School of Equine Management and Science, Royal Agricultural University, Cirencester, Gloucestershire, United Kingdom.
Equine and Livestock Nutrition Services, Tregaron, Ceredigion, Wales.
PLoS One. 2020 Jan 27;15(1):e0227151. doi: 10.1371/journal.pone.0227151. eCollection 2020.
Soaking hay fodder to reduce dust and soluble carbohydrate (WSC) contents prior to feeding is common practice among horse owners. Soaking can increase bacteria load in hay but no information exists on how this process alters the bacteria profile, which could pose a health risk or digestive challenge, to horses by introducing foreign bacteria into the gastrointestinal tract and so altering the normal profile. The current objectives were to map the bacterial profile of 3 different hays and determine how soaking alters this with the aim of improving best practice when feeding stabled horses. A Perennial Rye grass hay and two meadow s hays were soaked for 0, 1.5, 9 or 16 hours. Pre and post treatment, hays were analysed for WSC and total aerobic bacteria (CFU/g), and differences in bacteria family profiles were determined using ANOVA with significance set at P<0.05. Bacteria were identified via genomic DNA extraction and 16S library preparation (V3 and V4 variable region of 16S rRNA) according to the Illumina protocol. Differences in family operational taxonomic units (OTUs) between individual dry hays and different soaking times were identified via paired t-tests on the DESeq2 normalised data and false discovery rates accounted for using Padj (P<0.05). Mean % WSC losses and actual g/kg lost on DM basis (+/- SE) increased with soaking time being 18% = 30 (10.7), 38% = 72 (43.7), and 42% = 80 (38.8) for 1.5, 9 and 16 hours soak respectively. No relationship existed between WSC leaching and bacteria growth or profile. Grass type influenced bacterial profiles and their responses to soaking, but no differences were seen in richness or Shannon diversity indices. PCA analyses showed clustering of bacteria between meadow hays which differed from the perennial rye grass hay and this difference increased post soaking. Soaking hay pre-feeding causes inconsistent WSC leaching, bacteria growth and alterations in bacterial profiles which are unpredictable but may decrease the hygienic quality of the fodder.
在喂马之前，将干草饲料浸泡以降低粉尘和可溶碳水化合物（WSC）含量是马主的常见做法。浸泡可以增加干草中的细菌负荷，但目前尚不清楚这一过程如何改变细菌谱，因为它可能会通过将外来细菌引入胃肠道而对马匹造成健康风险或消化挑战，从而改变正常的细菌谱。目前的目标是绘制 3 种不同干草的细菌谱，并确定浸泡如何改变这一点，以期改善对圈养马的喂养实践。将多年生黑麦草干草和两种草地干草浸泡 0、1.5、9 或 16 小时。在处理前后，分析干草的 WSC 和总需氧细菌（CFU/g）含量，并使用方差分析（显著性水平设为 P<0.05）确定细菌家族谱的差异。通过基因组 DNA 提取和 16S 文库制备（16S rRNA 的 V3 和 V4 可变区）根据 Illumina 方案对细菌进行鉴定。通过对 DESeq2 标准化数据进行配对 t 检验，并使用 Padj（P<0.05）对虚假发现率进行校正，确定个体干草和不同浸泡时间之间的细菌分类单元（OTU）差异。平均 WSC 损失百分比和实际损失量（以 DM 为基础）（+/- SE）随着浸泡时间的增加而增加，分别为 18%=30（10.7）、38%=72（43.7）和 42%=80（38.8），浸泡时间分别为 1.5、9 和 16 小时。WSC 浸出与细菌生长或谱之间没有关系。草的类型影响细菌的分布及其对浸泡的反应，但丰富度或 Shannon 多样性指数没有差异。PCA 分析显示，浸泡前，草地干草之间的细菌聚类与多年生黑麦草干草不同，浸泡后这种差异增大。喂马前浸泡干草会导致不可预测的 WSC 浸出、细菌生长和细菌谱的改变，但可能会降低饲料的卫生质量。
