THE USE OF LYOPHILIZED TESTES FROM BULL (Bos indicus), RAM (Ovis aries) AND BUCK (Capra hircus) FOR MASCULINIZATION OF NILE TILAPIA (Oreochromis niloticus L.).
The use of 17α-Methyltestosterone (MT) is by far the most common means of masculinizing fry of various tilapia species. However, the use of synthetic hormones has been under increasing public criticism due to their possible health and environmental impacts. This study examined the alternative means of masculinization of Nile tilapia (O. niloticus) using lyophilized testes from bull, ram and buck. The experiment was conducted using Complete Randomized Design (CRD). Untreated diet (C1) and Methyl-testosterone treated diet (C2) served as negative and positive controls, while lyophilized testes of bull, ram and buck were T1, T2 and T3 respectively. Each of the treatments (T1, T2 and T3) was included at 60mg, 80mg and 100mg per 1kg of diets (i.e. I1, I2, I3). O. niloticus fry (average weight of 7.5±1.29mg) were fed ad-libitum three times daily for 28days using the treated and untreated diets. After this, conventional diet of the same composition was fed to all the treatment for 12weeks. Data on percentage frequency of male, female and intersex (hermaphrodite) sexes were obtained and analyzed using Descriptive and Correlation Statistics. The average overall effect of all the treatments on the percentage sexes of the Nile tilapia was significant (p<0.05) with 53.33±18.68% males, 25.13±10.81% intersexes and15.53±9.03% females. Inclusion level of 100mg of lyophilized testes of bull (T1I3) gave the highest percentage male population of 83.67±4.62%, no intersex and 16.33±4.62% female population. Inclusion level of 60mg of lyophilized testes of ram (T3I1) gave the least percentage male population of 35.00±21.79%, 47.00±23.39% intersex and 18.00±3.46% female population. In conclusion lyophilized testes of bull, ram and buck were efficient for masculinization of O. niloticus, however, 100mg inclusion of lyophilized bull testes in diet of fry gave the best.