**3.4 Microbial composition of the ileum**

Bacteria classified according to their respective Class and Order, found in the ileum of broiler chickens at different ages, are presented in **Table 5**. Sixteen bacterial microbiota at the Order level were found in the ileum. Of the 30,961 reads, Lactobacillales were the most abundant Order, from the Class Bacilli, at 51.36% of the total sequences. Clostridiales, a representative Order from the class Clostridia, was the most second Order accounted for 18.35% of the total sequences. At the Class level, only a few 0.90% Actinobacteria-related sequences were detected; these were related to Actinomycetales and Bifidobacteriales. At the Class level, Coriobacteriia,


#### **Table 5.**

*The abundance of bacterial 16S rDNA sequences (n =* **30,961***) identified from the* **ileum** *microflora of cobb 500 broiler chicken.*

*Microbial Diversity and Community Dynamics in the Intestines of Broiler Chicken Raised… DOI: http://dx.doi.org/10.5772/intechopen.103815*

Bacteroidia, and Erysipelotrichi represented small percentages of 0.32%, 0.14%, and 0.44%, respectively, of the total sequences. Across different age periods, Lactobacillales were the most dominant group, representing 98.69% at day 5, 90.59% at day 15, 99.63% at day 25 to 0.05% at day 35 of the sequences. Clostridiales were the second most abundant, sequences fluctuated from 0.14% at day 5, 0.57% at day 15, 0.11% at day 25, and 95.17% at day 35. Relatively, Actinomycetales (Class, Actinobacteria), Coribacteriales, (member from Class Coriobacteria), Bacteroidales, (Class, Bacteroidia), Streptophyta (Class, Chloroplast), Bacillales (Class, Bacilli), Erysipelotrichales (Class, Erysipelotrichi) group-related sequences were detected at smaller percentages across all age periods.

### **3.5 Microbial composition of the cecum**

Bacteria classified according to their respective Class and Order, found in the Cecum of broiler chickens at different ages, are presented in **Table 6**. Sixteen bacterial microbiota at the Order level were found in the cecum. Of the 27,842 reads, Clostridiales, were the most abundant Order, a representative Order from


#### **Table 6.**

*The abundance of bacterial 16S rDNA sequences (n =* **27,842***) identified from the* **cecum** *microflora of cobb 500 broiler chicken.*

#### *Animal Husbandry*

the Class Clostridia, at 62.81% of the total sequences. Lactobacillales, which was the most second Order from the Class Bacilli, accounted for 12.75% of the total sequences. At the Class level, only a few 6.1% Actinobacteria-related sequences were detected; these were related to Actinomycetales and Bifidobacteriales. At the Class level, Bacteroidia and Alphaproteobacteria represented small percentages of 7.47% and 0.79%, respectively, of the total sequences. Across different age periods, Clostridiales were the most dominant group, representing 62.55% at day 5, 38% at day 15, 72.55% at day 25 to 71.87% at day 35 of the sequences, Lactobacillales were the second most abundant, sequences fluctuated from 25.99% at day 5, 16.49% at day 15, 13.05% at day 25 and 0.13% at day 35. Smaller percentage of sequences for Bacteroidales, (Class, Bacteroidia), were observed day 5: 0.56%, day 15: 0.51%, day 25: 0.03% and day 35: 24.57%. Relatively, Coriobacteriales (member from Class Coriobacteriia), Bacillales (member from Class Bacilli), Erysipelotrichales (member from Class, Erysipelotrichi), Rhizobiales (member from Class, Alphaproteobacteria), and Rhodocyclales (Class, Betaproteobacteria) group-related sequences were detected at lower levels across age periods.
