Lysine-chloride interactions in the growing chick.

Nutritional interactions between dietary chloride and lysine in the young chick were investigated. Chloride, varying over four levels from .44 to 1.84% of the diet, was included in diets containing limiting (.7%) or adequate (1.1%) levels of lysine. Increasing chloride in diets containing either level of lysine resulted in a depression of growth rate and feed consumption (P less than .01). The efficiency of feed utilization for growth was significantly lowered only when chicks were fed diets containing the highest level of chloride (P less than .05). Plasma lysine concentrations were greater in chicks fed the lysine adequate diet; plasma arginine was unchanged. Plasma lysine and arginine concentrations were unaffected by chloride. In a second experiment chicks were fed a lysine deficient (.7%), lysine adequate (1.2%), high lysine (2.5%), or high lysine (2.5%) high arginine (2.3%) diet with varying levels of chloride. Increasing dietary chloride depressed weight gains. This effect was most dramatic in those chicks fed the high lysine diet. Increasing dietary arginine alleviated the effect of chloride in the high lysine diet. Plasma sodium and potassium were unaffected by dietary lysine and chloride levels. Plasma chloride tended to be greater in chicks receiving high chloride diets and were highest in chicks fed the high lysine diet. We conclude that dietary chloride does not influence the lysine requirement of chicks but exacerbates the lysine-arginine antagonism.