Effects of different proportions of sweet potato (Ipomoea batatas) leaf and tuber on sheep rumen fermentation in vitro

Department of Animal Nutrition and Feed Technology, IPB University, Bogor, Indonesia 16680

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Abstract

This study evaluated the in vitro rumen fermentation characteristics of sheep fed concentrates containing varying proportions of sweet potato ( Ipomoea batatas) leaves and tubers. Five treatments were formulated with leaf-to-tuber ratios of 60:40 (T0), 65:35 (T1), 70:30 (T2), 75:25 (T3), and 80:20 (T4). Rumen fluid was collected from eight sheep and incubated with 0.5 g of substrate and McDougall’s buffer at 39°C for 4 and 48 hours. Parameters measured included dry matter digestibility (DMD), organic matter digestibility (OMD), rumen pH, ammonia-nitrogen (NH3–N) concentration, total volatile fatty acids (VFA), total bacterial count, and protozoal count. Data were analyzed using a randomized complete block design with four replicates per treatment. Results indicated that increasing leaf proportion significantly enhanced DMD (P<0.01), OMD (P<0.01), NH3 –N concentration (P<0.05), and bacterial population (P<0.01), while total VFA production (P<0.01) and protozoal counts (P<0.01) decreased. The highest DMD (82.48 ± 3.42%), OMD (79.98 ± 3.27%), NH3–N (7.83 ± 1.32 Mm), and bacterial count (8.58 ± 0.06 log cells mL–1) were observed in T4. Rumen pH remained optimal across treatments (6.73 ± 0.05). These findings suggest that a concentrate containing 80% sweet potato leaves, and 20% tubers optimizes in vitro rumen fermentation in sheep.