Selenium Nanoparticle-Enriched and Potential Probiotic, Lactiplantibacillus plantarum S14 Strain, a Diet Supplement Beneficial for Rainbow Trout

Effects of supplemental Glycyrrhiza polysaccharide on growth performance and intestinal health in weaned piglets

In this study, we investigated the effects of supplemental Glycyrrhiza polysaccharide (GCP) on growth performance and intestinal health of weaned piglets. Ninety piglets weaned at 28 days of age were randomly allocated to three groups with five replicates per treatment. Piglets were fed the following diets for 28 days: (1) CON (control group), basal diet; (2) G500, CON + 500 mg/kg GCP; (3) G1000, CON + 1000 mg/kg GCP. The results showed that supplementation with 1000 mg/kg GCP increased the average daily gain (ADG) and decreased the feed-to-gain ratio (F/G) (P < 0.05). Serum diamine oxidase (DAO) and D-lactic acid (DL-A) levels were lower in the G1000 group (P < 0.05). Dietary GCP 1000 mg/kg improved mucosal trypsin activity in the duodenum, jejunum and ileum and increased lipase and amylase activity in the jejunum (P < 0.05). Moreover, in the G1000 group, ZO-1, claudin 1 and occludin levels were increased in the jejunum mucosa, whereas interleukin-1β (IL-1β) and IL-6 levels were decreased (P < 0.05). The 16S rRNA gene analysis indicated that dietary 1000 mg/kg GCP altered the jejunal microbial community, with increased relative abundances of beneficial bacteria. In conclusion, dietary GCP 1000 mg/kg can improve growth performance, digestive enzyme activity, intestinal immunity, barrier function and microbial community in weaned piglets.

Fish skin mucosal surface becomes a barrier of antibiotic resistance genes under apramycin exposure

Antibiotic resistance genes (ARGs) are a kind of emerging environmental contamination, and are commonly found in antibiotic application situations, attracting wide attention. Fish skin mucosal surface (SMS), as the contact interface between fish and water, is the first line of defense against external pollutant invasion. Antibiotics are widely used in aquaculture, and SMS may be exposed to antibiotics. However, what happens to SMS when antibiotics are applied, and whether ARGs are enriched in SMS are not clear. In this study, Zebrafish (Danio rerio) were exposed to antibiotic and antibiotic resistant bacteria in the laboratory to simulate the aquaculture situation, and the effects of SMS on the spread of ARGs were explored. The results showed that SMS maintained the stability of the bacterial abundance and diversity under apramycin (APR) and bacterial exposure effectively. Until 11 days after stopping APR exposure, the abundance of ARGs in SMS (mean value was 3.32 × 10-3 copies/16S rRNA copies) still did not recover to the initial stage before exposure, which means that enriched ARGs in SMS were persistently remained. Moreover, non-specific immunity played an important role in resisting infection of external contamination. Besides, among antioxidant proteins, superoxide dismutase showed the highest activity. Consequently, it showed that SMS became a barrier of antibiotic resistance genes under APR exposure, and ARGs in SMS were difficult to remove once colonized. This study provided a reference for understanding the transmission, enrichment process, and ecological impact of antibiotics and ARGs in aquatic environments.

Impact of Selenium Nanoparticle-Enriched Lactobacilli Feeding Against Escherichia coli O157:H7 Infection of BALB/c Mice

The effectiveness of selenium nanoparticle (SeNP)-enriched Lactiplantibacillus plantarum and Lactobacillus acidophilus was studied against Shiga toxin-producing Escherichia coli O157:H7 infection on the intestinal fragments and kidney tissue of BALB/c mice. Gut microbiota-targeted bacteria and E. coli O157:H7 counts were obtained by qPCR and PCR. Histology of ileum, colon, and kidney tissues and Stx secretions were analyzed until one-week post-infection. Mice fed with SeNP Lpb. plantarum in the preinfection feeding groups have lower E. coli O157:H7 counts and lower intestinal damage than those in the infected group. The lowest mean fecal probiotic counts were in the L. acidophilus group (7.61 log 10). In pretreatment groups of SeNP L. acidophilus and L. acidophilus, the mean counts of bacteria decreased to 104 CFU/g by day 7. The lowest Stx copy number was demonstrated in SeNP Lpb. plantarum feeding groups' day 7 (P < 0.05). Feeding groups with SeNP Lpb. plantarum had significantly higher members of Lactobacilli in their fecal microbiota than the control group on day 7. It was clarified that Se-enriched Lpb. plantarum and L. acidophilus can be useful as a method of preventing STEC infections. The viability of STEC infection exposure to selenium-enriched Lactobacillus spp. was decreased more than for non-Se-enriched Lactobacillus spp.

