Effects of a blended supplementation of Piliostigma thonningii and Daniella oliveri essential oils on reproductive performance, semen quality, and fertility indices in Bunaji bulls.

Abstract

This study investigated the effects of a blended essential oil formulation derived from Piliostigma thonningii (camel’s foot) and Daniella oliveri on the reproductive performance of Bunaji bulls. The combination was selected based on the complementary phytochemical profiles of both plants, which are rich in phenolics, flavonoids, and terpenoids with documented antioxidant, antimicrobial, and endocrine-modulating activities. These bioactive compounds are associated with improved testicular function, enhanced spermatogenesis, and better semen quality. In addition, both plants are widely distributed in tropical savanna ecosystems, making their combined use a cost-effective and sustainable phytogenic strategy for reproductive enhancement in livestock. A completely randomized design was used, involving fifteen clinically healthy Bunaji bulls (22–24 months old; 156.32 ± 0.70 kg average body weight), which were allocated into three dietary treatment groups. Over a 16-week experimental period, bulls received a basal diet supplemented with 0 ml/kg (T1, control), 10 ml/kg (T2), or 20 ml/kg (T3) of the blended essential oil mixture. The results indicated that dietary treatments had no significant effect (P > 0.05) on semen pH or colour, which remained consistently creamy white across all groups. However, supplementation with the blended essential oil significantly improved (P < 0.05) sperm concentration and ejaculate volume, with the highest values observed in T3. Likewise, sperm motility, percentage of live sperm, and live-to-dead sperm ratio were significantly enhanced (P < 0.05) in the supplemented groups compared with the control. In contrast, bulls in the highest supplementation group exhibited the lowest proportions of dead and morphologically abnormal sperm cells (P < 0.05). Although most specific sperm abnormality traits, including midpiece droplet, coiled tail, detached head, free tail, and bent tail, were not significantly influenced by dietary treatment (P > 0.05), scrotal length and circumference increased significantly (P < 0.05) with supplementation, with the greatest improvement recorded in T3. In conclusion, supplementation with the blended Piliostigma thonningii and Daniella oliveri essential oil mixture at 20 ml/kg improved testicular development and semen quality without adverse effects, demonstrating its potential as a natural and sustainable phytogenic alternative to synthetic reproductive enhancers in bull production systems.