Oral administration of Moringa oleifera leaf powder on some hematological and serum parameters of rainbow trout (Oncorhyncus mykiss) before and after exposure to Aeromonas hydrophila

To investigate the effect of oral administration of Moringa leaf powder, 360 rainbow trout (35.5 ± 0.5 g) were randomly divided into 12 tanks. The fish were fed with Moringa leaf powder levels of 0(control), 1, 2.5 and 5% for eight weeks. After the challenge test with Aeromonas hydrophila bacteria, the activity of alanine transaminase and aspartate aminotransferase enzymes in the 2.5% treatment significantly decreased compared to the control treatment (P<0.05). The optimal amount of Moringa leaf powder inclusion in the diet for aspartate aminotransferase enzyme based on polynomial regression analysis was 1.97% and 3.33% respectively for the periods before and after the challenge with bacteria. There was no significant change in the amount of alkaline phosphatase enzyme, the number of red blood cells, hemoglobin and hematocrit between all treatments compared to the control treatment in both periods before and after the challenge with bacteria (P<0.05). The amount of glucose showed a significant decrease in all treatments, especially in the 2.5% treatment compared to the control treatment in both stages (P<0.05). Regression analysis showed the optimal value of Moringa for this factor, 3.40% and 2.77%, respectively, before and after the challenge with bacteria. According to the results, moringa leaf powder at 2.5% can help reduce stress and possibly improve the general health of this fish. The appropriate dose was obtained from 1.97% to 3.4% based on polynomial regression model for serum biochemical parameters such as glucose and aspartate aminotransferase enzyme.