Effect of food restriction on growth and response to vaccination in Arian broilers

Due to the increase in the price of inputs and the necessity of nutrition management; the effect of food restriction on performance, growth and immune response was investigated in 960 Arian breed broiler chickens (480 male & 480 female). Therefore, two periods of food restriction were considered separately in two treatment groups (at the second week and the sixth week) using four diluted rations (0, 20, 30 and 40%) in three replications in a completely randomized design. After analyzing the data, the average traits were compared with Duncan's multiple range test, the effect of food restriction on the immune response to ND, AI, IB and IBD vaccines was also investigated with serology on the 20th and 42nd days of rearing, According to the results , the broilers in the first group with 20% dilution diet reached the weight of the control group (p < 0.05) at the age of 42 days, also the corrected food conversion coefficient was improved and had compensatory growth; In the second group, the chicks could not reach the control group at the age of 42 days (p < 0.05) and the improvement percentage index (weight gain) was not favorable, and more time was needed to reach the appropriate improvement index, and the same time the ability to compensate for the delay in growth and improvement. The response of the immune system to vaccination against ND, AI, IB and IBD in both treatment groups with low food restriction (20%), improved and significantly differen from the control group (p < 0.05), the titers of the first group treatments it was better than the second group  and it was lower in male than female chickens.