Effect of excess protein in feeds

bonderic · 發(fā)表于 2008-2-27 08:55:07

Excess protein in pig diets can be both risky to the pig health and performance and a waste of money, reminds Brendan Lynch and Karen O’Connell of the pig development unit for Teagasc Moorepark, Fermoy, Cork, Ireland.

Release Date: 2008年2月26日

Excess protein in pig diets can be both risky to the pig health and performance and a waste of money, reminds Brendan Lynch and Karen O’Connell of the pig development unit for Teagasc Moorepark, Fermoy, Cork, Ireland.
They say there are three primary reasons why feed formulators might limit the crude protein (CP) level in pig feeds:
1.  Price.  Protein feeds usually cost more per tonne than cereals.
2.  Pig performance. Feed conversion efficiency (FCE) will be better on low protein diets provided amino acid requirements are met
3.  Organic nitrogen excretion.  Because it is determined by CP in the diet, excess protein means more organic nitrogen excreted and possibly the need for more land to utilize this nitrogen.
While the pig needs the 10 essential amino acids in the diet, and in the correct proportions, diet formulators normally concern ourselves with five amino acids which are in relatively short supply in the common feed ingredients, they point out. The five are lysine, methionine, methionine plus cystine, threonine and tryptophan.  If the levels of all five in the diet are adequate and the total amount of digestible protein is adequate, then the levels of other essential amino acids will usually be sufficient, they explain.
The researchers say that protein that contains the perfect balance of the individual essential amino acids combined with adequate amounts of non-essential amino acids is referred to as “ideal protein.” The ideal blend is expressed relative to the lysine requirement.
The protein feeds most useful in pig feeds are those high in lysine, methionine and threonine.  Ingredients vary widely in the amount of proteins they contain that are most valuable in pig diets, caution the researchers.  For example, lysine varies from about 8 percent of the protein in whey to 2.2 percent of the protein in sorghum. They recommend that pig feeds have about 6 to 7 percent lysine in the protein. Methionine content of fish meals can be about 3 percent of the protein, while peas, beans and lupins are under 1 percent.  Whey protein is high in threonine (6 to 7 percent of protein) while wheat is low (about 2.75 percent of the protein).  This means that as we include “non-traditional” ingredients in pig feeds, we must do so with care and consider the content of several amino acids, they sum up.

[ 本帖最后由 bonderic 于 2008-2-27 09:12 編輯 ]