Bile acid-lowering properties of Lactobacillus plantarum Sanriku–SU3 isolated from Japanese surfperch fish

Transforming the fermented fish landscape: Microbiota enable novel, safe, flavorful, and healthy products for modern consumers

Regular consumption of fish promotes sustainable health while reducing negative environmental impacts. Fermentation has long been used for preserving perishable foods, including fish. Fermented fish products are popular consumer foods of historical and cultural significance owing to their abundant essential nutrients and distinct flavor. This review discusses the recent scientific progress on fermented fish, especially the involved flavor formation processes, microbial metabolic activities, and interconnected biochemical pathways (e.g., enzymatic/non-enzymatic reactions associated with lipids, proteins, and their interactions). The multiple roles of fermentation in preservation of fish, development of desirable flavors, and production of health-promoting nutrients and bioactive substances are also discussed. Finally, prospects for further studies on fermented fish are proposed, including the need of monitoring microorganisms, along with the precise control of a fermentation process to transform the traditional fermented fish to novel, flavorful, healthy, and affordable products for modern consumers. Microbial-enabled innovative fermented fish products that consider both flavor and health benefits are expected to become a significant segment in global food markets. The integration of multi-omics technologies, biotechnology-based approaches (including synthetic biology and metabolic engineering) and sensory and consumer sciences, is crucial for technological innovations related to fermented fish. The findings of this review will provide guidance on future development of new or improved fermented fish products through regulating microbial metabolic processes and enzymatic activities.

L-Theanine regulates lipid metabolism by modulating gut microbiota and bile acid metabolism

BACKGROUND

l-Theanine (LTA) is a biologically active ingredient in tea that shows great potential for regulating lipid metabolism. Bile acids (BA), an important end-product of cholesterol catabolism, participate in the regulation of lipid metabolism and gut microbiota. Here, we investigated the effect of LTA on lipid metabolism and the mechanism by which it regulates BA metabolism and gut microbiota. Male BALB/c mice were treated with LTA for 28 days.

RESULTS

Daily LTA doses of 100 and 300 mg kg^-1  d^-1 altered the gut microbiota in mice, predominantly by decreasing Lactobacillus, Streptococcus, Bacteroides, Clostridium and Enterorhabdus microbes associated with bile-salt hydrolase (BSH) activity, thereby decreasing the activity of BSH and increasing the levels of ileum conjugated BA (such as glycocholic acid (GCA) and lithocholic acid), thereby inhibiting the intestinal farnesoid X receptor (FXR)-fibroblast growth factor 15 (FGF15) signaling pathway. Inhibition of FXR-FGF15 signaling was accompanied by upregulation of cholesterol 7α-hydroxylase (CYP7A1) mRNA and protein expression and increased hepatic production of cholic acid, deoxycholic acid, GCA, glycine cholic acid and glycine ursodeoxycholic acid. Meanwhile, increasing hepatic unconjugated BA upregulated the mRNA and protein expression of liver 3-hydroxy-3-methylglutaryl-CoA reductase and downregulated the mRNA and protein expression of stearoyl-CoA desaturase-1, liver low-density lipoprotein receptor and type B scavenger receptor. Therefore, the serum levels of cholesterol and triglycerides decreased.

CONCLUSION

Our findings indicate that LTA regulates lipid metabolism by modulating the gut microbiota and BA metabolism via the FXR-FGF15-CYP7A1 pathway. © 2022 Society of Chemical Industry.

Effects of Bacillus subtilis natto JLCC513 on Gut Microbiota and Intestinal Barrier Function in obese Rats

AIMS

This study aimed to investigate the effects of Bacillus subtilis natto JLCC513(JLCC513)on gut microbiota, inflammation and intestinal barrier function in high-fat-diet (HFD) rats.

METHODS AND RESULTS

Sprague-Dawley (SD) rats were fed HFD for 16 weeks, and treated with JLCC513 in 9th weeks. The oral administration of JLCC513 decreased body weight, and reduced the inflammation level in HFD rats. Pathologically, JLCC513 prevented the detachment of ileal villus and increased the villus height in rat. Mechanistically, Western blot analysis showed that the protein levels of tight junction (TJ) proteins involved in intestinal barrier function, including zonula occludens-1 (ZO-1), occludin and claudin-1, were increased after JLCC513 treatment. Meanwhile, JLCC513 treatment also decreased the protein levels of toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB) and NOD-like receptor protein 3 (NLRP3), indicating inhibition of the TLR4/NF-κB/NLRP3 pathway. Furthermore, fecal analysis showed that JLCC513 increased the abundance of Lactobacillus and Oscillospira and the ratio of Firmicutes/Bacteroidetes (F/B), and decreased the levels of Blautia and C_Clostridium.

