Effects of diet supplemented with ethanolic extract of propolis on growth performance, hematological and serum biochemical parameters and disease resistance of Mozambique tilapia (Oreochromis mossambicus) against Streptococcus iniae

Abstract

In the present study, growth performance, serum biochemical, hematological parameters and disease resistance against S. iniae in Mozambique tilapia were determined after 60-day feeding period with ethanol extract propolis supplemented diets. Growth performance increased (P < 0.05) in 2 and 4 g kg−1 propolis supplemented groups. There were no changes in hematological values between all treatment groups (P > 0.05). Total protein, values in serum found significantly higher in P2 group (9.31 ± 0.66 g dL−1) compared to the P0 (7.49 ± 1.66 g dL−1). The highest serum cholesterol value was obtained in P4 (206.76 ± 24.57 mg dL−1) group and found significantly different from P0 (169.79 ± 17.11 mg dL−1). The lactate dehydrogenase, lysozyme and myeloperoxidase activity significantly increased in P1, P2, P4 and P8 groups. The highest lysozyme and myeloperoxidase activity values were obtained in P2 and P4 groups (for lysozyme 255.44 ± 3.41 mg L−1, 260.55 ± 4.29 mg L−1 and for myeloperoxidase 145.01 ± 3.82 U L−1 151.35 ± 4.17 U L−1 respectively) and found significantly different from P0 group. Propolis supplementation to the diets showed no differences on other serum biochemical parameters such as glucose, triglyceride, glutamic pyrivic transaminase and glutamic oxaloacetic transaminase. After challenge with S. iniae, fish fed with 2 and 4 g kg−1 propolis showed significant survival rates (72.55% and 68.63%, respectively) compared with other groups. This study indicates that growth performance and non-specific immune response of Mozambique tilapia can be enhanced by dietary supplementation with propolis and that the optimal level would be 2 g kg−1.