Final Exam GI Physiology: Ruminant Digestion Flashcards Preview

RUSVM Physiology II > Final Exam GI Physiology: Ruminant Digestion > Flashcards

Flashcards in Final Exam GI Physiology: Ruminant Digestion Deck (56)
Loading flashcards...
1

What is the principal distinguishing characteristic of ruminant digestion?

Fermentation of ingesta by microbes in the ruminoreticulum

2

What is fermentation?

The anaerobic oxidation of substrate followed by reduction of an organic molecule

3

Lactate formed from pyruvate is an example of what?

Fermentation

4

Methane formed from CO2 is an example of what?

Fermentation

5

Fermentation of amino acids yields what products?

Sulfates and Nitrates

6

What products are produced when sulfates and nitrates are reduced?

H2S
NH3
NH4+

7

In regards to fermentation of carbohydrates, put the following in order from which ferments fastest to which ferments slowest:
Simple sugars
Starches
Cellulose

Simple sugars RAPID
Starches MODERATE
Cellulose SLOW

8

What are the products of fermentation of simple sugars, starches, and cellulose (carbohydrates)?

CO2
CH4
Lactic Acid
VFAs
Acetic Acid
Proprionic Acid
Butyric Acid

9

T or F: Microbes can perform oxidation in the absence of oxygen.

TRUE

10

What enzyme is utilized by microbes in the rumen to oxidize pyruvate to acetyl CoA?

Pyruvate-ferrodoxin oxidoreductase

11

What enzyme in the rumen acts on the acetyl CoA produced?

Phosphotransacetylase

Adds Pi to Acetyl CoA --> Acetyl-Pi and Coenzyme A

12

What enzyme in the rumen is used by microbes along with ADP to act on Acetyl-Pi produced earlier?

Acetate kinase

Acetyl-Pi + ADP ---acetate kinase---> acetic acid + ATP

13

What are the waste products of carbohydrate fermentation?

Volatile Fatty Acids!

14

How do anaerobic microbes generate ATP?

By glycolysis and microbe-enzyme reactions in the rumen

15

In the rumen/reticulum, what are O2 and CO2 ultimately reduced into?

H2O and CH4

16

The ratio of VFA : Lactic acid is a function of ______ .

Diet

17

A low VFA : Lactic Acid (and therefore low rumen pH) ratio is indicative of what kind of diet?

High % of easily digestible carbs

18

What ruminal pH is considered normal?

pH of 6

19

What is a dietary cause of Ruminal Lactic Acidosis?

A low VFA : Lactic Acid ratio (caused by too much easily digestible carbs in diet)

20

What conditions can Ruminal Lactic Acidosis lead to?

Ulceration, pain, going off feed, systemic ketoacidosis

21

How is protein digested in the rumen?

Through microbial digestion and hydrolysis via pancreatic and brush border enzymes

22

What do microbes do to proteins in the rumen?

Hydrolysis of protein --> amino acids
Hydrolysis of amino acids ---deamination---> VFA

23

What is generated as a result of amino acid deamination to VFA?

AMMONIA (NH3)

24

What is produced Ammonia utilized for?

To make microbial protein

To be converted into urea by the liver

25

What % of protein escapes microbial digestion?

50%

26

The 50% of protein that escapes microbial digestion is hydrolyzed in the _______ and _________ via pancreatic and brush border enzymes.

Abomasum and Small Intestine

27

Protein hydrolyzed by pancreatic and brush border enzymes yield what products?

Small peptides and amino acids

28

Where are dead microbes digested?

Abomasum and small intestine

29

Where can urea be found after it is produced by the liver?

Urea can diffuse into GI tract lumen
Urea can be secreted by salivary glands

30

What enzyme converts urea into NH3 (ammonia) and CO2?

Microbial urease