Growth improvement in carp, Cyprinus carpio (Linnaeus), sterilized with 17 α-methyltestosterone

Abstract

The effect of dietary administration of 17α-methyltestosterone (17α-MT) (300 and 400 ppm) over a period of 30 days, starting with 1-day-old hatchlings, on the sex and growth of the carp, Cyprinus carpio (Linn.), was investigated. After the treatment period, the fry were reared on a hormone-free diet for 365 days. Administration of 17α-MT at 300 ppm resulted in a population of 8% males, 6% females and 86% sterile individuals. At 400 ppm, 17α-MT induced a female-free population, consisting of 98.25% sterile forms and 1.75% males. The control group consisted of 51% males and 49% females. At the end of the 12-month post-treatment rearing period, the increases in the mean final weights of the fish in the 300 and 400 ppm treated groups were 40.64% and 46.87% respectively when compared with the control. Loss of weight due to evisceration was only 5.59–7.42% in the hormone-treated groups, while it was 14.95% in the control fish, suggesting the availability of more edible meat per unit weight from hormone-treated fish. The results suggest that sterile fish produced by administration of 17α-MT would grow better and yield more meat per unit weight than untreated fish. They also suggest that production from composite fish culture (polyculture) can be further enhanced by using hormone-induced sterile fish.