背景:已经发现,饮食中添加低聚木糖(XOS)可以通过操纵盲肠微生物群和产生微生物来源的代谢物来影响肠道健康。但是没有研究调查和比较蛋内饲喂木二糖(XOS2)和木三糖(XOS3)对鸡的影响。这项研究调查了卵内饲喂这些XOS化合物对鸡孵化后肠道健康参数的影响。总共144个受精卵分为三组:a)未注射对照(CON),b)XOS2和c)XOS3。在胚胎的第17天,XOS2和XOS3组的卵通过羊膜囊注射稀释在0.5mL0.85%生理盐水中的3mgXOS2和XOS3.孵化后,小鸡饲养21d。在第14天采集血液以测量血浆免疫球蛋白。在第14天和第21天收集盲肠消化物,用于测量短链脂肪酸(SCFA),并在第7天和第21天进行微生物生态学和微生物代谢途径分析。
结果:认为结果在P<0.05时存在显著差异。ELISA定量测定第14天鸡的血浆IgA和IgG,显示治疗之间没有差异。气相色谱结果显示,盲肠SCFAs的浓度在第14天没有显着差异,而在第21天没有显着差异。然而,在第21天,XOS3中的SCFA浓度低于CON组。盲肠宏基因组学数据显示,与CON相比,XOS2中梭菌科在第7天的丰度显着下降,而梭菌科在第21天的丰度增加。与第7天的CON相比,XOS2中的梭状芽胞杆菌属1的相对丰度降低,与第21天的CON相比,XOS2和XOS3组中的Ruminococcus属扭矩降低。XOS2和XOS3组减少了硫酸软骨素降解I和L-组氨酸降解I途径的基因,这有助于改善肠道健康,分别,在第7天的微生物组中。相比之下,在第21天,XOS2和XOS3组丰富了硫胺素救助II,L-异亮氨酸生物合成IV,和O-抗原构建模块生物合成(E.大肠杆菌)途径,这表明改善了肠道健康。与XOS3和CON不同,微生物组丰富了与能量增强相关的途径,包括黄素生物合成I,蔗糖降解III,和卡尔文-本森-巴斯舍姆循环通路,在第21天的XOS2组中。
结论:在卵XOS2和XOS3饲喂中,在家族和属水平上促进了有益的细菌生长并减少了有害细菌。基于宏基因组的微生物代谢途径分析预测了XOS2和XOS3组中盲肠代谢物的可用性的有利变化。微生物群和代谢途径的调节表明,卵XOS2和XOS3喂养改善了肉鸡孵化期后的肠道健康。
BACKGROUND: Dietary supplementation of
xylooligosaccharides (XOS) has been found to influence gut health by manipulating cecal microbiota and producing microbe-origin metabolites. But no study investigated and compared the effect of in ovo feeding of xylobiose (XOS2) and xylotriose (XOS3) in chickens. This study investigated the effect of in ovo feeding of these XOS compounds on post-hatch gut health parameters in chickens. A total of 144 fertilized chicken eggs were divided into three groups: a) non-injected control (CON), b) XOS2, and c) XOS3. On the 17th embryonic day, the eggs of the XOS2 and XOS3 groups were injected with 3 mg of XOS2 and XOS3 diluted in 0.5 mL of 0.85% normal saline through the amniotic sac. After hatching, the chicks were raised for 21 d. Blood was collected on d 14 to measure plasma immunoglobulin. Cecal digesta were collected for measuring short-chain fatty acids (SCFA) on d 14 and 21, and for microbial ecology and microbial metabolic pathway analyses on d 7 and 21.
RESULTS: The results were considered significantly different at P < 0.05. ELISA quantified plasma IgA and IgG on d 14 chickens, revealing no differences among the treatments. Gas chromatography results showed no significant differences in the concentrations of cecal SCFAs on d 14 but significant differences on d 21. However, the SCFA concentrations were lower in the XOS3 than in the CON group on d 21. The cecal metagenomics data showed that the abundance of the family Clostridiaceae significantly decreased on d 7, and the abundance of the family Oscillospiraceae increased on d 21 in the XOS2 compared to the CON. There was a reduction in the relative abundance of genus Clostridium sensu stricto 1 in the XOS2 compared to the CON on d 7 and the genus Ruminococcus torques in both XOS2 and XOS3 groups compared to the CON on d 21. The XOS2 and XOS3 groups reduced the genes for chondroitin sulfate degradation I and L-histidine degradation I pathways, which contribute to improved gut health, respectively, in the microbiome on d 7. In contrast, on d 21, the XOS2 and XOS3 groups enriched the thiamin salvage II, L-isoleucine biosynthesis IV, and O-antigen building blocks biosynthesis (E. coli) pathways, which are indicative of improved gut health. Unlike the XOS3 and CON, the microbiome enriched the pathways associated with energy enhancement, including flavin biosynthesis I, sucrose degradation III, and Calvin-Benson-Bassham cycle pathways, in the XOS2 group on d 21.
CONCLUSIONS: In ovo XOS2 and XOS3 feeding promoted beneficial bacterial growth and reduced harmful bacteria at the family and genus levels. The metagenomic-based microbial metabolic pathway profiling predicted a favorable change in the availability of cecal metabolites in the XOS2 and XOS3 groups. The modulation of microbiota and metabolic pathways suggests that in ovo XOS2 and XOS3 feeding improved gut health during the post-hatch period of broilers.