Desempenho reprodutivo de Tilápias do Nilo melhoradas

Abstract

In order to achieve the goal of tilapicultures, breeding programs use as selection criteria weight at harvesting, ignoring the effect of this criterion on the reproductive characteristics. This study aimed to estimate the parameters of reproductive traits, and to estimate the genetic association between performance in weight and reproductive characteristics of females Nile Tilapia (Oreochromis niloticus) at first generation from AquaAmérica strain. The data set contained 399 females information for evaluating the characteristic likely to spawn (PD), multiple spawning (DM), interval between spawns (ID), spawning number (ND), volume of eggs (VO) and number of eggs per mL (NO) and 2672 information of males and females for performance characteristics weight of Nile Tilapia of the first generation from AquaAmérica strain kept in polyethylene hapas in Fish Farming Experimental Station of the State University of Maringá, Maringá - PR . Data were collected from December 2014 to February 2015. Genetic parameters were estimated using animal models unicaracter, bicaracter and repeatability. The heritability estimate was 0.46, 0.34, 0.17 and 0.10 for ND, ID, orally and IN, respectively, to PD heritability normal range was 0.95 while the binary scale was 0,53 already DM heritability normal and binary scale was 0.59 and 0.37, respectively. The estimated repeatability was 0.29 for VO and 0.16 for NO. Estimate of genetic correlations between weight and ID was negative (-0.21), however, PD, MD, NO and VO ranged from 0.25 to 0.64. The repeatability values for volume of eggs and number of eggs per mL is low indicating that the localized temporary effects have high participation in phenotypic variation. High heritability was observed for PD, MD and ND showing that the phenotypic variation observed among animals have additive genetic, coupled with the result of genetic gain, and thus good candidates for selection criterion. From reproductive traits measured only multiple spawning and spawning number shows genetic correlation with weight, indicating correlated response to selection for growth rate.