Effect of Sweet Potato Leaf Supplementation on Growth and Nutrient Digestibility in Sheep

Abstract The effects of feeding dried sweet potato (Ipomoea batatas) leaf (SPL) on growth performance, digestibility, and nitrogen (N) utilization were studied in sheep. Twenty-four rams with initial body weight of 18.5 ± 1.49 kg were randomly allocated to four treatments containing ad libitum natural grass hay alone (T1), hay + 150 g SPL (T2), hay + 300 g SPL (T3) and hay + 450 g SPL (T4) on as fed basis. Results indicated that dry matter (DM), organic matter (OM) and crude protein (CP) in-takes increased (P < 0.001) with increasing levels of SPL. Sheep fed with T2, T3 and T4 diets gained 55.1, 52.6 and 66.5 g per head per day, respectively, while the gain of non-supplemented sheep (9.19 g per head per day) differed (P < 0.05). Digestibility of DM, OM, and CP was higher (P < 0.01) for all supplemented sheep compared with the control. The CP digestibility and N retention were negative in non-supplemented sheep. Urinary N excretion decreased (P < 0.001) with the increasing levels of SPL supplementation. The N retention improved with the increasing levels of SPL and was the highest (P < 0.001) in sheep fed with T4 diet and the lowest in non-supplemented sheep. In conclusion, supplementing a basal diet of natural grass hay with SPL considerably improved the average daily gain, OM and CP digestibility and N retention.