Protein Flashcards
What are amino acids?
Organic Acids, composed of CHONS
How many AA are found in proteins?
21, all essential for protein synthesis
What are the four classifications of amino acids?
Neutral, Acidic, Basic, Imino
What are the three types of neutral amino acids?
Aliphatic, Aromatic, Sulfur-containing
What is denaturation and how is it caused?
Loss of structure
Caused by heat, UV light or chemical damage
Could help digestion
What is the Maillard reaction (browning)?
When protein and carbs form a complex Caused by excess heat Analyzed as ADIN On toast or crust of bread Indigestible`
What are the three tissues that protein is a part of?
Collagen- connective
Elastin- tendons and arteries
Keratin- hair, horns, hooves, wool, feathers, and nails
What are 5 types of nonstructural proteins?
Enzymes Hormones Antibodies Transport proteins Carbon skeleton used for energy
What is true protein?
protein composed of only AA
What is nonprotein nitrogen?
compounds not true protein in nature but contains nitrogen that can be converted to aA by microbes
What is Crude Protein?
protein composed of true protein and NPN
How do you analyze protein?
Kjeldahl Method
Analyzed for N, protein is approximately 16% nitrogen
(N x 6.25= CP)
What is apparent digestible protein?
portion of dietary protein that animal apparently digested and absorbed
kg protein intake- kg protein feces
assumes all protein in feces is indigestible
True Digestible Protein
portion of dietary protein actually digested and absorbed
kg intake- (kg protein in feces- kg metabolic fecal protein)
Protein Quality
refers to the amount and ratio of essential AA present in a dietary protein relative to animals requirements
Low Quality: deficient in one or more amino acids
Biological Value
Relationship of protein retained to protein absorbed (n)
Bio Value Equation
BV= Nret = Ni-(Fn +Un) x100
Nabs Ni-Fn
Protein Efficiency Ratio
comparison of protein sources using feeding trial to determine gain per unit of protein consumed
PER Equation
PER= BW gain
Protein Consumed
Dietary Essential Amino Acids
required in the diet b/c the animal doesn’t synthesize sufficient quantities to meet its requirements
Nonessential amino acids
not required b/c animal can synthesize but still needed in protein synthesis
What are all the dietary essential amino acids (private tim hall)
PHE- Phenylalanine VAL- Valine TRP- Tryptophan THR- Threonine ISO- Isoleucine MET- Methionine HIS- HIstidine ARG- Arginine LEU- Leucine LYS- Lysine
What is the limiting EAA?
The EAA present in the least amount relative to the animal’s requirement.
Species specific
Not necessarily the one in the least quantity
Usually lysine
How do you find the percentage that an amino acid in a food meets the animals requirement?
Supply/ Required
Soybean Meal % CP
51-55% CP
What is wrong with uncooked raw soybean meal?
Contains trypsin inhibitor that interferes with digestion
Need to heat to denature inhibitor before feeding
Which EAA is soybean meal high in?
LYS- Lysine
Cottonseed meal %CP
40-54%
What are two downsides to feeding cottonseed meal?
low in lysine
contains gossypol witch monogastrics can’t break down
Linseed (flax) meal %CP
38% CP
What two amino acids are present in low quantities in linseed meal?
Lysine and tryptophan
What is the max inclusion rate for animal products?
5-10% for nonruminants only
What EAA’s are animal-based products high and low in?
High in lysine
Deficient in SAA and TRP
Fish meal %CP
68-77% CP
What type of diets are fish meal included in?
Mainly in non ruminant diets (very costly)
Max inclusion rate is <5% due to high Ca an to avoid fishy taste
What is the biological value of fishmeal?
excellent protein quality
high in B-complex vitamins
Meat meal CP%
54%
What are the downsides to feeding meat meal alone?
lower protein quality than fish meal
Deficient in tryptophan
Meat and bone meal CP%
54%
What minerals are meat and bone meal high in?
Higher in Ca and P than just meat meal
Tankage CP%
64%
What is tankage made up of?
Mostly connective tissue
What occurs when there is a protein deficiency?
decrease in feed intake abdominal ascites decrease disease resistance decrease productive functions eventual death
What happens with a protein toxicity?
Decrease in feed intake dull, coarse hair coat decrease productuve functions increase blood, tissue ammonia Eventual death
What are the 4 steps of protein digestion in monogastrics?
true protein > chemical and auto enzymatic digestion > amino acids > absorption
What digestive steps happen in the stomach?
Pepsinogen uses HCL to activate and turn into Pepsin
What digestive processes occur in the SI?
In pancreatic juice, enzymes activate:
Trypsinogen > trypsin
Chymotrisinogen > Chymotrypsin
Procarboxypeptidase > carboxypeptidase
What do the specific enzymes in pancreatic juice do to amino acids?
Hydrolyze peptide bonds between specific amino acids
Which amino acids does trypsin hydrolyze?
LYS and ARG
Which amino acids does chymotrypsin hydrolyze?
TRP, PHE and TYR
Which amino acids does carboxypeptidase hydrolyze?
Terminal free carboxyl group
What three things to proteins change into?
dipeptides, tripeptides, free amino acids
What does the small intestine contain?
dipeptidase and tripeptidase, it releases more free amino acids
How are free amino acids absorbed?
active transport (requires energy) absorption rates are different
Why do the differences in rate of absorption of amino acids affect the cells?
All amino acids must be present in the cell for protein synthesis to occur
What is the process call of absorbing full protein and when does it occur?
phagocytosis, only occurs in certain newborn mammals (1-2 days after birth)
What is whole protein absorption beneficial?
allows absorption of antibodies (immunoglobulins) from colostrum
variable transfer of antibodies in utero
What do amino acids metabolize into?
Carbon skeletons > kreb’s cycle to make ATP and CO2, NH4 is a by-product
Why don’t ruminants have a dietary need for EAA?
Their microbes can convert nonprotein nitrogen into EAA’s
What are the steps of protein digestion in a ruminant?
true protein > microbial fermentation > chemical digestion > amino acids > absorption
What are carbs converted to during the change of NH3 to microbial cells
VFA’s with CO2 and CH4 as biproducts
How much percent of protein escapes bacterial breakdown in rumen?
40%
What happens to the other 60% of protein in rumen?
Broken down to ammonia and then turned into fermentable energy for the bacteria which then gets digested as a protein source
Urea, what is it and who should you feed it to?
Only feed to ruminants 42-45% Nitrogen Balance for S and P Change over gradually so microbes have time to adjust Need to thoroughly mix to avoid toxicity
What proportion should urea be fed?
not more than 1/3 of N in diet
not more than 1% of a concentrate diet
What is taurine and who needs it?
Cats need it!
Sulfur amino acid
Abundant in fish, birds and small rodents
What function does taurine have?
Aids in vision and cardiac function
What is deoxyribonucleic acid?
DNA
genetic information in all cells
template for RNA in process called transcription
What is messenger ribonucleic acid?
mRNA
contains information from DNA
template to synthesize protein in process called translation
