Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Aas, Norway.
Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway.
Front Immunol. 2020 Sep 2;11:1924. doi: 10.3389/fimmu.2020.01924. eCollection 2020.
Supplying novel feed ingredients for pig production is crucial to enhance food security and decrease the environmental impact of meat production. Several studies have focused on evaluating the beneficial health effects of yeast in pigs. However, its use as a protein source has been partially addressed. Previously, we have shown that yeast at high inclusion levels maintains growth performance and digestibility, while nutrient digestibility, intestinal villi height and fecal consistency were improved. The present study combined microbiome, short-chain fatty acid, and immune parameter analysis to investigate the effect of high inclusion of yeast in diets for post-weaning piglets. Our results showed that yeast did not have a significant impact on the hematological or biochemical parameters in blood. The different immune cell subpopulations isolated from blood and distal jejunal lymph nodes (DJLN) were analyzed by flow cytometry and showed that yeast diet induced an increased number of the subtype of leukocytes CD45+/CD3-/CD8+, a special type of Natural Killer (NK) cells. Also, a very mild to moderate infiltration of neutrophilic granulocytes and lower IgA level were observed in the colon of yeast fed piglets. The microbiome profiling in different compartments of the gastrointestinal tract of piglets was performed using 16S rRNA metabarcoding. The results showed that 40% replacement of dietary protein had a statistically significant effect on the microbial communities in cecum and colon, while the microbial population in ileum and jejunum were not affected. Analysis of predicted microbial metabolic pathways analysis revealed significant upregulation of short-chain fatty acids, ether lipid metabolisms, secondary bile acids, and several other important biosynthesis pathways in cecum and colon of pigs fed yeast. In conclusion, the results showed that diet containing 40% of yeast protein positively shaped microbial community in the large intestine and increased the number of a specific subpopulation of NK cells in the DJLN. These results showed that yeast modulates the microbiome and decreases the secretion of IgA in the colon of post-weaning pigs.
为了提高粮食安全并减少肉类生产对环境的影响，为猪生产提供新型饲料成分至关重要。已有多项研究集中于评估酵母对猪的有益健康影响。然而，其作为蛋白质来源的用途仅部分得到解决。此前，我们已经表明，高添加水平的酵母可保持生长性能和消化率，同时提高养分消化率、肠绒毛高度和粪便稠度。本研究结合微生物组、短链脂肪酸和免疫参数分析，研究了日粮中高添加酵母对断奶仔猪的影响。我们的研究结果表明，酵母对血液中的血液学或生化参数没有显著影响。通过流式细胞术分析从血液和回肠远端淋巴结（DJLN）分离的不同免疫细胞亚群，并表明酵母日粮诱导白细胞亚群 CD45+/CD3-/CD8+的数量增加，这是一种特殊类型的自然杀伤（NK）细胞。此外，在酵母喂养仔猪的结肠中观察到嗜中性粒细胞的轻度至中度浸润和较低的 IgA 水平。通过 16S rRNA 代谢组学对仔猪胃肠道不同部位的微生物组进行了分析。结果表明，日粮中 40%的蛋白质替代对盲肠和结肠中的微生物群落具有统计学意义，而回肠和空肠中的微生物群不受影响。预测微生物代谢途径分析表明，在酵母喂养的猪的盲肠和结肠中，短链脂肪酸、醚脂代谢、次级胆汁酸和其他几个重要的生物合成途径的微生物种群显著上调。总之，结果表明，含有 40%酵母蛋白的日粮可积极塑造大肠中的微生物群落，并增加 DJLN 中特定 NK 细胞亚群的数量。这些结果表明，酵母调节微生物组并减少断奶后仔猪结肠中 IgA 的分泌。
