Análisis comparativo revela las diversas respuestas inmunitarias del camarón blanco del Pacífico Litopenaeus vannamei...

Bacterial disease is the principal threat to farmed Litopenaeus vannamei, and outbreaks inflict heavy economic losses. Understanding the immune response mechanisms triggered by distinct pathogen-associated molecular patterns (PAMPs) will furnish a theoretical foundation and technical support for the precise prevention and control of bacterial diseases. In this study, three experimental groups were established and injected with lipopolysaccharide (LPS), peptidoglycan (PGN), or phosphate-buffered saline (PBS), respectively. The results showed that both the two PAMPs damaged the hepatopancreas, midgut, muscle, and gills, with the hepatopancreas suffering more severe lesions in the LPS group. In hepatopancreas homogenates, LPS stimulation significantly increased alkaline-phosphatase (AKP) and lysozyme (LZM) activities and significantly reduced total antioxidant capacity (T-AOC), whereas PGN stimulation significantly elevated superoxide dismutase (SOD) activity. In the hepatopancreas, 1,253 and 182 differentially expressed genes (DEGs) were detected post LPS and PGN stimulation, respectively. Further analysis on DEGs showed that LPS mainly activated innate immune defenses, whereas PGN tended to regulate metabolism and cellular repair to avoid excessive immunity. Overall, histopathological observations in the hepatopancreas, midgut, muscle, and gills, together with hepatopancreatic immune-enzyme activities and hepatopancreas transcriptomic profiling, indicate that LPS strongly induces innate immunity and oxidative stress, causing more severe tissue damage, while PGN elicits a more conservative immune modulation that balances the immune response and tissue protection, thereby lessening overall injury.