Protein Flashcards
what is the role of protein?
major component of body tissue; synthesizes tissue, hormones, enzymes, antibodies; chains of amino acids
what are the top 3 most limited amino acids in horses?
lysine, methionine, and threonine
how to remember the essential amino acids?
PVT TIM HALL
what does liebig’s law of minimum state?
growth is dictated by the scarcest resource
protein digestion begins where with what helping?
stomach with HCl and pepsinogen
after protein digestion in the stomach, where does it go next?
small intestine with peptidases and pancreatic zymogens (trypsinogen, chymotrypsinogen, and procarboxypeptidase)
explain how pepsinogen and HCl work together in the stomach for protein digestion?
pepsinogen +HCl –> pepsin
how does trypsinogen do its thing?
trypsinogen + enterokinase –> trypsin
trypsinogen + chymotrypsinogen + procarboxypeptidase does what?
interacts with trypsin to make trypsin chymotrypsin carboxypeptidase
what are common trypsin inhibitors?
plants, organs, fluids (soybeans, peas, beans, and wheat) in the pancreas and colostrum
why does the pancreas need trypsin inhibitors?
to avoid eating itself
why does colostrum need trypsin inhibitors
without it immunoglobulins (proteins) are broken down but they are needed for immunity in babies to not die
what activates trypsin inhibitors?
heat
what percent whole tract apparent N digestion?
11-30%
of the 11-30% N digestion how much occurs prececally?
30-60% mainly in the SI
enterocyte in protein absorption is ___% what and ___% what?
60% dipeptides (must be broken down before absorption) and 40% free AA which can be absorbed into the bloodstream
what are two other forms of protein that can be supplemented for absorption?
crystalline protein (made by bacteria) and NPN (non-protein nitrogen)
protein and NPN n the hindgut go through what?
bacterial fermentation (NPN prececally digested)
T/F; ammonia N is readily absorbed in the hindgut?
true
is NPN beneficial
no; harmful in extreme causes in horses.
what is the fate of protein?
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)
protein turnover occurs for what reasons?
degradation and synthesis; old and wornout tissues are rebuilt
explain horses and how protein quality effects them?
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.
what is a great source of AA for horses? why?
soybean; meets almost all AA requirements.
increased DM/CP intake = what?
increased CP digestibility
what forage species are high in protein?
alfalfa, legumes
what grains are high in protein?
corn, sorghum, oats
how does where protein is digested affect the bioavaliability?
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
protein requirements in horses?
depend on sex, genetic makeup, age, lactation, gestation, etc.
protein deficiency can cause
decreased growth, weight loss, fetal loss, decreased milk production, muscle loss, reduced feed intake, poor hair growth, reduced hoof growth
excess protein can cause?
fat deposition, N expelled as urea, potential for increased Ca/P loss bc it’s bound and excreted in urine
