Anatomical parameters of cardiopulmonary system in three different lines of chickens: further evidence for involvement in ascites syndrome

Abstract

The present study was designed to compare the anatomical parameters of the cardiopulmonary system in three different lines of chickens with different susceptibility to ascites syndrome. Eggs from three different genetic lines-commercial broiler and layer lines and one native to Iran--were incubated and hatched, and 1-day-old chicks used. The relative heart and lung weights, the volumes of the heart, lung and thorax cavity, the incidence of ascites, and the related physiological parameters in these chickens were followed. Lung weight as a percentage of body weight, the relative lung and heart volume, and the volumes of the thorax cavity, before and after removing heart and lung tissues, were lower in fast-growing broiler chickens compared with the layer and native chickens. Additionally, most of these parameters (e.g. relative lung weight, lung volume and thorax cavity) were significantly decreased with age in broiler chickens but were increased in layer and native chickens, which was concomitant with the incidence of ascites in broiler chickens. Our data indicate that all cardiopulmonary parameters investigated are extremely unfavourable to broiler chickens and suggest a reduction in gas exchange area in broilers, and therefore higher susceptibility to pulmonary hypertension and ascites.

Further evidence for the involvement of anatomical parameters of the cardiopulmonary system in the development of ascites syndrome in broiler chickens

“…Blood samples were collected in heparinised tubes from 30 embryos per Acta Veterinaria Hungarica 56, 2008 incubator by cardiac puncture at non-external pipping stage (460 h of incubation) to determine the plasma thyroid hormone (T3, T4) levels as described earlier (Hassanzadeh et al, 1997(Hassanzadeh et al, , 2005a.…”

“…Insufficient development of the lungs or the pulmonary blood vessels in broiler chickens may form the basis of ascites incidence. Hence, the anatomy and physiology of the avian respiratory and cardiopulmonary systems are important in the susceptibility to pulmonary hypertension syndrome and ascites Hassanzadeh et al, 2005a). Decuypere et al (2000) reported that ascites syndrome is multifactorial and mainly caused by exogenous and/or endogenous factors.…”

Hypoxic Pulmonary Arterial Hypertension in the Chicken Model

“…In addition to vascular dysfunction (e.g. remodeling and impaired endothelium-dependent relaxation), causes that may affect pulmonary pressure include an inherently low pulmonary vascular capacity, inadequate gas exchange area for blood cells, and a cardiac output that chronically increases in support of metabolic requirements (Wideman and Tackett, 2000;Wideman, 2001;Hassanzadeh et al, 2005). Therefore, it is difficult to eliminate PH in broilers solely by supplemental L-arginine.…”

“…Nevertheless, the energy content is in fact an undeniable adjuvant factor to increase incidence of PH when low temperatures and/or hypobaric hypoxia are present, although its mechanism has not been clearly elucidated (Tarquino et al, 1990). Interesting theories and well carried studies have been advanced, which include thyroid hormones metabolism (hypothyroidism) and hypoxemia (CamachoFernández et al, 2002;Hassanzadeh et al, 2005), but they do not focus on the principal issue which is pulmonary vasoconstriction due to low temperature and/or hypobaric hypoxia. In fact, they attribute PH to a metabolic disarrangement which results in hypoxemia.…”

Effect of citric acid on electrocardiographic parameters of broiler chickens with pulmonary hypertension

“…However, growth rate, oxygen requirements, anatomical and haematological parameters and cellular responses can all determine how resistant or susceptible a broiler is to pulmonary hypertension syndrome. In addition, environmental causes such as altitude, cold stress and rearing conditions such as feed, lighting, air quality and ventilation have all been implicated in the development of pulmonary hypertension (Hassanzadeh et al, 2005;Baghbanzadeh and Decuypere, 2008). It has been reported that chronic hypoxia interacting with the endogenous functions of embryos during embryonic development at high altitude, as adaptation mechanisms, changed the developmental trajectories of cardiopulmonary parameters in postnatal chickens, thus lowering their susceptibility to pulmonary hypertension (Hassanzadeh et al, 2004;Hassanzadeh et al, 2008), while hypoxia could cause the growing broiler to become more susceptible to pulmonary hypertension (Baghbanzadeh and Decuypere, 2008).…”