| Abstract: | 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) |
