Impact of Dietary Inclusion of Organic Zinc and Chromium on Physiological Response of Broiler Chickens Exposed to Cold Stress

The study was planned on 120 one-day-old broiler chickens, randomly distributed into 5 dietary treatments with 3 replicates having eight chickens each. Control birds (CON) were reared under thermoneutral conditions and offered a basal diet to meet their nutrient requirements. Treatment CS was offered the basal diet under cold stress. While, treatments ZNC100, CR2, and ZN+CR were offered basal diet under cold stress, supplemented with organic Zinc, organic Chromium or their combinations at 100, 2, or 100 + 2  mg/kg DM, respectively. Birds under CS treatment had higher feed intake compared to other treatments. Body weight gain and feed conversion ratio were not significantly affected by treatments. Digestibility of dry matter, crude protein, and nitrogen-free extra of birds under CON treatment were greater than CS, ZNC100, and CR2 treatments. The concentration of blood urea nitrogen and albumin to globulin ratio in CS treatment was higher compared to CON treatment. The antibody response of 21-day-old-broiler chickens in the CS group was lower than the birds of the ZN+CR group. The lowest activities of glutathione peroxidase and superoxide dismutase were found in the blood serum of the CS group. The percentage of dressing carcass in both CON and CS treatments were lower than those of birds under ZN+CR treatment. Moreover, the yield of breast and drumstick of the ZN+CR treatment was higher (P < 0.05) than the CON treatment. There was better production performance along with improved immune status in broiler birds fed a diet supplemented with organic Zinc and Chromium alone or their combination under cold stress.