EVALUATION OF WATER HYACINTH AS A FEED FOR RUMINANTS

Water-hyacinth hay (WHH) was fed in mixtures in digestion trials on sheep as graded levels mainly 0, 25, 50 and 100 % of the crude protein of the concentrate feed mixture (CFM) and as a sole feed. Before carrying out these six digestion traits, the weed (from a channel and a ditch) was analysed for different components. Samples from the ditch reflected higher contents of EE, CP, crude ash, ADF, ADL, cellulose and silica; whereas most of the minerals were lower than in those of the channel. The leaves contained more NDF, hemicellulose, cellulose, total phenols and phenolic tannin; but stems were higher in ADF and ADL than leaves. Ca/P ratio was narrow in the whole plant than in leaves or stems. Digestibility of OM means in vitro gas production system (58.4 %) was closely to the in vivo estimated value (59.5 %); although ME (6.35 MJ/kg DM) and NEL (3.39 MJ/kg DM) were lower in the in vitro estimation than those obtained from the animals (7.56 and 4.61 MJ/kg DM, respectively). Inclusion of water hyacinth in the rations reduced feed intake. Digestibility (except for CF) and nutritive values (but not nutritive ratio) decreased by increasing WHH levels in the rations. WHH was superior to rice straw (RS) concerning digestibility of DM and CP and feeding value as DCP, TDN, ME and NEL, although the lower feed intake of WHH than of RS. Digestibilities of WHH were similar to that of CFM plus RS, whereas WHH was less consumable and had a lower nutritionally value. Estimation of digestibility of WHH or RS by direct method was generally better than by indirect method. WHH had an positive effect on by-difference CF digestibility of CFM. The most pronounced changes in the blood profile caused by feeding WHH as a sole feed. These included increased total protein, albumin (P less-than-or-equal-to 0.05), total lipids (P less-than-or-equal-to 0.05) and cholesterol (P less-than-or-equal-to 0.05) and decreased creatinine, phospholipids, inorganic P and Ca (less-than-or-equal-to 0.01). These changes could clear the reasons of a death case after befall of tetany. Thus, it could be recommended that WHH may not be offered as a sole feed for ruminants but it could be replaced up to 50 % of concentrates in the complete feed diets.