Lesions induced in broiler chickens by cyclophosphamide treatment.

Cyclophosphamide (CY) is an immunosuppressant and inhibits cell division by alkylating nucleic acids. This study was performed to determine the toxic effects of CY treatment in broiler chickens. One-d-old White Plymouth Rock broiler chickens were treated with either 4 mg/d CY or phosphate buffered saline (PBS) for 4 consecutive days. Mortality of the CY-treated chickens was 65.4% (34/52), while that of the PBS-treated chickens was 10% (5/50). CY-treated chickens were significantly smaller and had delayed feathering and lower relative bursal weight compared to those PBS treated. Histologically, the lymphocytes were markedly depleted in the spleen and bursa. Bone marrow was severely hypocellular and replaced by adipose tissue. Diffuse vacuolation of hepatocytes with individual cell necrosis was present in the liver. There was segmental necrosis of lining epithelial cells of renal tubules with eosinophilic material and necrotic detritus within the lumens. The lesions in the liver, kidney and bone marrow were transient and repaired by 2 w of age.