THE EFFECTS OF REPLACEMENT OF FISH MEAL PROTEIN WITH A MIXTURE OF POULTRY BY-PRODUCT MEAL, FISH SILAGE AND FISH PROTEIN HYDROLYSATE ON THE GROWTH PERFORMANCES OF ASIAN SEA BASS (LATES CALCARIFER)

This feeding trial was conducted to investigate the effects of replacement of dietary fishmeal (FM) with a mixture of poultry by-product meal (PBM), fish silage (FS) and fish protein hydrolysate (FPH) on the growth performances of the Asian sea bass Lates calcarifer. Five isonitrogenous (46% crude protein) and isolipidic (12% crude lipid) diets were formulated to replace 0 (CON), 25 (FM 25), 50 (FM 50), 75 (FM 75) and 100% (FM 100) of fishmeal protein with the protein mixture (78% PBM, 11% FS, and 11% FPH). One additional diet, namely POM was designed to completely replace FM protein with PBM. The growth trial was conducted with ten fish (average initial weight, 1.72 g) stocked in triplicate in each of 60 L glass tanks and fed with the treatment diets to satiation by hand three times per day for 4 weeks. At the end of the feeding trial, decreasing final weight, weight gain percentage and SGR were noted with an increasing dietary PBM proportion. The final weight and weight gain percentage of fish fed with diets FM 25 and FM 50 were not significantly different from those of fish fed with the CON diet. Meanwhile, fish fed with diets FM 75, FM 100 and POM had significantly lower final weights and weight gain percentage than fish fed with the CON diet. Fish fed with the diets CON, FM 25, FM 50 and FM 75 had no significant difference in SGR. However, fish fed with the diets FM 100 and POM had a significantly lower SGR than fish fed with the CON diet. Therefore, the mixture of PBM, FS and FPH would seem to be able to replace dietary fishmeal protein for L. calcarifer up to 25 or 50% with no adverse effects.