Profiles of gut microbiome in Litopenaeus vannamei artificially infected with Vibrio parahaemolyticus causing...

As the primary defense against pathogen invasion, the dynamic equilibrium of the shrimp gut microbiome is recognized as a critical factor influencing pathogen colonization. In recent years, translucent post-larva disease (TPD) outbreaks during the early stages of shrimp farming have become a serious threat to the sustainable development of the shrimp industry. Compared with other vibriosis, TPD caused by certain Vibrio strains possessing drug resistance and high-virulence genes exhibits greater virulence in shrimp tissues, with mortality rates reaching up to 90%. However, no studies have yet explored the association between this pathogen and the gut microbiome. This study employed metagenomic sequencing technology to analyze differences in the axial distribution of the gut microbiome in shrimp at varying degrees of TPD infection. Histopathological sections revealed that multiple tissue lesions induced by TPD infection in shrimp were primarily concentrated in the midgut. Alpha diversity analysis indicated that the alpha diversity index of the shrimp gut microbiome showed an upward trend as pathogen load increased. Beta diversity analysis revealed the intestinal segment with the most significant microbial community changes during pathogen colonization. Within this region, the abundance of probiotics decreased, while that of pathogenic bacteria increased. Functional prediction results indicate that under TPD stress, the gut microbiome activates a multi-layered, synergistic defense adaptation program through nutritional metabolism shifts, biofilm reinforcement, and toxin efflux. This study elucidates the pathogenic mechanism of TPD from the perspective of pathogen-gut microbiome interactions, suggesting that controlling pathogen load and restoring targeted probiotics may serve as effective strategies for preventing and controlling TPD.