The effects on growth and survival of probiotic Bacillus spp. fed to Persian sturgeon (Acipencer persicus) larvae

This study addressed if sturgeon larvae grew and survived better when fed a probiotic. Bacillus spp. were bioencapsulated in Daphnia magna (Straus 1820) and fed to Acipencer persicus (Borodin 1897) larvae. Bacillus bacteria (three species in a commercial preparation, Protexin Aquatic) were bioencapsulated within Daphnia at three concentrations by holding the Daphnia in suspensions of 1 x 107, 2x107or 3x 107 bacteria per milliliter for 10 hours. The sturgeon larvae were fed one of the three probiotic treatments at a level of 30 percent body weight 5 times a day. The growth and survival of larvae fed the protbiotic enriched Daphnia were compared to those larvae fed a control treatment of unbioencapsulated Daphnia magna. The results showed that larvae fed the probiotic Bacillus spp. had increased final body weight and specific growth rate in comparison to control treatment. The probiotic bacillus also had significant positive effects on daily growth ratio, daily growth coefficient, average weight gain and survival in comparison to those fed the control treatment. The food conversation ratio was the one factor that decreased significantly in comparison with the control treatment. The amount of probiotic used did not improve performance, so larviculture can be increased merely by the addition of of low level of probiotics.