Utilisation of Water Hyacinth, (Eichhornia crassipes) as Partial Protein Supplement in the Diet of Ornamental Gourami (Trichogaster spp.)

Recently many researchers had carried out a research on utilisation of water hyacinth (Eichhornia crassipes) towards food fish such as catfish, carp, tilapia etc. Thus, this study will focus on utilising water hyacinth as a partial protein supplement in tropical freshwater aquarium fish which is ornamental gourami (Trichogaster spp.). There were four (4) treatments assigned according to different experimental diets that consist of control diet which not containing water hyacinth and three parts of water hyacinth plants (leaves as WHL diet, and petioles as WHP diet, and roots as WHR diet). All of this three types of diet were formulated with fish meal until reach 20% crude protein. Then, a feeding trial was conducted for 28 days. There were reduction in growth weight of -0.061 g, -0.073 g, and -0.080 g in WHL, WHP, and WHR diets respectively. Among the experimental diets, tannin content was higher in the WHL diet and WHP diet compared with WHR diet. The reduction of the growth performance were due to this tannins effect and also other antinutritional factors. The survival rate in control and WHR were highest compared to the other two diets. The temperature and pH do not affect the reduction of survival rate as both parameter were recorded in optimum level that suit for gouramis culture. Thus, it might cause by cannibalism that occurred within the feeding trial period. From the results obtained, it can be concluded that ornamental gourami was not suitable to be fed with the experimental diets due to tannins effect and other antinutritional factors. Further study can be carried out in order to get benefit from this plant such as increase the crude protein in feed formulation, focus only water hyacinth leaves as fish diet, and fermenting the experimental diet with extracellular enzyme.