Poly(lactic--glycolic acid) Microspheres Encapsulating a Viral-Binding Protein, PmRab7, for Preventing White Spot Syndrome Virus in Shrimp.

White spot syndrome virus (WSSV) is one of the most devastating pathogens affecting shrimp. Within a short time, it leads to a hundred percent mortality rate, which causes substantial economic losses. PmRab7 has been reported to bind to the envelope protein of WSSV, VP28, resulting in a reduction of viral replication. In order to apply PmRab7 in shrimp feed, the development of delivery systems is crucial. Poly(lactic--glycolic acid) (PLGA) is a biodegradable polymer extensively studied for drug delivery in the form of nanoparticles or microspheres (MSs). Despite its potential, PLGA has not been previously reported for antiviral use in shrimp. This study is the first to demonstrate the potential use of PLGA and chitosan-coated PLGA (PLGA/CS) MSs for the delivery of PmRab7 in shrimp. Both PLGA and PLGA/CS were optimized and characterized to allow for a sustained release of encapsulated PmRab7. Initial in vitro and in vivo evaluations demonstrated that both MSs are safe for use in shrimp, can sustain the release of PmRab7, and enhance its antiviral activity as shown by a decrease in the mortality rate in shrimp. The development of these MSs has the potential to significantly enhance disease control in shrimp aquaculture, leading to more effective and sustainable practices that will ultimately bolster the industry's growth and long-term stability.