Protein

Question 1

what is the role of protein?

Answer 1

major component of body tissue; synthesizes tissue, hormones, enzymes, antibodies; chains of amino acids

Question 2

what are the top 3 most limited amino acids in horses?

Answer 2

lysine, methionine, and threonine

Question 3

how to remember the essential amino acids?

Answer 3

PVT TIM HALL

Question 4

what does liebig’s law of minimum state?

Answer 4

growth is dictated by the scarcest resource

Question 5

protein digestion begins where with what helping?

Answer 5

stomach with HCl and pepsinogen

Question 6

after protein digestion in the stomach, where does it go next?

Answer 6

small intestine with peptidases and pancreatic zymogens (trypsinogen, chymotrypsinogen, and procarboxypeptidase)

Question 7

explain how pepsinogen and HCl work together in the stomach for protein digestion?

Answer 7

pepsinogen +HCl –> pepsin

Question 8

how does trypsinogen do its thing?

Answer 8

trypsinogen + enterokinase –> trypsin

Question 9

trypsinogen + chymotrypsinogen + procarboxypeptidase does what?

Answer 9

interacts with trypsin to make trypsin chymotrypsin carboxypeptidase

Question 10

what are common trypsin inhibitors?

Answer 10

plants, organs, fluids (soybeans, peas, beans, and wheat) in the pancreas and colostrum

Question 11

why does the pancreas need trypsin inhibitors?

Answer 11

to avoid eating itself

Question 12

why does colostrum need trypsin inhibitors

Answer 12

without it immunoglobulins (proteins) are broken down but they are needed for immunity in babies to not die

Question 13

what activates trypsin inhibitors?

Answer 13

heat

Question 14

what percent whole tract apparent N digestion?

Answer 14

11-30%

Question 15

of the 11-30% N digestion how much occurs prececally?

Answer 15

30-60% mainly in the SI

Question 16

enterocyte in protein absorption is ___% what and ___% what?

Answer 16

60% dipeptides (must be broken down before absorption) and 40% free AA which can be absorbed into the bloodstream

Question 17

what are two other forms of protein that can be supplemented for absorption?

Answer 17

crystalline protein (made by bacteria) and NPN (non-protein nitrogen)

Question 18

protein and NPN n the hindgut go through what?

Answer 18

bacterial fermentation (NPN prececally digested)

Question 19

T/F; ammonia N is readily absorbed in the hindgut?

Answer 19

true

Question 20

is NPN beneficial

Answer 20

no; harmful in extreme causes in horses.

Question 21

what is the fate of protein?

Answer 21

synthesis, energy, stored as fat, transamination (transfer of AA from one molecule to another; reversible) and deamination (removal of an amino group from an AA or other compound; not reversible)

Question 22

protein turnover occurs for what reasons?

Answer 22

degradation and synthesis; old and wornout tissues are rebuilt

Question 23

explain horses and how protein quality effects them?

Answer 23

more sensitive to quality of protein than ruminants; need less overall CP when it is higher quality. ruminants can make proteins higher quality due to being pre-gastric. can make microbial CP from low quality protein.

Question 24

what is a great source of AA for horses? why?

Answer 24

soybean; meets almost all AA requirements.

Question 25

increased DM/CP intake = what?

Answer 25

increased CP digestibility

Question 26

what forage species are high in protein?

Answer 26

alfalfa, legumes

Question 27

what grains are high in protein?

Answer 27

corn, sorghum, oats

Question 28

how does where protein is digested affect the bioavaliability?

Answer 28

foregut: amino acids are absorbed into blood/circulation for use
hindgut: little to no benefit to horses; excess just passes through and isn’t absorbed, can be used to make VFAs

Question 29

protein requirements in horses?

Answer 29

depend on sex, genetic makeup, age, lactation, gestation, etc.

Question 30

protein deficiency can cause

Answer 30

decreased growth, weight loss, fetal loss, decreased milk production, muscle loss, reduced feed intake, poor hair growth, reduced hoof growth

Question 31

excess protein can cause?

Answer 31

fat deposition, N expelled as urea, potential for increased Ca/P loss bc it’s bound and excreted in urine