Structural changes in the small intestine of female turkeys receiving a probiotic preparation are dose and region dependent

Gut microbiota have been shown to play a critical role in the maintenance of host health. Probiotics, which regulate gut microbiota balance, could serve as an effective alternative to antibiotic growth promoters. Since changes in the gastrointestinal tract, caused by a variety of different strains, groups and amounts of microorganisms, may be reflected in its histological structure, the aim of the present study was to examine the effects of rising doses of a mixed probiotic preparation on the structure and development of the small intestine of female turkeys. Eighty, three-day-old, healthy, female turkeys (Big-6 breed) were used in the current (16-week) study. The turkeys were randomly allocated to four weight-matched (59.70 ± 0.83 g) groups (n = 20), according to probiotic treatment dose (0, 10⁷ cfu•g⁻¹, 10⁸ cfu•g⁻¹ or 10⁹ cfu•g⁻¹, in 500 g•1000 kg⁻¹) (cfu – a colony-forming unit). Three, non-genetically modified strains of probiotic cultures obtained from poultry, four bacterial and one yeast culture, were used. Histomorphometric analysis of the structure of the small intestinal wall of the duodenum and jejunum was performed. All probiotic doses used in the current study exerted a beneficial effect on the histological structure of the small intestine; however, the observed effect was dose and region dependent. Significant increases in villi height, crypt depth, villi and crypt width, mucosa thickness, epithelial height, enterocyte number, absorption surface and intestinal ganglia geometric indices were observed, specifically in the duodenum of birds receiving an intermediate dose of probiotic (10⁸ cfu•g⁻¹). The probiotic doses used in the current study differed significantly in their effect on the small intestine (P < 0.01), with the intermediate dose (10⁸ cfu•g⁻¹) significantly improving 58% of the parameters assessed, compared to the control. The duodenum was more susceptible to the favourable effects of the probiotic than the jejunum (56% v. 31% improvement in the parameters assessed) (P < 0.01). The weakest favourable effect was observed in the group that received the highest dose of probiotic.     

Modulation of gut mucosal microbiota as a mechanism of probiotics-based adjunctive therapy for ulcerative colitis

This was a pilot study aiming to evaluate the effects of probiotics as adjunctive treatment for ulcerative colitis (UC). Twenty-five active patients with UC were assigned to the probiotic (n = 12) and placebo (n = 13) groups. The probiotic group received mesalazine (60 mg kg⁻¹ day⁻¹) and oral probiotics (containing Lactobacillus casei Zhang, Lactobacillus plantarum P-8 and Bifidobacterium animalis subsp. lactis V9) twice daily for 12 weeks, while the placebo group received the same amounts of mesalazine and placebo. The clinical outcomes were assessed. The gut mucosal microbiota was profiled by PacBio single-molecule, real-time (SMRT) sequencing of the full-length 16S rRNA of biopsy samples obtained by colonoscopy. A significantly greater magnitude of reduction was observed in the UC disease activity index (UCDAI) in the probiotic group compared with the placebo group (P = 0.043), accompanying by a higher remission rate (91.67% for probiotic-receivers versus 69.23% for placebo-receivers, P = 0.034). The probiotics could protect from diminishing of the microbiota diversity and richness. Moreover, the gut mucosal microbiota of the probiotic-receivers had significantly more beneficial bacteria like Eubacterium ramulus (P < 0.05), Pediococcus pentosaceus (P < 0.05), Bacteroides fragilis (P = 0.02) and Weissella cibaria (P = 0.04). Additionally, the relative abundances of the beneficial bacteria correlated significantly but negatively with the UCDAI score, suggesting that the probiotics might alleviate UC symptoms by modulating the gut mucosal microbiota. Our research has provided new insights into the mechanism of symptom alleviation in UC by applying probiotic-based adjunctive treatment.     

