Comparative Analysis of Non-Specific Immunity of Clarias Fuscus, Silurus Asotus, and Silurus Meridionalis

Clarias fuscus, Silurus asotus and Silurus meridionalis are economically important species in the aquaculture industry in China. However, comparative analysis of immune indices of C. fuscus, S. asotus, and S. eridionalis has been rarely been conducted. In the present study, head kidney and spleen indices and blood serum immunologically related enzyme activity of C. fuscus, S. asotus, and S. meridionalis were detected. Both head kidney and spleen body ratios were highest in S. meridionalis, followed by S. asotus, and lowest in C. fuscus. This suggests that the degree of lymphocyte proliferation and immune function of S. eridionalis might be strongest compared to S. asotus and C. fuscus. Blood serum lysozyme activity, superoxide dismutase (SOD) activity, and alkaline phosphatase activity, were highest in S. meridionalis, followed by S. asotus, but lowest in C. fuscus. Compared to S. asotus, acid phosphatase activity and catalase activity was higher in C. fuscus. Both acid phosphatase and catalase activities were highest in S. meridionalis, which was in line with lysozyme, superoxide dismutase (SOD), alkaline phosphatase, head kidney and spleen body ratios. This indicated that compared to S. asotus and C. fuscus, the immune function of S. meridionalis was strongest, and might have the greatest resistance to invaders like parasites, bacteria, and viruses. These results provide a theoretical basis for selection of varieties and optimization of germplasm in fish culture production and may be very valuable in future research.