CHEMICAL COMPOSITION AND IN VITRO DRY MATTER DIGESTIBILITY OF VINES AND ROOTS OF FOUR SWEET POTATO (ipomoea batatas) VARIETIES GROWN IN SOUTHERN ETHIOPIA

Abstract

Chemical composition and in vitro true dry matter digestibility (IVTDMD) of vine and its fractions (leaf, petiole and stem) and roots of two early maturing (Belela and Temesgen) and two medium maturing varieties (Beletech and Tulla) were investigated. Vine and root samples from each variety were harvested from triplicate plots (5.1m x 4.8m). Vine samples were partitioned in two equal parts: one part analyzed as whole vine and the second part was fractionated into leaf, petiole and stem. Differences in chemical composition and IVTDMD between vine and its fractions (leaf, petiole and stem) were significant (p<0.05). Leaf had crude protein (CP) content of 26.1, 22.3, 20.5 and 28.4%DM; Neutral detergent fiber (NDF) 25.4, 25.3, 30.7 and 30.2%DM and IVTDMD 90.7, 90.6, 87.5 and 90.1%; petiole had CP of 7.9, 12.1, 7.7and 10.0%DM; NDF 27.8, 29.4, 28.5 and 27.9%DM and IVTDMD 93.4, 93.4, 91.4 and 91.5% and stem had CP of 8.2, 10.9, 8.3 and 10.3%DM; NDF 38.5, 37.5, 40.4%DM and 40.2 and IVTDMD 78.2, 77.8, 74.4 and 76.3%, respectively, for Belela, Temesgen, Beletech and Tulla. In vine CP of 18.7, 18.1, 15.5 and 17.3%DM; NDF 32.7, 31.4, 38.3%DM and 36.9 and IVTDMD 86.2, 86.3, 83.1 and 83.5%, respectively, for Belela, Temesgen, Beletech and Tulla were found. There was also significant (p<0.05) variations in CP and NDF but not (p<0.05) in IVTDMD of roots between varieties. Root CP of 6.9, 7.7, 6.8 and 6.3 % DM; NDF 7.2, 6.0, 6.5 and 6.3 %DM and IVTDMD 94.3, 94.5, 94.9 and 94.6%, respectively, for Belela, Temesgen, Beletech and Tulla were found. In conclusion, Belela and Temesgen had better quality than Beletech and Tulla in most measured parameters.