This study investigated the effects of Piliostigma thonningii essential oil (PTEO) supplementation on feed intake and hematological parameters of growing sheep. Twenty-one healthy Yankassa ram lambs (6–7 months old; average weight: 10.55 ± 0.60 kg) were randomly assigned to three treatment groups in a completely randomized design. Each group received the same basal diet with different levels of PTEO: 0 ml/kg (T1 – control), 5 ml/kg (T2), and 10 ml/kg (T3), over a 16-week feeding period. Dry matter (DM), ether extract (EE), organic matter (OM), acid detergent fibre (ADF), and hemicellulose intake increased significantly (p 0.05) across treatments, with the highest values observed in T3. Similarly, crude protein (CP), non-structural carbohydrates (NSC), neutral detergent fibre (NDF), and cellulose intakes were higher in PTEO-supplemented groups compared to the control. The highest DM intake in T3 indicated that PTEO at 10 ml/kg diet did not compromise palatability. Hematological parameters followed a consistent ly positive trend with increasing PTEO supplementation. Packed cell volume (PCV) ranged from 35.55% to 41.29%, hemoglobin (Hb) from 11.76 to 13.04 g/dL, mean corpuscular hemoglobin concentration (MCHC) from 31.43% to 33.52%, neutrophils from 39.33% to 44.30%, and eosinophils from 5.00% to 7.51%, all increasing in the order T3 T2 T1. Red blood cells (RBC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), white blood cells (WBC), and lymphocyte counts were also higher in the PTEO-supplemented groups. Conversely, the neutrophil-to-lymphocyte ratio was highest in the control group (T1), while basophils and monocytes showed no significant differences among treatments. In conclusion, dietary supplementation of PTEO at 10 ml/kg improved nutrient intake and supported favorable hematological responses, indicating enhanced health and performance. PTEO may serve as a safe, sustainable alternative to synthetic feed additives in sheep production
Emmanuel Anaso (Mon,) studied this question.