Therapeutic effects of saponin components on porcine reproductive and respiratory syndrome virus-infected piglets.

The present study aimed to evaluate the potential therapeutic effects of Anemoside B4 (AB4), Panax notoginseng saponins (PNS), Notoginsenoside R1 (SR1), Saikosaponin A (SSA) and Saikosaponin D (SSD) on piglets infected with porcine reproductive and respiratory syndrome virus (PRRSV). A total of 132 completely healthy piglets were randomly divided into 22 groups consisting of six animals each. Control piglets were intramuscularly injected with 2 ml of PRRSV (NJGC strain) solution containing 10⁶ TCID₅₀ virus/ml. For low-, middle- and high-dose saponin treatment groups, the piglets were initially administrated with the same volume of PRRSV solution, followed by intraperitoneal injection with AB4, PNS, SR1, SSA or SSD at 1, 5 or 10 mg/kg b.w. on day 3. The piglets in drug control group were intraperitoneally injected with 10 mg/kg b.w. of each saponin without prior PRRS challenge, while those in blank control group were injected with the same amount of normal saline. The results indicated that all the five saponin components could decrease the incidence and severity of PRRSV-induced immunopathological damages, including the elevated body temperature, weight loss, anaemia and internal inflammation. Moreover, the saponin components could enhance protein absorption and immune responses. Taken together, this study reveals that the saponin components are effective against PRRSV infection and strengthen the immune system and thus may serve as potential antiviral therapeutic agents.