8 – Amino Acid Intro Flashcards
Crude protein
- Measured using to Kjeldahl reaction=nitrogen measurement
o Assume all proteins are 16% (nitrogen x 6.25=protein)
o *not true all the time
o Says NOTHING about AA content of diet
o Directly measuring=expensive
o NOT all nitrogen is from AA-protein - *not totally useless to be used as an industry standard
What does just measuring nitrogen allow for? (NOT GOOD)
- Intentional or unintentional contamination of feeds
- Ex. melamine
What happens with the minimum protein required as pigs get older?
- Decreases
- *largest when younger and growing the fastest
o Need more calories per weight of feed - *lactating or pregnant animal=also higher
Essential AA
- AA that can’t be synthesized OR cannot be synthesized in sufficient amounts to maximize production
- Ex. mnemonic: PVT TIM HALL
Non-essential AA
- AA can be synthesized in amounts that meet their requirements to maximize production
Conditionally essential AA
- Essential in SOME species but not all
- Essential in SOME life stages
- *can partially replace the requirement for an essential AA
What essential AA do humans NOT require?
- Histidine
What conditionally essential AA do cats require?
- Glutamine
- Taurine
- *high levels of methionine, arginine and leucine
What conditionally essential AA does trout/salmon require?
- Taurine
Taurine
- *only found in animal products
- Synthesized directly from Cysteine and indirectly Methionine (sulfur in R groups)
o Low in grain-free diets (so dogs may actually need more taurine, and predisposed to DCM) - Beta-sulfonic AA
- often considered with the AA (even though not technically an AA)
- *essential in cats
Broiler chickens in first 2-4 weeks after they hatch: dietary requirement at certain stage of life example
- Glycine required to MAXIMIZE PRODUCTION
What is amino acid sparing? Example
- Replacing one AA with another
- Cys can replace ~50% of Met requirement
- Tyr can replace ~50% of Phe requirement
- *requirement for Met is give as Met AND Met+Cys
o Met is expensive and Cys is slightly cheaper
What are the 2 conditions to meet the requirement for Met?
- Must have at least _____Met in diet
- Must be at least _______Met+Cys in diet
What is needed to synthesize a non-essential AA? (2)
- Carbon skeleton
- Amino group
*the major source of AA groups for synthesis of non-essential AAs is OTHER non-essential AAs
What happens if you don’t have enough non-essential AA in the diet? (example with broiler diets, all meet essential AA, but have different levels of non-essential AA)
- *have a lower average daily gain
- If have more essential Aas=higher average daily gain
- *why crude protein isn’t totally useles
