Potential role of dietary chitosan nanoparticles against immunosuppression, inflammation, oxidative stress, and histopathological alterations induced by pendimethalin toxicity in Nile tilapia.

A 21-days feeding screening period was conducted to highlight the protective efficacy of dietary chitosan nanoparticles (CSNPs) on pendimethalin (PD)-induced toxicity in Nile tilapia (Oreochromis niloticus). Hematology, non-specific immune response, the antioxidative enzymes [superoxide dismutase (SOD) and catalase (CAT), glutathione reduced (GSH), and glutathione peroxidase (GPx)] in the liver and anterior kidney, changes of pro-inflammatory cytokine genes [interleukins-8 (IL-8), interleukins-1ß (IL-1ß), and tumor necrosis-α (TNF-α)] in the anterior kidney and histopathological alterations were assessed. Fish (50 ± 7.5 g) were randomly assigned into four groups (Three replicates), the first group served as the negative control and fed on the control diet only, and the second group served as the positive control and fed on the control diet supplemented with CSNPs (1 g kg-1 diet). The two other groups were exposed to 1/10 96-h LC50 PD (0.5 mg L-1) in rearing water and simultaneously fed the control diet alone or supplemented with CSNPs (1 g kg-1 diet), respectively. Fish were fed on the experimental diets twice a day for 21 days. The results revealed that PD exposure caused a significant decline in the survival rate of the Nile tilapia, as well as in most of the hematological indices, respiratory burst activity, phagocytic activity, total immunoglobulin levels, lysozyme, and bactericidal activity. Additionally, PD toxicity markedly suppressed most of the antioxidative enzymatic activities in both tissues together with upregulation of immune genes (IL-8 and TNF-α); however, IL-1ß expression remained unaffected. The histopathological results revealed marked pathological changes in spleen, liver and intestine with a notable decrease of intestinal goblet cells in PD-exposed groups. Conversely, CSNPs exerted protective effects through improving the above mentioned parameters. Thus, CSNPs supplementation exhibited defensive effects against PD toxicity in Nile tilapia that might provide an insight into the promising role of CSNPs as a potential immunomodulatory feed additive for tilapia in aquaculture.