This study was carried out to determine and compare the apparent digestibility of dry matter (DM), crude protein (CP), crude fat (CF), gross energy (GE), and the apparent availability of minerals (P, Ca, Mg, Mn, Cu, and Zn) of emergent (leaf and petiole), submerged (root and rhizome) and total biomass meal of water hyacinth for Nile tilapia. Four diets were prepared, containing 0.10% chromic oxide-III, one being the reference diet (purified) and the others containing 30% of each ingredient. The Nile tilapias (125.5 ± 10.5 g) were fed until satiation and the feces were collected by the modified Guelph system. The apparent digestibility of emergent biomass meal (DM = 57.8, CP = 72.3, CF = 63.2, and GE = 62.0%) was higher than the apparent digestibility of the total biomass (DM = 45.7, CP = 57.3, CF = 50.3, and GE = 42.3%) and submerged (DM = 38.3, CP = 50.8, CF = 43.5, and GE = 32.0%) biomass meal. The apparent availability of P, Ca, Mg, Mn, Cu, and Zn of emergent biomass meal was also higher. The emergent biomass meal had higher apparent digestibility and apparent availability compared to submerged and total biomass meal.
aquatic macrophyte; availability; energy; minerals; protein
