CAUSAS E EFEITOS ENTRE CARACTERES FENOTÍPICOS DE IMPORTÂNCIA EM pacu Piaractus mesopotamicus

Abstract

Pacu is a species native to South America that stands out in aquaculture production, and the products most valued by the industry are gutted fish, fillets, and ribs. Soon the need arises for the selection of these characters for genetic improvement. Correlation is an important technique in the selection process, however, it does not allow evaluating the cause and effect relationship between the characters. It is necessary to combine other methods, such as trail analysis, to understand these effects. Thus, the objective was to evaluate, through trail analysis, the cause and effect relationship between the morphometric variables and the pacu body weights on the income of economic importance. For this, 400 juveniles were stored in an excavated tank (66 m2) for 196 days, with commercial feed with 35% crude protein. Every 28 days, 20 fish were selected and stunned for morphometric evaluation and obtaining body weights and yields. Multicollinearity was eliminated by regression using the “Stepwise” procedure with the “backward” option and later the trail coefficients were estimated. In the analysis of the phenotypic characters, distinct effects and highly significant correlations were observed with the products obtained from the pacu processing, with CP being the most important measure to understand the variation in head weight and AC for rib and fillet weight. While for body yields, measurements and morphometric ratios through trail coefficients were not decisive in understanding these variables, thus emerging the need for further studies evaluating other measurable measures.