Synergistic interaction of nanoparticles and probiotic delivery: A review

Nanotechnology is an expanding and new technology that prompts production with nanoparticle-based (1-100 nm) organic and inorganic materials. Such a tool has an imperative function in different sectors like bioengineering, pharmaceuticals, electronics, energy, nuclear energy, and fuel, and its applications are helpful for human, animal, plant, and environmental health. In exacting, the nanoparticles are synthesized by top-down and bottom-up approaches through different techniques such as chemical, physical, and biological progress. The characterization is vital and the confirmation of nanoparticle traits is done by various instrumentation analyses like UV-Vis spectrophotometry (UV-Vis), Fourier transform infrared spectroscopy, scanning electron microscope, transmission electron microscopy, X-ray diffraction, atomic force microscopy, annular dark-field imaging, and intracranial pressure. In addition, probiotics are friendly microbes which while administered in sufficient quantity confer health advantages to the host. Characterization investigation is much more significant to the identification of good probiotics. Similarly, haemolytic activity, acid and bile salt tolerance, autoaggregation, antimicrobial compound production, inhibition of pathogens, enhance the immune system, and more health-beneficial effects on the host. The synergistic effects of nanoparticles and probiotics combined delivery applications are still limited to food, feed, and biomedical applications. However, the mechanisms by which they interact with the immune system and gut microbiota in humans and animals are largely unclear. This review discusses current research advancements to fulfil research gaps and promote the successful improvement of human and animal health.

Dietary Effects of Selenium Nanoparticles on Growth Performance, Survival Rate, Chemical Composition, and Muscle Bioaccumulation of Nile Tilapia (Oreochromis niloticus)

This study evaluated the effect of selenium nanoparticles on growth performance, survival rate, chemical composition, and bioaccumulation of selenium in the muscle of Nile tilapia (Oreochromis niloticus). Fish with an average weight of 33.1 ± 1.0 g were distributed in 12 fiberglass tanks and fed for 56 days with different levels of selenium nanoparticles, 0, 0.5, 1, and 2 mg/kg of diet, considered as control, T1, T2, and T3, respectively. Body weight increase (BWI), specific growth rate (SGR), and food conversion ratio (FCR) were significantly influenced by 2 mg/kg of selenium nanoparticles compared to the other treatments, in particular control and T1 with 0.5 mg/kg selenium (P < 0.05). The survival rate was also significantly affected in T2, especially compared to the control (P < 0.05). In addition, protein, ash, and moisture percentages of muscle showed statistically different levels in fish fed a diet containing 2 mg/kg of selenium nanoparticles compared to the control treatment (P < 0.05). The results of the selenium bioaccumulation in the muscle of trial diets showed a significant difference in selenium nanoparticle bioaccumulation among treatments, with the highest revealed in the 2 mg/kg nanoparticle group (P < 0.05). Overall, selenium nanoparticles significantly improved the growth performance, survival, and chemical composition (protein in particular) of Nile tilapia, especially in the T2 and T3 treatments.

