Dietary biogenic selenium nanoparticles improve growth and immune-antioxidant indices without inducing inflammatory responses in Nile tilapia.

The present study evaluated the use of green-synthesized selenium nanoparticles (SeNPs), using the microalgae Pediastrum boryanum as a diet additive in aquaculture to improve the growth performance, health, and immune response of Nile tilapia. Nile tilapia were fed different concentrations of green SeNPs (79.26 nm) as follows: 0, 0.75, and 1.5 mg/kg of SeNPs for 8 weeks. Following the trial, growth performance, biochemical indices, antioxidant and pro-inflammatory cytokine-related genes, and tissue histological examinations were performed. The study showed that SeNPs significantly improved (P < 0.05) growth performance and innate immune parameters (P < 0.001, IgM, and lysozyme) at both supplemented doses compared with the control. The protein profile and liver function enzymes were normal compared with those in the control group (P > 0.05). Serum malondialdehyde and superoxide dismutase levels were not significantly changed, while reduced glutathione and catalase were significantly enhanced (P < 0.01, P < 0.05) in the SeNPs 1.5 mg/kg compared to the control group. No inflammatory response was detected upon SeNP supplementation, as indicated by the absence of changes in the expression of pro-inflammatory cytokine genes. The earlier assays' results were histopathologically evidenced, where hepatic and splenic tissue architectures in SeNPs groups did not reveal any deviation from the control group. Our findings indicate that green selenium nanoparticles can potentially improve the growth and immunological response of Nile tilapia, offering opportunities for incorporating health benefits into functional foods and nutraceuticals, which corresponds to the increasing consumer interest in eco-friendly, environmentally sustainable dietary supplements.