SURVEY OF THE EFFECTS OF NEEM LEAF EXTRACT ON THE WATER QUALITY AND PHYTOPLANKTON COMMUNITY IN FRESHWATER CATFISH POND IN BINH DUONG PROVINCE
Keywords:neem, Azadirachta indica, water quality, phytoplankton, Pangasius hypophthalmus.
In Vietnam, the total area of freshwater catfish pond reached 1959 hectares in 2015 to satisfy the national and international markets. The use of synthetic chemicals in fish farms has threatened the environmental ecology and also fish quality so it is really necessary to carry out researches on alternative compounds from plants. The extract of neem Azadirachta indica has been widely applied as an environmental insecticide, especially in fish pond to control fish diseases and parasites in several countries around the world. However, there has not been widely applied in Vietnam. In this study, the effects of neem leaf extract on the water quality and phytoplankton community in freshwater catfish pond in Binh Duong province was investigated. It was shown that at a concentration of 90 mg / L, the extracted from neem leaf have a positive impact on water quality; reduce the concentration of parameters such as COD, N-NO3-, P-PO43-, SD, and SS value. pH value of water was not affected by adding extract at this concentration. In case of plankton community, the result indicated that slightly change in occurrence frequency of phytoplankton community in water was noticed and no change in phytoplankton species composition such as Anisonema sp., Euglena acus, Phacus pleuronectes, Trachelomonas armata and Trachelomonas, which means neem leaf extract might be an environmental friendly to be used in Pangasius hypophthalmus fish pond.