Effects of chronic glyphosate exposure on antioxdative status, metabolism and immune response in tilapia (GIFT, Oreochromis niloticus)

Glyphosate (Gly) is an active ingredient of herbicide, its underlying toxicity on fish is still unclear. The aim of this study was to evaluate chronic toxicity of Gly on tilapia via determining antioxidative status, metabolism, inflammation and immune response. The fish were exposed to different concentrations of Gly (0, 0.2, 0.8, 4 and 16 mg/L) for 80 days. The blood, liver, gills and spleen were collected to assay biochemical parameters and genes expression after 80 days of exposure. The results showed that treatments with higher Gly (4 and/16 mg/L) significantly increased the levels of TC, TG, AST, ALT, LDL-C and MDA, and apparently decreased the levels of SOD, GSH, CAT, HDL-C, HK, G3PDH, FBPase and G6PD in serum, liver and/or gills. The gene expression data showed that the treatments with Gly adversely affected Nrf2 pathway in liver, gills and spleen, as shown by significant changes of nrf2, keap1, ho-1, nqo1 and gsta mRNA levels. Meanwhile, inflammatory response was activated via enhancing the mRNA levels of nf-kappa b2, ref, rela tnf-alpha, and it-1 beta, and immunotoxicity was caused through downregulating the genes expression of c-lzm, hep, igm, hsp70 and c3 in liver, gills and/or spleen of tilapia after Gly exposure. Moreover, the mRNA levels of cyp1a and cyp3a were upregulated in 16 or 0.2 mg/kg Gly group in liver. Overall results suggested chronic Gly exposure reduced antioxidative ability, disturbed liver metabolism, promoted inflammation and suppressed immunity. Interestingly, the Nrf2 and NF-kappa B signaling pathways played key roles in Gly chronic toxicity.

Automated summary

The study evaluated the chronic toxicity of Glyphosate on tilapia by examining oxidative status, metabolism, inflammation, and immune response. Exposure to higher concentrations of Gly led to increased levels of certain parameters and decreased levels of others in serum, liver, and gills. Gene expression data showed adverse effects on the Nrf2 pathway, inflammatory response, and immune function. Overall, chronic Gly exposure reduced antioxidative ability, disrupted liver metabolism, promoted inflammation, and suppressed immunity, with key roles played by Nrf2 and NF-kappa B signaling pathways.