| Salecan is a novel water-souble linear β-1,3-glucan produced by Agrobacterium sp. ZX09, and it has many kinds of biological activities. Using Salecan as substrate, a novel β-1,3-glucanase-producing strain S09 which belongs to Paenibacillus species was found out. S09 could secrete β-1,3-1,4-glucanase,β-1,3-glucanase and Salecan hydrolase SalA. SalA had specificity in hydrolyzing Salecan. The final hydrolysate was Salecan oligosaccharide SO8 with homogeneous molecular weight and structure. In this study, physicochemical properties of Salecan oligosaccharide were analyzed, and the regulating effect of SO8 on intestinal physiology and pathology on C57BL/6j mice were investigated.3 week-old C57/BL6j mice were fed with a diet containing Salecan oligosaccharide or Salecan for 4 weeks. We can find the following significant differences in the Salecan oligosaccharide treated mice. The weight of faeces in 24 h after 2,3,4 weeks were increased by 93.7%,159.5% and 87.5%, containing more water. Respectively, the weight of cecum wall and contents were incerased by 29.3% and 65.7%, and higher SCFAs were detected in the cecum contents. As high-throughput sequencing shows, the intake of Salecan oligosaccharide changed the composition of the cecal microbial community of the mice. RT-PCR confirmed that the population of the main probiotics lactobacillus and bifidobacterium were increased by 2.33- and 7.06-fold.7 week-old C56/BL6j male mice were treated with 4% dextran sulphate sodium(DSS) dissolved in drinking water for 4 days to induce ulcerative colitis(UC). To evaluate the therapeutic potential of Salecan oligosaccharide, the mice were given gavage of Salecan oligosaccharide at the dose 20 mg/kg/day for six days. As the results showed, Salecan oligosaccharide dispose reduced the UC degree caused by DSS, lowered the disease activity index, protected the colon from being shortened, the length of colon increased by 29.5%. Salecan oligosaccharide could also alleviate the tissue damage and pathological change and crypt distortion of colon, attenuate the inflammation of colon, inhibit the increase in myeloperoxidase activity (51.1%), stop the spleen swelling by 33.37%.The blood routine test showed that Salecan oligosaccharide can improve the symptoms of anemia in UC mice. Furthermore, RT-PCR analysis reflected that Salecan oligosaccharide could inhibit the increasing of TNF-α mRNA level by 46.2%.In conclusion, Salecan oligosaccharide exert beneficial effects on gut health through fatty acids and the stimulated proliferation of the intestinal probiotics. And it can reduce the colonic damage and inflammation in DSS-induced colitis. |
