Research in: Agricultural & Veterinary Sciences

This study investigated the impact of Piliostigma thonningii Schum. essential oil (PTS) supplementation on nutrient digestibility, nitrogen metabolism and ruminal fermentation characteristics in growing rams. Twenty-one clinically healthy Yankassa ram lambs (average initial weight: 10.55 ± 0.60 kg) were randomly allocated into three dietary treatments (n = 7 per group) in a completely randomized design. The experimental period lasted for 90 days. Treatment groups included a control (T1) receiving the basal diet alone, while T2 and T3 were supplemented with 5 mL/kg and 10 mL/kg diet of PTS, respectively. Digestibility of dry matter (DM), crude protein (CP), ether extract (EE), crude fiber (CF), nitrogen-free extract (NFE), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL) and cellulose was significantly higher (P < 0.05) in T3 compared to the control, indicating enhanced nutrient utilization with higher PTS inclusion. Ash and hemicellulose digestibility were significantly greater (P < 0.05) in T2 than T3, though both outperformed the control group (P < 0.05). Nitrogen intake, fecal nitrogen output, total nitrogen loss and percentage nitrogen utilization showed significant improvement (P < 0.05) in PTS-supplemented groups, with T3 recording the highest values. Urinary nitrogen and nitrogen retention were notably elevated in T2, while T3 showed intermediate values, both significantly higher than the control (P < 0.05). Rumen fermentation parameters demonstrated significant modulation by PTS. Supplemented groups recorded lower (P < 0.05) rumen pH, ammonia nitrogen, methane emissions, acetic acid concentration and acetate-to-propionate ratio. Conversely, total volatile fatty acids (TVFA), iso-butyric, iso-valeric and valeric acid levels were significantly increased (P < 0.05) in T2 and T3. Butyric and propionic acid concentrations peaked in T3 (P < 0.05), indicating improved fermentation efficiency. In conclusion, dietary inclusion of Piliostigma thonningii essential oil notably enhanced nutrient digestibility, nitrogen retention and ruminal fermentation efficiency in growing rams. The 10 mL/kg diet supplementation level was found to be the most effective in optimizing performance and promoting overall animal well-being.