A number of viral diseases have significantly impeded the growth of the aquaculture industry. Antiviral drugs represent an effective means of controlling infection. However, the efficacy of the entire therapeutic process is contingent upon the availability of an efficient delivery system. This study selected three common antiviral drugs and constructed corresponding drug delivery systems utilising single-walled carbon nanotubes (SWCNTs) as carriers. The reliability of carbon nanotubes as delivery carriers was evaluated by detecting the therapeutic effect on infectious splenic and renal necrosis virus (ISKNV). The findings demonstrated that SWCNTs can effectively enhance the absorption of the three drugs into the body, prolong their metabolic half-life, and improve the survival rate of fish infected with ISKNV. The Ribavirin-SWCNTs (RBV-SWCNTs) group exhibited the most pronounced protective effect, with a mortality rate of less than 25%. It was observed that SWCNTs facilitated the rapid transportation of ribavirin, with the drug content in the RBV-SWCNTs group being approximately double that of the free ribavirin group. Furthermore, this system markedly diminished the viral load, augmented enzyme activities, and elevated antiviral gene expression. This study indicated that carbon nanotubes are optimal carriers for antiviral drugs, which have considerable potential as a delivery vehicle for antiviral drugs to prevent viral infections in aquaculture.
To investigate the impact of betaine on high-carbohydrate-diet-induced oxidative stress and endoplasmic reticulum (ER) stress, mandarin fish (Siniperca chuatsi) (23.73 ± 0.05 g) were fed with control (NC), betaine (BET), high carbohydrate (HC), and high carbohydrate + betaine (HC + BET) diets for 8 weeks. The results showed that betaine significantly promoted the growth of mandarin fish irrespective of the dietary carbohydrate levels. The HC diet induced oxidative stress, as evidenced by significantly elevated MDA levels. The HC diet significantly stimulated the mRNA levels of genes involved in ER stress (ire1,perk,atf6,xbp1,eif2α,atf4,chop), autophagy (ulk1,becn1,lc3b), and apoptosis (bax). However, betaine mitigated HC-diet-induced oxidative stress by modulating antioxidant enzymes and alleviated ER stress by regulating the mRNA of genes in the PERK-eIF2a-ATF4 pathway. Additionally, betaine significantly reduced the mRNA levels ofbecn1andbax, along with the apoptosis rate, indicating a mitigating effect on autophagy and apoptosis. Overall, dietary betaine improved growth, attenuated HC-diet-induced oxidative stress and ER stress, and ultimately alleviated apoptosis in mandarin fish. These findings provide evidence for the use of betaine in aquafeeds to counter disruptive effects due to diets containing high carbohydrate levels.Keywords:mandarin fish;high carbohydrate diet;betaine;oxidative stress;ER stress
危险品化学品经营许可证（带存储）