Pathology and histopathology of gossypol toxicity in broiler chicks

Two experiments were conducted to determine the toxicity, pathology, and hi stopathology of purified gossypol in broiler chicks. Gossypol was added to broiler feed at 0, 100, 200, and 400 mg/kg of feed in Experiment 1 and at 0 , 800, and 1600 mg/kg of feed in Experiment 2. Day-old broiler chicks were fed these diets from 1 to 21 days in Experiment 1 and from 1 to 23 days in Experiment 2. In Experiment 1, body weight and feed intake at 21 days were not significantly affected by dietary gossypol. However, chicks fed gossypo l at 400 mg/kg of feed had poor feed conversion ratio compared with the oth er treatment. Feed conversion ratios were 1.493, 1.564, 1.471, and 1.60 for chicks fed gossypol at 0, 100, 200, and 400 mg/kg of feed, respectively (E xperiment 1). Chicks fed 400 mg/kg gossypol also had mild perivascular lymp hoid aggregate formations and bilary hyperplasia in the liver. In Experimen t 2, gossypol at 1600 mg/kg resulted in 28.1% mortality. Gossypol at 800 an d 1600 mg/kg feed resulted in significant decreases in body weight and feed intake of chicks. The average body weights of 23-day-old chicks in Experim ent 2 were 676, 224, and 111 g for 0, 800, and 1600 mg/kg gossypol, respect ively. Feed conversion ratios of chicks fed 800 and 1600 mg/kg gossypol wer e significantly higher than those of chicks fed control diets (1.383 vs. 1. 564 vs. 1.745 for 0, 800, and 1600 mg/kg gossypol, respectively). Plasma ir on and hematocrit values were significantly reduced by gossypol at 800 and 1600 mg/kg of feed. Enlarged gallbladder was the only gross pathology sympt om associated with gossypol levels. Severe cases of perivascular lymphoid a ggregate formation, biliary hyperplasia, and hepatic cholestasis were obser ved in chicks fed 800 and 1600 mg/kg of gossypol in feed. No gossypol-relat ed changes were observed in kidney tissues of chicks. These results show th at gossypol is toxic to broiler chicks at high levels. This study also show s that histopathologic changes in liver due to gossypol also occur at level s lower than the levels that affect body weight.