Changes in intestinal morphology and microbiota caused by dietary administration of inulin and Bacillus subtilis in gilthead sea bream (Sparus aurata L.) specimens

Changes produced in gilthead sea bream (Sparus aurata L.) intestinal morphology and microbiota caused by dietary administration of inulin and Bacillus subtilis have been studied. Gilthead sea bream specimens were fed diets containing 0 (control), inulin (10 g kg^?1), B. subtilis (10⁷ cfu g^?1), or B. subtilis + inulin (10⁷ cfu g^?1 + 10 g kg^?1) for four weeks. Curiously, fish fed the experimental diets (inulin, B. subtilis, or B. subtilis + inulin) showed the same morphological alterations when studied by light and electron microscopy, while significant differences in the signs of intestinal damage were detected by the morphometric study. All of the observed alterations were present only in the gut mucosa, and intestinal morphometric study revealed no effect of inulin or B. subtilis on the intestinal absorptive area. Furthermore, experimental diets cause important alterations in the intestinal microbiota by significantly decreasing bacterial diversity, as demonstrated by the specific richness, Shannon, and range-weighted richness indices. The observed alterations demonstrate that fish fed experimental diets had different signs of gut oedema and inflammation that could compromise their body homeostasis, which is mainly maintained by the epithelial lining of the gastrointestinal tract. To our knowledge, this is the first in vivo study regarding the implications of the use of synbiotics (conjunction of probiotics and prebiotics) on fish gut morphology and microbiota.     

Intestinal Microbiota Diversity of the Flat Fish Solea senegalensis (Kaup, 1858) Following Probiotic Administration

Pleuronectiforms are an important group of fish, and one of their species, Solea senegalensis (Kaup 1858), has been extensively studied at different levels, although information about its intestinal microbiota and the effects of different factors on it is very scarce. Modern aquaculture industry demands strategies which help to maintain a microbiologically healthy environment and an environmentally friendly aquaculture. In this context, probiotics seem to offer an attractive alternative. The intake of probiotics could modify the composition of the intestinal microbiota, which is a key component in excluding potential invaders and maintaining health. The aim of this study was to evaluate by 16S rRNA gene analysis using polymerase chain reaction-denaturing gradient gel electrophoresis the effect of administering fresh or lyophilized cells of Pdp11 on the intestinal microbiota of farmed Senegalese sole, using sodium alginate to facilitate the incorporation of bacterial cells to the feed. The results obtained showed that the composition of fish intestinal microbiota was affected when fish received a diet supplemented with sodium alginate and fresh or lyophilized probiotic cells. In all cases, the dominant bacterial groups belonged to γ-Proteobacteria and mainly the Vibrio species. The use of sodium alginate reduced the incidence of populations with <97% 16S rRNA gene sequence identity to uncultured microorganisms in the intestinal microbiota until non-detected limits. On the other hand, the supplementation of the diet with probiotics produced an increase of the predominant species related to Vibrio genus.     

Cross‐effects of dietary probiotic supplementation and rearing temperature on antioxidant responses in European seabass [Dicentrarchus labrax (Linnaeus, 1758)] juveniles

Temperature modulates the metabolism in both fish and bacteria and therefore the effect of probiotic bacteria on its host may vary accordingly. The current study aim was to evaluate the effect of probiotic supplementation (Bacillus sp., Lactobacillus sp., Enterococcus sp., Pediococcus sp.) in juvenile seabass, Dicentrarchus labrax, when reared under different temperatures (17, 20 and 23°C). A control diet was tested against a probiotic‐supplemented diet, with a concentration of 3 × 10⁹ CFU probiotic/kg diet. Antioxidant responses (TG, GSH, GSSG, GR, CAT and GSTs) and lipid peroxidation (LPO) were evaluated after 70 days of dietary probiotic supplementation. An effect of temperature was observed on LPO, which increased significantly in fish reared at 17°C (p < .05) compared to the 20 and 23°C groups. Total glutathione (TG) was significantly higher in the probiotic treatments in fish reared at 17 and 20°C (p < .05). In addition, a probiotic temperature interaction was observed for TG, reduced glutathione (GSH) levels, and for reduction of the oxidized glutathione ratio (GSH/GSSG; p < .05). In conclusion, the current study showed a strong temperature effect on oxidative stress responses, with an anti‐oxidant role of dietary probiotic supplementation at different rearing temperatures.     