CONCLUSIONS

JLCC513 alleviated intestinal barrier dysfunction by inhibiting TLR4/NF-κB/NLRP3 pathway and regulating gut microbiota disorders.

SIGNIFICANCE AND IMPACT OF STUDY

Our study might provide new treatment strategies for the obesity and metabolic diseases.

In vitro antioxidant, anti-glycation, and bile acid-lowering capacity of peanut milk fermented with Lactiplantibacillus plantarum Kinko-SU4

Plant-based milk-like products from soybeans and other legumes and nuts have been explored worldwide, owing to their nutritional and functional characteristics. This study was conducted to develop new functional food materials from peanut (Arachis hypogaea) milk (PM) with desirable health functions to mitigate lifestyle and age-related diseases. The antioxidant, anti-glycation and bile acid-lowering properties of PM fermented with lactic acid bacteria Lactiplantibacillus plantarum Kinko-SU4 (FPM) were determined in vitro. L. plantarum Kinko-SU4 lowered the pH level from 6.4 to 4.3, 3.9, and 3.7 at 10, 24, and 48 h, respectively. The lactic acid concentration was 4.4 mg/mL after 48 h of incubation. The starter degraded the dissolved proteins in PM, including Ara h 1, one of the peanut allergens. Although the total phenolic content was 36% lower in FPM than in unfermented PM, O2 - radical-scavenging capacity was high in FPM. Anti-glycation in a bovine serum albumin-fructose model and the bile acid-lowering capacities of PM were distinctly increased following fermentation. The result of this study infers that PM fermented with L. plantarum Kinko-SU4 can be considered a desirable food material to prevent and ameliorate chronic lifestyle diseases, particularly in the elderly.

Identification and probiotic potential of lactic acid bacteria from camel milk

In the present study, a total of 80 presumed lactic acid bacteria (LAB) were isolated from camel milk. Selected LAB were identified as Lactococcus lactis (cam 12), Enterococcus lactis (cam 14) and Lactobacillus plantarum (cam 15) and their potential were tested by tolerance & de-conjugation of bile salts, antimicrobial activity, surface hydrophobicity and adhesion potential) along with this of probiotics were evaluated for curd formation and assessed for sensory properties and syneresis. Selected LABs showed antimicrobial activity against wide range of pathogenic bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus and Escherchiaia. coli). LAB (cam 12, cam 14 and cam15) were highly sceptible to chloramphenicol, vancomycin, and tetracyclin. In vitro adhesion studies with Caco-2 cells demonstrated strong adhesion activity with hydrophobicity (99%) was observed. Acute oral toxicity of E. lactis and L. plantarum showed non-toxic, non-virulent and safe for industrial application. The study provides potential LAB which may act as a substitute of functional food, synthetic feed and industrial curd formulation with in the shortest span (240 min at 28–32 °C).

Technological roles of microorganisms in fish fermentation: a review

Fermentation is an important way to process and preserve fish. It not only gives the product a unique flavor and texture, but it also contributes to increased nutritional value and better functional properties. The production of fermented fish relies on naturally occurring enzymes (in the muscle or the intestinal tract) as well as microbial metabolic activity. This review focuses on the role of microorganisms on texture change, flavor formation, and biogenic amines accumulation in fermented fish. In addition, the production conditions and the major biochemical changes in fermented fish products are also introduced to help understand the factors influencing the quality of fermented fish. Moreover, prospects for further research of fermented fish are discussed.

