The clinical biochemistry of chicks with aflatoxicosis : some effects of supplementary choline, folate, threonine, lysine and lysine plus arginine

Abstract

Aflatoxin (2.5ug/g diet) was fed to broiler chicks for 24-26 days in five separate feeding trials in which the effects of supplementary choline, folate, threonine, lysine, and lysine plus arginine were examined. Weight gain, feed intake, feed conversion, and hepatic lipid responded in a manner typical for aflatoxicosis. Plasma concentrations of LDH, taurine, tyrosine, phenylalanine, arginine, ornithine, citrulline, glutamine, ammonia and perhaps BUN were increased in response to aflatoxin, while plasma levels of threonine, lysine, total protein, albumin/globulin (A/G) ratio, uric acid, cholesterol, calcium, inorganic phosphate, total iron, total iron binding capacity, and percent saturated transferrin, decreased. -- Intraperitoneal (IP) administration of choline, but not dietary choline, moderated the influence of aflatoxin on the majority of the biochemical parameters. -- Lysine supplementation improved the performance of chicks with aflatoxicosis, while threonine had a negative effect. This may be related to ornithine detoxification of aflatoxin through the opposing effects of these two amino acids on the activity of the enzyme arginase, which catalyzes the conversion of arginine to ornithine and urea. -- Plasma lysine concentration varies considerably as a result of genetic differences in lysine metabolism. Data indicates that chicks with high plasma lysine concentration are more resistant to aflatoxicosis than chicks with low plasma concentrations of lysine.