EFFECTS OF WATER HYACINTH OR WATER LETTUCE SUBSTITUTION FOR GUINEA GRASS ON NUTRIENT DIGESTIBILITY BY GROWING SHEEP

Abstract

Two in vivo digestion trials were conducted (using the total collection method) to study the -- effects of water hyacinth (Eichhornia crassipes) or water lettuce (Pistia stratiotes) substitution for guinea grass (GG) on nutrient digestibility by growing sheep. Each trial involved 24 ram- lambs fed diets contain in various levels of ground water hyacinth (WH) or water lettuce (WL) hay. In trial I, a control diet made up of 46% ground maize, 30% ground GG hay, 15% groundnut cake, 8% cane molasses and 1% oyster shell was compared with diets in which 10, 20, or 30% WH hay replaced the same amounts of GG hay in the diets. Trial II was conducted in a similar manner using 10, 20 or 30% WL hay as replacements for equal amounts of GG hay. In trial I, the digestion coefficients for dry matter (DDM), organic matter (DOM), rude fiber (DCF) and gross energy (DGE) among the WH treatments were not different (P>0.05). Digestion coefficient for crude protein (DCP) was lower (P<0.05) for the WH-30 diet than for the other diets. The percent digestible ether extract (DEE) was higher (P<0.05) for the WH-0 and WH-10 diets than for the WH-20 and WH-30 diets with no differences (P>0.05) between either the WH-20 and WH-10 diets or WH-20 and WH-30 diets. The percent digestible ash (DAsh) among the experimental diets followed the general trend WH-l0>WH-0>WH-20>WH-30 (P<0.05). The coefficients of digestible nitrogen free extract (DNFE) among the various diets followed the trend WH-30 = WH-10> WH-0>WH-20 (P<.05). In trial 11. there were no differences (P>0.05) among the WL treatments for DDM, DOM, DNFE and DGE. The percent DCP followed the trend (WL-0>WL-10 WL-30>WL-20 (P<0.05). Results obtained for percent DCF showed higher values (P<0.05) for the WL-20 and WL- 30 diets than for the WL-0 and WL- 10 diets with no differences (P>0.05) between either the WL-20 and WL-30 diets or the WL-0 and WL-30 (P<0.05). The results showed that WH and WL hays could be incorporated into the diets of growing sheep at levels of up to 30% with reasonably good levels of utilization and that WH and WL hays compared favourably with GG hay as roughapes for growing sheep. However, the high level of ash in the aquatic weeds may limit the amount that could be successfully incorporated into livestock diets without adverse effects.