A comparative study on chitosan nanoparticle synthesis methodologies for application in aquaculture through toxicity studies.

Chitosan nanoparticles (CSNPs) have been recently used for various applications in aquaculture, especially as drug carriers. The aim of this study was to synthesise and investigate a superlative method of CSNP synthesis for application in aquaculture through aquaculture-based toxicology screening methods. Two different methods were analysed: the first a direct ionic gelation method (A) and the other involving a low-molecular-weight chitosan microparticle intermediate method (B). Dynamic light scattering characterisation revealed that the CSNP particle sizes were 192.7 ± 11.8 and 22.9 nm from methods A and B, respectively. The LC50 values for brine shrimp toxicity were found to be 1.51 and 0.02 ppt in 24 h for methods A and B, respectively. Acute toxicity studies in Litopenaeus vannamei rendered LC50 values of 3235.94 and 2884.03 ppt in 24 h for methods A and B, respectively. Zebrafish toxicity studies revealed mortality rates of 21.67% and 55% at 20 mg/L concentration for methods A and B, respectively, with an increased expression of intracellular reactive oxygen species in method B. From these findings, it can be concluded that a comparatively reduced toxicity of CSNPs derived from ionic gelation method makes it more appropriate for application in aquaculture.

Curcumin loaded chitosan nanoparticles fortify shrimp feed pellets with enhanced antioxidant activity.

Chitosan nanoparticles (CSNPs) have been recently explored as a potential drug carrier to enhance the bioavailability and aqueous solubility of drugs. Curcumin, an antioxidant with a remarkable antiradical scavenging activity was encapsulated in CSNPs to revamp its bioavailability. While changes in the optimal farming condition can induce oxidative stress in the animals, curcumin loaded chitosan nanoparticles (Cur-CSNPs) were amalgamated into shrimp feed pellets to ameliorate its antioxidant content in an attempt to bolster the organisms against oxidative stress. Cur-CSNPs were synthesized in two different concentrations of curcumin as Cur-CSNPs A and B. Characterization of the synthesized Cur-CSNPs revealed asymmetrical nanoparticles with semispherical geometry and a zeta potential ˃50 mV. HPLC studies substantiated encapsulation efficiencies of 77.53% and 80.35% for Cur-CSNPs A and B respectively. DPPH, ABTS and FRAP assays manifested a significant enhancement in the antioxidant property of the Cur-CSNPs fortified feed pellets. This is the first study to investigate and demonstrate the ability of Cur-CSNPs to enhance the antioxidant property of aquaculture feed pellets. These findings substantiate that Cur-CSNPs fortified feed may be applied to reinforce aquaculture animals against oxidative stress.