Evaluación de microbiota de las costas de Sonora y Baja California contra cepas patógenas de Vibrio parahaemolyticus y Vibrio harveyi, agentes causales de la necrosis hepatopancreática en camarón blanco (Litopenaeus vannamei)

Abstract

Aquaculture faces great economic losses in white shrimp (Litopenaeus vannamei) farming due to microbial and viral diseases. One of these diseases is Acute Hepatopancreatic Necrosis (AHPND), which emerged in China in 2009 and was reported in Mexico until 2013. The causal agents of AHPND in white shrimp are Vibrio parahaemolyticus and Vibrio harveyi, which caused 80% of crop losses in the states of Sonora, Sinaloa and Nayarit, Mexico. For this reason, the aim of this study focused on identifying marine bacteria as probiotics, capable of inhibiting the causal agents of AHPND. The bacteria were isolated from clams, crabs, algae, and marine water from ecosystems in Sonora and Baja California. Their hemolytic ability, cellulose and amylase degradation of the selected strains, and their ability to inhibit pathogens were analyzed. The identification of the probiotic strains was performed with biochemical assays using the API system and was confirmed by amplification of the 16S rRNA gene. We obtained 10 isolates presented antagonistic ability against V. harveyi and were identified as: H3 Aeromonas hydrophila, while isolates J1, G10, H3 M, H2, G2, G2.1, 14 2.1, G3.2 and E 2.1 as Bacillus pumilus. In the case of V. parahaemolyticus were: G2.1, H2, J1, G3.2 and E2.1. For the hemolytic activity assays, isolates J1, G10 and E2.1 (B. pumilus) presented β hemolysis. The isolates identified as B. pumilus and A. hydrophila showed antagonistic activity against V. paraheamolyticus and V. harveyi, so they can be classified as potential probiotics based on the results obtained, which contribute to the knowledge of new beneficial strains for biocontrol of these pathogens and their application will avoid the use of antibiotics in aquaculture, reducing the incidence of resistance to these drugs.