Submitted to: Animal Feed Science And Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/28/2000
Publication Date: N/A
Citation: Interpretive Summary: In north Sumatra, Indonesia, there is an abundance of concentrate feedstuff such as rice bran, cassava meal, molasses, and palm kernel cake. The former three are low in crude protein while palm kernel cake averages about 15%. An inexpensive, local source of supplemental protein are tropical legume trees, which can be stripped and the leaves hand fed daily to confined lambs. The tropical tree legumes found best suited for this purpose are Calliandra calothyrsus, Paraserianthes falcataria and Gliricidia sepium. The leaves of these trees, however, contain tannins, which are antiquality factors and can depress dry matter intake and digestibility. When concentrate diets were supplemented at either 15 or 30% of dry matter in a growth trial and an intake trial, dry matter intake was increased compared with the control (no legume leaves). Although intake increased from tree legume supplementation, both dry matter and nitrogen digestion decreased. Calliandra calothyrsus, highest in tannin concentrations, was most extreme Supplementation of these tannin-containing legume trees to high concentrate diets was not beneficial in this study. These legumes appear to be better sources of crude protein for tropical forage diets where total nitrogen intake may be limiting.
Technical Abstract: Calliandra calothyrsus, Paraserianthes falcataria and Gliricidia sepium leaves were supplemented at both 25 and 50% of dietary crude protein to a basal concentrate and fed to growing ram lambs. A control diet consisted of concentrate and the forage grass Brachiaria brizantha. Dry matter intakes and ADG of tree legume supplemented treatments were lower (P <0.05) than control lambs, but increasing the amount of tree leaves fed did not result in further decreases in either dry matter intake or ADG. Dry matter digestibility was lower (P <0.05) in both 25 and 50% dietary treatments compared with the control, while NDF digestibility was lower (P <0.001) only in the 50% dietary treatments. Increasing the amount of leaves fed from all three tree species led to decreased NDF digestibility. Fecal NDF-N was higher in tree-supplemented groups (P <0.01) compared with control and increased (P <0.05) with increasing amounts of tree leaves fed. Both apparent and true N digestibility were lower (P <0.05) in C. calothyrsus, than in the other tree legume treatments. True N digestibility of 91% for the control was higher (P <0.01) than the tree legume treatments supplemented at both 25 (range, 83-86%) and 50% dietary CP (range, 74-79%). Increasing the amount of tree leaves fed, regardless of tree species, decreased N digestibility in the diets. Higher fecal NDF-N and lower N digestibility in tree leaf supplemented lambs indicated that condensed tannins present in these tree species were binding protein and rendering it less available for digestion. Supplementation with C. calothyrsus, which had the highest levels of SPHE and SPRO, affected N utilization more negatively than did supplementation with either P. falcataria or G. sepium.