Effects of a high-concentrate diet on rumen pH and epithelial transcriptome expression in Holstein cattle

---

Shigeru Sato, Rie Nagata, Natsuki Ohtani, Yo-Han Kim, Toshihiro Ichijo and Shiro Kushibiki

Iwate University, Japan
Gifu University, Japan
National Institute of Livestock and Grassland Science, Japan

: J Vet Sci Med Diagn

Abstract

---

Rumen pH and the expression of the epithelial transcriptome were investigated in cattle fed with a high-concentrate diet to reveal the transcriptomic adaptation of the ruminal epithelium. Four rumen-cannulated healthy Holstein cattle weighing 192±12 (mean±SE) kg were studied. The cattle were fed a high-concentrate diet, in which the ratio of roughage to concentrate was 2:8, or hay to satiation for one week four times each. During the experiment, rumen pH was measured continuously every 10 min using a radio transmission system (YCOW-S; DKK-TOA Yamagata, Yamagata, Japan). Rumen papillae samples were collected from the ventral sac of the rumen at 1 week after the high-concentrate (CON group) and hay satiation (HAY group) feedings in the fourth experiment. A customized bovine oligonucleotide microarray comprising 15,268 unique genes (GPL9284; Agilent Technologies) was used to detect genes expressed in the rumen papillae in a one-color microarray analysis. Pathway and network analysis of differentially expressed genes were performed using ingenuity pathway analysis (IPA) software (Ingenuity Systems, Redwood City, CA, USA). The 24-h mean pH of the ruminal fluid in the CON group was significantly (P<0.05) lower than that in the HAY group. Using IPA, the CLCA3P, PENK, MYBPC3, CD3G, SLITRK2, PRSS27, MUC1, PHLDA2, LOC10272488/PRODH, and SYNPR genes were identified as activated upstream regulators, and the DES, VNN1, SYT1, BMP6, MYO7B, FHL1, PI3C2G, STC1, DUSP26, and HSD11B2 genes were identified as activated downstream regulators. Differentially expressed genes that were significantly (P<0.05) expressed in the CON group included transporter genes (CLC25A19, SLC25A40, SLC16A1, SLC13A2, SLC25A45, SLC23A1, SLC27A2, SLC23A3 and SLC27A3), long-chain fatty acid oxidation genes (ACADS, ACADL and ACADM), an insulin-like factor gene (IGFBP6), and cholesterol genesis genes (ACAT2 and FDFT1). These results suggest that feeding cattle a high-concentrate diet decreases the rumen pH, which in turn affects the expression of the ruminal epithelial transcriptome. Specifically, genes related to cellular inflammatory reactions, the maintenance of homeostasis, and the cytoskeleton appear to be important for the short-term adaptation of the ruminal epithelium in cattle fed a high-concentrate diet.

Biography

---

Email: sshigeru@iwate-u.ac.jp