The interaction of
methionine or
lysine with lead in the diet of chicks was studied. In experiment 1,
lead acetate to supply 0 or 1000 ppm lead was added to a diet that was either deficient in the total
sulfur-containing
amino acid (TSAA) content (62% of the requirement) or supplemented with DL-
methionine to provide 100% of the requirement (NRC, 1977). Supplementing the 0 ppm lead diet with
methionine improved
body weight gain. Dietary addition of 1000 ppm lead significantly decreased
body weight gain; however, supplemental
methionine partially alleviated the lead-induced growth depression (
methionine X lead interaction was significant). Liver
glutathione levels were markedly increased by supplemental
methionine and also by lead but no
methionine X lead interaction was detected. In experiment 2, the interaction between an essential non-
sulfur-containing
amino acid,
lysine, and dietary lead was investigated. Two levels of lead, 0 or 1000 ppm, were fed in diets either deficient or adequate in
lysine (85 or 100% of the requirement, respectively). Addition of
lysine to the
lysine-deficient basal diet increased growth. The magnitude of the lead-induced growth depression was not affected by dietary
lysine content. The
lysine level of the diet did not influence the liver
glutathione concentration.(ABSTRACT TRUNCATED AT 250 WORDS)