Microbial Sequencing of Water and Intestines in Penaeus vannamei Shrimp Farming

While early-life probiotic supplementation is a common practice in shrimp larviculture, its long term efficacy and mechanisms remain poorly understood. Crucially, it is unknown whether the probiotics successfully colonize the intestine or merely exert transient effects, and if these early interventions have lasting consequences through the grow-out phase. This study investigated the effects of a probiotic mixture administered during the larval stage of Penaeus vannamei on survival, microbial communities, and subsequent long term health. Our findings revealed that larval probiotic supplementation significantly enhanced postlarval survival rate of P. vannamei. Although the supplemented probiotics did not stably colonize the intestinal tract, they significantly altered the assembly and function of the microbial communities in both the larval intestine and rearing water. This was marked by increased species diversity, a reduction in potential pathogens, and an enrichment of beneficial genera in the water. Functional prediction indicated a significant upregulation of microbial pathways related to uorum sensing and ABC transporters. Remarkably, this early life probiotic pretreatment induced strong carry-over effects during the grow-out phase. Under challenge with Vibrio parahaemolyticus, shrimp from the probiotic group exhibited significantly enhanced disease resistance, evidenced by a lower intestinal Vibrio load, elevated serum alkaline phosphatase activity, and upregulation of immune, Mucin 1 and intestinal barrier genes. Histological analysis confirmed a healthier hepatopancreas with increased populations of R cells and B cells. Additionally, microbiome analysis revealed that, in the probiotic group, the beneficial bacterial genus increased , while the potentially pathogenic bacterial genus decreased. Functional prediction showed more active energy metabolism pathways . In conclusion, our study demonstrated that early probiotic supplmentation, even without permanent colonization, could critically reshape the initial microbial succession. This microbial programming leaded to improved larval performance and conferred lasting enhancements in immune competence and disease resistance in shrimp, providing a novel theoretical foundation for optimizing probiotic strategies in sustainable aquaculture.