Influence of cold–dry (harmattan) season on colonic temperature and the development of pulmonary hypertension in broiler chickens, and the modulating effect of ascorbic acid

Abstract

Influence of cold–dry (harmattan) season on colonic temperature and the development of pulmonary hypertension in broiler chickens, and the modulating effect of ascorbic acid Ndazo S Minka,1 Joseph O Ayo2 1Department of Animal Health and Husbandry, College of Agriculture and Animal Science, Division of Agricultural Colleges, Ahmadu Bello University, Mando-Kaduna, Nigeria; 2Department of Physiology, Faculty of Veterinary Medicine, Ahmadu Bello University, Zaria, Nigeria Abstract: The influence of cold–dry (harmattan) season on colonic temperature (CT) and the development of pulmonary hypertension (PH), as well as the effect of ascorbic acid (AA), were investigated in Anak male broilers during the harmattan season (November–January) of 2010–2013. A total of 150 broiler chickens per season served as subjects. At the age of 4 weeks, the broilers were randomly divided into two groups consisting of three replicates of 25 birds each: group I, the control, was not administered AA; group II was AA-treated, administered with 200 mg/kg body weight of AA, every day at 7 am and 7 pm for a period of 3 weeks. The mortality rate and CT of the birds were recorded during the daytime and nighttime. Ten birds from each group were sacrificed at weeks 4, 5, 6, and 7 for the assessment of PH and ascites syndromes. The mean ambient temperature value of 24.3°C±0.1°C recorded in the daytime was higher (P<0.05) than the value of 17.2°C±0.1°C recorded during the nighttime. The average level of dust was 8.2 mg/m3. The control birds were hypothermic during the nighttime and had high mortality rates compared with the AA-treated birds. Broilers with obvious signs of ascites demonstrated a uniquely continuous increase in CT. At weeks 6 and 7 of age, 80% of the control broilers that were sacrificed exhibited an increase (P<0.05) in the weight of right ventricle to the weight of total ventricles, packed cell volume, and erythrocyte count with low hemoglobin content, which indicated PH syndrome. The remaining 20% of the control birds and those that died had ascites syndrome in addition to the PH syndrome. These syndromes were not observed in the AA-treated birds. In conclusion, the harmattan season induced PH in broilers with no obvious clinical signs; the harmattan may compromise the welfare, health, productivity, and meat quality of the birds, effects which were ameliorated by AA. Keywords: ascorbic acid, broilers, cold–dry (harmattan), colonic temperature, hypothermia, pulmonary hypertension/ascites