Peroxiredoxin-4 supplementation modulates the immune response, shapes the intestinal microbiome, and enhances AHPND resistance in Penaeus vannamei

Peroxiredoxin-4 from Penaeus vannamei (LvPrx4) is considered a damage-associated molecular pattern (DAMP) that can activate the expression of immune-related genes through the Toll pathway. We previously demonstrated that the recombinant LvPrx4 (rLvPrx4) can enhance shrimp resistance against Vibrio parahaemolyticus, causing acute hepatopancreatic necrosis disease (VPAHPND), which causes great production losses in shrimp farming. Herein, we showed that the rLvPrx4 had a thermal tolerance of around 60 degrees C and that the ionic strength had no noticeable effect on its activity. We discovered that feeding a diet containing rLvPrx4 to shrimp for three weeks increased the expression of the immune-related genes LvPEN4 and LvVago5. Furthermore, pre-treatment with rLvPrx4 feeding could significantly prolong shrimp survival following the VPAHPND challenge. The shrimp intestinal microbiome was then characterized using PCR amplification of the 16S rRNA gene and Illumina sequencing. Three weeks of rLvPrx4 supplementation altered the bacterial community structure (beta diversity) and revealed the induction of differentially abundant families, including Cryomorphaceae, Flavobacteriaceae, Pirellulaceae, Rhodobacteraceae, and Verrucomicrobiaceae, in the rLvPrx4 group. Metagenomic predictions indicated that some amino acid metabolism pathways, such as arginine and proline metabolism, and genetic information processing were significantly elevated in the rLvPrx4 group compared to the control group. This study is the first to describe the potential use of rLvPrx4 supplementation to enhance shrimp resistance to VPAHPND and alter the composition of a beneficial bacterial community in shrimp, making rLvPrx4 a promising feed supplement as an alternative to antibiotics for controlling VPAHPND infection in shrimp aquaculture.