During animal development process, goats undergo a drastic change in nutrient supply from high-fat milk diets during non-rumination phase to forage based diets during rumination phase. The shift in nutrient supply is closely associated with the bacteria colonization process in ileum and their potential roles in host fermentation capacity. Generally, anaerobic digestion of carbohydrate depends on a wide range of bacterial groups, especially fibrolytic bacteria, and leads to the formation of volatile fatty acids, carbon dioxide, hydrogen and microbial biomass.

Researchers in the Institute of Subtropical Agriculture, Chinese Academy of Sciences (ISA) employed high-throughput sequencing of 16S rRNA, chemical analysis of volatile fatty acids and fiber-degrading enzyme activities, and statistical techniques to explore age-related changes in ileal bacterial community for grazing goats and their potential roles in host fermentation capacity. The ages are d 0, 7, 28, 42 and 70.

The team found that each age group harbored its distinct bacteria. "Total bacteria number and bacterial diversity increased with age,"said Dr JIAO Jinzhen, a researcher at ISA . "At the phylum level, abundances of Cyanobacteria, TM7, Bacteroidetes and Fibrobacteres increased, while Proteobacteria abundance decline from d 0 to 70. At the genus level, Enterococcus, Lactobacillus and Escherichia dominated on the day born, while Prevotella, Butyrivibrio, Ruminococcus, SMB53 and Fibrobacter surged in abundance after d 20."

Besides, the highest activity of amylase and xylanase were detected at d 42 and 70, respectively. Correlation analysis indicated that bacterial genera such as Bacteroides, Clostridium, Lactobacillus, Propionibacterium, Enterococcus and p-75-a5 might participate in the elevated fermentation capacity in goat ileum.

This research was supported by funding from the Open Foundation of Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences (Grant No. ISA2016301), and National Natural Science Foundation of China (Grants No. 31601967, 31320103917, 31561143009).

The study entitled "Composition of Ileal Bacterial Community in Grazing Goats Varies across Non-rumination, Transition and Rumination Stages of Life"has been published in the September issue of Frontiers in Microbiology, details could be found at http://journal.frontiersin.org/article/10.3389/fmicb.2016.01364/full.

Contact: TAN Zhiliang

E-mail: zltan@isa.ac.cn

Institute of Subtropical Agriculture, Chinese Academy of Sciences