Effects of genetics and early-life mild hypoxia on size variation in farmed gilthead sea bream ( Sparus aurata )
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Effects of genetics and early-life mild hypoxia on size variation in farmed gilthead sea bream (Sparus aurata) Erick Perera & Enrique Rosell-Moll & Fernando Naya-Català & Paula Simó-Mirabet Josep Calduch-Giner & Jaume Pérez-Sánchez
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Received: 30 March 2020 / Accepted: 9 November 2020 # Springer Nature B.V. 2020
Abstract The present study evaluated, in an 18-month gilthead sea bream trial, the time course effects of genetics on individual size variation and growth compensation processes in families selected by heritable growth in the PROGENSA® breeding program. Families categorized as fast, intermediate, and slow growing had different growth trajectories with a more continuous growth in fast growth families. This feature was coincident with a reduced size variation at the beginning of the trial that clustered together the half-sib families sharing the same father. Regression analysis evidenced that the magnitude of compensatory growth was proportional to the initial size variation with no rescaling of families at this stage. By contrast, the finishing growth depensation process can mask, at least partially, the previous size convergence. This reflects the different contribution across the production cycle of genetics in growth. How early-life experiences affect growth compensation at juvenile stages was also evaluated in a separate cohort, and intriguingly, a first mild-hypoxia pulse at 60– 81 days post-hatching (dph) increased survival rates by 10%, preventing growth impairment when fish were exposed to a second hypoxia episode (112–127 dph). The early hypoxia experience did not have a negative impact on growth compensatory processes at juvenile stages. By contrast, a diminished capacity for growth E. Perera : E. Rosell-Moll : F. Naya-Català : P. Simó-Mirabet : J. Calduch-Giner : J. Pérez-Sánchez (*) Nutrigenomics and Fish Growth Endocrinology, Institute of Aquaculture Torre de la Sal (IATS-CSIC), 12595 Ribera de Cabanes, Castellón, Spain e-mail: [email protected]
compensation was found with repeated or late hypoxia experiences. All this reinforces the use of size variation as a main criterion for improving intensive fish farming and selective breeding. Keywords Size heterogeneity . Growth compensation . Early-life hypoxia . Selective breeding . Gilthead sea bream
Introduction Growth trajectories of most animals are nearly identical when rescaled by body mass at maturity and time to reach mature size (Sibly et al. 2015). However, how metabolic processes fuel and regulate growth across life is under debate, though growth deceleration with increasing size appears mostly related to a limited diffusion rate of nutrients and oxygen (O2) (Glazier 2010). Besides, not all individuals grow at the same rate and the large size variation of animals from the same cohort illustrates the propensity of individuals to grow at different rates (Pfister and Stevens 2002; Peacor et al. 2007; Teder et al. 2008). Growth variability is in fact a key ecological attribute differentiating individuals, populations, and species
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