Abstract
A 42-day feeding trial was conducted with young yellowtails (163.6g) for the purpose of improving undesirable hematological characteristics caused by feeding a soy protein concentrate (SPC) diet (moist type pellet). Zero, 50, 100, 250, 500, and 1000mg of iron proteinate (Fe-P; 10-13% Fe) were respectively added per each 100g of the SPC diet, containing 20g SPC, 45g brown fish meal, and 166mg Fe-P. A reference diet of hundred grams contained 65g of brown fish meal and 166mg Fe-P and used as a control.
Although no meaningful effects of dietary Fe-P supplements on growth performances and Fe accumulation in the liver and spleen were found in the dietary groups, significantly lower red blood corpuscle count, hematocrit value, hemoglobin concentration, and serum Fe saturation rates were detected in fish fed a control diet without the Fe-P supplementation. There were no marked differences in desirable hematological characteristics and serum Fe saturation rates between groups fed diets with above 250mg of supplemental Fe-P and the reference diet.
These results suggest that undesirable hematological characteristics in yellowtails fed the SPC diet could be improved by preparing dietary Fe-P content, above 400mg per 100g of SPC diet.