Alleviating effect of selenium-enriched Lactobacillus plantarum 6076 on dextran sulfate sodium-induced colitis and liver inflammation in mice

The aim of this study is to investigate the alleviating effect of selenium-enriched Lactobacillus plantarum (SL) 6076 on colitis and liver inflammation induced by sodium dextran sulfate (DSS) in mice and its potential molecular mechanisms. Lactobacillus plantarum (LA) was cultured for 3 generations on MRS medium containing sodium selenite to generate SL. LA (3.2 × 1011 CFU mL-1), low selenium Lactobacillus plantarum (LS) (3.9 × 1010 CFU mL-1, 0.35 mg mL-1 Se) and high selenium Lactobacillus plantarum (HS) (2.8 × 1010 CFU mL-1, 0.52 mg mL-1 Se) were continuously fed to mice for 21 d to observe their effects on DSS-induced colitis and liver inflammation in mice. The composition of gut microbiota was detected through high-throughput 16S rRNA sequencing, and inflammatory cytokines, oxidative stress parameters, and serum biochemical indicators were measured in the colon and liver using quantitative polymerase chain reaction (qPCR) and biochemical analysis methods. The results showed that SL alleviated inflammation symptoms in the colon and liver, reduced the expression of inflammatory factors in the colon and liver, regulated oxidative stress responses in the colon, downregulated NF-κB-P65 pathway factors, and altered the composition and structure of the gut microbiota. In summary, DSS-induced colitis may cause liver inflammation, and SL had a significant relieving effect on both colon and liver inflammation. The intervention effect of SL was better than that of LA, while HS was better than LS. SL had a significant alleviating effect on DSS-induced colitis, and may exert its therapeutic effect by downregulating NF-κB-P65 signaling pathways and regulating the structure of intestinal microbiota. This study provides a new approach for the treatment of colitis.

Biosynthesis of selenium nanoparticles by lactic acid bacteria and areas of their possible applications

Lactic acid bacteria, being generally recognized as safe, are the preferred choice among other microbial producers of selenium nanoparticles. For successful production of SeNPs, it is necessary to take into account the physiological properties of the bacterium used as a biotransformer of inorganic forms of selenium in Se⁰. The antimicrobial and antioxidant activity of SeNPs allows to use them in the form of pure nanoparticles or biomass of lactic acid bacteria enriched with selenium in preparation of food, in agriculture, aquaculture, medicine, veterinary, and manufacturing of packing materials for food products. To attract attention to the promising new directions of lactic acid bacteria applications and to accelerate their implementation, the examples of the use of SeNPs synthesized by lactic acid bacteria in the mentioned above areas of human activity are described.

Nano selenium-enriched probiotic Lactobacillus enhances alum adjuvanticity and promotes antigen-specific systemic and mucosal immunity

Nano selenium-enriched probiotics have been identified to improve immune responses, such as alleviating inflammation, antioxidant function, treatment of tumors, anticancer activity, and regulating intestinal flora. However, so far, there is little information on improving the immune effect of the vaccine. Here, we prepared nano selenium-enriched Levilactobacillus brevis 23017 (SeL) and heat-inactivated nano selenium-enriched L. brevis 23017 (HiSeL) and evaluated their immune enhancing functions on the alum-adjuvanted, inactivated Clostridium perfringens type A vaccine in mouse and rabbit models, respectively. We found that SeL enhanced immune responses of the vaccine by inducing a more rapid antibody production, eliciting higher immunoglobulin G (IgG) antibody titers, improving secretory immunoglobulin A (SIgA) antibody level and cellular immune response, and regulating Th1/Th2 immune response, thus helping to induce better protective efficacy after challenge. Moreover, we confirmed that the immunoenhancement effects are related to regulating oxidative stress, cytokine secretion, and selenoprotein expression. Meanwhile, similar effects were observed in HiSeL. In addition, they show enhanced humoral immune response at 1/2 and 1/4 standard vaccine doses, which confirms their prominent immune enhancement effect. Finally, the effect of improving vaccine immune responses was further confirmed in rabbits, which shows that SeL stimulates the production of IgG antibodies, generates α toxin-neutralizing antibodies rapidly, and reduces the pathological damage to intestine tissue. Our study demonstrates that nano selenium-enriched probiotics improve the immune effect of the alum adjuvants vaccine and highlight its potential usage in remedying the disadvantages of alum adjuvants.