Sex Reversal Dynamics of Nile Tilapia and Impact on Growth Performance

Nile tilapia (Oreochromis niloticus) is an economically important freshwater species for finfish aquaculture, globally. In commercial farming of O. niloticus, over-reproduction during grow-out is a major concern. Production of all-male populations of tilapia is desirable and has been identified as one of the most effective techniques to increase growth and production. Various methods have been used to produce all male tilapia including; hormone treatment (17-α methyltestosterone), temperature shock and the YY technology. However, the latter two methods have limited documentation in Kenya. Therefore, the current study aimed at comparing the effectiveness of temperature and hormone sex reversed O. niloticus fry and impact on growth in aquaria glasses and later in nine hapa nets for a period of 3 months. Nile tilapia fry of 3 days old after egg yolk absorption were used in the experiment over a period of 18 days. Hormone use involved a dose of 60mg/kg of feed while temperature shock was set between 30 and 34 0C. Analysis for SGR using one way ANOVA showed no significant difference between hormone and temperature induced sex reversed fish (F=0.0975, P=0.7705). Sex reversal efficacy of 93.33% and 92.86% was attained using MT and Temperature shock respectively. In conclusion, temperature shock could be used as an alternative method to the use of hormone for sex reversal of O. niloticus fry.