Nutritional and Anti-Nutritional Properties of Water Hyacinth: Its Potential as a Fish Feed Ingredient and Implications for Biodiversity Conservation

Abstract

The growing cost and limited availability of conventional aquaculture feed ingredients highlight the need for alternative, locally available, and sustainable feed resources. Water hyacinth (Pontederia crassipes) is an invasive aquatic species widely distributed across Ethiopia and represents both an environmental challenge and a potential resource. This study aimed to evaluate the suitability of water hyacinth as a fish feed ingredient by assessing its nutritional and anti-nutritional composition, while exploring its potential role in biodiversity conservation through the utilization of this invasive species. Samples of water hyacinth (leaves, roots, and whole plant) were collected from selected freshwater bodies and analyzed using standard proximate analysis methods to determine moisture, crude protein, crude fiber, ash, lipid, and carbohydrate contents. Mineral composition (calcium, potassium, and phosphorus) was determined using established analytical procedures, while anti-nutritional factors, including trypsin inhibitors, phytates, tannins, and oxalates, were quantified following standard protocols. The proximate analysis revealed that the leaves contained the highest crude protein (9.49%) and dry matter content (93.8%) compared to other plant parts. The roots exhibited higher crude fiber and ash contents. The overall carbohydrate and lipid contents of the whole plant were within ranges that can provide adequate energy for fish nutrition. Mineral analysis indicated that calcium, potassium, and phosphorus levels in both leaves and roots exceeded the minimum dietary requirements for most freshwater fish species. Although anti-nutritional factors such as trypsin inhibitors, phytates, tannins, and oxalates were detected, their concentrations were below critical levels that could adversely affect fish health. These findings suggest that water hyacinth has the potential to serve as an economically viable, nutritionally adequate, and environmentally sustainable ingredient in aquaculture feeds. Its utilization could reduce feed production costs, support sustainable aquaculture practices, and contribute to the management of invasive species, thereby aiding in aquatic biodiversity conservation.