Nutrient digestibility, Nitrogen balance and blood profile of west african dwarf Goats fed residue-concentrate diet supplemented with Yeast

Abstract

This study evaluated the effects of Saccharomyces cerevisiae (SC) supplementation on feed dry matter intake (DMI), nutrient digestibility, nitrogen utilisation, haematological, and serum biochemical indices of West African Dwarf (WAD) goats. Four dietary treatments were prepared, which were composed of millet chaff and concentrate at a 70:30 ratio supplemented with varying levels of yeast inclusion: 0% (T1), 0.5% (T2), 1.0% (T3), and 1.5% (T4). Twenty WAD goats (7-8 months; ⁓8 kg) were randomly placed on these 4 diets (n = 5) for 21 days, which included 14 days of adaptation and the last 7 days of digestibility trial. During the trial, feed was offered, and refusal was measured, and faecal and urine samples were collected on a daily basis to determine DMI, nutrient digestibility, and nitrogen balance. On the last day, blood samples were collected for haematological and serum biochemical analyses. Data obtained were subjected to one-way analysis of variance, and means were separated at P < 0.05. Results showed that SC supplementation significantly (P < 0.05) improved DMI, nutrient digestibility, and nitrogen utilisation. Haematological parameters were not significantly affected (P > 0.05), while serum total protein, globulin, urea, total bilirubin, and aspartate aminotransferase were significantly influenced (P < 0.05), but most parameters remained within normal physiological ranges. Goats fed the T3 diet (1.0% SC) showed the most improvements over the control in DMI (139.43–197.14 g/d) and recorded the highest digestibility of DM (28.12–60.08%), crude protein (45.17–69.28%), neutral detergent fibre (22.21–58.22%), acid detergent fibre (18.15–43.56%) and acid detergent lignin (15.57–32.01%), respectively, as well as greater nitrogen absorption (0.88–2.14 g/d) and retention (0.8–2.13 g/d). Overall, SC supplementation enhanced nutrient utilisation and physiological status in the WAD goats fed a residue-based diet without adverse health effects, with 1.0% identified as the optimal inclusion level.