Andrologia. 2018;e13044. wileyonlinelibrary.com/journal/and | 1 of 9 https://doi.org/10.1111/and.13044 © 2018 Blackwell Verlag GmbH 1 | INTRODUCTION The current shift towards the consumption of formulations derived from natural products is necessitated by insufficient therapies to manage certain ailments and social problems (Eboetse, Ikechukwu, Olugbenga, Ayodele, & Caramel, 2011). More so, the desire for reg- imen with minimal side effects is responsible for the heightened public curiosity in natural products. Thus, recent research paradigm focuses on herbal remedies and dietary food supplements as a means of solving health challenges and social problems (Eboetse et al., 2011; Eisenberg et al., 1998). However, there is growing experimen- tal evidence indicating that some of these dietary food supplements, fruits, vegetables and seeds have antifertility effects (Abarikwu, Ogunlaja, Otuechere, & Gideon, 2017; Chauhan & Agarwal, 2010; Koriem, 2013). For instance, fenugreek seed-supplemented diet was reported to induce male infertility by targeting the testes. It reduced sperm concentration and altered the testicular seminiferous tubules and the interstitial tissues of rabbits (Kassem, Al-Aghbari, AL-Habori, Accepted: 6 April 2018 DOI: 10.1111/and.13044 ORIGINAL ARTICLE Telfairia occidentalis -supplemented diet induces changes in sperm parameters and testosterone level in rats R-C. C. Njoku | S. O. Abarikwu | A. A. Uwakwe | C. J. Mgbudom-Okah Department of Biochemistry, University of Port Harcourt, Choba, Nigeria Correspondence Sunny O. Abarikwu, Department of Biochemistry, University of Port Harcourt, Choba, Nigeria. Emails: sunny.abarikwu@uniport.edu.ng; abarikwus@gmail.com Summary The growing patronage on herbal remedies and formulations from natural products in most developing countries has warranted research into certain health challenges including their antifertility effects. This study assessed the effects of boiled Telfairia occidentalis (TO) seed-supplemented diets on the level of testosterone and semen quality in Wistar rats. Boiled TO seed diets at 10%, 15% and 30% were given to rats for 60 days. Our study showed that sperm quality was impaired as evidenced by the decreased number of motile spermatozoa, epididymal sperm numbers, percentage live/dead ratio and increased numbers of abnormal spermatozoa comparable to con- trol values ( p < .05). Feeding of rats with 10% and 15% TO seed-supplemented diets increased testosterone levels nonsignificantly, while in the 30% TO seed diet animals, the level of serum testosterone was found to decrease significantly compared to control values. Furthermore, TO diet caused a nonsignificant increase in the activity of superoxide dismutase and the concentrations of reduced glutathione and malondi- aldehyde except for the significant increase in malondialdehyde level in the testes of the 10% TO diet group. A nonsignificant decrease in myeloperoxidase activity was also observed in the 10% and 15% but not 30% TO diet group. Histological damages characterised by severe loss of germ cells were more pronounced in the 10% TO diet group. Fourier transform infrared spectroscopy analysis of boiled TO seeds revealed the presence of esters, alkenes, hydroxyl and alcohol functional groups. Thus, boiled TO seed-supplemented diet evoked antifertility effects in rats, and the effects on the toxicity end points investigated were not dose-dependent. KEYWORDS diet, sperm quality, Telfairia occidentalis, testes, testosterone