Abstract

RAMIREZ-TIRADO, Horacio et al. Factors affecting the density of Vibrio parahaemolyticus in the hepatopancreas of shrimp Penaeus vannamei in production units in Northwest Mexico. Abanico vet [online]. 2025, vol.16, e2024-40.  Epub July 04, 2025. ISSN 2448-6132.  https://doi.org/10.21929/abavet2025.1.

Vibrio parahaemolyticus acts as an opportunistic and primary pathogen in shrimp production units, causing Acute Hepatopancreatic Necrosis Disease (AHPND) and the much more virulent postlarvae glass disease (HLVD) than the AHPND strain. However, the variables that determine the density of this pathogen in production units are not yet clear. For this reason, the aim of this study was to determine the physical, chemical and biological variables that favour its development in the hepatopancreas of Penaeus vannamei shrimp, in the water and sediment of culture ponds. The research was carried out in commercial farms located on the northwest coast of Mexico. At each farm, water, sediment and shrimp samples were collected for bacteriological analysis (CHROMAgar Vibrio plate seeding), water quality (nitrite NO2 -, nitrate NO3 -, ammonium NH4 +, phosphate PO4 3- and alkalinity CaCO3), organic matter and pH (in sediment), as well as measurements of salinity, temperature, dissolved oxygen, pH (in water) and transparency. To analyze the association of physical, chemical and biological variables with the density of V. parahaemolyticus in the shrimp hepatopancreas, a Generalized Linear Model (GLM) was constructed. The model that best explained the data had an explained variance of 34.85%. Bacteriological examination showed that the northern and southern zones showed the highest average density of V. parahaemolyticus in the shrimp hepatopancreas. The model revealed a significant effect (P < 0.05) on the density of V. parahaemolyticus in culture pond water and sediment, culture cycle, dissolved oxygen, salinity, pH in culture water, NH4 + and alkalinity. The evidence found for the effect of some of the factors on the density of V. parahaemolyticus in the shrimp hepatopancreas suggests constant monitoring to avoid densities detrimental to shrimp health.

Keywords : shrimp farms; environmental variables; generalized linear model; Vibrio parahaemolyticus.

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