Effect of total fish meal replacement with vegetal protein alone or combined with rendered animal protein on growth performance and tissue composition of european catfish (silurus glanis L.)

Abstract

A feeding trial was conducted for six weeks to determine the effect of the replacement of fishmeal (FM) either with vegetal protein (mainly soybean) and rendered animal protein combined or vegetal protein alone on growth and carcass composition of European catfish, Silurus glanis. One hundred and thirty five fish (average weight 70.90±5.10g ±SD) were randomly distributed into three treatments in triplicate. Fish were fed with either of three isonitrogenous (35% crude protein) and isocaloric (16.70 MJ/kg DE) experimental diets. The diets were: fish meal (FM) based diet, fish meal protein replaced with a combination of vegetal protein and rendered animal protein (AP), and fish meal replaced with vegetal protein only (SM). Weight gain (%), specific growth rate, protein efficiency ratio, and apparent net protein utilization of FM diet fed groups were similar (P>0.05) with AP diet fed group being significantly higher (P < 0.05) than the SM group. Feed conversion ratio with FM diet was similar (P < 0.05) to that of the AP diet, and significantly lower than SM diet. The present experiment indicated that vegetal protein alone cannot replace total FM protein in the diet of Silurus glanis, however, vegetal protein and rendered animal protein combined, can replace total fish meal protein, with no detrimental effect on growth performance, feed utilization, and body composition.