evaluation of thyroid hormones, blood gases, body antioxidant status, the activity of blood enzymes and bone characteristics in broiler chickens with cold induced ascites

a total of 150 day old female chickens (ross 308) were randomly allocated to 2 groups with 5 replicate and 15 chicks in each replicate to determine the effects of cold induced ascites on performance, antioxidant status, blood enzyme activities and bone metabolism. the two experimental treatments were: 1) chicks that reared under normal temperature (nt) and 2) chicks that reared under cold temperature (ct). the experiment was terminated at 42 day of chicken age. feed intake was reduced significantly by ascites during the starter period. weight gain of nt birds was higher than ct birds during the starter, grower, finisher and the whole period (p<0.05). feed conversion ratio was greater for ct birds during the grower, finisher and the whole period (p<0.05). total mortality was greater in ct birds than nt ones during the whole period (p<0.05). cold-induced ascites increased the right ventricular, total ventricular and ventricular septum weights and right ventricular (rv)/total ventricular (tv) ratio at day 42 (p<0.05). blood po2, o2 saturation, ph and t4 level were lower and blood pco2, t3 and calcium level was higher in ct birds than nt birds (p<0.05). the birds of both treatments had the same tibia length but femur length was shorter in ct birds (p<0.05). the diameter of both tibia and femur was smaller in ct birds (p<0.05). ct birds had a higher incidence of leg problems than nt ones during the whole period of the experimental phase (p<0.05). in conclusion, cold induced ascites reduced the performance, increased mortality and caused leg problems in broiler chickens.