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 Fe₃O₄ nanoparticles (Fe₃O₄ NPs) to inhibit the growth of Vibrio harveyi bacteria and evaluates their toxicity towards white leg shrimp (Litopenaeus vannamei). The characterization results of the Fe₃O₄ NPs synthesis show an average crystallite size of 21.41 nm. The antibacterial activity of chitosan-capped Fe₃O₄ NPs colloidal (Cs/Fe₃O₄ 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 Fe₃O₄ 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 Fe₃O₄ NPs colloid capped with chitosan at 5,000 and 10,000 mg/L. The toxicity test was conducted on white leg shrimp at 48 h and 96 h of exposure, with the highest mortality occurring at a concentration of 125 mg/L, resulting in 5 % mortality (P > 0.05) with an LC₅₀ value of 338.84 mg/L. Fe₃O₄ 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.