The comparison of immune system, microbial population, blood parameters and performance traits of five common broiler strains in Iran

This research was conducted to compare the immune system status, microbial population, blood parameters and performance traits of five common broiler strains in Iran. For this purpose, fertile eggs were prepared from broiler breeder flocks with 31 to 33 weeks of age including Arbor Acres, Arian, Ross 308, Cobb and Hubbard and a total of 260 one-day old broiler chick were raised in the same production condition for 49 days in a completely randomized design with 5 treatments(strains),4 replicates and 13 birds in each replication. The mean of live body weight, feed conversion ratio and production index were not significant among treatments. The highest and lowest feed intake were related to Ross 308 and Arian, respectively(p < 0.05). The difference was not significant in total white blood cells, lymphocyte, heterophile, eosinophil, monocyte and heterophile/lymphocyte ratio among treatments at 21 and 42 d.The effect of strain was not significant on relative weights of immune system organs including spleen and bursa of Fabricius at 21 and 42 d.The activity of aspartate aminotransferase enzyme did not show any significant difference among different experimental strains. The different experimental treatments had no significant effect on lactobacillus and Escerichia coli population and blood triglyceride, HDL and LDL concentrations at the end of experimental period.In general,the results of this examination showed that production index,immune system and microbial population of these strains were almost the same in identical production conditions so that broiler producers can raise each of these strains according to the quality of their one- day old chicks