Expression profile of immune-associated genes in the kidney of cultured large yellow croaker Larimichthys crocea in the East China Sea area

To explore the effect of environment conditions on immune activity of fish, eight immune-associated genes responsible for innate immunity were selected from the GenBank, i.e. Pgrn-a, Ifit2, P-hepcidin, Lect2, β2m, Irf1, Il25 and Hsp96, and the mRNA expressions of them in the kidney of cultured large yellow croaker Larimichthys crocea in different sea areas in the East China Sea were examined with qPCR techniques. In the contrasts of immune-associated gene expression between areas and populations, significant differences were found, expression levels of these immune-associated genes were lower in the clear water area than in the poor water quantity area, and lower in May than in October. MY was more sensitive to environmental factors than DQ, which was coincident with the water quality in the culturing areas. Differential analyses of the expression levels of these immune-associated genes showed that significant up-regulation could be triggered by poor environmental factors. The expression patterns indicated that the expression levels of these genes were sensitive to ecological changes, thereby the immune-associated genes, especially Pgrn-a, Ifit2, β2m, Il25 and Hsp96, might serve as immediate and sensitive indicators of population immunologic vigor and ecosystem health. But the expression of immunity-associated genes at the level of gene transcription is highly influenced by multiple factors, and the exact causes or influencing factors of the up-regulation or down-regulation of these genes still need further thorough investigation.