Hemoglobin Powder as a Dietary Animal Protein Source for Juvenile Nile Tilapia

A 6-week feeding trial was conducted to determine the amount of dietary hemoglobin powder (HP; 92% crude protein, CP) that could be used to replace fish meal (FM, 68% CP) in the diet of juvenile Nile tilapia Oreochromis niloticus. Fish were fed eight isonitrogenous diets that contained FM, HP, or both as the dietary animal protein sources. Fish meal was used as the only source of animal protein (20%) in the control diet. Percent replacement of FM by HP on the basis of crude protein were as follows; 0% (control, diet 1), 12.5% (diet 2), 25% (diet 3), 50% (diet 4), 100% (diet 5), 25% + amino acids (AA) (diet 6), 50% + AA (diet 7), 100% + AA (diet 8). Weight gain (WG) and specific growth rate (SGR) of the fish fed experimental diets 2, 3, 4, 6, and 7 were not significantly different (P > 0.05) from those of fish fed the control diet. Feed conversion ratio (FCR), protein efficiency ratio (PER), and protein productive value (PPV) of fish fed diets 2, 3, 4, 5, 6, and 7 were not significantly different from those of fish fed the control diet. However, WG and SGR of fish fed diets 5 and 8 were lower than those of fish fed the control diet; FCR, PER, and PPVs were significantly lower only in the fish fed diet 8. Positive effects were not shown in the groups with AA supplementation. Therefore, these findings suggest that up to 50% of FM protein can be replaced by HP protein in juvenile Nile tilapia diets.