Study of the effects of spray drying in whey-starch on the probiotic capacity of Lactobacillus rhamnosus 64 in the gut of mice

Exploring the roles of starch for microbial encapsulation through a systematic mapping review

Microorganism encapsulation protects them from stressful conditions and assists in maintaining their viability, being especially beneficial when the carrier material is a renewable and biodegradable biopolymer, such as starch. Here, a systematic mapping was performed to provide a current overview on the use of starch-based systems for microbial encapsulation. Following well-established guidelines, a systematic mapping was conducted and the following could be drawn: 1) there was a significant increase in publications on microbial encapsulation using starch over the past decade, showing interest from the scientific community, 2) ionotropic gelation, emulsification and spray drying are the most commonly used techniques for starch-based microbial encapsulation, and 3) starch play important functions in the encapsulation matrix such as assisting in the survival of the microorganisms. The information gathered in this systematic mapping can be useful to guide researchers and industrial sectors on the development of innovative starch-based systems for microbial encapsulation.

Lacticaseibacillus rhamnosus: A Suitable Candidate for the Construction of Novel Bioengineered Probiotic Strains for Targeted Pathogen Control

Probiotics, with their associated beneficial effects, have gained popularity for the control of foodborne pathogens. Various sources are explored with the intent to isolate novel robust probiotic strains with a broad range of health benefits due to, among other mechanisms, the production of an array of antimicrobial compounds. One of the shortcomings of these wild-type probiotics is their non-specificity. A pursuit to circumvent this limitation led to the advent of the field of pathobiotechnology. In this discipline, specific pathogen gene(s) are cloned and expressed into a given probiotic to yield a novel pathogen-specific strain. The resultant recombinant probiotic strain will exhibit enhanced species-specific inhibition of the pathogen and its associated infection. Such probiotics are also used as vehicles to deliver therapeutic agents. As fascinating as this approach is, coupled with the availability of numerous probiotics, it brings a challenge with regard to deciding which of the probiotics to use. Nonetheless, it is indisputable that an ideal candidate must fulfil the probiotic selection criteria. This review aims to show how Lacticaseibacillus rhamnosus, a clinically best-studied probiotic, presents as such a candidate. The objective is to spark researchers’ interest to conduct further probiotic-engineering studies using L. rhamnosus, with prospects for the successful development of novel probiotic strains with enhanced beneficial attributes.

Dietary β-hydroxy-β-methylbutyrate improves intestinal function in weaned piglets after lipopolysaccharide challenge

OBJECTIVES

The aim of this study was to explore the effects of β-hydroxy-β-methylbutyrate (HMB) on intestinal function of lipopolysaccharide (LPS)-challenged piglets.

METHODS

Forty weaned piglets were used in a 2 × 2 factorial design. The major factors were challenge (saline or LPS) and diet (basal diet or 0.6% HMB-Ca diet). After 15 d of treatment with LPS or HMB, blood and intestine samples were obtained.

RESULTS

The results showed that in LPS-injected pigs, HMB supplementation significantly increased jejunal villus height and ileal villus height-to-crypt depth ratio and decreased ileal crypt depth (P < 0.05). HMB also improved intestinal function indicated by elevated activities of intestinal mucosal disaccharidase and tricarboxylic acid cycle key enzymes. Furthermore, HMB significantly downregulated mRNA expression of Sirt1 in jejunum and mRNA expression of AMPKα1 and Sirt1 in ileum (P < 0.05), with a concurrent decrease of AMPKα phosphorylation in jejunum and ileum. Microbiota analysis indicated that HMB supplementation significantly increased α-diversity and affected relative abundances of Romboutsia and Sarcina at the genus level, accompanied by increased concentrations of all short-chain fatty acids except propionate in the terminate ileum of LPS-injected piglets.

CONCLUSION

Dietary HMB supplementation could improve intestinal integrity, function, microbiota communities, and short-chain fatty acid concentrations in LPS-challenged piglets, suggesting its potential usage as a feed additive in weaned piglets to alleviate intestinal dysfunction triggered by immune stress.

