Effect of Oral Administration of Methallibure (I.C.I. 33, 828) in Growing Cockerels

Abstract

Effect of oral administration of Methallibure (I.C.I. 33, 828) upon body weight, feed intake, comb growth and testicular development in 4-18 weeks old cockerels were examined at the two dosages, 0.0015% (E1) and 0.003% (E2).(1) Body weight was suppressed by the administration of this drug. This suppression in body weight gain should be ascribed to reduced appetite in the treated birds, since firstly no difference was observed between E2 and an appropriate control group (C2) which was not treated but received the same amount of feed consumed one day before by E2 group, and secondly there was no difference between two treated groups with difference levels of administration. Appetite was strongly suppressed in the first week after the normal ration was changed to the experimental one, and thenafter, it returned to the normal level proportionally to their body weight gain.(2) Testicular weight in the treated group was smaller than in the control. This was more evident at the 10th week of age than at the 19th week. Spermatogenesis was somewhat inhibited by the drug but almost normal in sperm formation by the age of 19 weeks. It was suggested that the levels of administration used in this study were not sufficient to inhibit their gonadal activity as the cockerels approached to their full maturation.(3) Comb weight in 0, 003% methallibure administred cockerels was significantly smaller than the controls, which suggests that androgen secretion was inhibited markedly in the treated group. The activity of thyroid was accelerated in the treated group. Other organs such as liver, spleen, pancreas and kidney were not affected much but adrenal was smaller in the treated groups.(4) Water content in feces of treated groups was 6 to 12% higher than in the control.(5) Both fertility and hatchability by the use of those treated cockerels after 22 weeks were not affected at all. This suggests that the effect of the drug may not persist for a long period after withdrawal of the agent.