Genetic parameters for weight gain and body measurements for Nile tilapias by random regression modeling

Conti, Ana Carolina Müller; Oliveira, Carlos Antônio Lopes de; Martins, Elias Nunes; Ribeiro, Ricardo Pereira; Bignardi, Annaíza Braga; Porto, Emília Paiva; Oliveira, Simone

doi:10.5433/1679-0359.2014v35n5p2843

Cited by 1 publication

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“…In this study and the one from Nguyen et al (2010), the fish were harvested at an average body weight of 560 g, whereas it was only 250-300 g in the latter studies (Nguyen et al 2007;Ponzoni et al 2011;Hamzah et al 2014). In agreement with our findings regarding the small common family effect for body shape, other studies in Nile tilapias, using multi-trait models (Yoshida et al 2013) and random regression analysis (Rutten et al 2005;Turra et al 2012;Conti et al 2014), reported that common family effect is more important in early than later phases of growth.…”

Section: Discussionsupporting

confidence: 93%

Correlated changes in body shape after five generations of selection to improve growth rate in a breeding program for Nile tilapia Oreochromis niloticus in Brazil

et al. 2016

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Body shape is a commercial trait of great interest as it impacts profit and productivity of aquaculture enterprises. In the present study, we examined correlated changes in two measures of body shape (depth to length ratio, DL-R and ellipticity of mid sagittal plane, EL-H) from a selection program for high daily weight gain in a Nile tilapia population reared in freshwater cages in Brazil. Genetic parameters for body shape and its genetic association with growth traits (body weight and daily gain) were also estimated from 8,725 individuals with growth performance recorded over five generations from 2008 to 2013. Mixed model analysis showed that the selection program resulted in substantial improvement in growth performance (about 4 % genetic gain per generation or per year) and also brought about trivial changes in body shape. The heritabilities ranged from 0.470 to 0.564 for growth traits and 0.180 to 0.289 for body shape. The common family effects were low for all traits studied, accounting for only 3-11 % of total phenotypic variance. The genetic correlations between body shape and growth traits were weak, i.e., -0.385 between EL-H and growth traits and 0.28 between DL-R and body weight or daily gain. Strong and negative genetic association was found between the two body shape traits (rg = --0.955). Harvest body weight and daily gain are essentially the same traits, as indicated by the close to one genetic correlations between the two characters. Our results demonstrated that the selection process to increase growth rate had small, but slowly constant effect in body shape traits; and in the long term, the fish would have become rotund.

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