Department of Animal Sciences, University of Illinois, Urbana 61801, IL, USA.
Università degli Studi del Molise, 86100, Campobasso, Italy.
J Anim Sci. 2023 Jan 3;101. doi: 10.1093/jas/skad277.
Stressors such as lack of access to feed, hot temperatures, transportation, and pen changes can cause impairment of ruminal and intestinal barrier function, also known as "leaky gut". Despite the known benefits of some nutritional approaches during periods of stress, little is understood regarding the underlying mechanisms, especially in dairy cows. We evaluated the effect of feeding a Saccharomyces cerevisiae fermentation product (SCFP; NutriTek, Diamond V, Cedar Rapids, IA) on the ileal transcriptome in response to feed restriction (FR), an established model to induce intestinal barrier dysfunction. Multiparous cows [97.1 ± 7.6 days in milk (DIM); n = 5/group] fed a control diet or control plus 19 g/d SCFP for 9 wk were subjected to an FR challenge for 5 d during which they were fed 40% of their ad libitum intake from the 7 d before FR. All cows were slaughtered at the end of FR, and ileal scrapping RNA was used for RNAseq (NovaSeq 6000, 100 bp read length). Statistical analysis was performed in R and bioinformatics using the KEGG (Kyoto Encyclopedia of Genes and Genomes) and GO databases. One thousand six hundred and ninety-six differentially expressed genes (DEG; FDR-adjusted P ≤ 0.10) were detected in SCFP vs. control, with 451 upregulated and 1,245 downregulated. "Mucin type O-glycan biosynthesis" was the top downregulated KEGG pathway due to downregulation of genes catalyzing glycosylation of mucins (GCNT3, GALNT5, B3GNT3, GALNT18, and GALNT14). An overall downregulation of cell and tissue structure genes (e.g., extracellular matrix proteins) associated with collagen (COL6A1, COL1A1, COL4A1, COL1A2, and COL6A2), laminin (LAMB2), and integrins (ITGA8, ITGA2, and ITGA5) also were detected with SCFP. A subset of DEG enriched in the GO term "extracellular exosome" and "extracellular space". Chemokines within "Cytokine-cytokine receptor interaction pathways" such as CCL16, CCL21, CCL14, CXCL12, and CXCL14 were downregulated by SCFP. The "Glutathione metabolism" pathway was upregulated by SCFP, including GSTA1 and RRM2B among the top upregulated genes, and GSTM1 and GPX8 as top downregulated genes. There were 9 homeobox transcription factors among the top 50 predicted transcription factors using the RNAseq DEG dataset, underscoring the importance of cell differentiation as a potential target of dietary SCFP. Taken together, SCFP downregulated immune-, ECM-, and mucin synthesis-related genes during FR. Homeobox transcription factors appear important for the transcriptional response of SCFP.
应激因素，如饲料获取不足、高温、运输和圈舍变化等，会导致瘤胃和肠道屏障功能受损，这种现象也被称为“肠漏”。尽管在应激期间，一些营养方法已被证实具有益处，但人们对其潜在机制，尤其是在奶牛方面，仍知之甚少。我们评估了在饲料限制（FR）期间，饲喂酿酒酵母发酵产物（SCFP；NutriTek，Diamond V，爱荷华州雪松急流市）对回肠转录组的影响，FR 是一种诱导肠道屏障功能障碍的成熟模型。经产奶牛（产奶天数为 97.1±7.6 天；n=每组 5 头）饲喂对照日粮或对照日粮加 19 g/d SCFP 9 周，在 FR 期间进行 5 d 的 FR 挑战，在此期间，它们的采食量限制为 FR 前 7 d 的 40%。所有奶牛在 FR 结束时进行屠宰，使用回肠刮取 RNA 进行 RNAseq（NovaSeq 6000，100 bp 读长）。在 R 和使用京都基因与基因组百科全书（KEGG）和 GO 数据库的生物信息学中进行统计分析。在 SCFP 与对照之间检测到 1696 个差异表达基因（DEG；FDR 调整 P 值≤0.10），其中 451 个上调，1245 个下调。由于粘蛋白糖基化的基因（GCNT3、GALNT5、B3GNT3、GALNT18 和 GALNT14）的下调，“粘蛋白型 O-聚糖生物合成”是下调最明显的 KEGG 途径。细胞和组织结构基因（如细胞外基质蛋白）的总体下调与胶原蛋白（COL6A1、COL1A1、COL4A1、COL1A2 和 COL6A2）、层粘连蛋白（LAMB2）和整合素（ITGA8、ITGA2 和 ITGA5）有关，也在 SCFP 处理中检测到。GO 术语“细胞外小泡”和“细胞外空间”中富集的 DEG 子集。“细胞因子-细胞因子受体相互作用途径”中的趋化因子，如 CCL16、CCL21、CCL14、CXCL12 和 CXCL14，在 SCFP 作用下下调。“谷胱甘肽代谢”途径被 SCFP 上调，包括在 top 上调基因中 GSTA1 和 RRM2B，以及在 top 下调基因中 GSTM1 和 GPX8。在使用 RNAseq DEG 数据集预测的前 50 个转录因子中，有 9 个同源盒转录因子，这突显了细胞分化作为饲料 SCFP 潜在靶点的重要性。总之，在 FR 期间，SCFP 下调了与免疫、细胞外基质和粘蛋白合成相关的基因。同源盒转录因子似乎对 SCFP 的转录反应很重要。
