The study of some blood immune factors of Nile tilapia, Oreochromis niloticus during the replacement of diatary fish meal with blood powder

The aim of this study was to evaluate the effect of substituting the dietary fish meal with blood powder on some blood immune factors of Nile tilapia. 150 speciemns of tilapia (30 ± 0.5 g) were fed diets containing 0 (control group), 25, 50, 75, and 100 % of blood powder, each in three replicates for 8 weeks. After this period, fish were anesthetized and the blood samples were taken from the caudal peduncle of fish with a heparinized syringe for evaluating the blood immune indicators. No significant differences were observed in ACH50, glucose, and triglyceride among the blood powder-fed fish and the control group (P>0.05). The highest reported value of ACH50 (148.36±23.13), was observed in 75% treatment and the highest values of glucose (145.72±21.44) and triglyceride (451.68±49.61) were observed in 100% blood powder fed treatment. However, there were significant differences in the activity of lysozyme, immunoglobulin, total protein, and cholesterol in the groups receiving blood powder with different percentages compared to the control group (P<0.05).  The results of this research showed that it is possible to replace fish meal with blood powder in the diet of Nile tilapia due to its strengthening effect on immune system.