Effects of feeding level and feeding frequency on growth, feed efficiency and nitrogen and phosphorus loss in seabass (Lates calcarifer Bloch) fed diets with defatted soybean meal partially replacing fishmeal

Satun Coastal Fisheries Research and Development Center, Muang, Satun 3Feeding management is crucial for feed efficiency, nutrient utilization, growth of cultured aquatic species and the amount of organic waste produced. This study aimed at investigating effects of two levels offeeding at two feeding frequencies on growth performance, feed efficiency and nitrogen and phosphorus loss in Asian seabass when fed diets with defatted soybean meal (SBM) replacing fish meal. Three diets were formulated to contain defatted SBM to replace fish meal at 0, 10 and 20% of fish meal protein. Each diet wasgiven to the fish at either 4% of body weight (BW) or to satiation. At each feeding level, the fish were fed at two feeding frequencies, once and twice daily. Fish with an average initial weight of 2.04±0.06 g/fish werereared for twelve weeks in the flow through system. Growth of fish reduced with an increasing amount of defatted SBM incorporated in diets as observed in other carnivorous species. Within groups of fish fed thesame diet, different growth performance and feed efficiency differed due to both feeding level and frequency. Weight gain of fish that were fed diet with defatted SBM replacing 10% of fish meal protein (diet 2)until satiation was not significantly different from fish fed fish meal based diet at 4% BW. Furthermore, feeding fish the former diet twice daily resulted in an improvement of FCR, PER and PPV of fish to those ofthe fish fed fish meal based diet at satiation twice daily. Nitrogen and phosphorus loss was affected by diet, feeding level and frequency. Fish fed diet 2 until satiation twice daily lost nitrogen and phosphorus in theamount similar to that of fish fed fish meal based diet until satiation