Abstract

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.

摘要

本研究的目的是评估长期高浓度日粮饲喂对奶牛瘤胃上皮 (RE) 的影响。因此，将 12 头泌乳中期经产奶牛分成两组，随机饲喂高精饲料（HC，精料：草料 = 6:4）或低精料日粮（LC，精料：草料 = 4:6），每组 20 头周。与 LC 组相比，HC 诱导了瘤胃液中脂多糖 (LPS) 水平的显着上调和 pH 值的降低。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RE较LC组升高。在喂食 HC 的奶牛的 RE 中观察到比喂食 LC 的奶牛的磷酸化 NF-κB p65、IL-6 和肿瘤坏死因子 α (TNF-α) 的蛋白质丰度更高。HC组促凋亡反应相关蛋白（细胞色素c、BAX和caspase-3）丰度高于LC组，而抗凋亡因子蛋白（Bcl-2）丰度HC组低于LC组. 因此，本研究表明，长期高精饲料饲喂可上调瘤胃液中 LPS 水平，并诱导瘤胃上皮细胞的促炎反应和瘤胃上皮细胞凋亡。