effect of zinc sulfate and organic chromium supplementation on the performance, meat quality and immune response of japanese quails under heat stress conditions

this study was conducted to investigate the effects of different levels of zinc sulfate and chromium picolinate on the performance, immune response and meat quality of japanese quails under heat stress condition. the birds (n = 540; 7-d-old) were randomly assigned to 9 treatment groups consisting of 3 replicates of 20 birds each in a 3 × 3 factorial arrangement of treatments [zinc (0, 40, 80 mg/kg); chromium (0, 500, 1000 μg/kg)]. birds were kept in floor cages in a temperature controlled room and subjected to heat stress for 8 h/d (9.00 to 17.00) from 7 d to the end of the study. zn was supplemented to the basal diet as znso4 and cr as chromium picolinate. a linear decrease in feed intake and an improvement in feed conversion ratio were found by supplementing zn and cr to the quails diets. chromium supplementation increased daily weight gain linearly. by  increasing the level of dietary zn and cr in the diet, heterophil to lymphocyte ratio and meat quality parameters were improved linearly. the results of this study revealed positive effects of zn and cr supplementation on the performance, immune responses and meat quality of quails under heat stress condition. it seems that supplementation of the quail's diets with 80 mg/kg zn and 1000 mg/kg cr can be greatly helpful for improving the adverse effects of heat stress.