Chemical composition and nutritive value of leaves and stems of tropical weed Chromolaena odorata

Abstract

Chromolaena odorata (Siam weed) has been classi®ed as a weed plant in West Africa. Data from C. odorata foliage after 4, 6, 8, 10 and 12 weeks of regrowth showed that the leaf fraction had a crude protein content above 194 g kg±1 dry matter (DM) and an average leaf to stem ratio of 2á1:1. Chemical analysis of the leaf fraction of an 8-week-old regrowth indicated a high crude protein content (258 g kg±1 DM) and a high degradable nitrogen content (60á7 g N kg±1 digestible organic matter), but low neutral-detergent ®bre (331 g kg±1 DM), aciddetergent lignin (53á1 g kg±1 DM), total extractable phenolic (37á1 g kg±1 DM), extractable tannin (0á72 absorbance at 550 nm) and extractable condensed tannin (1á4 g kg±1 DM) contents. In sacco degradability analysis of the 8-week-old regrowth leaf sample showed a high 48 h organic matter (935 g kg±1 DM) and crude protein (953 g kg±1 DM) degradability. The leaf sample had an organic matter degradability of 670 g kg±1 DM as estimated by cumulative gas production in vitro after 24 h incubation. There was little or no phenolic-related antinutritive factors in C. odorata. Additionally, leaf samples had no effect on rumen protozoa activity estimated as the rate of [14C]leucine Selenomonas ruminantum bacterial protein breakdown. Data from this study suggest that C. odorata leaves are of high nutritive value and might have the potential to be used as a protein supplement to ruminants. There is need for further investigation to test whether C. odorata leaves may have any deleterious effect on the host animal