Effect of fish meal substitution with dried bovine hemoglobin on the growth, blood hematology, antioxidant activity and related genes expression, and tissue histoarchitecture of Nile tilapia (Oreochromis niloticus)

Our study was designed to highlight the efficacy of fish meal (FM) replacement with dried bovine hemoglobin (DBH) on the Oreochromis niloticus (O. niloticus) growth, health antioxidant activity, and antioxidant-related gene expression for 70 days. Fish (n = 225, average weight: 36.37 ± 0.05 g) were fed diets with different replacement percentage of FM with DBH: 0 % (DBH0), 2.5 % (DBH2.5), 5 % (DBH5), 7.5 % (DBH7.5) and 10 % (DBH10), where DBH0 was kept as control diet. At the end of the feeding trial, the fish were exposed to bacterial challenge with the pathogenic bacteria Aeromonas veronii (A. veronii). Compared to the DBH0 group, there was a notable increase in the growth parameters with a lower feed conversion ratio in all DBH groups, with DBH10 recording the highest growth. The DBH (0–5 %) diets did not alter the leukogram and erythrogram of O. niloticus, whist, the DBH (7.5–10 %) diets badly affected the leukogram and erythrogram of the fish. The DBH7.5 and DBH10 diets significantly increased (p