The aim of the present study was to evaluate how long-term high-concentrate diet feeding affected rumen epithelium (RE) of dairy cows. So, 12 mid-lactating multiparous cows were divided into two groups randomly fed either with high-concentrate diet (HC, concentrate: forage = 6: 4) or low-concentrate diet (LC, concentrate: forage = 4:6) for 20 weeks. Remarkable upregulation of lipopolysaccharide (LPS) level and depress of pH in rumen fluid were induced by HC compared with LC group. mRNA abundance of interleukin-6 (IL-6), interleukin-8 (IL-8), C-C motif chemokine ligand 5 (CCL5), caspase-3, caspase-8, and caspase-9 were elevated in RE of HC group compared with LC group. Greater protein abundance of phosphorylated NF-κB p65, IL-6, and tumor necrosis factor α (TNF-α) was observed in RE of cows fed HC than that fed LC. Abundance of protein related to proapoptotic response (cytochrome c, BAX and caspase-3) in HC group was greater than that in LC group, while the abundance of anti-apoptotic factor protein (Bcl-2) was lower in HC group than LC group. Therefore, the present study demonstrated that long-term high-concentrate diet feeding upregulated LPS level in rumen fluid and induced the proinflammatory response in the rumen epithelium and apoptosis of rumen epithelial cells.

本研究的目的是评估长期高浓度饮食喂养如何影响奶牛的瘤胃上皮（RE）。因此，将12头泌乳中期的多头母牛分为两组，随机喂养高浓度日粮（HC，浓缩液：草料= 6：4）或低浓度日粮（LC，浓缩液：草料= 4：6），共20头周。HC组与LC组相比，脂多糖（LPS）水平明显升高，瘤胃液pH降低。白细胞介素6（IL-6），白细胞介素8（IL-8），CC基序趋化因子配体5（CCL5），caspase-3，caspase-8和caspase-9的mRNA丰度HC组的RE较LC组升高。饲喂HC的奶牛的RE中磷酸化的NF-κBp65，IL-6和肿瘤坏死因子α（TNF-α）的蛋白丰度高于饲喂LC的奶牛。HC组细胞凋亡相关蛋白（细胞色素c，BAX和caspase-3）的丰度高于LC组，而抗凋亡因子蛋白（Bcl-2）的丰度低于LC组。 。因此，本研究证明长期高浓度饮食喂养可提高瘤胃液中LPS的水平，并诱导瘤胃上皮的促炎反应和瘤胃上皮细胞的凋亡。