Antiviral activity by fish antimicrobial peptides of epinecidin-1 and hepcidin 1–5 against nervous necrosis virus in medaka

The nervous necrosis virus (NNV)-medaka infection model was used in this study for analysis of NNV infection and treatment of NNV with the antimicrobial peptides (AMPs) of epinecidin-1 and hepcidin 1–5 at the organismal level. Our results showed that co-treatment of AMPs with the virus was effective in promoting a significant increase in medaka survival. Re-challenge with the virus also showed high survival suggesting that these two AMPs enhanced fish survival. However, pretreatment or post-treatment with AMPs showed that both of these AMPs increased medaka survival and suggested that AMPs can be used as drugs to rescue infected medaka. The data presented here indicate that epinecidin-1 and hepcidin 1–5 have in vivo antivirus activity against the NNV, and hepcidin 1–5 functions like a lytic peptide after an in vitro assay. Infection after pretreatment, co-treatment, and post-treatment with epinecidin-1 or hepcidin 1–5 was verified by RT-PCR which showed both peptides can downregulate NNV and interferon gene expressions. In addition, our results suggest that epinecidin-1 or hepcidin 1–5 may prove to be an effective chemotherapeutic agent for aquaculture in the future.