Morphometric comparison of the growth curve in Nile tilapia (Oreochromis niloticus) sexually reverted to masculinized and feminized
Aquaculture is an industry in development around the world that allows covering the nutritional demand with a high nutritional value. Within this industry, monosex crops of some species, such as the Nile tilapia (Oreochromis niloticus), stand out. In this study, the effect of the administration of 17α-ethinyl estradiol and 17α-methyltestosterone on the morphometry of Nile tilapia at different times was evaluated. Nile tilapia were raised under controlled conditions and divided into three groups: control: no hormone treatment; feminized: treated with 17α-ethynyl estradiol and masculinized: treated with 17α-methyltestosterone. The measurements were made at 5, 10, 15, 25, 35, 40, 50, 60 and 70 days after fertilization with the morphometric technique “truss protocol.” The data were analyzed using a general linear model of repeated measurements and analysis of variance of comparison of means. The growth curve was made using the Gompertz logistic model. The results showed that the masculinized larva presented a higher growth rate and increased daily gain of weight 2.05-2 mg compared to the controls and feminized 1.67-3 mg and 7.57-4 mg, respectively. The sexual reversion of Nile tilapia with 17 α-methyltestosterone increases the growth curve of the masculinized organism and the uniformity of the final size.