Abstract: The effects of compound butafosfan solution on chronic heat stress were studied by detecting the performance, body temperature, contents of some endocrine hormones （such as T₃, T₄, insulin and cortisol） and some serum biochemical parameters (such as CPK, ALP, LDH and GLU) of chronic heatstressed broilers respectively. 45 One-day-old broilers were randomly assigned to 3 treatment groups, 15 birds each, and were administered orally saline water and two levels of compound butafosfan solution. The birds were fed basal diet and reared further two weeks under high ambient temperature after heat exposure at 14 days old. The experimental results showed that the compound can improve the performance to a certain extent in heatstressed broilers, and also can significantly influence the serum endocrine hormones and biochemical parameters. The preparation can notably decrease the rectal temperature and serum contents of CPK, ALP and LDH, however, can increase the T₃/T₄ ratio and contents of insulin and glucose in chronic heat-stressed broilers. But the compound has no effect on serum cortisol content in heat-stressed broilers. Therefore, the compound butafosfan solution could exert the anti-stress action by regulating the contents of some endocrine hormones and altering some biochemical indices in heatstressed broilers.

Key words: broiler, heat stress, compound butafosfan solution, endocrine hormone, biochemical index