Effect of fishmeal on the growth, survival and feed efficiency of milkfish ( Chanos chanos) fry

Abstract

This study was undertaken to determine whether the nutritional value of milkfish fry diets could be improved by (1) partially replacing corn gluten meal by white fishmeal (0, 15, or 30% of dietary protein) and (2) supplementing diets containing corn gluten meal as the sole protein source with either the inorganic or lipid-soluble fractions of white fishmeal. The five diets were formulated so that their proximate compositions and amino acid profiles were similar. The latter were patterned after milkfish fry. The fry had an initial average weight of 8 mg, and were fed eight times during the daylight hours between 05.40 and 18.20 h over a period of 6 weeks. The study was conducted in 60-l aquaria with water temperature at 27–29°C, salinity at 18–20 ppt, and a flow rate of 1.5–2.0 l/min. Growth was significantly better ( P≤0.01) for fish fed the diet where 30% of the protein originated from fishmeal relative to those given diets of lower fishmeal content. Feed efficiency and survival did not significantly differ ( P>0.05) among fish fed the diets where 30 or 15% of the protein originated from fishmeal. Significantly ( P≤0.01) poorer growth, survival and feed efficiency were observed in fish fed diets containing corn gluten meal as the only protein source. Further supplementation of this diet with the mineral or lipid fractions of white fishmeal did not improve these performance parameters. It is concluded that the nutritional value of protein from white fishmeal is higher than that of protein from corn gluten meal for milkfish fry. Also, diets for milkfish fry should contain not less than 15% of the protein from fishmeal to support good growth, survival and feed efficiency.