The influence of diet-induced obesity on avian cardiomyopathy.

摘要

Dilated Cardiomyopathy (DCM) is a heart disease associated with rapid growth, high metabolic processes and high mortality in poultry. However, little is known of the causes of DCM in chickens (Gallus domesticus). The objectives of this study were: (1) to determine the appropriate dose of furazolidone for induction of Cardiomyopathy in broiler chickens; and (2) to evaluate the influence of obesity on the incidence of cardiomyopathy in broiler chickens. To meet objective one, 280 broiler males were individually weighed and randomly assigned to experimental diets containing 0, 200, 400, 500, 600 and 700 parts per million (ppm) furazolidone. The diets comprised 3,200 and 3,275 kcal ME/kg, and 23 and 20% CP at 0-3 and 4-8 weeks of age (WOA), respectively. To meet objective two, 360 broiler males were individually weighed and randomly assigned to experimental diets containing either 3,070 kcal ME/kg and 20% CP or 3,343 kcal ME/kg and 23% CP with or without 700 ppm furazolidone at 4-8 and 0-8 WOA. The diets were replicated four times and feed and water were provided at free choice. Mean body weights (BW) and feed consumption (FC) from which BW gain (BWG) and feed conversion ratios (FCR) were calculated, were measured weekly. At 8 WOA, blood serum was obtained from 20% of birds from each treatment and analyzed for metabolic profiles. The birds were sacrificed and heart, liver, spleen, gall bladder and abdominal fat (AF) were excised and weighed. Feeding 500-700 ppm furazolidone decreased FC, BWG, liver and AF weight, glucose and bilirubin levels and elevated serum glutamic oxaloacetic transaminase. The hearts exhibited dilated left ventricular chambers of the broiler birds. Feeding 700 ppm furazolidone with either 3,070 or 3,343 kcal ME/kg diet decreased FC, BWG and increase FCR and heart, AF and liver weight of broiler males, a sign of onset of cardiomyopathy. Interestingly, feeding furazolidone in the 3,343 kcal ME/kg diets increased FC when compared with birds fed the 3,070 kcal ME/kg diets. Birds fed furazolidone containing diets had significantly lower rCt values signifying an increased expression of heart Cardiac Troponin (TnT) and Phospholamban (PLN) and liver PLN of the broiler males.