Influence of anti-androgen cyproterone acetate on sperm characteristics, testosterone level, testicular and liver histology in male goldfish (Carassius auratus)

Cyproterone acetate (CA), a synthetic anti-androgen, was injected intraperitoneally into fish at two doses (5 and 50 mg/kg body weight) to evaluate its effects on physiological, biochemical, and reproductive parameters. A total of 180 fish were divided into three groups: Control (C), low-dose (LCA), and high-dose (HCA), with two replicates per group. Fish were observed daily for behavior, and water quality was controlled throughout the study. After 28-days of exposure, blood samples were collected to analyze plasma biochemical parameters. Sperm motility, concentration, and histological analyses of testes and liver tissues were also conducted. Results showed a significant dose-dependent decrease in cholesterol, triglycerides, and testosterone levels in the CA-treated groups, with the highest reduction observed in the HCA group (P < 0.05). Sperm motility was significantly reduced in the low-dose (66.1 ± 2.2 %) and high-dose (36.5 ± 3.9 %) groups compared to the control group (79.5 ± 2.2 %). Similarly, sperm concentration and motility time were significantly reduced in the CA-treated groups (P < 0.05). The gonadosomatic index (GSI) also decreased significantly in the treated groups, with the HCA group showing the lowest GSI (P < 0.05), indicating impaired gonadal development. Histological analysis of the testes revealed delayed spermatogenesis, with the HCA group predominantly showing immature gonadal stages (Stage II), and a significant reduction in spermatocytes and spermatozoa. Liver histology indicated necrosis, cell death, blood congestion, and vacuolization in both the LCA and HCA groups, particularly at the high dose (P < 0.05), suggesting hepatotoxicity. In conclusion, CA exerted significant endocrine-disrupting effects in fish, impairing sperm motility, gonadal development, and liver function in a dose-dependent manner. The high-dose treatment caused pronounced effects, including hepatocellular injury and a severe decline in reproductive health. These findings highlight the potential risks of cyproterone acetate as an endocrine disruptor and emphasize the importance of its effects on aquatic species, particularly in ecotoxicological assessments.