Heavy Metal Content of Water Hyacinth (Pontederia (Eichhornia) crassipes) and Its Safe Inclusion Levels in Ruminant,...

Water hyacinth poses significant environmental challenge in many countries. As part of the effort of reducing its negative effect, there is a great interest to use it as animal feed. However, reports of its safe inclusion level are not consistent. Since the heavy metal content of water hyacinth differed with the water quality it grows in, the safe inclusion level recommendation based on single research results can't be reliable to use widely. This study made a review of the heavy metal content of water hyacinth published to 2025 and presented widely applicable safe inclusion level of water hyacinth to ruminant, poultry, and swine based on the 95th percentile value of the heavy metals content report and the maximum tolerable limit of heavy metals reported by NRC (2005). Therefore, based on these values, water hyacinth leaf can be included in ruminants', poultry and swine rations up to 13.5%, 9.19% and 18.4%, respectively, without posing a problem on animals due to the heavy metal intake. Water hyacinth shoot can be included in cattle, sheep and poultry ration up to 17.3%. For swine, it can be included up to 24.4%. The whole plant water hyacinth can safely be used in ruminants and nonruminants' rations up to 6.23% and 6.15%, respectively. These recommendations are safe for 95% of the areas where heavy metal content of water hyacinth reported.