Ascites syndrome mortality and cardiological response of broiler chickens subjected to cold exposure: effects of verapamil and L-carnitine supplementation

Abstract

In Experiment 1 ascites related mortality was 6%, 0%, 16% and 19% after 1, 2, 3, and 4 weeks of cold exposure (100 C), respectively. After 4 weeks of cold exposure ascites related mortality was 24% in verapamil supplemented cold exposed broilers, in comparison to a 35% mortality in non- supplemented cold exposed broilers. Body weight was significantly depressed by cold exposure. Hematocrit was significantly elevated by cold exposure. Verapamil decreased hematocrit only in the ascitic cold-exposed population. RV/TV, RV/LV ratios were significantly increased by cold exposure in the ascitic population. Verapamil had no apparent effect on these variables. The ECG analysis employed accurately reflected the right ventricular hypertrophy observed by invasive measures. Right ventricular calcium, but not left, was significantly increased by cold exposure. verapamil non- significantly decreased calcium accumulation to control levels. In Experiment 2, there was a 0%, 4.3%, and 26% ascites related mortality after 1, 2, and 3 weeks of cold exposure, respectively. Ascites mortality was 13.5% and 14% in carnitine supplemented and control groups, respectively. Carnitine supplementation restored body weight in cold exposed birds to control levels. A significant decrease in hematocrit after the first week of cold exposure occurred in the healthy population of broilers, whereas ascitic broilers did not exhibit the same response. After 3 weeks of cold exposure, ascitic birds exhibited significant increases in hematocrit, whereas healthy birds did not. Cold exposure increased RV/TV and RV/LV ratios in ascitic birds. Carnitine supplementation of cold-exposed ascitic birds resulted in an increase in both of these variables. Significant increases in the RV/BW and LV/BW were apparent after 7 days of cold exposure. Carnitine did not appear to effect these variables. Significant increases in MRV/BW were evident after 2 weeks of cold exposure. Numerically greater responses to cold exposure were observed in the ascitic population in comparison to the healthy population.