Influence of Hormonal Induction and Broodstock Nutrition on Reproductive Performance and Spawning Quality of Greater Amberjack (Seriola Dumerili, Risso, 1810)

Abstract

Greater amberjack Seriola dumerili is an excellent candidate marine fish species for European aquaculture. To date, the aquaculture production of this species has been very limited, due to the reproductive dysfunctions in captivity and the poor spawning quality. The main objective of the present thesis was to examine the Influence of hormonal induction and broodstock nutrition on spawning quality. In this sense, four specific objectives were established, in order to (1) compare the quality of spontaneous spawn with those obtained by either GnRHa injection or GnRHa implant protocols; (2) examine the effects of supplemental protein, histidine, and taurine in broodstock diets on eggs quality; (3) evaluate the effects of increasing dietary n-3 LC-PUFA levels on spawning performance and egg quality; and (4) investigate the effects of increased ARA levels in broodstock diets on reproductive performance. This thesis showed for the first time that it is possible to obtain very high-quality spontaneous spawn in greater amberjack, in relation to adequate tank size, environmental conditions, and broodstock nutrition. Weekly treatments with the GnRHa injections lead to spawns with similar egg and larval quality than spontaneous spawning and better than in previous studies. Raising histidine contents in broodstock diets from 1 to 1.5% optimized the reproductive performance of greater amberjack, particularly to improve fecundity and fertilization rates. Additionally, Increase in n-3 LC-PUFA levels up to 1.7% in broodstock diet improved the spawning quality in terms of fecundity, fertilization rate, egg viability at 24 h, hatching and larval survival rates. Finally, increase in ARA dietary level up to 3.2 g / kg of feed improved the reproductive performance of the broodfish as well as egg and larval quality.