The Effect of Varying Levels of Purified Condensed Tannins on Performance, Blood Profiles, Meat Quality and Methane Emission by Male Bapedi Sheep Fed a Grass Hay and Sheep Pellet-Based Diet

Abstract This study determined the effect of purified condensed tannin inclusion levels in a diet on production, haematological indices, blood biochemical components, meat quality and methane emission by yearling indigenous male Bapedi sheep on a grass hay and sheep pellet-based diet in a 28-day trial. The diets contained similar (P>0.05) nutrients but with different (P<0.05) purified condensed tannin supplementation levels. A complete randomized design was used. Twenty-four yearling male Bapedi sheep were assigned to four dietary treatments having different purified condensed tannin levels of 0 (GH80P20PCT0), 30 (GH80P20PCT30), 40 (GH80P20PCT40) and 50 (GH80P20PCT50) g/kg DM. A quadratic type of equation was also used to determine condensed tannin supplementation levels for optimal performance and methane emission reduction by sheep. Supplementing diets with purified condensed tannins did not affect (P>0.05) intake, digestibility and performance of male Bapedi sheep. Supplementing diets with purified condensed tannins had no effect (P>0.05) on blood components of male Bapedi sheep. Bapedi sheep meat pH and sensory attributes were not influenced (P>0.05) by purified condensed tannin level in the diet. However, supplementing diets with purified condensed tannins decreased (P<0.05) methane emission by 51 to 60%. A 49.08g supplementation level with purified condensed tannins per kg DM diet was calculated, with the use of quadratic equations, to result in the lowest methane emission by male Bapedi sheep. Meat of male Bapedi rams on diets containing 30, 40 or 50g of purified condensed tannins per kg DM contained higher (P<0.05) antioxidant activities than meat from rams fed a feed without purified condensed tannins. These results indicate that purified condensed tannin supplementation levels used did not have adverse effects on Bapedi sheep. However, supplementation levels of 30, 40 or 50g of purified condensed tannins per kg DM diet reduced methane emission by 51 to 60%, and increased sheep meat antioxidant activity values. Supplementing diets with purified condensed tannins has potential to reduce methane production and emission by sheep. However, long-term studies are recommended to ascertain the present findings.