Epigenetics in aquaculture: An Overview

Abstract

In contrast to livestock mammals, where both fertilization and early development are internal; and farmed birds, where fertilization is internal but early development is external, in farmed aquatic animals both fertilization and early development are usually external. Thus, fish offer excellent opportunities to study the influence of the environment on embryonic and larval development. Epigenetics provide organisms with the ability to integrate genomic, internal and external information to produce phenotypes matched to specific environments. I this talk, we argue that epigenetics has a promising future in aquaculture, particularly related to aspects such as nutritional and reproductive programming. The former is of relevance in the adaptation of carnivorous fish to an increasing plant-based diet. On the other hand, reproductive programming can aid in the selection of broodstock capable of producing offspring with desired production characteristics such as tolerance to temperature or crowding. In this regard, the impact of the early life on the epigenome is relevant for its possible long-lasting consequences. In its many years of history, this edition of Aquaculture Europe is the first to devote a full day session on epigenetics, a reflection of the increasing interest and the convenience of integrating this discipline into aquaculture research and production. In this talk, we provide some general considerations, illustrate some applications and present data from studies carried out with the European sea bass (Dicentrarchus labrax), a temperate fish species of economic relevance for aquaculture. We demonstrate intrinsic and extrinsic influences on DNA methylation and the phenotype during different stages of the lifecycle. We identify loci altered with age and show that moderate early developmental temperature changes are associated with genome-wide changes in DNA methylation and with parent-specific responses of genes involved in sexual development as well as other important production traits. The ultimate goal is to develop a set of epigenetic markers to improve the selection and evaluation of stocks