Effects of selenium nanoparticles on larval development, ontogeny of antioxidant enzymes and fatty acid profile in Arabian yellowfin seabream (Acanthopagrus arabicus)

Selenium (Se) is an essential trace element that has vital effects on growth, antioxidant capacity and early development in marine fish larvae. However, traditional livefoods such as rotifer and artemia lack of Se. In this regard, a 50-day feeding experiment was conducted in order to examine the effects of Rotifer and Artemia enrichment with selenium nanoparticles (SeNPs) on growth, antioxidant capacity and fatty acid profile of Arabian yellowfin seabream (Acanthopagrus arabicus) larvae. Four levels of SeNPs were used to prepare the experimental emulsions,including control (0), 0.5, 1.0 and 5 mg SeNPs L−1. Larvae were stocked at density of 50 larvae L−1 into twelve 250-L cylindrical tanks. Tanks supplied with seawater (23 ± 1 ºC; 40.0 ± 1.0 g L−1). Green water was used from day first until 20 days after hatch (DAH). Rotifers (15 ml−1) were offered to larvae from day 2–21 DAH and Artemia metanauplii (1–3 Artemia ml−1) were offered to larvae from day 18–45 DAH. Fish were sampled at 0, 7, 10, 15, 22, 30, 40, 45, 50 DAH. The Se concentration in the livefoods and larval whole body linearly increased with the increment of SeNPs level in the experimental emulsions. Larvae wet weight showed quadratic response and increased with SeNPs up to 1 mg mg SeNPs/L, then decreased in SeNPs (5.0) group. The activity of antioxidant enzymes including catalase, superoxide dismutase glutathione peroxidase, and total antioxidant capacity increased but malondialdehyde level decreased in larvae fed the SeNPs-enriched livefoods and showed both linear and quadratic responses. Lysozyme activity in the whole body of larvae fed SeNPs-enriched livefoods had both linear and quadratic responses and in the most of the sampling times was higher than the control group. Docosahexaenoic acid (DHA) level in the livefoods and larval whole body increased with SeNPs. In conclusion, livefoods enrichment with SeNPs at 1 mg L−1 is recommended to elevate the antioxidant capacity and non-specific immune response in A. arabicus larvae.