?-Linolenic Acid And Krill Oil Altered The Metabolic Activity Of Microorganisms And Microbiota In Mouse Colon

There are more than 1014 microbes in human gut, and the diversity and densities of the microbiota increase from stomach to colon. Microbiota is not just passive residents, whereas the genetic composition and metabolic activity of gut bacteria respond to different dietary intake. Over the last decade, the microbiota in gut has been research hotspot with increasingly more and more literatures published, due to its impact upon various health conditions. For instance, high-glucose and high-fat diet-induced changes of gut associated microbial communities are now suspected of contributing to growing chronic illness, including obesity, diabetes and inflammatory bowel disease.?-Linolenic Acid(ALA) and Krill Oil(KO) are widely used as dietary supplement. Both ALA and KO have high content of ?-3 polyunsaturated fatty acids(PUFAs). As broadly reported, ?-3 PUFAs have multiple impacts on human health, including anti-inflammatory effects on bowel diseases and antihyperlipidemic action. However, the interactions between the gut microbiota and ?-3 PUFA supplement are not very clear.In this study, Kun-Ming mice were orally administered with ALA or KO daily for 30 days. The impact of ALA and KO on metabolic activity of microorganisms in gut were investigated by evaluating the colonic fecal moisture and SCFAs levels. The colonic bacterial communities in the ALA, KO and control groups were identified and analized. In addition, we tried to find out some relationships between serum biomarkers and microbiota in gut after the administration with ALA and KO.The results showed that administration with ALA and KO has no significant effect on body weight, dietary intake and excretion in a Kun-Ming mouse model. Different dose of ALA at low, medium and high dose(1, 2, 4 g/kg, respectively), and KO(0.25, 0.5, 1 g/kg, respectively) could elicit the changes of some serum biomarkers, such as decreasing expression of cholesterol and triglycerides. In general, high concentration of serum cholesterol and triglycerides may increase the risk of cardiovascular diseases. In this study, ALA and KO both at medium dose could reduce the concentration of serum cholesterol and triglycerides significantly. Meanwhile, ALA and KO at medium dose could significantly increase colon fecal moisture and the production of SCFAs. It can be seen that the type, number and abundance of microorganisms were changed in different groups through DGGE analysis. The principal component analysis also showed that there were some differences among ALA, KO and the control groups.In summary, dietary intake of ALA and KO could significantly decrease the levels of cholesterol and triglycerides in serum, which have some beneficial effects on physical health. ALA and KO could increase the colon facal moisture and the concentration of SCFAs, and change the intestinal microbiota. It suggests that ALA and KO account for the variety of intestinal microbiota,which resulted the changes of serum biomarkers, colon fecal moisture and SCFAs. Therefore, ALA and KO may have the potential of prevention of cardiovascular diseases through production of SCFAs and reduction of cholesterol and triglycerides.