The Effect of Yeast-Enriched (Saccharomyces cerevisiae) Daphnia magna on Growth and Stress Resistance in Persian Sturgeon (Acipenser persicus) Larvae

This study was carried out to evaluate the effect of commercial live bakery’s’ yeast(Saccharomyces cerevisiae), (marketed as Amax), on growth and survival of Persian sturgeon(Acipenser persicus) larvae (74.9 ± 9.7mg) during 30 days. Sturgeon larvae were fed on Daphnia magna enriched at three suspensions of yeast, Amax, (0, 50, 100, and 150 mg yeast per litter). The feeding level was 30 percent of total biomass per day. The daily ration was divided into five feeding portions and fed by hand. Growth parameters were influenced by yeast-enriched daphnia (P<0.05). Feeding on enriched daphnia caused a higher specific growth rate and a better feed conversion ratio than those received control daphnia (no enrichment; P<0.05). Feed efficiency was increased significantly (P<0.05) at experimental treatments in comparison to the control diet. The highest growth was observed in the treatment with 150 mg yeast. There was also a positive relationship between enrichment levels and growth related parameters. However, no significant difference observed in the condition factor among the treatments (P>0.05). Survival rate of the larvae improved by using Amax compared to control diet (p0.05). Fish fed on yeast-enriched daphnia showed a higher resistance to unwanted environmental factors (P>0.05). In conclusion, the current experiment indicated that the supplementation of daphnia with Saccharomyces cerevisiae can increase the growth performance and feed efficiency and also up-grade the stress tolerance in Acipenser persicus larvae when facing with unfavorable environmental conditions.