1.1 Introduction The human microbiome comprises diverse microbiologic ecosystems and is composed of a variety of bacteria, archaea, microeukaryotes, and viruses. Although investigators have appreciated the diversity of our microbial world for decades, scientists were constrained by the inability to culture many bacteria in the laboratory. Paradigms in biomedical science and medicine are changing in a fundamental way as investigators explore potential contributions of human-associated microbes to health and expand our understanding of disease susceptibility and pathogenesis. In the 21st century, investigators are attempting to develop a more balanced mindset as investigators seek to understand the role of the human microbiome in physiology and manipulate it to optimize health and prevent or treat disease. In recent years, investigators have increased our understanding of microbial communities and their corresponding metagenomes at different human body sites greatly. Healthy gastrointestinal (GI) microbiome should include age, sex, race/ethnicity, and diet. The Human Microbiome Project documented the importance of considering sex and race/ethnicity in evaluating differences between microbiomes of individuals. The human GI microbiome comprises diverse microbial communities that differ based on their location along the length of the GI tract (esophagus, stomach, small intestine, and large intestine or colon). Most human intestinal microbiome studies have relied on stool specimens. Probiotics have showed to possess anti mutagenic, anti carcinogenic and hypocholesterolemic properties. It is well-known that probiotics have a number of beneficial health effects in humans and animals, including the reduction of symptoms in lactose intolerance and enhancement of the bio availability of nutrients. Further, they were also observed to have antagonistic actions against intestinal and food-borne pathogens, to decrease the prevalence of allergies in susceptible individuals and to have immunomodulatory effects. Typically, the bacteria colonise the intestinal tract first and then reinforce the host defence systems by inducing a generalised mucosal immune response, balanced T-helper cell response, self-limited inflammatory response and secretion of polymeric IgA. Scientific reports showed that the Taiwan native lactic acid bacterium from newborn infant faeces identified as Lactobacillus paracasei subsp. paracasei NTU 101 and its fermented products proved to be effective for the management of blood cholesterol and pressure, prevention of gastric mucosal lesion development, immunomodulation and alleviation of allergies, anti-osteoporosis and inhibition the fat tissue accumulation.

1.2 Materials The strain used in the current study was L. paracasei subsp. paracasei NTU 101 (lyophilized powdered, Vigiis 101-LAB; probiotic powder from SunWay Biotech Co., Ltd., Taipei, Taiwan). The Vigiis 101-LAB mixed lactose, crystalline cellulose, and excipient were made into capsules (Vigiis 101-LAB capsule) containing 5 billion bacteria per capsule for the gut flora clinical trial. Maltodextrin was used as a placebo.

1.3 Randomized, double-blind clinical criteria of effects of Vigiis 101-LAB capsule I on gut flora (clinical trial) Vigiis 101-LAB capsule was administered orally once per day, one capsule each time. The entire study took 4 weeks, and subjects were prohibited from eating fermented food products, such as miso, kimchi, fermented dairy products, oligosaccharide-containing foods, and lactic acid bacteria-containing products. Subjects also avoided consuming excessive gas-producing foods (such as soybeans and sweet potatoes) during their daily meals and avoided foods that can cause abdominal distension or promote peristalsis (such as lactic acid beverages and oligosaccharide-containing beverages). After the trial started, subjects recorded their daily number of bowel movements and completed relevant questionnaires at weeks 0, 2, and 4. The subjects visited the doctor once every 2 weeks for monitoring gastrointestinal function and physiological characteristics. At weeks 0, 1, 2, 3, and 4, fecal samples from the subjects were collected and put into bottles containing an anaerobic diluent and shaken to uniformly mix the feces and diluent.

1.4 Outcome measurements Fecal moisture content and pH value testing. Blood biochemical tests were carried out in the laboratory.

1.5. Statistical analysis Data are expressed as the mean ± standard deviation (SD). The statistical significance of the biochemical analyses was determined by one-way analysis of variance (ANOVA) using the general linear model procedure of the statistical product and service solutions software (SPSS Institute, Inc., Chicago, IL, USA). This was followed by ANOVA with a paired t-test to evaluate the difference before and after sample and placebo administration, while the Student t-test was used to compare the difference between test and placebo groups (P ≤ 0.05).