Integrated metatranscriptomics identifies Lachnospiraceae as keystone taxa regulating rumen biohydrogenation and milk ω-6/ω-3 polyunsaturated fatty acids ratio in dairy cows (microbiomejournal.biomedcentral.com)

• Rumen microbiota explains 41% of variation in milk ω-6/ω-3 PUFA ratio.
• Lachnospiraceae (Butyrivibrio, Eubacterium) identified as key biohydrogenation regulators.
• B. hungatei preferentially metabolizes ALA, Eubacterium I metabolizes LA.

"Analysis of 95 Holstein cows showed rumen bacterial composition explained 41% of milk ω-6/ω-3 PUFA ratio variation. Lachnospiraceae, particularly Butyrivibrio and Eubacterium, were identified as central regulators. In vitro experiments confirmed B. hungatei preferentially hydrogenates α-linolenic acid while Eubacterium I metabolizes linoleic acid. These findings provide a multi-omics framework for developing microbiome-targeted strategies to improve dairy nutritional quality."