Bacterial biota of shrimp intestine is significantly modified by the use of a probiotic mixture: a high throughput sequencing approach

The use of probiotics is a common practice of current shrimp aquaculture. Despite the immunophysiological responses that have been measured in shrimp exposed to probiotics, no information is currently available on the effect of this practice on the intestinal microbiota. The objective of this work was to evaluate the effect of a probiotic mixture on the intestinal microbiota of shrimp cultured under farm conditions. A culture-independent method based on high-throughput-sequencing (16S rRNA) was used to examine intestinal bacterial communities. A traditional system (without probiotics) was used as the reference. Targeted metagenomics analysis revealed that the probiotic mixture was based on bacteria in the phyla Proteobacteria and Firmicutes. A total of 23 species of bacteria were detected in the probiotic mixture; of these, 11 were detected in the intestine of shrimp reared in both systems, and 12 were novel for the system. Eight of the novel species were detected in shrimp cultured with the probiotic mixture; however, none of these novel species were related to marine or inclusively aquacultural environments, and only one (Bacillus subtilis) was recognized as probiotic for shrimp. The use of the probiotic mixture modified the bacterial profile of the shrimp intestine; however, most of the bacteria incorporated into the intestine were nonindigenous to the marine environment with no previous evidence of probiotic effects on any marine organism. The use of this probiotic mixture may represent a risk of causing environmental imbalances, particularly because farms using these types of probiotic mixtures discharge their effluents directly into the ocean without prior treatment.     

Efficacy of Probiotic Milk Formula on Blood Lipid and Intestinal Function in Mild Hypercholesterolemic Volunteers: A Placebo-control,Randomized Clinical Trial

Several studies have reported that probiotics could modulate host lipid metabolism via altering the intestinal microbiota. Hence, the current study was aimed to assess the efficacy of a mixture of probiotic-contained milk formula (PMF) with three different bacterial strains [Lactobacillus acidophilus (La5), Lactobacillus casei (TMC), Bifidobacterium lactis (Bb12)] on lipid profile and intestinal function in healthy mild hypercholesterolemic volunteers. Totally, 40 healthy mild hypercholesterolemic subjects (180–220 mg/dL) were randomly assigned into two groups as placebo or experimental group. All the subjects were requested to drink either PMF (experimental) or skimmed milk drink formula-placebo (30 g mixed with 200 mL of water) for 10 weeks and continued by 2 weeks of the follow-up period. Supplementation of PMF for 10 weeks significantly improved (p < 0.05) the fecal weight, fecal movement (decreased fecal gastrointestinal passing time) by improving intestinal microbiota (increasing beneficial bacterial species like Lactobacillus, Bifidobacterium spp.), and lag time of low-density lipoprotein (LDL) oxidation. Also, intake of PMF substantially reduced (p < 0.05) the levels of total cholesterol (TC; 8.1%) and low-density lipoprotein cholesterol (LDL-c; 10.4%) and thus showcasing its cardioprotective efficacy. PMF considerably improves gastrointestinal function by modulating fecal movement, intestinal microbiota, and decrease cholesterol and might be helpful in the management of hypercholesterolemia.

