Evaluation of the productive efficiency of three strains of tilapia sex reversal in a recirculation system (RAS)

Abstract

This study was conducted to evaluate the productive performance of three strains. Nile tilapia (Oreochromis niloticus), hybrid of Spring (O. niloticus x O. mossambicus) and Pargum-UNAM from 25\% hybrid Rocky Mountain (Oreochromis aureus x Oreochromis niloticus), 25\% pink O. niloticus and 50\% of red hybrid Florida Red Tilapia (O. urolepis hornorum x O. mossambicus), reared in a recirculating aquaculture system (RAS). The study lasting 75 days was carried out in polyethylene tanks with an individual capacity of 3.146,6 L. Each tank was divided in three compartments. Fry were previously masculinized with 17-alpha-methyltestosterone (MT) hormone, counted individually, weighed and randomly distributed into three equal groups of 60 each. The first group Nile tilapia, had an average initial weight of 1,43 g +/- 0,38 the second, hybrid of Spring, recorded a weight of 1.20 +/- 0.23 g and the third red Pargum-UNAM, weighed 1.28 +/- 0.24 g. The variables measured were: daily weight gain, feed conversion and survival rate for each of the strains. At the end of the trial, the strains of Nile tilapia and hybridizes of Spring, showed a better performance (growth and conversion factor) with significant differences (P <= 0.05) compared with Pargum-UNAM, which showed a lower weight and conversion factor. There were not significant differences among the strains in survival (P <= 0.05).