Animal Nutrition- Protein

Why are some amino acids essential?

The body cannot synthesize enough of the AA to meet their requirements

Non essential= the body tissues can synthesize enough

What are the 10 essential amino acids?

PVT TIM HALL

Phe, Val, trp, thre, Ile, met, his, arg, Lys, leu

For all animals, are only 10 AA essential?

No, it depends on the species and physiological state if they are growing or lactating

What should the amount of AA be relative to?

It should be relative to its energy requirement in ME

If it is lower than that it can be limiting

What is the limiting AA?

The AA that is lowest relative to its energy requirements and this makes the protein supply inadequate

Protein synthesis will decrease, less of other AA will be incorporated, young animals grow slower, lactating animals produce less milk, adults may lose muscle mass

Cannot just feed more of an AA to make up for the limiting AA

AA functions

They make proteins but also they affect metabolism in other ways

What if absorbed AA is not used for proteins?

They will be catabolized/ broke down and the carbon skeleton is used to make ATP, glucose, or fatty acids

When is the amount of protein of calories greatest?

In younger animals, lactating animals, and fed for weight reduction

Are some AAs recaptured better than others?

Yes, proteins are constantly being turned over too

Protein in rumens overview

More than half of protein ruminants eat is usually degraded in rumen and used by microbes to make cellular proteins

Ruminants derive half to nearly all of their AA needs from these rumen microbes when they pass down into eh small intestine and then are digested