In vitro evaluation of vitamin D3 as an antiviral and immune modulator against novel yellow catfish calcivirus (YcCV) in channel catfish kidney (CCK) cell line in aquaculture.

This study investigates the antiviral, immunomodulatory, and antioxidant effects of VD3 on Channel catfish kidney (CCK) cells infected with Yellow Catfish Calicivirus (YcCV). CCK cells were treated with various concentrations of VD3 (0, 60, 120, 180 pM) and infected with YCCV, and 180 pM VD3 was determined as the optimal dose. The experimental groups included a control group, a YcCV group, and a VD3 + YcCV group. We assessed oxidative stress, immune response, and apoptosis in these groups. Our results demonstrated that VD3 significantly increased cell viability in the VD3 + YCCV group compared with the YcCV group, with no significant cytotoxicity observed. Antioxidant analysis demonstrated that VD3 plays a promising role in regulating virus-induced oxidative stress, significantly reducing malondialdehyde (MDA) levels (P < 0.05). Furthermore, VD3 + YcCV treatment also increased both superoxide dismutase (SOD) and Lysozyme (LZM) activities (P < 0.05). Moreover, compared with the viral group, VD3 + YcCV also significantly reduced ROS activities (P < 0.05). Additionally, VD3 demonstrated its effect by a decrease in apoptosis, reducing the apoptotic cell population from 30% in the YcCV group to 17% in the VD3 + YcCV group. VD3 also induced the upregulation of immune-related genes (vdr, irf3, ifn-α, jak-1, stat-1, mx-1, and ifp-35). These results demonstrate that VD3 enhances cellular antiviral immune responses, reduces oxidative stress, and modulates immune gene expression, suggesting its potential as an immunostimulant for viral infections.