The increase in demand for feed is due to the increase in shrimp culture and the upgrading of systems towards intensive and super intensive. The positive performance of beneficial bacteria (probiotics) in promoting shrimp reproduction and breeding has been proven, and Bacillus sp. is considered one of the most widely used bacteria in aquaculture. This research was conducted in order to investigate the effect of indigenous probiotic Bacillus vallismortis IS03 (GenBank: JQ085958.1) on the growth performance of Litopenaeus vannamei in the earthen pond of two sites, Mond and Delvar, with different management conditions, and each site included 3 treatments (adding probiotic to water, the addition of probiotics to feed and control without probiotics) and each treatment consisted of three replicates. During the 100 days of the breeding period in the Mond ponds with a stocking density of 225,000 pieces per hectare, the lowest feed conversion ratio (FCR) was observed in the water treatment (1.47) followed by feed (1.48), which was significantly different from the control treatment (p< 0.05). The highest survival rate was observed in the feed treatment (98.07%) followed by the water treatment (97.45 %), which were significantly different from the control treatment (p<0.05). The highest amount of harvested biomass was in the water and feed treatments, respectively, which had a significant difference with the control treatment (p<0.05) and the specific and relative growth rates in the water and feed treatments did not have a significant difference with the control. In Delvar site earthen pond with a stocking density of 5000 pieces per hectare, the lowest FCR was observed in the water treatment (1.60) followed by feed (1.62), which had a significant difference with the control treatment (1.74) (p< 0.05) and the highest percentage of survival rate was observed in the water treatment (80.72%) followed by the feed treatment (80.09%), and there was a significant difference between the water treatment and the control (p<0.05). The highest amount of harvested biomass was in the water treatment and then the feed treatment, respectively, and a significant difference was observed with the control (p<0.05). There was no significant difference between the relative and specific growth rates in the treatments and the control (p>0.05). However, the amount of final weight of shrimp at the time of harvesting in the water treatment was significantly different from the control treatment (p<0.05). According to the results and significant and positive effects of the probiotic Bacillus vallismortis IS03 on growth indicators, especially at high concentrations, this bacterium can be introduced as a suitable probiotic to be added to the water of shrimp culture earthen ponds.
Keywords: Bacillus valismortis, Native probiotic, Western white shrimp, Litopenaeus vannamei, Growth Indices, Earthen pond