     

Effects of probiotics on growth,survival, and intestinal and liver morphometry of Gangetic mystus (Mystus cavasius)

The usage of probiotics proved advantageous in aquaculture due to its positive impact on fish growth, immune response and environment. This study was aimed to assess the effects of probiotics on growth, survival and histometry of intestine and liver in Gangetic mystus (Mystus cavasius) using two separate experiments for a period of 8 weeks (in aquaria) and 16 weeks (in earthen ponds). Three different probiotic treatments were incorporated i.e. commercial probiotic one; CP-1 (T1), commercial probiotic two; CP-2 (T2), Lab developed (Lab dev.) probiotic (T3) including a control. The results indicated that the probiotics usage especially Lab dev. probiotic (T3) significantly improved the growth parameters such as weight gain (g) and specific growth rate (SGR, %/day) as well as ensured better feed conversion efficiency. Zero mortality was observed in aquaria whereas probiotic application enhanced survivability in earthen ponds. Moreover, all probiotic treatment exhibited positive results for different histo-morphometric features of intestine and liver. Mucus secreting goblet cells and fattening of mucosal fold increased significantly with probiotic usage. The amount of regular shaped nucleus was maximum in T3 with least intra cellular distance between liver tissues in earthen ponds. The greatest value for hemoglobin with lowest glucose level was observed in T3 as well. Furthermore, probiotic ensured low concentration of ammonia during culture. Overall, it was anticipated that the application of probiotics in Gangetic mystus culture resulted positive effect on its growth, feed utilization, survivability, histo-morphometry, immunity and hematological parameters.     

Impact of early inoculation of probiotics to suckling piglets on postweaning diarrhoea – A challenge study with Enterotoxigenic E. Coli F18

Postweaning diarrhoea caused by Enterotoxigenic Escherichia coli (ETEC) is a threat to the pig industry. With an intensified focus on finding alternatives to the use of medical zinc oxide and antibiotics in newly weaned pigs, the objective of this study was to investigate the effect of early inoculation of probiotics to suckling piglets on subsequently ETEC faecal shedding and immune parameters in ETEC F18-challenged weaned piglets. Sixty pigs weaned on day 28 of age were assigned to three treatment groups: (i) Negative Control (non-challenged), (ii) Positive Control (challenged) and (iii) Probiotic (challenged and inoculated with a multi-species probiotic product during suckling). On days 1 and 2 postweaning, pigs in the Positive Control and Probiotic groups were challenged with 5 × 10⁸ colony-forming unit ETEC F18/pig/day, whereas pigs in the Negative Control group were provided with NaCl. Growth and diarrhoea incidence were not significantly affected by ETEC challenge or probiotic administration. ETEC F18 shedding and C-reactive protein concentration in plasma were significantly lower in the Negative Control group, confirming a successful challenge model. Pigs in the Probiotic group had a significantly reduced number of pigs shedding ETEC F18 and STb toxin in faeces compared with the Positive Control group. Probiotic application did not significantly impact the concentration of C-reactive protein, haptoglobin and cytokines in plasma nor haematology numbers. In conclusion, weaned pigs administered with a multi-species probiotic product early in life had a more rapid response towards the pathogen challenge and a faster clearance of ETEC compared with the Positive Control group. Administration of a multi-species probiotic to newborn piglets may thus promote resilience in the newly weaned pig. However, further studies with pigs subjected to a more severe pathogen challenge are needed to confirm these results and to investigate the mechanism of action of the probiotic intervention.     

Effect of Intestinal Microbiota Alteration on Hepatic Damage in Rats with Acute Rejection After Liver Transplantation

