The effects of the synthetic steroid 17-alpha-methyltestosterone on the growth and organ morphology of the channel catfish ( Ictalurus punctatus)

Groups of juvenile channel catfish ( Ictalurus punctatus) were administered 17-alpha-methyltestosterone (MT) at levels of 1.0, 5.0, and 10.0 mg/kg dry diet over a period of 16 weeks and the effects on weight, length, and organ morphology were determined. At moderate and high levels, MT produced reduced growth rates which were reflected in a significantly decreased weight and length when compared to the control group. No significant changes in weight and length were noted at the 1 mg/kg level. In all hormone treated groups, marked morphological changes were observed in the kidney along with an increase in the renosomatic index. However, only the 1 and 5 mg/kg groups showed hepatotrophic activity with an elevated hepatosomatic index. It was clear that 17-alpha-methyltestosterone retarded growth when administered at moderate and high dosage levels. Moreover, its strong androgenic properties were reflected by a precocious maturation of the testes of treated males. Prolonged treatment led to deleterious effects on body organs as evidenced by a marked edema in the renal tubules and many of the renal corpuscles of the kidney, and a hepatotrophic response causing weight increases in the liver. Attempts of growth enhancement of juvenile channel catfish through the use of anabolic steroids have been unsuccessful. However, other anabolic steroids should be tested in order to find a hormone that not only promotes growth but has little or no detrimental effects on the internal organs.