Acute hepatopancreatic necrosis disease (AHPND) is a devastating condition impacting marine shrimp production worldwide. The objective of this study was to evaluate the effects of four probiotic formulations on Pacific white shrimp (Litopenaeus vannamei) infected with pathogenic Vibrio parahaemolyticus causing AHPND. In addition, bacterial community composition analyses of shrimp gastrointestinal tract (GIT) and aquaculture water before and after infection were conducted by sequencing variable region 4 of the 16S rRNA gene on the Illumina MiSeq platform. Treatments included: (1) Lactobacillus casei (P1), (2) L. casei and Rhodopseudomonas palustris (P2), (3) L. casei, Saccharomyces cerevisiae and R. palustris (P3), and (4) a commercial probiotic EM ® (EM), which showed shrimp survival of 11.7%, 26.7%, 36.7% and 73.3% respectively. Treatments causing lower survival showed greater relative abundance (>60%) of family Vibrionaceae in the GIT compared to treatments with higher survival. Diversity indices from GIT samples revealed that treatments showing higher survival had higher Shannon index values (4.69 ± 0.133), compared with those of treatments with lower survival (0.17 ± 0.004). Diversity indices from water samples did not show significant differences after infection (Shannon index 4.64 ± 0.53). The results showed that probiotics could effectively mitigate AHPND while maintaining diverse microbial composition in shrimp GIT, thus maintaining sustainability in the shrimp aquaculture industry.

Acute hepatopancreatic necrosis disease (AHPND) is a devastating disease affecting aquaculture shrimp industry around the world. Probiotics may provide an effective approach to reduce the detrimental impact of this disease in shrimp ponds. The present study was conducted to determine the inhibitory effects of probiotics against the Vibrio parahaemolyticus strain that causes AHPND. Probiotic solutions (whole microbial cultures and supernatants) consisting of three microbial cultures including Lactobacillus casei, Saccharomyces cerevisiae, and Rhodopseudomonas palustris individually and in various combinations were tested against V. parahaemolyticus. Disk diffusion tests and challenge tests in liquid media were conducted. Findings revealed inhibition zones with greater diameters in disks treated with whole microbial cultures (min: 7.83 mm, max: 11.33 mm) in comparison to those treated with only supernatants (min: 7.00 mm, max: 8.50 mm). Results from the challenge test showed greater inactivation of the pathogen after 48 h (6.56 ± 0.07 to 5.43 ± 0.03 log 10 reduction) when treated with L. casei and L. casei in combination with other two probiotics. In conclusion, the probiotic solutions that included L. casei, the combination of L. casei and R. palustris, and the combination of L. casei, S. cerevisiae and R. palustris have the potential for inhibiting AHPND in shrimp aquaculture.

Shrimp has been among the top value-added products targeted for production by the aquaculture industry. The increasing demand for shrimp has led to a massive increase in production in several countries across the world. Intensive and super-intensive production systems are facing great challenges handling newly emerging shrimp diseases. The use of antibiotics was one of the first approaches when dealing with such diseases, but the effects of misusing antibiotics and the appearance of antibiotic resistant bacteria are of public concern. As an alternative, probiotics have been applied in aquaculture systems to increase disease resistance, improve feed efficiency, maintain water quality and enhance the growth of aquatic organisms. In this study, the ability of three probiotic microbes to tolerate salinity levels commonly found in intensive shrimp production systems were evaluated. Lactobacillus casei, Saccharomyces cerevisiae and Rhodopseudomonas palustris were cultured in MRS broth, yeast and mold broth, and Van Neil's broth, respectively, enriched with 1 and 2% NaCl. Microbial survival between treatments were compared as well as the metabolic activity in terms of acidity levels. Additionally, cell morphology was compared using scanning electron microscopy. L. casei and S. cerevisiae showed no significant differences (P>0.05) in media with 1% and 2% NaCl in terms of microbial survival and media acidity levels at 24 h. R. palustris showed a prolonged lag phase extending up to 12 h in 1% and 48 h in 2% NaCl media, and acidity of the media did not vary significantly. Cell morphology of all microbes did not change significantly across all treatments. From these results, it was concluded that L. casei, S. cerevisiae and R. palustris are suitable for application in aquaculture ponds with up to 2% salinity.