Partial replacement of soybean meal with fermented copra meal in milkfish (Chanos chanos, Forsskal) diet

Abstract

Feeding trials were conducted to determine the optimum partial replacement level of soybean meal (SBM) with fermented copra meal (FCM). Isonitrogenous and isocaloric diets containing 0, 5, 10, 15, 20, and 25% of the locally produced FCM partially replacing SBM protein by 0, 12, 27, 41, 56, and 71%, respectively and fully replacing copra meal were formulated. The diets were fed to the fish with an initial weight of 2.83±0.14 g for 12 weeks. Thereafter, the best diet was further tested in a preliminary feeding trial in brackishwater grow-out ponds to verify the performance of the formulated diet against a commercial milkfish feed in an outdoor grow-out system. The results of the indoor tank feeding trial indicated that weight gain of the fish was significantly better in the group fed diet 2, with 5% dietary FCM but further increase in the FCM inclusion level up to 20% of the diet did not exhibit statistical differences against the control. Moreover in the preliminary pond feeding trial, growth and feed conversion ratio (FCR) of the fish fed the FCM diet were significantly higher than the commercial control diet. Survival and nutrient composition of the fish carcass were not adversely affected by the treatments. Hence, optimum dietary FCM inclusion level was determined at 5% of the milkfish diet replacing 100% copra meal and 12% SBM protein. However, in terms of economics, up to 20% FCM can be included in the diet replacing 56% SBM protein may be possible with growth comparable to the FCM-less control.