Effect of probiotic Bacillus vallismortis IS03 on growth performance and feed efficiency in Pacific white shrimp (Litopenaeus vannamei) in earthen ponds

The positive performance of beneficial bacteria (probiotics) in promoting aquatic production has been proven, and Bacillaceae family is considered to be one of the most widely used bacteria in aquaculture. This study was conducted to investigate and compare the effect of indigenous probiotic Bacillus vallismortis IS03 (JQ085958.1) at 1011 CFU kg-1 concentration, on the growth performance, feed efficiency, and the amount of harvested biomass of western white shrimp in earthen culture ponds. Two treatments were considered for this purpose addition of the probiotic to water, addition of the probiotic to feed, and a control group (without the probiotic).  The lowest feed conversion ratio was recorded in the water treatment (1.60) and then, in the feed treatment (1.62), which were significantly different from the control group (1.74) during the 100 days of the culture period in ponds with a stocking density of 500,000 per hectare (p<0.05). The percentage of survival in the water treatment (80.72%) and in the feed treatment (80.09%) was recorded, and there was a significant difference between the water treatment and control group (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 final weight of shrimp at harvest was significantly different in the water treatment compared to the control treatment (p<0.05). Considering the positive and significant effects of the probiotic B. vallismortis IS03 in the method of adding to water on the survival rate, harvested biomass, and feed conversion ratio, this bacterium can be suggested as a suitable probiotic to be added to the water of shrimp rearing ponds.