Xylooligosaccharide Supplementation Mitigates Growth Performance Impairment and Intestinal Injuries in Enterohemorrhagic <i>Escherichia coli</i>-Challenged Broilers

Xylooligosaccharide (XOS) is a typical prebiotic; however, whether it protects chickens from enterohemorrhagic <i>Escherichia coli</i> (EHEC) challenge remains unknown. This study investigated the protective effects of XOS on the growth and gut health of EHEC-challenged broilers. A total of 270 1-day-old broilers were divided into three groups (nine replicates per group): negative control (were not challenged), positive control (EHEC-challenged from days 8 to 11), and XOS (EHEC-challenged broilers supplemented with 1.6 g/kg XOS). Samples were collected from broilers at 14 days. XOS addition alleviated EHEC-induced decline in growth performance, liver index, and the villus height:crypt depth ratio in both the duodenum and ileum of broilers. XOS also attenuated the increase in the relative mRNA expression of the ileal proinflammatory cytokine interleukin 6 and the tight junction protein occludin in EHEC-challenged broilers. Microbiota analysis revealed that EHEC challenge reduced or tended to reduce the abundance of several beneficial bacteria (such as Firmicutes, <i>Fournierella</i>, and <i>Lysinibacillus</i>) and increased or tended to increase the abundance of multiple harmful bacteria (such as Proteobacteria, <i>Aquabacterium</i>, <i>Methylotenera</i>, and <i>Arthrobacter</i>) in the ileum. However, XOS addition mitigated these changes and downregulated or tended to downregulate certain disease-related pathways of the ileal microbiota. In conclusion, XOS supplementation mitigated poor growth performance and intestinal damage in EHEC-challenged broilers, and was probably involved in the attenuation of gut microbiota disturbances that might protect against EHEC infection. These findings provide a basis for the application of XOS to limit the risk of EHEC infection.