Rumen epithelial functional adaptation in alpine ewes: transcriptomic effects of micronutrient premix and concentrate...

Ovine species inhabiting harsh environments frequently develop enhanced functional adaptations. This study aims to (1) characterize rumen epithelial modifications in lactating Hulunbeier ewes under alpine conditions, and (2) elucidate how these adaptive responses are modulated by micronutrient supplementation and varying concentrate feed levels. Thirty lactating Hulunbeier ewes were randomly assigned to one of the three dietary groups and fed the same roughages with one of the following concentrates: 1) 550 g/d of local concentrate (LF) as the control, 2) 550 g/d of formulated concentrate (FF), and 3) 700 g/d of formulated concentrate (FS). Daily feed intake were recorded, and rumen epithelial tissues were collected for transcriptome analysis after slaughter on day 37 of the experiment. Transcriptomic analyses were performed on a subset of 11 ewes (LF, n = 4; FF, n = 4; FS, n = 3). No independent qPCR validation was conducted; results are therefore preliminary. In the exploratory cross-breed comparison, Hulunbeier sheep showed a suggestive trend toward enhanced expression of energy metabolism genes (ATP5MC2, ATP5PO, UQCRH) and genes encoding mitochondrial respiratory chain components relative to lowland Hu sheep. Supplementation with micronutrient premix upregulated key detoxification genes (CYP1A1, LOC101119706) and modulated immune-related pathways. In contrast, high concentrate levels promoted biosynthetic processes while suppressing cellular signaling functions. Gene Set Enrichment Analysis further indicated activation of thermogenesis pathways in the high-concentrate group, accompanied by altered expression of electron transport chain genes. PPARA may be involved in volatile fatty acid metabolism in response to micronutrient supplementation, but this requires direct experimental testing. Collectively, with the caveat of small sample size and lack of qPCR validation, these pilot-scale transcriptomic findings generate hypotheses that may underlie nutritional modulation of rumen function in alpine-adapted sheep; however, further validation with larger sample sizes and correlated phenotypic measurements is warranted. These results provide preliminary insights for developing targeted nutritional strategies to enhance ruminant production in breeds adapted to extreme environments.