Effect of dietary microminerals in early weaning diets on growth, survival, mineral contents and gene expression in gilthead sea bream (Sparus aurata, L) larvae

In previous studies, combined inclusion of Zn, Mn and Se in early weaning diets improved larval growth, but suggested a potential toxicity by one of these elements. The present study aimed to determine the effect of the single inclusion of Zn, Mn, Se or Cu, their combination (Control+) or their absence (Control-) on larval diets. At the end of the trial, survival was significantly (p < .05) lowest in fish fed C+ diet (17.16 +/- 7% mean +/- SD), followed by that of larvae fed Mn diet (21.91 +/- 7%). The highest survival was obtained by Cu diet (35.27 +/- 15%), followed by C- diet (34.58 +/- 9%). Cu and Se supplementation significantly improved total length and body weight, in comparison with the C- fish. On the contrary, fish fed Mn and C+ showed the lowest growth. Supplementation with Zn or Cu significantly increasedCuZnsod,whereasgpxwas significantly upregulated in fish fed Se and C+ diets. ARA/EPA level was significantly highest and DHA/EPA lowest in larvae fed the Cu diet in fish fed C+ diet. The results pointed out the importance of supplementation with Cu, as well as Se and Zn, on early weaning diets for gilthead sea bream, and the potential toxic effect of Mn.