EFFECT OF CARBOHYDRATES ADDITION ON AQUATIC PRODUCTION AND WATER QUALITY IN SIMULATED AQUACULTURE PONDS

摘要

Artificial feed is the main nutrient input of an intensive fish or shrimp pond. However there is a low nutrient retention: 13% for carbon, 29% for nitrogen and 16% for phosphorus (Avnimelech and Ritvo 2003). In consequence, the organic matter load ofthe water pond is increased. If the load is too high water quality problems will occur. Fast decomposition of organic matter reduces the rate of organic matter accumulation and facilitates water quality management. Because fish feeds have very high protein content, the organic matter accumulating will be relatively nitrogen rich and carbon poor. The decomposition pathways and rates are strongly affected by C/N ratio of the organic matter source. The manipulation of this C/N ratio with carbon addition has been suggested as a way to reduce the accumulation of inorganic nitrogen in a pond and improve water quality (Avnimelech 1999). The aim of this experiment was to evaluate the effect on the microbial degradation of 49% protein fish feed with and withoutthe addition of carbohydrate source (wheat flour).