Paeoniae Radix Rubra extract inhibits largemouth bass ranavirus (LMBV) replication by suppressing inflammatory response and oxidative stress.

Largemouth bass ranavirus (LMBV) is a highly pathogenic virus belonging to the genus frog virus. This virus is characterised by rapid transmission and high mortality rates, posing a serious threat to the aquaculture of Micropterus salmoides. Paeoniae Radix Rubra (PRR) is a traditional medicinal plant in China with various biological activities, including anti-inflammatory, heat-clearing, and detoxifying effects. However, its effects on LMBV have been rarely reported. Therefore, this study evaluated the antiviral activity of Paeoniae Radix Rubra extract (PRRE) against LMBV using methods such as Cytopathic effect (CPE), qRT-PCR, TCID50, and Western blot. The results showed that PRRE exhibited significant dose-dependent inhibitory effects on LMBV infection and the inflammation it induces. Additionally, this study evaluated the antiviral activity of PRRE in Micropterus salmoides via oral administration. The results indicated that PRRE improved the survival rate of Micropterus salmoides infected with LMBV, inhibited LMBV gene expression, and reduced tissue pathology and inflammatory responses during infection. In summary, these results indicate that PRRE has great potential in the prevention and control of LMBV, providing scientific support for its further application.