Optimizing chitosan nanoparticles for oral delivery of double-stranded RNA in treating white spot disease in shrimp: Key insights and practical implications.

Delivering double-stranded RNA (dsRNA) in shrimp is challenging due to the lack of an effective carrier system. This study optimized chitosan nanoparticles (CNs) from two sources-α-chitosan from shrimp and β-chitosan from squid-to encapsulate antiviral dsRNA for oral administration via shrimp feed. Using response surface methodology (RSM), formulations were refined for encapsulation efficiency, particle size, polydispersity index, and zeta potential. Both types of CNs demonstrated high encapsulation efficiency (>95 %), small sizes (<300 nm), and stable zeta potential (>20 mV). Shrimp-derived CNs provided superior RNase protection and controlled release, while squid-derived CNs showed a burst release. Incorporated into feed, both types of CNs remained stable for over a month. Shrimp-derived CNs offered greater dsRNA protection (>70 %) and improved efficacy against white spot syndrome virus (WSSV), significantly reducing mortality. These results position shrimp-derived CNs as promising dsRNA carriers for combating WSSV in shrimp aquaculture.