A first insight into genotype × diet interactions in European sea bass (Dicentrarchus labrax L. 1756) in the context of plant-based diet use

This preliminary study assessed genotype _ diet interaction in late growth of European sea bass (Dicentrarchus labrax) fed with either a ￠sh meal (FM)- or a ￠sh oil (FO)-based diet (M) or an all-plant-based (PB) diet. Atotal of 550 ￠sh from 224 families were reared together and tagged. DNAwas sampled and microsatellites were used to assign parentage. When ￠sh weight was 192 _ 54 g, two tanks were fed with M (FM: 100%; FO: 100%) and two others with PB (FM: 0% and FO: 0%). Body weight (BW), fork length (FL) and ￠llet lipid content (CorrFat) were analysed with a linear model and with REML methodology.We observed no signi￠cant di!erences between groups, but a slightly lower (P50.03) daily growth coe⁄cient in sea bass fed PB than in those fed M. Heritability estimates of BWdi!ered signi￠cantly from zero (PB: 0.37 _ 0.18; M: 0.47 _ 0.24). Sire _ diet interactions were signi￠cant and genetic correlations ranged between 0.51 and 0.87, showing genotype _ diet interaction for BWand CorrFat. For the ￠rst time, genetic parameters in the context of total replacement of marine ￠shery by-products were estimated in European sea bass, showing re-ranking of family performances with extremely contrasted diets.