The antiviral property of Sargassum fusiforme polysaccharide for avian leukosis virus subgroup J in vitro and in vivo.

Avian Leukosis Virus Subgroup J (ALV-J) is an oncogenic retrovirus, mainly spread by vertical and horizontal transmission, which have caused severe losses in world poultry industry. Sargassum fusiforme polysaccharide (SFP), a marine algae sulfated polysaccharide, has attracted more attention due to its variously biological activities. In this study, the anti-ALV-J property of SFP was assessed in vivo and in vitro. The results demonstrated that different Mw of SFPs showed virustatic activity to ALV-J in vitro by combining with the virus when ALV-J adsorbed onto the host cells. When treated with SFPs, the ALV-J gene and protein expression reduced clearly and SFP-3 (Molecular weight 9 kDa) had the best antiviral effect. Results in vivo showed that the immunosuppression of the ALV-J infected chickens were relieved by SFP-3. Moreover, SFP-3 obviously inhibit the viral shedding and alleviated the organs damage caused by ALV-J. This study offered a new method for ALV-J treatment and enriched the potential application of SFP.