Effects of dietary salmon intake on the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in peripubertal male Wistar Han rats.

Dioxins and dioxin-like polychlorinated biphenyls (dl-PCBs) are persistent organic pollutants with known reproductive toxicity, particularly related to sperm quality. To explore the effects of dietary TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) exposure and the potential modulating influence of seafood nutrients, a 90-day feeding trial was conducted using prepubertal Wistar Han rats. The study used a 2 × 2 factorial design comparing diets based either solely on casein, or diets containing Atlantic salmon fillet as 50% of the protein source, with or without TCDD (200 ng/kg feed). The reproductive outcomes assessed were sperm count and plasma testosterone levels. Proteomic profiling of testis and hypothalamus was performed to provide further mechanistic insights. TCDD exposure resulted in significant accumulation in liver tissue but did not affect sperm count or testosterone levels. However, proteomic analysis revealed 247 differentially expressed proteins in testis tissue (FDR <0.1), indicating effects on the redox balance, mitochondrial function, and cellular metabolism. No significant proteomic changes were observed in the hypothalamus, and no interactions between TCDD and the salmon-based diet were found with regards to molecular or reproductive endpoints. These findings suggest that moderate, subchronic dietary TCDD exposure induces subcellular stress responses in testis tissue without overt effects on sperm parameters in peripubertal rats. Inclusion of salmon fillet in the diet did not mitigate TCDD toxicity under these experimental conditions.