Histopathological effect of cold environment on pulmonary tissue in Local (Gallus Gallus) and foreign ( Turkey broiler) breeds of chickens in Iraq

Abstract

The present study was carried out on forty local and foreign broiler chickens (twenty for each) (one day old), reared for 35 days under cold environment (January and February-2015). The aim of this study was to assess the histopathological effect of cold stress and the cellular response of pulmonary tissue. All experimental animals were weighed then sacrificed and the lungs were collected and weighed. Specimens were fixed by 10% neutral buffer formalin. Routine histological preparations were carried out. Hematoxylin & Eosin was used for staining. At the end of the experiment, both breeds showed different signs of respiratory response. The work revealed that the pulmonary cellular lesions in foreign breed were more severe andmore extensive than inlocal breed. In local breed, the cellular regenerative response represented by infiltration of immune cells was more efficient , and consequently, the current study revealed that Iraqi local breed was more resistant to environmental stress than European foreign breed which registered a respiratory infection at the end of rearing period. The larger relative size of the lung in European breed may explain the higher injury of its pulmonary tissue. It was concluded that the local breed was more adaptive to cold stress than the foreign breed.