Dietary supplementation with low and high polymerization inulin ameliorates adipose tissue inflammation via the TLR4/NF-κB pathway mediated by gut microbiota disturbance in obese dogs

Inflammation induced by gut microbiota disorder plays an important role in promoting obesity. Inulin has beneficial effects on gut microflora and metabolic endotoxaemia. However, the chain length of inulin determines its different physiological effects. This study aimed to investigate the effect of low polymerization inulin (LPI) and high polymerization inulin (HPI) on inflammation in dogs with obesity induced by a high-fat diet and its potential mechanism. HPI, relative to LPI, significantly reduced the concentrations of LPS, IL-6 and TNF-α in serum and downregulated both the mRNA and protein expression of TLR4, NF-κB, TNF-α and IL-6 in adipose tissue. HPI and LPI intervention reduced adipose tissue fatty accumulation, which improved obesity. Supplementation with LPI and HPI increased gut microbiota diversity and altered specific bacterial populations at both the phylum and genus levels. The relative abundances of Prevotella, Fusobacterium and Enterobacter, which were positively correlated with the serum concentrations of LPS, IL-6 and TNF-α, were reduced. Our results demonstrate that both LPI and HPI can be used as an effective strategy for reducing inflammation and regulating gut microbiota, which can ameliorate obesity in dogs. Moreover, HPI exerts more positive regulation of the inflammatory response and gut microbiota dysfunction than LPI. •Gut microbiota alterations leading to dysfunction in the cross-talk between the gut and adipose tissue plays an important role in obesity.•Inflammation induced by LPS translocation activating TLR4 / NF-κB pathway is one of the main performances of dysfunction in the cross-talk between the gut and adipose tissue.•The effects of low and high polymerization inulin on gut microbiota, LPS translocation, and TLR4 / NF-κB pathway induced inflammation of adipose tissue are different.•Importantly, high polymerization inulin relative to low polymerization inulin displays the more outstanding anti-obesity effect, which is related to ameliorate adipose tissue inflammation via inhibiting the TLR4/NF-κB pathway mediated by gut microbiota disturbance.•This study provides a scientific basis for inulin against obesity in dogs.