Dietary replacement of fish meal with soybean meal for the optimal growth of Juvenile Milkfish, Chanos chanos (Forsskal, 1775) in seawater tanks

The core of the current study is to find out a different source of diet that stimulates better growth rate and low-cost feed for commercial fish milkfish Chanos chanos. This study was to assess the impact of partial replacement of fish meal by soybean meal in the diet of juvenile milkfish, Chanos chanos (initial weight 25 ± 0.6 g). The juveniles were fed with two types of iso-nitrogenous diets (40% crude protein). Plant protein source diet (D1) comprised of soybean meal 45% and 10% fish meal, while animal protein source diet (D2) contained fish meal 25% and soybean meal 30%. The trial was conducted with two replications for 60 days. Fish juveniles (10 each) were stocked in outdoor fiberglass seawater tanks (5000 Liters). Results revealed that final weight gain (WG), and specific growth rate (SGR) were significantly lower in fish fed D2 diet. Fish fed D1 had better feed efficiency, weight gain (21.88 ± 1.9 g), and SGR (1.05 ± 0.3), while D2 had a lower growth rate, WG (18.71 ± 2.3 g) and SGR (0.93 ± 0.2). The maximum growth rate found on plant diet which is significantly higher weight gain than D2. In D2 feed conversion ratio (0.54 ± 0.21) was significantly higher (P≤0.05). Condition factor among both treatments did not differ significantly (P≥0.05). The survival rate remained constant (100%) in both treatments. Based on the obtained results, it is recommended that 45% soybean meal with addition of 10% fishmeal (40% protein) is more effective than 30% soybean meal with addition of 25% fish meal to the omnivorous milkfish for aquaculture.