Liver and muscle transcriptomes differ in mid-lactation cows divergent in feed efficiency in the presence or absence of supplemental rumen-protected choline

Authors: CAPUTO, MALIA - University Of Wisconsin; Li, Wenli; KENDALL, SOPHIA - University Of Wisconsin; LARSEN, ANNA - University Of Wisconsin; WEIGEL, KENT - University Of Wisconsin; WHITE, HEATHER - University Of Wisconsin

Submitted to: Metabolites
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2023
Publication Date: 9/18/2023
Citation: Caputo, M.J.; Li, W.; Kendall, S.J.; Larsen, A.; Weigel, K.A.; White, H.M. Liver and Muscle Transcriptomes Differ in Mid-Lactation Cows Divergent in Feed Efficiency in the Presence or Absence of Supplemental Rumen-Protected Choline. Metabolites 2023, 13, 1023. https://doi.org/10.3390/metabo13091023
DOI: https://doi.org/10.3390/metabo13091023

Interpretive Summary: Improving dairy cow feed efficiency is critical to the sustainability and profitability of dairy production. However, there can be significant variations in feed efficiency among cows fed the same diet. Currently the underlying mechanisms that contribute to such variation are not fully understood. We hypothesize that tissue-specific mechanisms might play a role in such variations and feed treatment may not be the major source contributing to feed efficiency differences among individuals. The objectives of this study were 1) to identify genes contributing to high (HE) and low (LE) feed efficiency in both liver and muscle and 2) determine if rumen-protected choline supplementation in mid-lactation might significantly influence performance or feed efficiency. Out data indicated that rumen-protected choline supplementation does not have a significant impact on feed efficiency. Importantly, between HE and LE, different set of genes were identified as differentially expressed in liver and muscle tissues. For liver, the differentially expressed genes (DEGs) were enriched in molecular pathways related to oxidative stress and immunity. In muscle, the DEGs were predominantly enriched in glucose and fatty acid metabolism. Our study suggested that liver and muscle nutrient metabolism might be a source of variation in feed efficiency and that the impact of nutrient supplementation in feed efficiency warrants further investigation.

Technical Abstract: Improving dairy cow feed efficiency is critical to the sustainability and profitability of dairy production, yet the underlying mechanisms that contribute to individual cow variation in feed efficiency are not fully understood. The objectives of this study were to: 1) identify genes and associated pathways that are altered in cows with high or low residual feed intake (RFI) using RNA sequencing, and 2) determine if rumen-protected choline supplementation in mid-lactation would influence performance or feed efficiency. Mid-lactation multiparous Holstein cows were randomly assigned to either supplementation of 0 g/d (CTL; n = 32) or 30 g/d of a rumen-protected choline product (RPC; 13.2 g choline ion; n = 32; Balchem Corporation). The 12 cows with the highest RFI (low feed efficient; LE) and 12 cows with the lowest RFI (high feed efficient; HE), balanced by dietary treatment, were selected for blood, liver, and muscle analysis. No differences in production or feed efficiency were detected with RPC supplementation, although albumin was greater and arachidonic acid tended to be greater in RPC cows. Concentrations of beta-hydroxybuterate were greater in HE cows. There were interactions between feed efficiency and dietary treatment for plasma triglycerides, heptadecanoic acid, and alanine aminotransferase, and tended to be an interaction for glucose and myristic acid. Between HE and LE, 268 and 315 differentially expressed genes in the liver and muscle tissue, respectively, were identified through RNA sequencing. Pathway analysis indicated differences in cell cycling, oxidative stress, and immunity in liver and differences in glucose and fatty acid pathways in muscle. The current work implicates liver and muscle post-absorptive nutrient metabolism as a source of variation in feed efficiency.