The effect of feeding 11-ketotestosterone on the food conversion efficiency and tissue protein and nucleic acid contents of juvenile carp, Cyprinus carpio L.

Juvenile common carp were fed 11-ketotestosterone for 60 days with the diet and the effect on food conversion efficiency, organ weights and protein and nucleic acids (RNA, DNA) content of the liver, kidney, brain and muscle were observed. Feeding of the steroid increased the food conversion efficiency of all the experimental groups studied as compared with controls. A decrease in weight of brain, liver and kidney in relation to body weight was noticed after 60 days of the hormone feeding. No change in the visceral weight was observed. These changes in relative weights of the organ were ameliorated 30 days after the withdrawal of the steroid from the food. The weight of the viscera decreased compared with the control weight during this time. Feeding of the hormone brought variable changes in the total proteins, RNA/DNA, protein/RNA and protein/DNA in all the organs studied. In addition to these findings, changes in the moisture, total lipid and ash contents of the muscle were also observed. The results are discussed in the light of existing knowledge of the effect of anabolic-androgenic steroids on the growth processes of different organisms.