Effects of Zinc Oxide Nanoparticles on the Performance of Broiler Chickens Under Hot Climatic Conditions

This study aimed to investigate the effects of different levels of zinc oxide nanoparticles on broilers' performance, nutrient digestibility, carcass criteria, and blood biochemistry. A total of 120 1-day-old unsexed broiler chickens (Ross 308) were fed zinc oxide nanoparticles at different levels (0, 20, 40, or 60 mg/kg) in their diets. Each treatment included 6 replicate pens with 5 birds each. The experiment lasted 42 days. The brooding temperatures were 37.8 degrees C, 35.8 degrees C, and 29.9 degrees C during 1-10 days, 11-21 days, and 22-42 days of age, respectively. The results revealed that dietary supplementation of nanoparticles of zinc oxide at 20, 40, and 60 mg/kg diet significantly improved body weight, body weight gain, and feed conversion ratio showing linear effects (P < 0.05) compared to the birds fed the control diet under hot climatic conditions. Dietary addition of zinc oxide nanoparticles at 20, 40, and 60 mg/kg linearly increased (P < 0.05) the nutrient digestibility of crude protein, crude fiber, and ether extract compared to the control group. Birds fed the supplemented diets had improved liver and kidney function without any negative effects on zinc, inorganic phosphorus, triiodothyronine (T-3), and thyroxine (T-4) levels in serum compared to the control. Diets supplemented with zinc oxide nanoparticles linearly (P < 0.05) improved the dressing percent and reduced abdominal fat percent compared to the control group. In view of the above findings, it can be concluded that dietary supplementations of zinc oxide nanoparticles at 20, 40, and 60 mg/kg resulted in improved growth performance, nutrient digestibility, carcass criteria, and liver and kidney functions of broiler chickens under hot environmental conditions.