In vitro selection and molecular characterization of indigenous yeasts from Litopenaeus vannamei with probiotic potential to prevent Vibrio parahaemolyticus infection

Abstract

This study aimed to identify indigenous yeast strains from whiteleg shrimp (Litopenaeus vannamei) exhibiting probiotic potential and antagonistic activity against Vibrio parahaemolyticus. Samples were collected from shrimp intestines, sediment, and rearing water in shrimp ponds located in Banyuwangi, Jember, and Gresik. Subsequent screening was conducted based on anti-V. parahaemolyticus activity, biofilm inhibition, tolerance to temperature, pH, and bile salts, co-aggregation ability, hemolytic activity, pathogenicity in shrimp, and growth phase. Candidate probiotic yeast isolates were further identified using the Sanger method, with species identification based on sequence analysis against the GenBank NCBI database. A total of 120 yeast isolates were successfully obtained from the samples and screened, resulting in the identification of three candidate probiotic yeast isolates, i.e., GU12, GU13, and BA9. Molecular identification revealed that isolate GU12 exhibited 99.46% similarity to Kodamaea ohmeri (MK394144.1), whereas isolates GU13 and BA9 were identified as Candida parapsilosis (PX025649.1), with 100% similarity. Further studies are recommended to conduct additional biosafety evaluations and in vivo validation before applying these isolates in shrimp aquaculture as safe and environmentally sustainable alternatives for the prevention of bacterial diseases.