Response of Broiler Chicks to a Single Dose of Aflatoxin

Abstract 270, day-old broiler chicks (Peterson×Peterson) were divided into 5 groups of 54 birds. Each group was composed of 27 males and 27 females. The five groups of birds received crude aflatoxin administered directly into the gizzard, in doses of 0.0, 0.4, 0.8, 1.6, and 3.2 mg./kg. body weight, respectively of aflatoxin B1 equivalents. The experiment lasted for 46 days, and the parameters tested were mean body weight gain, mean body weight/liver weight ratio and hepatic microscopic changes. Transitory growth suppression was observed in male chicks receiving 3.2 mg./kg. of the toxin on day 4 and 11, but this was overcome by day 32. The ratio of liver weight to body weight was decreased in birds receiving lower doses of toxin but increased, apparently as a result of congestion and hyperplasia, in birds receiving higher doses of aflatoxin. Two male chicks which received 3.2 mg./kg. of toxin died of icterus and massive necrosis of the liver. The chief microscopic changes observed in the livers of chicks given toxin were hepatic cell degeneration, bile-duct hyperplasia and focal lymphoid nodules. By day 46, chicks in the 3.2 mg./kg. group had no detectable lesions, but livers in the 1.6 and 0.8 mg./kg. groups showed mild residual bile-duct hyperplasia.