Abstract
Background: Phytogenic feed additives are products derived from plants used to improve the performance and health of animals. Nowadays, this type of phytogenic feed additive is widely used as an alternative to antibiotic growth promoters in poultry feed, and clove bud is one of the most effective medicinal herbs that has caught the attention of researchers. Aim: This experiment was conducted to evaluate the effects of adding clove bud powder to the broiler chicken’s feed on the hematological profile, biochemical parameters, lymphoid organs, and cell-mediated immunity. Method: A total of 360 unsexed chicks (Ross 308) were allotted to three groups. All chicks were raised under the same normal management conditions from 1 day to 6 weeks of age. The first group was fed a basal diet and the other two groups were assigned to add 0.5% and 1.0% of clove bud powder to the basal diet. The studied traits were total leukocyte counts (TLC), differential leukocyte counts (DLC), blood cholesterol level, blood liver enzymes [aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase (ALP) enzymes], the weight of lymphoid organs (bursa of Fabricius and spleen), and cell-mediated immunity. Results: Despite the significant and varied changes (p ≤ 0.05) that resulted from adding clove buds powder to the broiler feed in the second and third weeks, the results at the end of the experiment indicated that there was no negative effect of adding clove powder on the TLC and DLC, as well as the heterophils/lymphocytes ratio. In addition, feeding on a diet containing clove buds powder had no significant effect on the level of cholesterol and liver enzymes in the blood, except for (ALP), which showed a significant increase (p ≤ 0.01) in comparison to the control group. Moreover, the results showed in the second and fifth weeks a significant increase (p ≤ 0.05) in the relative weight of the spleen, but, in general, there were no significant effects at the end of the experiment on the relative weight of the lymphoid organs. Furthermore, the broiler chickens that consumed clove bud powder at a rate of 0.5% showed a highly significant (p ≤ 0.01) cellular immune response. Conclusion: This study concluded that the addition of clove bud powder had no negative effect on leukocyte counts or differentiated leukocyte counts. The addition also raised the spleen weight and improved the level of blood alkane phosphatase activity and cellular immune response in broiler chickens during the growth stages.