Azadeh Zahmatkesh - Department of Anaerobic Bacterial Vaccine Research and Production, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
Saeid Ansari Mahyari - Department of Animal Sciences, College of Agriculture, Isfahan University of Technology, Isfahan ۸۴۱۵۶-۸۳۱۱۱, Iran
Ahmad Riasi - Department of Animal Sciences, College of Agriculture, Isfahan University of Technology, Isfahan ۸۴۱۵۶-۸۳۱۱۱, Iran
Amir Hossein Mahdavi - Department of Animal Sciences, College of Agriculture, Isfahan University of Technology, Isfahan ۸۴۱۵۶-۸۳۱۱۱, Iran

Chicken gut microbiota is affected by factors such as diets, environmental ,and bird age. In the current study, the effects of age and region on the ileum bacterial population of broiler chickens were investigated. A total of ۲۶۷۹ chickens in four geographical regions of Iran were sacrificed in the first to eighth week of age. Stool samples were collected and DNA was extracted and analyzed for the detection of Lactobacillus, Enterococcaceae, Clostridiaceae, Streptococcaceae, and Actinobacteria, using specific primers and probes. Purified amplicons were quantified by QuantiFluor® and pooled for sequencing. Findings showed that L. acidophilus was the dominant bacterium during the first four weeks, and was substituted with L. crispatus and L. salivarius in the next four weeks. So, the Lactobacillus family was the most dominant bacteria at all ages showing its essential role in chicken physiology. The age of chickens significantly affected the percentage of L. crispatus, L. acidophilus, L. salivarius, Clostridiaceae, Enterococcaceae, Streptococcaceae, and Actinobacteria. The breeding region influenced Streptococcaceae, with the highest percentage in the hot region. Chicken weight had a significant effect on Enterococcaceae. Broiler breeder age and distance to the nearest farm had no effect on ileum bacterial populations. This study showed there are several factors during the broiler breeding period that have an impact on microbial population changes at different ages.

۱۶S rRNA, Heat stress, Microbiota, Breeder age, Weight gain