Study of the toxicity of Fe3O4 nanoparticles on Pacific white leg shrimp (Litopenaeus vannamei) and the antibacterial efficacy against Vibrio harveyi

Nanotechnology has rapidly developed in various fields. The unique, specific, and very small dimensions of nanoparticles have many functions in technical and biological advancements, such as drug delivery and antibacterial applications. This study investigates the potential antibacterial properties of chitosan-stabilized Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs) to inhibit the growth of Vibrio harveyi bacteria and evaluates their toxicity towards white leg shrimp ( Litopenaeus vannamei ). The characterization results of the Fe 3 O 4 NPs synthesis show an average crystallite size of 21.41 nm. The antibacterial activity of chitosan-capped Fe 3 O 4 NPs colloidal (Cs/Fe 3 O 4 NPs) was found at a chitosan concentration of 15,000 mg/L, with an inhibition zone against V. harveyi of 6.12 ± 0.02 mm, and Fe 3 O 4 NPs colloidal without chitosan capping at 6.17 ± 0.01 mm. Both treatments showed significantly greater antibacterial activity (P<0.05, n=3) compared to the treatment with Fe 3 O 4 NPs colloid capped with chitosan at 5,000 and 10,000 mg/L. The toxicity test was conducted on white leg shrimp at 48 hours and 96 hours of exposure, with the highest mortality occurring at a concentration of 125 mg/L, resulting in 5% mortality (P > 0.05) with an LC 50 value of 338.84 mg/L. Fe 3 O 4 NPs have the potential to be developed as therapeutic agents or as bacterial growth inhibitors in the field of aquaculture by coating feed as a supplement (nano feed) due to their antibacterial properties and low toxicity levels towards cultured organisms.