Associations between morphometric variables and weight and yields carcass in PirapitingaPiaractus brachypomus

Abstract

The objective of this work was to evaluate the association between morphometric variables and carcass characteristics in Pirapitinga. We used a thousand specimens of Pirapitinga with an average weight of 1,200 g, which were stunned, slaughtered, weighed, measured, and processed for morphometric and processing yield analysis, to obtain weights, carcass and fillet yields. Initially, the linearity of the variables was verified. Pearson's simple and partial correlation tests were performed between all metrics. Track analysis was performed considering the weights and yields of carcass and filet as dependent variables and the others as independent variables. Ridge regression models were used to eliminate the effects of multicollinearity among the independent variables. Observations showed that the simple correlations between body weights and yields were superior to the partial ones in terms of magnitude. The length and circumference of the specimens were the measures most linearly associated with weight, carcass weight and fillet with rib weight. As for carcass yield and fillet yield, linear correlation coefficients were low and not significant when associated with body weights.With the path analysis, we could observe significant positive correlations between the morphometric measurements for weight, carcass weight and fillet with rib weight.The standard length, body circumference and body circumference/body height ratio are the most correlated. The latter are the most important variables in the evaluation of body weights in Pirapitinga fish. They can serve as criteria for indirect selection in searching for fish with better carcass characteristics. As for fillet and carcass yields, the morphometric variables have not shown to be efficient for indirect selection. K E Y W O R D Sbreeding fish, correlation, multivariate, path analysis, round fish

Application of morphometric measures in estimation of body weight and discrimination ofAstyanax lacustrisandAstyanax fasciatus

“…According to El‐Ibiary and Joice (), the linear measures are reliable parameters for estimating carcass and filet weight, but not for the yield of these components. This fact was also found by Ribeiro et al, , when studying the association between morphometric variables of weight and yield of pirapitinga ( Piaractus brachypomus ) concluded that the morphometric variables were not efficient for indirect selection of animals.…”

“…The correlation between morphometric measures and ratios associated with yield has been object of many studies (Diodatti et al, ; Melo et al, ; Reis Neto et al, ; Ribeiro et al, ). However, this simple correlation allows the evaluation of only the direction and magnitude of the association between two characters, providing no information regarding the direct and indirect effects of a group of characters related to a dependent variable of greater importance (Cruz, ; Ribeiro et al, ). Thus, with the intent of better understanding the causes involved in the association between characters, the path analysis studies the direct and indirect effects of characters over a base variable, of which estimates are obtained by regression equations, in which variables are previously standardized (Cruz & Carneiro, ).…”