Document Type : Research Paper
Department of Fisheries, Faculty of Agriculture and Natural Resources, University of Gonbad Kavoos, Gonbad Kavoos, Golestan, Iran
Department of Biology, Faculty of Science, University of Gonbad Kavoos, Gonbad Kavoos, Golestan, Iran
Agh Ghala Sturgeon Center, Gonbad Kavoos, Golestan, Iran
Artemia urmiana nauplii were used as a vector in bioencapsulation processing to carry blends of five probiotic bacilli called Protexin aquatic,including Bacillus circulans, B. subtilis, B. licheniformis, B. laterosporus and B. Polymyxa to digestive system of Beluga Huso huso larvae. Nauplii were bioencapsulated with three concentrations of 1×105 (T1), 2×105 (T2) and 3×105 (T3) bacteria per mililiter in suspension and were fed to Beluga larvae for 10 hours. The larvae were fed on the base of the 50% of their body weight for 6 times a day in a completely randomized design and the results were compared with control group (unbioencapsulated Artemia nauplii) in fourteenth day of experiment. The results suggest a positive effect of probiotic bacillus on growth of Beluga larvae compared to the control group. The highest weight was obtained in fish fed by bioencapsulated Artemia with a concentration of 1×105 bacteria/mL. . Food conversion rate significantly decreased in experimental treatments. The probiotic bacilli had significant positive effects on the specific growth rate, relative gain ratio, survival rate, average daily growth and thermal growth coefficient in comparison with control (P<0.05). However, condition factor did not show any significant difference (P>0.05). The results showed that probiotic bacilli have the highest ability in increasing the growth of Beluga larvae and fish fed by bioencapsulated Artemia with a concentration of 1×105 bacteria/mL had the best results.