Respirable dust: Effects on the incidence of ascites in broiler chickens

The effect of the application of canola oil to straw litter to remove airborne respirable dust on growth performance and the incidence of ascites syndrome was evaluated using 800 male broilers studied in two 6-wk periods. Since the effect of early feed restriction on broilers is well documented in terms of reducing the incidence of ascites syndrome, the effect of feed restriction served as a reference to the effect of litter oiling. Two pens housed birds that were early feed restricted and two pens received feed nd libitum throughout the 6-wk trial. The litter in two of the pens received biweekly additions of oil to the litter (totaling 0.8 L/m(2) of oil over 6 wk). At 6 wks of age all birds were scored for the incidence of ascites syndrome at the processing plant. Hearts were removed, dissected and the right ventricular cross sectional area (RVA) was digitally recorded. Adding oil to the litter for the nd libitum-fed birds did not result in differences in bodyweight or mortality, however, it did reduce the ascites syndrome score from 0.97 to 0.78 and the RVA values from 0.44 to 0.37 cm(2). Adding oil to the litter reduced the RVA values similar to those occurring with feed restriction.