Transcriptomes of Litopenaeus vannamei reveal modulation of antioxidant system induced by dietary archaeal carotenoids

Oxidative stress induced by factors such as ammonia nitrogen has become a major issue in shrimp farming. The effects of carotenoids on the growth and antioxidant capability of Litopenaeus vannamei juveniles were investigated in this study using dietary archaeal carotenoids supplementation. For four weeks, shrimp were given diets containing 0 mg/kg (Ctrl) and 55.98 mg/kg (Car) archaeal carotenoids. Dietary archaeal carotenoids significantly enhanced the astaxanthin content in shrimp muscles and carapaces, as well as the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity ( P <0.05). The malonaldehyde (MDA) content in Car group significantly decreased ( P <0.05). The transcriptome analysis was conducted to determine the molecular processes in response to archaeal carotenoids supplementation. A total of 1 536 differentially expressed genes (DEGs) were detected, including 538 upregulated DEGs and 998 downregulated DEGs. GO functional enrichment analysis between Ctrl and Car indicated that 26 GO terms including extracellular region, metabolic process, and proteolysis were enriched. The KEGG pathway enrichment analysis revealed that the amino sugar and nucleotide sugar metabolism, cysteine and methionine metabolism, glycine serine and threonine metabolism, and amino acid biosynthesis were enriched. Archaeal carotenoids influenced the expression of several important genes involved in reactive oxygen species (ROS) generation, Nrf2 signaling, and antioxidant enzymes. Seven DEGs were chosen to confirm the RNA-Seq data using qRT-PCR. The genes and pathways discovered in this work assist to elucidate the molecular processes through which archaeal carotenoid enhances L. vannamei antioxidative system.