Immune Responses of Broiler Chicks Fed Chromium Picolinate in Heat Stress Condition
Majid Toghyani, Sayedhamid Zarkesh, Mahmoud Shivazad, Abbasali Gheisari
The present study was conducted with two hundreds and forty male broiler chicks to evaluate the e# ect of chromium (Cr) from Cr picolinate on immune responses of heat-stressed broiler chicks. In a completely randomized design, diets were supplemented with 0 (control), 500, 1000 and 1500ppb Cr. Antibody titers against Newcastle and Infiuenza virus at 18 and 30d, heterophil to lymphocyte ratios, albumin to globulin ratios and concentration of immunoglobulin G in serum were measured at 21 and 42d. On day 42, thymus, spleen and bursa of Fabricius were collected, weighed and expressed as a percentage of live body weight. Antibody titers against Newcastle and Infiuenza virus were elevated at 30d of age in broiler chicks fed supplemental Cr. Heterophil to lymphocyte ratios decreased in broiler chicks fed 1000 and 1500ppb supplemental Cr. Concentration of immunoglobulin G in serum was increased by Cr supplementation especially at level of 1500ppb. Albumin to globulin ratios and weights of lymphoid organs were not a# ected by supplemental Cr. The results suggest that Cr supplementation improves some immune responses of heat-stressed broiler chicks.
Keywords: broilers, chromium, heat stress, immune response