Integrated physiological, metabolome, and transcriptome analysis of the hepatopancreas in Penaeus vannamei under ammonia stress.

Ammonia nitrogen is a common environmental factor in aquaculture systems. High levels of ammonia nitrogen threaten the health of shrimp. This study aimed to investigate ammonia nitrogen stress in the hepatopancreas of Penaeus vannamei by integrating physiological, metabolome, and transcriptome analysis. The study revealed that exposure to ammonia nitrogen resulted in injury to the hepatopancreas, deformation disorder of the lumen, blurred boundaries, and increased vacuoles. After ammonia nitrogen stress, the activities of ammonia-metabolizing enzymes (glutamate dehydrogenase and glutamine synthetase) increased significantly, while the activity of transglutaminase decreased significantly. In addition, antioxidant enzymes (glutathione peroxidase, catalase, and superoxide dismutase) were significantly decreased. Additionally, the activity of energy metabolizing enzyme (hexokinase) was increased, and immune enzyme (alkaline phosphatase) activity was decreased. The accumulation of metabolites, such as d-myo-inositol, hexadecenoic acid, aspartate, and ornithine in the metabolite groups, showed significant differences under ammonia stress. Transcriptome analysis suggested that the KEGG pathways were significantly enriched in energy and primary metabolism, metabolism of cofactors and vitamins, and signaling pathways. The comprehensive analysis of metabolome and transcriptome displayed significant enrichment pathways, including TCA cycle, purine metabolism, pyrimidine metabolism, and folic acid biosynthesis under ammonia nitrogen stress. Simultaneously, six genes were found to respond to ammonia stress, including inositol oxygenase-like, histone h1-β, postembryonic, blood cell protein-glutamine-glutamyltransferase-like, receptor tyrosine protein phosphatase T-like, trichohyalin-like, and thyroxine 5-deiodinase-like. The results showed that ammonia nitrogen stress caused hepatopancreas tissue damage, changed in enzyme activities, metabolic process, and related gene expression in P. vannamei. [ABSTRACT FROM AUTHOR]