Typical indigenous bacteria in the cecum of ddY mice fed a casein-beef tallow diet or whole-egg diet

With the aim to prove the existence of food ingredient-susceptible indigenous bacteria (SIBs) in the gut, the gut microbiota of ddY mice fed a diet containing 20% milk casein and 17% beef tallow (CT diet) or 40% whole-egg powder (Egg diet) for 14 days were analyzed by 16S ribosomal RNA gene (V4) amplicon sequencing. At the genus level, abundance levels of Desulfovibrionaceae sp., Oscillospira, and Bacteroides were high in mice fed the CT diet. At the operational taxonomic unit level, Bacteroides acidifaciens- and Bacteroides caecimuris-like bacteria were highly abundant in mice fed the CT diet. Faecalibaculum rodentium- and Allobaculum stercoricanis-like bacteria were highly abundant in the mice fed the Egg diet. These sets of taxa were assumed to be estimates of casein-tallow SIBs and egg SIBs, respectively, in the gut microbiome. Among the SIBs, B. caecimuris and F. rodentium could be isolated using blood and liver agar. PRACTICAL APPLICATIONS: B. caecimuris and F. rodentium are regarded as casein-tallow and/or egg SIBs in mice. It is possible to demonstrate functionality with orally administered food ingredients. Isolation and application of human or livestock SIB is considered promising for the development of new probiotics and functional foods.

Effect of rice bran fermented with Saccharomyces cerevisiae and Lactobacillus plantarum on gut microbiome of mice fed high-sucrose diet

To clarify the effect of rice bran (RB) and fermented RB (FRB) in a high-sucrose and low-dietary fibre diet on the gut microbiome, the in vitro bile acid-lowering capacity and caecal microbiota of ICR mice fed with 20% RB or FRB diets for two weeks were determined. The caecal microbiome was analysed by 16S rRNA gene amplicon sequencing. The in vitro bile acid-lowering capacity was high for FRB. In mouse experiments, triacylglycerol and total cholesterol were generally lower with FRB, although the faecal frequency was highest in mice fed with RB. The Shannon-Wiener and Simpson's indices for alpha-diversity in the microbiome of mice fed with RB and FRB, were higher than mice fed the control diet. At the phylum level in the caecal microbiome, Firmicutes and Bacteroidetes were high with FRB and RB, respectively. At the operational taxonomic unit level, some bacterial groups related to diabetes and gut toxicity, such as Lachnospiraceae and Enterorhabdus mucosicola, were high for RB but not for FRB diets. These results suggest that FRB, rather than RB, intake improve the intestinal environment and blood lipid condition.

Lactobacillus plantarum AN1 cells increase caecal L. reuteri in an ICR mouse model of dextran sodium sulphate-induced inflammatory bowel disease

To clarify the different effects of live and heat-killed probiotics on inflammatory bowel disease (IBD), the anti-inflammatory and protective effects of Lactobacillus plantarum AN1 cells isolated from the fermented fish aji-narezushi on murine macrophage RAW264.7 cells and in ICR mice with dextran sodium sulphate (DSS)-induced IBD were determined. L. plantarum AN1 cells showed anti-inflammatory activities in vitro, indicated by secretion of nitric oxide (NO) from RAW264.7 cells in the presence and absence of Escherichia coli 0111 lipopolysaccharide (LPS). L. plantarum AN1 cells also protected RAW264.7 cells against hydrogen peroxide toxicity. There was no difference between these effects in heat-killed and ultraviolet irradiation-killed cells. In the murine IBD model, both live and heat-killed L. plantarum AN1 cells via drinking water tended to ameliorate atrophy of colon length, mucosal tissue damage, and spleen enlargement. Amplicon sequencing of 16S rDNA (V4) revealed that both live and heat-killed AN1 cells increased abundance of indigenous lactic acid bacteria, particularly Lactobacillus reuteri. The results suggest that increased indigenous lactic acid bacterial abundance and feeding with L. plantarum AN1 cells synergistically improve effects against IBD.

Protective effects of heat-killed Lactococcus lactis subsp. lactis BF3, isolated from the intestine of chum salmon, in a murine model of DSS-induced inflammatory bowel disease

Oxidative stress is considered an etiological factor responsible for several symptoms of inflammatory bowel disease (IBD). In vitro anti-inflammatory activities of heat-killed Lactococcus lactis subsp. lactis BF3 have been reported. In this study, the anti-inflammatory effect of these cells was examined using a dextran sodium sulphate (DSS)-induced murine IBD model. Administration of heat-killed L. lactis BF3 via drinking water suppressed the IBD symptoms, such as shortening of colon length, damage to the colon mucosa as observed under the microscope, and spleen enlargement. This result suggests that heat-killed L. lactis BF3 has the potential to treat IBD.