Digestive tract microbiota of beef cattle that differed in feed efficiency

Area of Science:

• Animal Science
• Microbiology
• Genomics

Background:

• Gut microbiota plays a crucial role in animal health and performance.
• Understanding the relationship between host performance and microbial composition is vital for optimizing livestock production.
• Previous research suggests variations in cattle performance may be linked to differences in digestive tract microbial populations.

Purpose of the Study:

• To investigate if cattle exhibiting different average daily gains (ADG) possess distinct digestive tract microbiota.
• To compare microbial diversity and composition across various segments of the digestive tract in high- and low-ADG steers.
• To identify specific microbial clades associated with performance differences in cattle.

Main Methods:

• Two experiments involving individually fed steers on a standardized diet were conducted.
• Ruminal digesta (Experiment 1) and digesta from rumen, duodenum, jejunum, ileum, cecum, and colon (Experiment 2) were collected from steers with the highest and lowest ADG.
• Bacterial 16S rRNA gene sequencing was performed to analyze microbial community structure and diversity (Chao1, Shannon, Simpson indexes) and identify differentially abundant taxa using PERMANOVA.

Main Results:

• Experiment 1 showed no significant differences in overall microbial diversity in the rumen between high- and low-ADG steers, but six microbial clades were differentially abundant.
• Experiment 2 revealed no significant differences in microbial diversity in the rumen, duodenum, ileum, cecum, and colon.
• In the jejunum, a trend towards differences in Chao1 and Simpson diversity indexes was observed, and PERMANOVA indicated significant differences in microbial classification groups, with 11 clades found to be differentially abundant, primarily from the Families Corynebacteriaceae and Coriobacteriaceae.

Conclusions:

• While overall microbial diversity may not consistently differ across all digestive tract segments based on ADG, specific jejunal microbial communities are associated with performance variations in steers.
• The identification of differentially abundant taxa in the jejunum suggests a potential link between specific gut bacteria and cattle growth performance.
• These findings highlight the importance of localized intestinal microbiota in influencing ruminant animal performance.