A total of 481 samples, including 417 shrimp and molluscan shellfish samples from retail shops and farms and 64 water samples from shrimp and molluscan shellfish farms in the Mekong Delta located the southern part of Vietnam, were examined for the presence of Vibrio parahaemolyticus (VpAHPND) caused acute haepatopancreatic necrosic disease (AHPND) in shrimp. VpAHPND strains were isolated in two of 298 (0.7%) molluscan shellfish samples from retail shops, seven of 71 (9.9%) shrimp samples from shrimp ponds, and two of 42 (4.8%) water samples from shrimp ponds. VpAHPND strains were classified into two types of O antigen, including O1 and O3, in which O1 was the predominant. VpAHPND strains isolated showed high resistance rates to colistin (100%), ampicillin (93.8%), and streptomycin (87.5%). These results indicate that VpAHPND is widely prevalent in environment in the Mekong Delta, Vietnam.

Background: Alternative materials for antibiotics used in white leg shrimp farming were extensively investigated. The promising effects of plant based extracts in controlling aquaculture diseases has been reported elsewhere. This study was conducted to examine the effect of Solanum procumbens Lour. extract on survival, growth performance, innate immunity and protection against acute hepatopancreas necrosis disease caused by Vibrio parahaemolyticus (VpAHPND) in white leg shrimp. Methods: From March 2021 to September 2021, four difference diets were examined including the supplementation of S. procumbens L. extract at 0.0%, 0.5%, 1.0% and 1.5%. After 30 days of culture, the experimental shrimp was examined for survival rate, growth responses, innate immune parameters and mortality as challenged with VpAHPND. Result: The results indicated shrimp fed diets with and without S. procumbens L. extract supplementation showed no significant differences in survival and growth performances. However, the innate immune parameters were likely increased in shrimp fed diets at 1.0% and 1.5% extract supplementation and shrimp fed diets at 1.0% and 1.5% extract supplementation reduced the accumulate mortality of VpAHPND challenged shrimp by 47.6%. S. procumbens L. could be a potential material for enhancing innate immunity of white leg shrimp and can protect shrimp from AHPND infection.