Comparative Study of Ultrastructural Observations on Blood Cells of Local Omani and Cobb 500 Broiler Chickens: Ultrastructural Observations on Blood Cells of Two Strains of Chickens.

Abstract

The local Omani chicken represents a long-established indigenous chicken breed in the Sultanate of Oman. Many farmers in Oman raise local chickens for meat and egg production. Therefore, to ensure an enhanced production of local breed chickens, it is important to assess their health performance. The present study was conducted to describe the comparative ultrastructural details of the blood cells of Omani and Cobb 500 chickens. Twenty apparently healthy 35-old birds (10 per strain) of either sex reared at the Poultry Research Unit at the Agricultural Experiment Station, Sultan Qaboos University. The blood was collected from wing vein into tubes containing EDTA as anticoagulant. The blood was further processed for transmission electron microscopic study. The results obtained showed that all blood cells of both Cobb 500 and Omani chicken were similar. The heterophil nucleus had a multi-lobed nucleus. The number of nuclei lobes ranges from 2 to 3. The Eosinophil had a distinctive appearance and mostly had a lobulated nucleus. Basophil was round in appearance and had four types of granules (dense granules, mottled granules, web or net granules and myelin granules) which can be seen clearly. The lymphocytes were the smallest leukocytes and it was characterized as small round cell with few cytoplasmic process. The monocytes were round in shape with kidney-shaped or indented nucleus. The nucleus had more heterochromatin patches compared to euchromatin. The thrombocytes were distinguished from other cells by their dense nucleus and the large vacuoles found in the cytoplasm. In conclusion, this study shows great similarities in the ultrastructure of all blood cells composition between local Omani and Cobb 500 broiler breeds.