Protein requirements for broilers....

[mike67909]

Quote:
Amino acids are the building blocks of protein. The protein is broken down in the gut and absorbed in the body for building muscle and other biological functions. A large amount of the protein isn't absorbed and is deficated out, especially when older. That is the reason why the finisher has less protein, since the chicken craps most of it out since they are not growing as fast. They need more when younger since they grow faster. Faster growth = need more protein, slower (older) = less protein. If you could feed something with less protein when older it might help your pocket book and not might not effect your chickens??

Edit: I raise freedom rangers on a unmedicated 20% feed till slaughter (25-50 at a time). Nothing like your operation.

 

[jaku]

I've wondered about this too. I've noticed absolutely no difference when I've switched protein levels (went from 20%-22%,) and I don't do enough to make a HUGE difference in cost, but just figured I was doing better by upping it to 22%. I was considering saving myself a little and taking it back down to 20%.

 

[Olive Hill]

Jeff -- have you read The Nutrient Requirements of Poultry? It'd be a great place to start to answer your own question. From there be sure to read some of the actual reports from the studies done on this, they give the amino acid requirements as a ratio to lysine whereas, if I remember correctly, the NRC gives the amino acid needs only as a percentage of the diet. Which isn't a problem, but seeing it both ways can be helpful.

I think a lot of the high protein hype these days comes, at the simplest level, from a general misunderstanding of what protein is and what it does. Protein is made up of amino acids. You can't fully separate the two. Broilers will never need a "low" protein diet, because their amino acid needs compared to those of other chickens is relatively high. (In fact, I recall reading a study somewhere where broilers fed a low CP diet with supplemental amino acids were actually quite significantly stunted, but I digress...) The amino acids needs -- and by extension protein needs -- have to support the rapid growth and development the birds are bred for. And amino acids are protein, amino acid needs are met with protein so high amino acid need leads to high (balanced) protein needs. Though that certainly doesn't mean they need as high a protein level as we're seeing some feeding these days. The problem (and money waste) comes when the amino acid profile of the protein is inappropriate and/or when people mistakenly think upping the crude protein overall can make up for a given amino acid deficiency without understanding which amino acids can be synthesized into another in the body. The chicken can't make just any amino acid into any other. And a high crude protein content doesn't guarantee a good amino acid profile -- no way, no how.

So, are you feeding too much protein? Maybe. But you might also be feeding not enough of any give amino acid. How do you know? Analyze your feed recipe.

ETA: I don't think, "in the real world", there is such a thing as a perfectly balanced amino acid profile and CP%. Most of us don't have at our disposal individual supplemental amino acids to formulate the perfect ration. Rather it's a balancing act. Knowing what amino acids certain feedstuffs are strong in providing and trying to balance that to come up with a decent ration that'll meet the birds' needs without breaking the bank.