In order to screen strains with potential prebiotic effects on Pacific white leg shrimp(Litopenaeus van-namei),a strain(RHVJ)with high temperature(80℃)tolerance was isolated from the intestine of healthy Pacif-ic white leg shrimp with body weight of(3.1±0.4)g,and identified by morphological observations,physiological and biochemical determination,and gene sequence alignment.The strain RHVJ was detected for pathogen antago-nism,safety,tolerance analysis,and growth characteristics.The results showed that RHVJ was a gram-positive Ba-cillus,and tentatively identified as a Bacillus based on physiological and biochemical characteristics.The 16S rDNA sequence of RHVJ was found to be completely matched with Bacillus licheniformis strains MH305331.1 and NR074923.1,and its gyrB sequence also showed 100%consistency with CP038186.1 and CP023729.1.The strain RHVJ was identified as Bacillus licheniformis,inhibited the growth of Vibrio parahaemolyticus and Aeromonas veronii,and not pathogenic to Pacific white leg shrimp based on physiological and biochemical identification re-sults.When cultured in environments with bile salt concentrations ranging from 0 to 1.2 g/L and pH levels between 3 and 11,and subjected to water bath treatments at temperatures from 37 to 90℃for either 5 or 15 minutes,the RHVJ strain demonstrated sustained proliferation.It exhibited optimal growth under conditions of 27℃,pH 7,and 20 salinity.The B.licheniformis RHVJ from the intestine of Pacific white leg shrimp had good environmental adapt-ability and safety,as well as some ability to antagonize pathogenic bacteria,and were used as a candidate strain for the development of probiotics.The findings laid the foundation for its application in prawn culture.
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