A 40-year journey into fish reproductive endocrinology, from the lab to the market

Abstract

Since the mid-70s fish farming developed into a thriving and productive activity and research in fish reproductive endocrinology became a broad field covering a spectrum from basic research to its zootechnical translation. This review summarizes a journey along 40 years of research in the reproductive endocrinology of a marine teleost the sea bass (Dicentrarchus labrax), which resulted in a wealth of basic information and its transfer to the aquaculture industry as practical uses and new technologies. Sea bass is a good example of a cultivated fish species where basic reproductive endocrinology research has been driven by applied challenges. Since early studies on gonad morphology, seasonal changes of reproductive hormone levels and hormonal and environmental shifting of gametogenesis and spawning, novel discoveries were made on gametogenesis/ steroideogenesis, structure/function of gonadotropis, multiplicity of GnRH/GnRHR and Kiss/GPR54 systems and their functional significance, cross-communication between the components of the brain-pituitary-gonad axis and their environmental control, and key processes such as puberty, cyclical reproduction and sex differentiation. As we entered into the genomic era, associated technologies such as recombinant hormone production and gene-transfer, among others, have been used to identify and study genes involved in reproduction and their regulation by environmental and endocrine factors. The output of this research enabled the industry to produce good quality gametes and viable juveniles on demand and in a more sustainable manner.