Dietary xylo-oligosaccharide improves intestinal functions in weaned piglets

This study aimed at investigating the effects of dietary xylo-oligosaccharide (XOS) on intestinal functions (i.e., intestinal morphology, tight junctions, gut microbiota and metabolism) and growth performance in weaned piglets. 19 weaned piglets were randomly divided into two groups (n = 9/10): a control group (basic diet) and a XOS treated group in which piglets were fed 0.01% XOS for 28 days. Growth performance, blood cells and biochemical parameters, serum cytokines, intestinal morphology, tight junctions, gut microbiota, and the metabolic profiles of the gut digesta were analyzed. The results showed that dietary supplementation with XOS had little effects on growth performance, blood cells and biochemical parameters, and intestinal morphology. However, the inflammatory status and intestinal barrier were improved in XOS-fed piglets evidenced by the reduction of IFN-γ and upregulation of ZO-1. Microbiota analysis showed that XOS enhanced α-diversity and affected the relative abundances of Lactobacillus, Streptococcus, and Turicibacter at the genus level. The alterations in the microbiota might be further involved in carbohydrate metabolism, cell motility, cellular processes and signaling, lipid metabolism, and metabolism of other amino acids by functional prediction. A metabolomics study identified three differentiated metabolites, including coenzyme Q6, zizyphine A, and pentadecanal, which might be produced by the microbiota and further affect host metabolism. In conclusion, dietary XOS improved the inflammatory status, gut barrier, and microbiota communities, which might be used as a potential feed additive to prevent gut dysfunction caused by weaning in the pig industry.

Intestinal Immunomodulation and Shifts on the Gut Microbiota of BALB/c Mice Promoted by Two Bifidobacterium and Lactobacillus Strains Isolated from Human Samples

Bifidobacterium animalis subsp. lactis IPLA 20020 and Lactobacillus gasseri IPLA 20212, two strains isolated from human samples, were evaluated for safety and influence over the intestinal microbiota and cytokine production by the intestinal tissue of adult BALB/c mice. Mice were divided into four groups receiving during 8 days PBS or a suspension of each strain, prepared fresh or lyophilized (bifidobacteria), at an amount of 4x10⁸ viable cells/day. This dose could be comparable to the probiotic intake of a human adult who consumed about 100-200 mL of functional fermented milk per day, considering the usual level of probiotics in commercial products. No microbial translocation to liver or alterations in food intake, weight, and behavior were observed in treated mice. Intestinal content of secretory immunoglobulin A (s-IgA) was not affected, discarding any adverse effect on the mucosa-associated immunity. The profile of intestinal proinflammatory/regulatory cytokines after intervention evidenced that the microbial strain administered and its cellular state (fresh or lyophilized) as well as the host tissue analyzed (small or large intestine) influenced the immune response and suggests a moderate shift towards a T helper 1 profile (Th1) in the large intestine after the administration of both strains. Changes on relative levels of some intestinal microbial groups were evidenced after intervention. It is noteworthy that butyrate was positively associated with a balanced pro-Th1 immune response. Therefore, B. animalis subsp. lactis IPLA20020 and L. gasseri IPLA 20212 could be considered potential probiotic candidates to be included in functional foods for balancing the intestinal immune response.

Growth in Hyper-Concentrated Sweet Whey Triggers Multi Stress Tolerance and Spray Drying Survival in Lactobacillus casei BL23: From the Molecular Basis to New Perspectives for Sustainable Probiotic Production

Lactobacillus casei BL23 has a recognized probiotic potential, which includes immune modulation, protection toward induced colitis, toward induced colon cancer and toward dissemination of pathogens. In L. casei, as well as in other probiotics, both probiotic and technological abilities are highly dependent (1) on the substrate used to grow bacteria and (2) on the process used to dry and store this biomass. Production and storage of probiotics, at a reasonable financial and environmental cost, becomes a crucial challenge. Food-grade media must be used, and minimal process is preferred. In this context, we have developed a “2-in-1” medium used both to grow and to dry L. casei BL23, considered a fragile probiotic strain. This medium consists in hyper-concentrated sweet whey (HCSW). L. casei BL23 grows in HCSW up to 30% dry matter, which is 6 times-concentrated sweet whey. Compared to isotonic sweet whey (5% dry matter), these growth conditions enhanced tolerance of L. casei BL23 toward heat, acid and bile salts stress. HCSW also triggered intracellular accumulation of polyphosphate, of glycogen and of trehalose. A gel-free global proteomic differential analysis further evidenced overexpression of proteins involved in pathways known to participate in stress adaptation, including environmental signal transduction, oxidative and metal defense, DNA repair, protein turnover and repair, carbohydrate, phosphate and amino acid metabolism, and in osmoadaptation. Accordingly, HCSW cultures of L. casei BL23 exhibited enhanced survival upon spray drying, a process known to drastically affect bacterial viability. This work opens new perspectives for sustainable production of dried probiotic lactobacilli, using food industry by-products and lowering energy costs.