Weight and morphometric growth of different strains of tilapia (Oreochromis sp)

Abstract

-The objective of this study was to evaluate the morphometric growth and weight gain of strains of tilapia (Thai, Red, UFLA and Commercial) by nonlinear models. Initially, 500 male fingerlings of each strain, at 85 (Red and UFLA) and 86 (Thai and Commercial) days of age, were stocked separately in raceways with 56 m 3 . Twenty fish of each strain were randomly sampled, weighed and measured monthly. Five nonlinear models (Brody, von Bertalanffy, Gompertz, logistic and exponential) were tested, choosing one that best fit to the data. The variables studied were: weight, standard length (SL), head length (HL), height 1 (H1), height 2 (H2), height 3 (H3), first distance (D1), second distance (D2), first width (W1), second width (W2) and third width (W3). The exponential model had the best fit to weight and morphometric data, with the exception of W2, in which the best fitted model was von Bertalanffy. The convergence of the exponential model to data indicates that the cultivation period studied was not enough for the strains to reach maturity weight. The UFLA strain presented the lowest value for parameter "a" (initial weight estimate), 8.71 g, and the highest for parameter k (specific growth rate), 0.0127, when compared with other evaluated strains. However, the highest k of UFLA was not enough to overcome the final weight observed for the Commercial strain (603.1 g), which was higher than all other strains. Regarding the morphometric measurements, the UFLA strain also had the highest k for the variables SL, HL, HH, H1, H2, H3 and D2, and similar k to Commercial and Thai strains for the variables D1 and W3 respectively. The strains differ as to weight gain and morphometric growth.

Modeling the weight gain of freshwater-reared rainbow trout ( Oncorhynchus mykiss ) during the grow-out phase

“…This algorithm is described as more robust than others offered in statistical software (Elzhov et al, 2013;Lugert et al, 2017). This is especially important, as non-convergence situations of models for aquaculture data are described by several authors (Costa et al, 2009;Mansano et al, 2012;Allaman et al, 2013;Sousa Júnior et al, 2014).…”

Ganho genético após uma geração de seleção individual para peso final e variáveis morfométricas em tilápia

“…Além disso, outros autores também observaram diferenças nos padrões morfométricos de animais submetidos a melhoramento genético por seleção ou entre diferentes linhagens. ALLAMAN et al (2013) observaram diferentes relações morfométricas de tilápias com diferentes origens e, dentre elas, a linhagem Gift obteve maior peso, maior altura e largura comparado a outras populações. BOSCOLO et al (2001) e LEONHARDT et al (2006 observaram que a linhagem com maior desempenho zootécnico também apresentava diferenças morfométricas em relação as demais.…”

General and specific combining ability in Serrasalmidae

“…The main products for the fish processing industry are carcass, filet and ribs, so the species most appropriate for development of a breeding programme is pirapitinga, which had higher estimates of genetic value for these traits. However, industry is paid for a fish based only on its weight and not the bodily characteristics (Allaman et al., ; Freato et al., ), thus tambaqui remains the best alternative for breeding programmes. In addition, selection for body weight allows the indirect selection of animals with higher carcass, steak and trunk weights, and, considering that processing time is the same for any fish, large or small, a batch of heavier animals will generate a greater amount of meat than a batch of lean animals.…”