effect of quantitative feed restriction and meal feeding on the performance, carcass compositions and ascites syndrome in broiler chickens

this experiment was conducted to compare the effects of quantitative feed restriction and meal feeding on the performance, carcass compositions and ascites syndrome in male broiler chickens (ross 308). in this study, 5 schedule feed restrictions include: 1) ad libitum food intake (al group), 2) feeding maintenance energy requirement from 7 to 14 d of age 3) feeding to support 50% of the normal growth energy requirement from 7 to 14 d of age 4) meal feeding from 7 to 14 d of age (mf14) and 5) meal feeding from 7 to 21 d of age (mf21), were used. three hundred day-old male broilers in a completely randomized design (with five treatments, five replicates per treatment and 12 birds per pen) were raised until 42 days. at the age of 21 d the chickens were exposed to a temperature of 15°c, which induced ascites. traits measured included performance, carcass characteristics and parameters of the heart and blood. the results indicated that quantitative feed restriction reduced weight gain and feed intake compared to al group (p<0.05). at the end of experiment, feed conversion ratio of mf14 group was less than fed group for 50% growth (p<0.05). feed restriction had no significant effect on percentage of carcass composition (carcass, breast, thigh and abdominal fat). al and mf14 broilers had high hematocrit and hemoglobin concentration. mf14 groupcompared with the quantitative feed restriction groups had a greater heart weight (p<0.05). ascites index (rv/tv ratio), right ventricle weight and percentage of heart were not affected by feeding regimes. the overall results showed that less severe restriction (meal feeding treatments) on compared with more severe restriction (quantitative feed restriction treatments) was better to realize the complete compensatory growth. according to blood factors, severe feed restriction can decrease ascites susceptibility in broiler chickens.