The effect of Aspergillus niger on the nutritive value of water hyacinth as fish feed using solid state fermentation

Abstract

Water hyacinth typically has high moisture content, low protein profile and high crude fiber content. Its value as a feed resource can be improved through solid-state fermentation with the fungi species, Aspergillus niger. This study was conducted with the aim of producing environmentally friendly and nutrient rich fish feed at low cost from water hyacinth. Water hyacinth leaf and whole plant were collected, dried, milled, sterilized and subjected to incubation with Aspergillus niger for a period of eight weeks. Fermentation resulted in an increase (p<0.05) in crude protein and ash contents, a decrease (p<0.05) in dry matter, crude fiber, nitrogen free extract and fat contents of fermented water hyacinth leaf and whole plant. The results suggested that water hyacinth with six weeks fermentation period contained the highest level of crude protein of both leaf and whole plant. Hence, biological treatment of water hyacinth using Aspergillus niger improved its nutritive value, and this finding might be used to produce fish feed and to reduce environmental pollution.