Background <p>Heavy metal contamination poses a major threat to marine organisms, particularly species such as <i>Sardinella aurita</i>, by compromising their health and disrupting the balance of marine ecosystems. This study examines the impact of diets enriched with either white or red muscle from <i>Sardinella aurita</i> collected in the Gulf of Gabes on the reproductive health of male rats, focusing on biochemical, histological, and reproductive parameters.</p> Methods <p>Male Wistar rats were assigned to three groups: Control rats (CON) received only commercial pellets (standard diet). The RED group was fed pâté supplemented with red muscle from <i>Sardinella aurita</i>, while the WH group received pâté containing white muscle from <i>Sardinella aurita</i>. a. Over a 60-day period, we assessed serum testosterone levels, sperm counts, and testicular histology. Lead concentrations in fish muscle and rat testes were determined using atomic absorption spectrophotometry, while histopathological evaluations were performed by staining tissue sections with hematoxylin and eosin.</p> Results <p>The findings reveal several concerning changes, including reduced testes weight, lower serum testosterone levels, and a decrease in both sperm count and motility. Furthermore, the study reports an increase in testicular oxidative stress and lipid peroxidation, accompanied by alterations in the activity of antioxidant enzymes. Hematological changes were also observed, along with the accumulation of heavy metals in both the fish muscle and the rat testes. Additionally, testicular histology showed abnormalities, reflecting structural alterations.</p> Conclusions <p>These results highlight the potential reproductive risks linked to the consumption of fish contaminated with heavy metals, underscoring the need for monitoring seafood safety and addressing environmental contamination to protect both marine life and human health.</p>