Gastrointestinal Microbial Population Response and Performance of Broiler Chickens Fed with Organic Acids and Silver Nanoparticles Coated on Zeolite under Heat Stress Condition

The aim of this study was to evaluate gastrointestinal microbial population response and performance of broiler chickens fed organic acids and silver nanoparticles coated on zeolite under heat stress condition. In this experiment, 375 one-day old broiler chicks (Cobb 500) were randomly divided into 5 treatments containing 5 replicates with 15 birds in each replicate. Five dietary treatments were compared: (1) basal diet (control), (2) basal diet containing 1% zeolite, (3) basal diet containing 1% of zeolite coated with 0.5% silver nanoparticles, (4) basal diet containing 1 g/kg organic acids and (5) basal diet containing 1% zeolite-coated with 0.5% silver nanoparticles and 1 g/kg organic acids. Feed intake and body weight were recorded in the course of the whole experiment for each treatment, and the feed conversion ratio were calculated subsequently. On days 21 and 42 of the experiment, one chicken in each replicate slaughtered to enumerate gastrointestinal microbial population. The results of the experiment indicate that diet containing nanosilver with organic acid decreased broiler body weight compared with the control and zeolite treatment at 21-42 days of age (P<0.05). Also feed conversion ratio was significantly higher in the nanosilver coated on zeolite group than in the control, zeolite and organic acids groups in the whole experimental period (P<0.05). However, there was no significant difference between the experimental treatments on the responses of gastrointestinal microbial population (P>0.05). In conclusion, the present results showed, although silver nanoparticles and organic acids did not have particular effect on performance parameters and increasing the number of useful intestinal microbial population (lactic acid), yet they did not have destructive effects on outcome either. Therefore, these additives can be used in broilers diet.