Isolation, characterization, application, and effect of bacteria with probiotic potential from the prawn Macrobrachium tenellum in Guasave, Sinaloa, Mexico

The prawn Macrobrachium tenellum is a species with high expectations for farming. However, like all cultivated species, it is exposed to bacterial infections caused by captivity and cultivation conditions. In this sense, probiotics in aquaculture have been used as an alternative against the excessive use of antibiotics in farming, thus preventing diseases. In the present work, 106 strains with probiotic potential were isolated, of which 77 are bacilli, and 29 are lactic acid bacteria (LAB) [(intestine (43), stomach (42) and hepatopancreas (21)] from the shrimp M. tenellum collected from a freshwater environment in Guasave, Sinaloa. Biochemical characterization of the isolated bacterial strains and molecular identification of the 16S ribosomal gene were performed. According to the hemolytic activity, the isolates MT4H2 (bacilli) and MT1E2 (LAB) showed gamma hemolysis (Ɣ), and the LAB strain presented catalase-negative. Both were Gram (+). They presented high hydrophobicity values (99.93 and 73.21%) in autoaggregation (90%) and coaggregation (99%). Regarding biofilm formation, both presented moderate capacity. On salinity tolerance, they grew in concentrations of 0 to 9% NaCl and a pH tolerance within a range of 5 to 9. Regarding enzyme activity, they exhibited activity in both proteases and lipases. Both presented resistance to some of the antibiotics tested. Only the strain of bacillus exhibited antagonistic activity against Vibrio parahaemolyticus. They were identified as Pontibacillus sp. and Pediococcus pentosaceus at a molecular level.