Integrated analysis of muscle proteomics and neurotransmitter-targeted metabolomics in Penaeus vannamei infected with Enterocytozoon hepatopenaei (EHP)

Penaeus vannamei is one of primary farmed shrimp species in the world, and its growth specification is the key indicator for evaluating its commercial value. In recent years, hepatopancreatic microsporidiosis (HPM) caused by Enterocytozoon hepatopenaei (EHP) has been rampant in global shrimp farms, severely effecting the growth of shrimp and causing substantial economic losses to the aquaculture industry. This study has pioneered the use of a combined analysis of muscle proteomics and plasma neurotransmitter-targeted metabolomics to investigate the systemic changes in P. vannamei under EHP infection. Muscle proteomics identified 199 differential proteins, among which 127 were up-regulated and 72 were down-regulated. The expression of hemoglobin subunit L2 (HcL2) related to the immune response to pathogen infection was significantly up-regulated, while the expression of phosphodiesterase (PDE) related to immunity and metabolism regulation was significantly down-regulated. Some differential proteins were also related to the growth of shrimp, such as the significant up-regulation of epidermal growth factor-related protein 1 (EGFrP1) and myosin heavy chain (MYH), indicating that the muscle tissue repair and compensatory effects of EHP infected shrimp were enhanced. The neurotransmitter-targeted metabolomics analysis revealed that EHP infection caused metabolic disorders in shrimp, manifested by a significant decrease in the level of L-glutamicacid, and significant increases in 3-hydroxykynurenine and kynurenine levels. This indicates that the overall activity of the tryptophan-kynurenine (Trp-Kyn) metabolic pathway was enhanced, while the synthesis of 5-HT was inhibited. This study contributes to understanding the molecular mechanisms underlying growth inhibition in EHP-infected shrimp from a perspective of neuroendocrinology.