Studio preliminare in vitro delle proprietà antivirali di silvafeed ENC 400® nei riguardi di Reovirus e Metapneumovirus aviari

A Chestnut (Castanea spp.) extract (Silvafeed ENC400®) containing tannins and currently used in the animal feed industry, were tested for in vitro antiviral activity against avian reoviruses (ARV) and metapneumoviruses (AMPV). The MTT assay was used to evaluate the 50% cytotoxic concentration (CC50) of the vegetable extract on VERO cells. The potential extra - or intra -cellular antiviral properties of the compound were tested before and after the adsorption of the viruses to VERO cells. The inhibitory effects of the tested compound were expressed as IC50 (concentration of the compound corresponding to 50% inhibition of viral cytopathic effect) The CC50 for SilvafeedENC400® was 243.04 µg/ml. The examined compound had clear extra-cellular antiviral effect (express as IC50) against both ARV (54 µg/ml) and AMPV (58 µg/ml). The antiviral activities observed were always associated to a low in vitro cytotoxicity. Therefore these preliminary results suggest that the examined compound might be good candidate in the control of some avian virus infections. Nevertheless, further in vivo experiments are required to confirm these findings.