Effect of Iron Supplements on a Soy Protein Concentrate Diet on Hematology of Yellowtail

Abstract

A 42-day feeding trial was conducted with young yellowtails (163.6 g) 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 1000 mg of iron proteinate (Fe-P; 10-13 %Fe) were respectively added per each 100 g of the SPC diet, containing 20 g SPC, 45 g brown fish meal, and 166mg Fe-P. A reference diet of hundred grams contained 65 g of brown fish meal and 166 mg 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 250 mg 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 400 mg per 100 g of SPC diet. © 1994, The Japanese Society of Fisheries Science. All rights reserved.