Studies on microbial programming in formula fed neonatal piglets and their susceptibility to Escherichia coli infection later in life

现代猪品种的过度繁殖导致了更频繁地使用人工饲养和以牛奶为基础的配方喂养仔猪。考虑到新生儿肠道的微生物定植主要受环境和饮食等因素的影响，本项目的假设是人工饲养和配方喂养代表了生命早期的应激因素，这i)影响了肠道微生物与宿主之间的相互作用，ii)增加了生命后期对疾病的易感性。这些假设将在两个新生仔猪实验中得到证实。第一阶段试验采用因子设计，研究不同环境和日粮影响下新生仔猪出生后两周小肠生理反应、细菌生态系统以及先天免疫和适应性免疫反应的发展。因此，仔猪将i)由母猪饲养而不添加配方奶，ii)由母猪饲养并接受额外的牛乳配方奶，iii)在隔离箱内饲养并饲喂母猪奶，或iv)在隔离箱内饲养并饲喂牛乳配方奶。这种设计可以区分环境和饮食引起的影响。通过MUC基因和细胞因子的基因表达分析，研究空肠消化性双糖酶（乳糖酶、麦尔糖酶、蔗糖酶）活性、形态变化和粘蛋白组成，以及上皮内、固有层和血液免疫细胞表型。将通过16S rRNA和rDNA的深度测序以及细菌代谢产物（D-/ l -乳酸、短链脂肪酸、生物胺、铵、酚类和吲哚类）的分析来表征腔内和粘膜相关的微生物组。此外，代谢组学方法将用于鉴定血清和尿液中与不同肠道定植模式相关的生物标志物。在第二个试验中，将21日龄断奶的差异饲养仔猪用产肠毒素大肠杆菌菌株攻毒，研究其粘膜和全身反应。预计该项目将进一步深入了解早期肠道定植对宿主发育和后期疾病易感性的影响。研究结果不仅与动物健康相关，还可作为人类新生儿的模型。

Hyper-proliferacy in modern pig breeds has resulted in more frequent use of artificial rearing combined with feeding of bovine milk-based formula of piglets. Taking into account that the microbial colonization of the neonatal intestinal tract is mainly influenced by factors such as the environment and the diet, the hypothesis of this project is that artificial rearing and formula feeding represent early life stress factors, which i) affect the developing gut microbiota-host interplay and ii) increase the susceptibility to disease later in life. These hypotheses will be addressed in two experiments with newborn piglets. In a first experiment, the development of the small intestinal physiological reactions, the bacterial ecosystem and the innate and adaptive immune reactions of neonatal piglets during the first two weeks of life will be studied under the influence of different environments and diets using a factorial design. Therefore, piglets will be i) reared by the sow without formula supplementation, ii) reared by the sow and receive additional bovine milk-based formula, iii) reared in isolators and fed sow milk, or iv) reared in isolators and fed bovine milk-based formula. This design will allow distinguishing between the environmental and diet-induced effects, respectively. Jejunal activity of digestive disaccharidases (lactase, maltase, sucrase), morphological changes and mucin composition as well as intraepithelial, lamina propria and blood immune cell phenotypes will be characterized accompanied by analysis of gene expression of MUC genes and cytokines. The luminal and mucosa-associated microbiome will be characterized by deep sequencing of 16S rRNA and rDNA together with analysis of bacterial metabolites (D-/L-lactate, short chain fatty acids, biogenic amines, ammonium, phenols and indols). In addition, a metabolomics approach will be used to identify biomarkers in the serum and urine associated with different intestinal colonization patterns. In a second experiment, differentially raised piglets will be challenged after the weaning at the age of 21 days with an enterotoxigenic Escherichia coli strain and the mucosal and systemic reactions will be studied. It is anticipated that the project provides further insight into the effect of early intestinal colonization on host development and the disease susceptibility later in life. The results will have relevance for both animal health, but serve also as a model for human neonates.