Silver nanoparticles treatment for Aeromonas hydrophila infection in Nile tilapia (Oreochromis niloticus): In vivo and in vitro study.

Abstract

Bacterial infections present major challenges in aquaculture, especially for Nile tilapia. Aeromonas species are commonly associated with diseases in freshwater fish. Silver nanoparticles (AgNPs) are promising for use in aquaculture due to their antibacterial, antifungal, and antiviral properties. This study investigates in vitro and in vivo reactions to low concentrations of silver nanoparticles (AgNPs) as an antibacterial solution against Aeromonas hydrophila, aiming to find an alternative remedy for this pathogen, particularly one that exhibits resistance to numerous antibiotics. Four aquariums contained fish acclimated to 1, 3, 6, and 12 μg/L of AgNPs, which were dissolved in water for three weeks. Then, 0.2 ml of A. hydrophila (1 × 10 CFU/ml) was injected intraperitoneally, and the fish were monitored over five days. Our results demonstrated that the incorporation, even at lower concentrations, of a single dose of AgNPs (1 μg/L), caused blood immune cell activation (lymphocytes, neutrophils, monocytes, and Eosinophils). Plasma glucose levels decreased, as did triglycerides and cholesterol levels. ALT and AST in general also declined. This research investigated the effectiveness of silver nanoparticles (AgNPs) as an antibacterial solution against A. hydrophila, particularly in cases of antibiotic resistance. The findings suggest that AgNPs may be safely used in aquarium water at concentrations of 1, 3, and 6 μg/L to combat this pathogen. They not only act as a bactericidal agent but also enhance fish immunity, reducing mortality from infections. The minimum bactericidal concentration (MBC) for Nile tilapia (Oreochromis niloticus) can be achieved at 1 μg/L in aquarium water.