Growth Response and Humoral Immunity of Broiler Chickens Fed Organic Acids and Zeolite Coated with Silver Nanoparticles under Heat Stress Conditions

This study was designed to evaluate the effect of organic acid (Biotronic) and silver nanoparticles coated on zeolite on performance and humoral immune response of broiler chickens under heat stress conditions using a total of 375 one day-old broiler chicks (Cobb 500). Chicks were allocated to five treatments, five replicates and 15 chicks per each replicate using a completely randomized design. Treatments included: (1) control (2) 1% Uncoated zeolite, (3) zeolite-coated with 0.5% silver nanoparticles, (4) 1 g/kg organic acids and (5) zeolite-coated with 0.5% of silver nanoparticles and 1g/kg organic acids. Heat stress was exposed at 34˚ C in sixth week. Chicken’s performance indices were measured periodically. Blood samples were taken to determine antibody response, sheep red blood cells (SRBC) and heterophile to lymphocyte ratio at the end of the third, fourth, fifth and sixth weeks. The results of experiment indicated that diet containing Nano silver with organic acid decreased broiler body weight compared with the control and organic acids treatment at growth period (days 42-21 of breeding) (p<0.05). Also feed conversion ratio was significantly higher in the Nano silver coated on zeolite treatment than control treatment, zeolite and organic acids groups in the whole experimental periods (1-24 days) (p<0.05). However, the results of the experiment showed no significant differences between all treatments on immune system (p>0.05). In conclusion, the use of Nano silver and organic acid at the above levels had no effect on immune system, but the diet of silver nanoparticles increased the feed conversion ratio in chickens.