This experiment had been done to evaluate the effects of physical feed restriction method with different intensity and duration on broiler immune system. One hundred fifty Ross 308 male broiler chicks in a completely randomized design were divided into 5 experimental treatments. The experimental treatments were include physical limitations in 25 and 50% lower than the recommended by catalogue of rearing strain in two periods of 7 and 14-day with two control treatments (feed intake as ad libitum). Each limitations severity level was applied in 3 iterations of 10 pieces. All experimental treatments before and after the limitation period until slaughter (day 42) were fed ad libitum as a control group of chicks. The results showed that the effects of feed physical restriction had no significant effects on response of immune system against SRBC injection (first injection) parameters in broilers (P>0.05). But feed physical restriction had significant effects on response of immune system against SRBC injection (second injection) parameters in broilers (P<0.05). The fourth, second and first treatment statistically showed the greatest effect on the response of immune system against SRBC injection (second injection) in broiler chickens. Also, feed physical restriction had no significant effects on response of immune system parameters against bronchitis and Gambaro vaccine injection in broilers (P>0.05). But, feed physical restriction had significant effects on response of immune system parameters against Newcastle vaccine injection in broilers (P<0.05).
