Antiviral activity of chlorogenic acid against largemouth bass virus (
Micropterus salmoides
) in vitro and in vivo
Ruixian Huo, Hannan Gong, Renjie Yu, Dekun Tang, Xiaohui Bai, Min Yang, Qiwei Qin, Yifang Chen, Shina Wei Abstract
The largemouth bass ( Micropterus salmoides [Lacepède, 1802]) is a commercially important aquaculture species, but its production is severely threatened by largemouth bass virus (LMBV), necessitating the development of effective antiviral strategies. Chlorogenic acid (CGA), a natural polyphenol compound, exhibits broad biological activities, but its effect on LMBV infection remains unclear. This study evaluated the effects of CGA on LMBV infection using both in vitro and in vivo experiments. Using LMBV‐permissive fathead minnow (FHM) cells as an established in vitro infection model, we found that CGA reduced the transcription and protein expression of the LMBV major capsid protein (MCP). CGA treatment reduced the transcript levels of inflammation‐related genes IL‐1β, IL‐6, IL‐8 and TNF‐α, both pre and post viral infection. CGA increased the expression of antioxidant‐related genes such as Nrf2, SOD, CAT and GPx while decreasing Keap‐1 expression. Western blot analysis further confirmed that CGA suppressed the phosphorylation of JNK, ERK and p38. In vivo, largemouth bass were fed diets supplemented with 0 (NC), 200 (L200), 400 (L400) and 600 (L600) mg/kg CGA for 8 weeks. CGA treatment improved growth performance, decreased hepatic MDA levels and increased antioxidant enzyme activity, including CAT, SOD and GPx. The CGA‐supplemented groups exhibited lower transcript levels of pro‐inflammatory cytokines TNF‐α and IL‐1β, alongside elevated expression of anti‐inflammatory cytokines IL‐10 and TGF‐β, compared to the NC group. CGA supplementation notably elevated the mRNA expression levels of Nrf2, CAT, SOD and GPx while reducing the mRNA expression level of Keap‐1. Dietary CGA supplementation significantly improved survival rates in LMBV‐challenged largemouth bass and inhibited LMBV‐MCP transcription in the liver, spleen and head kidney. In summary, CGA demonstrates notable anti‐LMBV activity in both in vitro and in vivo settings. These effects were accompanied by changes in Mitogen‐Activated Protein Kinase (MAPK)‐associated proteins and inflammatory‐ and antioxidant‐related responses. Therefore, CGA represents a promising candidate for development as a dietary supplement to control LMBV infection.