COMPARATIVE EVALUATION OF ENDOCRINE, LIPID, AND HEPATIC EFFECTS OF THREE KOLA SPECIES IN ADULT MALE RABBITS

Abstract

Kola nuts and bitter kola are widely consumed in Nigeria for their nutritional and ethnomedicinal benefits; however, concerns exist regarding their long-term safety. This study compared the effects of three different kola species seed diets on endocrine, lipid, and hepatic biomarkers in male rabbits. Fifty (50) male rabbits (130 ± 14 g) were randomly assigned into ten experimental groups of five rabbits each consisting of five (5); one control and nine treatment groups that received 5%, 10%, and 20% dietary inclusion of the test substance for 12 weeks. Serum testosterone, LH, FSH, ALT, AST, ALP, TC, LDL-c, and HDL-c were analyzed using standard enzymatic and immunoassay methods. Results showed that C. acuminata and G. kola significantly increased testosterone levels, with peak values at 5% (4.00 ± 0.02 ng/mL) and 10% (5.94 ± 0.28 ng/mL), respectively. LH and FSH were significantly reduced across all treated groups. TC levels increased significantly in all treatments, with the highest value observed in G. kola 20% (55.30 ± 1.85 mg/dL). LDL-c increased notably at higher inclusion levels, whereas HDL-c showed minimal variation. Liver enzymes (ALT, AST, ALP) were elevated, particularly in C. acuminata 20% (ALT: 48.30 ± 1.61 IU/L), indicating hepatocellular stress. Food intake declined significantly in all treated groups, with the greatest reduction at 10% inclusion (12.03 ± 0.12 g), and body weight gain was markedly reduced, especially at 20% inclusion (6.30 ± 4.20 g). Chronic dietary intake of C. acuminata, C. nitida, and G. kola seeds alters endocrine function, disrupts lipid homeostasis, induces hepatic stress, and suppresses growth performance in a dose-dependent manner. These findings highlight potential risks associated with prolonged high-dose consumption and underscore the need for moderated intake and further toxicological evaluation.