Studies on the effect of extrusion processing on availavility of trace elements to rainbow trout

点击翻译按钮获取中文摘要

A series of feeding experiments was conducted to determine the effect of extrusion processing of soybean meal (SBM) on trace element availability in partially replaced fish meal based diet to rainbow trout. SBM was extruded by different conditions such as temperature, and replaced with white fishmeal. The experimental diets were fed to the juvenile rainbow trout for 21 weeks.The growth of the fish fed the diet replaced white fish meal with SBM extruded at 145ﾟC is much higher than that of the fish on the diet included SBM extruded at 100ﾟC.The same trend was obtained in mineral status in fish body.Consequently, the graded levels of high temperature (150ﾟC) extruded SBM (0,30,60%) were replaced with white fishmeal and the graded levels of Zn were supplemented to the 30% extruded SBM included diet. The experimental diets were fed to the juvenile rainbow trout for 12 weeks.The growth reached a plateau by the supplementation with 20 mg Zn/kg among the 30% extruded SBM included diets and Zn content became to the equivalent amount in fish fed the fish meal diet by 40mg Zn/kg. The growth of fish receiving the 60% extruded SBM included diet was lower than the other groups, but the mineral status in fish body was not influenced by dietary treatment.The results of these studies demonstrated that high temperature such as 150ﾟC extrusion cooking influences the quality of SBM very efficiently, and that extruded SBM might be a very suitable material for substitution of fishmeal in terms of trace element.