Leucine imbalance in corn-soybean meal diets for laying hens

Three experiments were conducted to study leucine X isoleucine X valine interactions in hens fed low-protein, corn-soybean meal diets. Addition of 0.75% L-leucine to diets containing 10 to 12% protein resulted in less feed intake and lowered production that could be overcome only by the addition of both 0.175% L-isoleucine and 0.35% DL-valine. Hens fed diets containing 16% and 19% protein were unaffected by the addition of as much as 2.25% L-leucine. Reduction of protein by dextrose dilution of high-protein diets resulted in improved performance when compared with regular low-protein diets because of the better amino acid balance in the diluted diets. This response was not correlated with the leucine content of the low-protein diets. It was concluded that the possibility of a leucine X isoleucine X valine interaction impairing the performance of hens fed low-protein corn-soymeal diets is very remote.