EFFECT OF LYOPHILIZED TESTES FROM BULL (Bos indicus), RAM (Ovis aries), AND BUCK (Cabra hireus) ON OCCURRENCE OF PHENOTYPIC MALE IN NILE TILAPIA (Oreochromis niloticus) FRY

Abstract

The effect of lyophilized testes from a bull, ram, and buck on masculinization, growth, and survival of Oreochromis
niloticus was investigated. A commercial diet was supplemented with the lyophilized bull, ram, and buck testes at
60, 80 and100 mg/kg diets, Control (CT1) was not supplemented while Control (CT2) was supplemented with
40mg/kg Methyl-testosterone. Diets were fed to satiation daily for 28 days to triplicate groups of randomly
distributed O. niloticus fry. The feeding trial was continued with commercial diets for 12 weeks. In the end of
which fifty fish were randomly selected from each aquarium for phenotypic male and female determination. Mean
final weights and survival rates were recorded. Percentage phenotypic male was significantly highest (P<0.05)
in fish fed bull testes treated diets (60 mg/kg=82.46%; 8 0mg/kg=82.35% and100 mg/kg=82.93%) and least in
the buck groups (60 mg/kg=36.98%; 80mg/kg=36.97% and 100 mg/kg=36.69%). Intersex was highest in the buck
groups (60 mg/kg=45.78%; 80 mg/kg=46.13% and 100 mg/kg=46.38%), while the bull and CT1 groups recorded
none. MWG and SGR were significantly high (P<0.05) in CT2 than in other groups. The result of this study
revealed that lyophilized testes of bull successfully masculinized O. niloticus