Experimental diets dictate the metabolic benefits of probiotics in obesity

Diet composition influences probiotic and postbiotic effects on broiler growth and physiology

Dietary ingredient and nutrient composition may affect the efficacy of additives in broilers. Specific feed ingredients can represent dietary challenging conditions for broilers, resulting in impaired performances and health, which might be alleviated by dietary probiotics and postbiotics. We assessed the effects of a Lactobacilli probiotic (Pro) and postbiotic (Post) when added to a standard (SD) and challenge (CD) diet. A completely randomized block study with 2 diets (SD, CD) and 3 additive conditions (Control, Pro and Post) involving 1,368 one-day-old Ross male broilers, equally distributed among 36 pens, from d1 to d42 was conducted. Both diets were formulated to contain identical levels of nutrients, with CD formulated to be richer than SD in nonstarch polysaccharides using rye and barley as ingredients. Readout parameters included growth performance parameters, footpad lesions score, blood minerals and biochemical parameters, and tibia health, strength, and composition. Compared to SD, CD decreased BW (1,936 vs. 2,033 g; p = 0.001), increased FCR (p < 0.01) and impaired tibia health and strength (p < 0.05) at d35, thereby confirming the challenging effect of CD. Pro and Post increased BW in CD (+4.7 and +3.2%, respectively, at d35; P < 0.05) but not in the SD group, without affecting FCR. Independently of the diet, Pro increased plasma calcium, phosphorus and uric acid at d21 (+6.2, +7.4, and +15.5%, respectively) and d35 (+6.6, +6.2 and +21.0%, respectively) (P < 0.05) while Post increased plasma magnesium only at d21 (+11.3%; P = 0.037). Blood bile acids were affected by additives in an age- and diet-dependent manner, with some opposite effects between dietary conditions. Diet composition modulated Pro and Post effects on broiler growth performance. Additionally, Pro and Post affected animal metabolism and leg health diet-dependently for some but not all investigated parameters. Our findings show that the effects of pro- and postbiotics on the growth performance and physiology of broilers can be dependent on diet composition and thus possibly other factors affecting diet characteristics.

Effect of Continuous Ingestion of Bifidobacteria and Inulin on Reducing Body Fat: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Comparison Study

Bifidobacterium animalis subsp. lactis GCL2505 has been shown to have several positive health effects, including improved defecation frequency and reduced visceral fat. It is known that combined intake of GCL2505 and inulin increases the total number of bifidobacteria compared with ingestion of GCL2505 alone. This randomized, double-blind, placebo-controlled, parallel-group study was conducted to confirm that consumption of GCL2505 and inulin reduces abdominal fat (n = 120). Participants consumed a test beverage containing 1 × 1010 colony-forming units of GCL2505 per 100 g and 2.0 g of inulin per 100 g for 12 weeks. A change in the visceral fat area (VFA) was set as the primary endpoint. There were significant reductions in VFA and total fat area. The intervention significantly increased the total number of bifidobacteria and affected the levels of several lipid markers. Regression analysis of bifidobacteria and measured parameters showed that total bifidobacteria correlated with VFA and body mass index (BMI), while endogenous bifidobacteria and Bifidobacterium animalis subsp. lactis correlated only with BMI, suggesting that increases in both contributed to the decrease in VFA. These results suggest that combined intake of GCL2505 and inulin improves the intestinal environment and reduces abdominal fat in association with the SCFA-mediated pathway.

Small intestine vs. colon ecology and physiology: Why it matters in probiotic administration

Research on gut microbiota has generally focused on fecal samples, representing luminal content of the large intestine. However, nutrient uptake is restricted to the small intestine. Abundant immune cell populations at this anatomical site combined with diminished mucus secretion and looser junctions (partly to allow for more efficient fluid and nutrient absorption) also results in intimate host-microbe interactions despite more rapid transit. It is thus crucial to dissect key differences in both ecology and physiology between small and large intestine to better leverage the immense potential of human gut microbiota imprinting, including probiotic engraftment at biological sensible niches. Here, we provide a detailed review unfolding how the physiological and anatomical differences between the small and large intestine affect gut microbiota composition, function, and plasticity. This information is key to understanding how gut microbiota manipulation, including probiotic administration, may strain-dependently transform host-microbe interactions at defined locations.

Modulation of the Microbiome-Fat-Liver Axis by Lactic Acid Bacteria: A Potential Alleviated Role in High-Fat-Diet-Induced Obese Mice

The major characteristics of obesity are abnormal lipid metabolism, chronic inflammation, and imbalanced gut microbiota. It has been reported that lactic acid bacteria (LAB) possess potential for alleviating obesity, considering which the strain-specific functions and diverse mechanisms and the roles and mechanisms of various LAB are worthy of investigation. This study aimed to validate and investigate the alleviating effects and underlying mechanisms of three LAB strains, Lactiplantibacillus plantarum NCUH001046 (LP), Limosilactobacillus reuteri NCUH064003, and Limosilactobacillus fermentum NCUH003068 (LF), in high-fat-diet-induced obese mice. The findings demonstrated that the three strains, particularly LP, suppressed body weight gain and fat deposition; ameliorated lipid disorders, liver and adipocyte morphology, and chronic low-grade inflammation; and reduced lipid synthesis via activating the adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling pathway. In addition, LP and LF decreased the enrichment of bacteria positively correlated with obesity, like Mucispirillum, Olsenella, and Streptococcus, but facilitated the growth of beneficial bacteria negatively correlated with obesity, like Roseburia, Coprococcus, and Bacteroides, along with increasing the short-chain fatty acid levels. It is deduced that the underlying alleviating mechanism of LP was to modulate the hepatic AMPK signaling pathway and gut microbiota by the microbiome-fat-liver axis to alleviate obesity development. In conclusion, as a diet supplement, LP has promising potential in obesity prevention and treatment.

Gut mycobiome in metabolic diseases: mechanisms and clinical implication

Obesity, type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD) are three common metabolic diseases with high prevalence worldwide. Emerging evidence suggests that gut dysbiosis may influence the development of metabolic diseases, in which gut fungal microbiome (mycobiome) is actively involved. In this review, we summarize the studies exploring the composition changes of gut mycobiome in metabolic diseases and mechanisms by which fungi affect the development of metabolic diseases. The current mycobiome-based therapies, including probiotic fungi, fungal products, anti-fungal agents and fecal microbiota transplantation (FMT), and their implication in treating metabolic diseases are discussed. We highlight the unique role of gut mycobiome in metabolic diseases, providing perspectives for future research on gut mycobiome in metabolic diseases.