Metabolic effects of low aflatoxin B1 levels on broiler chicks.

The effects of daily ingestion of aflatoxin B1 (AFB1) on growth, feed intake, plasma glucose, plasma cholesterol, plasma amino acids, plasma albumin, plasma ceruloplasmin, muscle amino acids, liver lipid, and bone strength were studied. For 3 weeks, beginning at an age of 2 days, broiler chicks were dosed daily per os with 50 or 100 micrograms of AFB1 per kg of body weight. Body weight and feed consumption were recorded daily, and metabolic responses were determined at 3 weeks. Treatment with AFB1 did not significantly alter body weight or feed intake. Relative liver weight showed a significant increase at the highest dose, with a significant concomitant increase in liver lipid and decrease in hepatic zinc. Relative spleen and heart weights were not affected by the toxin. Plasma glucose and cholesterol were significantly elevated at the highest dose. AFB1 significantly decreased plasma lysine and histidine and significantly increased muscle histidine, arginine, and valine. AFB1 decreased plasma albumin and markedly increased plasma ceruloplasmin. Dimensions of the long bones (femur and tibiotarsus) were not altered by the toxin. However, AFB1 caused a significant linear decline in the resistance of bone to breakage ("bone breaking strength"). The results indicate that low levels of AFB1 reduced bone strength in broiler chicks. The alterations in blood parameters indicated that AFB1 can disrupt metabolism even at low levels.