Study of different levels of Lactobacillus spp and Bacillus spp probiotics in larval-culture tanks on larvae quality indices of Litopenaeus vannamei

The past studies have shown that the use of some probiotics has improved growth, reproductive and immune systems in crustaceans. Litopenaeus vannamei is the most important culture species of crustaceans in the country and this shrimp grows better than other shrimps. In this study, the effect of both probiotics based on quality indicators includes: larval stage index (LSI), larval condition index (LCI), larval dry weight, larval survival, Simultaneity of larval maturation to post larvae, time of emergence of first post larvae, duration of larval period and salinity and formalin stress tests in order to investigate Improvements in qualitative growth indices and immune system of Vanami shrimp larvae were examined. For this purpose, three concentrations of Bacillus probiotic with dose 6×105, 3×105 and 1×105 and three concentrations of Lactobacillus probiotic with dose 6×106, 3×106 and 1×106   were added to the water tank of Vanami shrimp larvae. The results showed that the larval quality indices at level 3 of both Bacillus and Lactobacillus probiotics were the best response and respectively, respectively 67±3.2 and 62±7.28, dry weight 139±3.99 and 138±22.23, larval stage index 11.55±0.26 and 11.46±0.11, larval condition index 1.86±0.06 and 1.88±0.13, Simultaneity of larval maturation to post larvae 1.45±0.23 and 1.41±0.04, time of emergence of first post larvae 7.5±1.1 and 7.7±1.52, duration of larval period 8.91±0.73 and 9.11±0.6 and salinity and formalin stress tests also show significant differences for all indicators except dry weight index and time of emergence of the first larval post for Bacillus probiotic. Finally, it can be concluded that the use of both probiotics increases growth, faster development, and longer survival and increases the resistance of the immune system.