Research Project: Using Metatranscriptomics to Investigate the Liver and Blood Microbiome in the Young Calf and Mid-lactation Cows with Feed-induced Acidosis

Location: Cell Wall Biology and Utilization Research

Project Number: 5090-31000-028-051-I
Project Type: Interagency Reimbursable Agreement

Start Date: Jun 1, 2023
End Date: May 31, 2027

Objective:
The overall goal of this research is to investigate the structure and changes of the liver and blood microbiome in two critical phases of dairy cattle production and its association with feed induced acidosis. The three objectives are as follows: 1. Investigate the core microbiome in the liver and blood with a longitudinal study in the young calf starting at birth and all the way to first lactation. 2. Quantify the community structure and differences in liver and blood microbiota in young calves using our established model of feed induced acidosis in young calves during pre- and postweaning periods. We will assess correlations among rumen, liver, and blood microbiomes and how these correlations change over time. 3. Investigate the liver and blood microbiome changes in mid-lactation cows with induced acidosis, and how these changes correlated with the development of ruminal acidosis.

Approach:
This project focuses on the two critical phases in dairy cattle production: pre- and postweaning periods in young calves and mid-lactation period in adult cows. The main approach we will employ to study the blood and liver microbiome is metatranscriptomics. We plan to first build the baseline of a core microbiome in the liver and blood by a longitudinal study starting with the newborn calf and all the way to first lactation; then, we will use our established, acidosis-inducing model in young calves to study the prevalence and difference of liver microbiome in acidotic calves and how the communities of the liver microbiome evolve over time at three critical time points: pre-weaning (2-4 weeks of age), weaning (8 weeks of age) and post-weaning (12-16 weeks of age); finally, we will induce ruminal acidosis in mid-lactation cows to investigate the liver and blood microbiome changes and how these changes correlated with the development of acidosis. A group of 16, mid-lactation cows will be enrolled, with eight of them subjected to acidosis inducing diet and the rest of the eight on standard diet. Deep metatranscriptomic sequencing using the liver tissues and blood samples will be performed.