, CH4, O2, Moisture, temperature)

Answer 1

65% CO2
27% CH4
0.6% O2
85-90% RH
38-40 C

Question 2

pH control in rumen (3)

Answer 2

Saliva bicarb (but not really - thanks George)
HPO4-2
absoprtion of FA

Question 3

Rumen Phases and such (3)

Answer 3

contraction every 2-3 minutes
solid phase is today’s food (fermenting the most)
liquid is from yesterday

Question 4

Relative numbers of Bacteria/protozoa/fungi

Answer 4

^10/^6 cells/ml
fungi is ^5

protozoa and microbes have equal mass

Question 5

Epimural Bacteria

Answer 5

obligate anaerobes and ureolytic. Maintains the oxygen gradient and urea gradient

Question 6

Bacterial attachment (habitat) (4)

Answer 6

rumen epithelium
surface of protozoa
50% free in liquid
75% total attached to feed particles

Question 7

Benefits of attachment (4)

Answer 7

substrate closer to the enzyme
keeps enzymes from proteases
prolong digestion (retention)
reduces protozoa being a predator

Question 8

Ruminococcus albus digests ___,not ____

Answer 8

cellulose, not protein

Question 9

Bacteroides ruminicola digests ___, not ____

Answer 9

protein, not cellulose

Question 10

Benefits of pre-gastric fermentation

Answer 10

non-protein nitrogen

better use of fibers (break beta1,4)

Question 11

Importance of the anaerobic environment

Answer 11

the microbes take out 3-4 ATP instead of 36-38 so the energy is in the VFAs still.

Question 12

Can ruminants survive with NPN

Answer 12

Yes

Question 13

Feeding urea (9)

Answer 13

0.5-1% in diet (too much, there is not enough CHO to go with it)
not in dairy rations (becuase it is usually silage ration and not palatable)
improve feed intake
readily fermentable CHO
Feed low levels daily
Adequate supply of P and S
mix well
Can be economical

Question 14

Methods of Urea cycling (3)

Answer 14

Saliva
Simple diffusion
urea transporters

Question 15

Using NPN does what?

Answer 15

Urea —> CO2 + 2NH3 —> Bacterial growth

Question 16

Requirements for microbial growth (5)

Answer 16

ATP from CHO ferm.
N source
Micronutrients (S, P, vitamins)
Match N and ATP requirements (need to be equal)
Protozoa cannot use NH3 so they eat bacteria, AA and peptides instead

Question 17

Total CP =

Answer 17

fraction A B and C

Question 18

Protein fractions available for bacteria and they include what types of protein

Answer 18

A and some of B1, B2, B3

RDP and DIP (degradable intake protein)

Question 19

Fractions that escape rumen degradation and types

Answer 19

varying amounts of B1, B2, B3

RUP (rumen undegradable) and UIP (undegradable intake protein)

Question 20

Objective for ammonia curves (3)

Answer 20

The more CHO ferm, the more ATP for availability
We want the curves of A, B1, and B2 for protein and CHO fermentation to be aligned
Ammonia levels need to be as flat as possible to minimize wasted Ammonia

Question 21

Rumen N outputs (4)

Answer 21

microbial protein (deads)
Bypass protein
Trace amounts of sloughed off epithelial cells; enzymatic secretions (endogenous)

(microbial and bypass = metabolizable protein)

Question 22

Why is Microbial protein good? (3)

Answer 22

microbial proteins are 50-80% metabolizable (2 - 3.7 kg CP)
80% digestible protein output
has a good EAA profile

Question 23

What are the two most EAA?

Answer 23

Lysine (most) and Met

Question 24

what are good sources of EAA?

Answer 24

Bacteria and Fish meal (except FM gives fishy smell and taste)

Question 25

Factors affecting Rumen MP production (6)

Answer 25

ATP available
Ammonia levels
Synchronization of fermentation
preformed AA/peptides
other nutrients
rumen environment (for bacteria to live on)

Question 26

Major factors in Rumen Ammonia concentration (4)

Answer 26

time after feeding
frequency of feeding
protein/N source
Energy availability

Question 27

Factors affecting microbial growth

Answer 27

the more volume leaving the rumen, the more bacteria leaving as well (microbes leave with solid and fluid)
When there is a higher dilution rate, there is less maintenance energy requirements, less protozoa problems, and shorter generation time
Acidic rumen is less active

Question 28

2 types of protozoa

Answer 28

entodiniomorphs

holotrichs

Question 29

Functions of protozoa (5)

Answer 29

greater VFA production
proteolytic and can reduce microbial protein
do the slower fermentation of starch and sugars
remove O2
more CH4 production

Question 30

Effects of rumen defaunation

Answer 30

increases total protein and microbial flow to SI
improved feed efficiency - more ADG and milk yield
less cellulose digestion - higher propionic acid and less butyric and acetic acids
decreased rumen pH

Question 31

Reasons for defaunating

Answer 31

research

practical - for high concentrate diets (acidosis) and feeding Unsat Fatty acids

Question 32

Benefits of supplying bypass protein

Answer 32

Maximize bacterial protein production

for high-production ruminants that Bacterial protein is not enough (expensive)

Question 33

Factors that affect rumen degradation (3)

Answer 33

Protein structure (type)
Rumen passge rate
pH

Question 33

Factors that affect rumen degradation (3)

Answer 33

Protein structure (type)
Rumen passge rate
pH

Question 34

Protein denaturation ______ degradation

Answer 34

lowers

Question 34

Protein denaturation ______ degradation

Answer 34

lowers

Question 35

Manipulating protein degradation (3)

Answer 35

Chemical treatment (bonds form and then break after the rumen)
Put a FA polymer on it (smartamine but expensive)
Heat treatment (increases B1 and 2) 

Do not over do though because it increases Factor C

Question 35

Manipulating protein degradation (3)

Answer 35

Chemical treatment (bonds form and then break after the rumen)
Put a FA polymer on it (smartamine but expensive)
Heat treatment (increases B1 and 2) 

Do not over do though because it increases Factor C

Question 36

Importance of urea cycling

Answer 36

reduces the total protein needed in the diet (by like 10%)

The more CP in the diet, the less is recycled

Question 36

Importance of urea cycling

Answer 36

reduces the total protein needed in the diet (by like 10%)

The more CP in the diet, the less is recycled