<b>Evaluation of Nile tilapia strains (<em>Oreochromis niloticus</em>) in different phases of rearing</b> - DOI: 10.4025/actascianimsci.v26i2.1864

Abstract

The present research had as objectives to evaluate the productive performance during the initial phase and growing and the fillet yield obtained in the fatten phase of different strains of Nile tilapia existents in Brazil. The studied strains were: the intraspecific hybrid (HIB), resulting from crossing between the male Chitralada (Thailand), and the female Bouaké (Brazilian); the Bouaké (BOK) popularly known like Nile tilapia; the Chitralada, first Thailand generation (CHI₁); the Chitralada, second Thailand generation (CHI₂). This experiment was carried out in the period from December 2000 to August 2001 and had four phases as characteristic. To the three first phases was used an installation type greenhouse, with 24 boxes, with capacity to 250L, where were tested the four treatments, with six replicates. To the fourth phase, the fishes were individually marked and put in a land tank with 300m^². The obtained results to the final weight for the growing phase (3^a phase) were: 93,66g (HIB); 71,79g (BOK); 108,17g (CHI₁) e 114,31g (CHI₂), and for apparent feed conversion ratio 1,77 (HIB); 1,98 (BOK); 1,46 (CHI₁) e 1,45 (CHI₂) and for weight gain there was the increasing from 47% to 49% (CHI₁ and CHI₂, respectively) and 17% (HIB) in relation to BOK. The CHI₁ and CHI₂ and the HIB showed a mayor tolerance and a mayor storage density and final biomass than the BOK. To the average values of carcass weight in the fatten phase (4^ª phase) were: 261,99g (HIB); 177,98g (BOK); 292,75g (CHI₁) e 307,82g (CHI₂); the strains CHI1, CHI2 and the HIB presented the best results, obtaining significative differences of BOK. The results obtained to fillet yield showed that there was no significative difference between the strains. These results showed, that the strains with best general performance, was Chitralada (CHI1 and CHI2), followed by hybrid (HIB) and the Bouaké (BOK) strains.