The previous studies all focus on the effect of probiotics and antibiotics on infection after liver transplantation. Here, we focus on the effect of gut microbiota alteration caused by probiotics and antibiotics on hepatic damage after allograft liver transplantation. Brown-Norway rats received saline, probiotics, or antibiotics via daily gavage for 3 weeks. Orthotopic liver transplantation (OLT) was carried out after 1 week of gavage. Alteration of the intestinal microbiota, liver function and histopathology, serum and liver cytokines, and T cells in peripheral blood and Peyer’s patch were evaluated. Distinct segregation of fecal bacterial diversity was observed in the probiotic group and antibiotic group when compared with the allograft group. As for diversity of intestinal mucosal microbiota and pathology of intestine at 2 weeks after OLT, antibiotics and probiotics had a significant effect on ileum and colon. The population of Lactobacillus and Bifidobacterium in the probiotic group was significantly greater than the antibiotic group and the allograft group. The liver injury was significantly reduced in the antibiotic group and the probiotic group compared with the allograft group. The CD4/CD8 and Treg cells in Peyer’s patch were decreased in the antibiotic group. The intestinal Treg cell and serum and liver TGF-β were increased markedly while CD4/CD8 ratio was significantly decreased in the probiotic group. It suggested that probiotics mediate their beneficial effects through increase of Treg cells and TGF-β and deduction of CD4/CD8 in rats with acute rejection (AR) after OLT.     

Survival of Lactobacillus casei strain Shirota in the intestines of healthy Chinese adults

Lactobacillus casei strain Shirota (LcS) is a widely used probiotic strain with health benefits. In this study, the survival of LcS in the intestines of healthy Chinese adults was assessed and the effects of LcS on stool consistency, stool SCFAs and intestinal microbiota evaluated. Subjects consumed 100 mL per day of a probiotic beverage containing 1.0 × 10⁸ CFU/mL of LcS for 14 days. LcS were enumerated using a culture method and the colony identity confirmed by ELISA. Fourteen days after ingestion, the amount of LcS recovered from fecal samples was between 6.86 ± 0.80 and 7.17 ± 0.57 Log₁₀ CFU/g of feces (mean ± SD). The intestinal microbiotas were analyzed by denaturing gradient gel electrophoresis. Principal component analysis showed that consuming LcS significantly changed fecal microbiota profiles. According to redundancy analysis, the amounts of 25 bacterial strains were significantly correlated with LcS intake (P < 0.05), 11 of them positively and fourteen negatively. Concentrations of acetic acid and propionic acid in feces were significantly lower during the ingestion period than during the baseline period (P < 0.05). These results confirm that LcS can survive passage through the gastrointestinal tract of Chinese people; however, they were found to have little ability to persist once their consumption had ceased. Furthermore, consumption of probiotic beverages containing LcS can modulate the composition of the intestinal microbiota on a long‐term basis, resulting in decreased concentrations of SCFAs in the gut.     

Membrane filter method to study the effects of Lactobacillus acidophilus and Bifidobacterium longum on fecal microbiota

A large number of commensal bacteria inhabit the intestinal tract, and interbacterial communication among gut microbiota is thought to occur. In order to analyze symbiotic relationships between probiotic strains and the gut microbiota, a ring with a membrane filter fitted to the bottom was used for in vitro investigations. Test strains comprising probiotic nitto strains (Lactobacillus acidophilus NT and Bifidobacterium longum NT) and type strains (L. acidophilus JCM1132^T and B. longum JCM1217^T) were obtained from diluted fecal samples using the membrane filter to simulate interbacterial communication. Bifidobacterium spp., Streptococcus pasteurianus, Collinsella aerofaciens, and Clostridium spp. were the most abundant gut bacteria detected before coculture with the test strains. Results of the coculture experiments indicated that the test strains significantly promote the growth of Ruminococcus gnavus, Ruminococcus torques, and Veillonella spp. and inhibit the growth of Sutterella wadsworthensis. Differences in the relative abundances of gut bacterial strains were furthermore observed after coculture of the fecal samples with each test strain. Bifidobacterium spp., which was detected as the dominant strain in the fecal samples, was found to be unaffected by coculture with the test strains. In the present study, interbacterial communication using bacterial metabolites between the test strains and the gut microbiota was demonstrated by the coculture technique. The detailed mechanisms and effects of the complex interbacterial communications that occur among the gut microbiota are, however, still unclear. Further investigation of these relationships by coculture of several fecal samples with probiotic strains is urgently required.     

Robustness of Gut Microbiota of Healthy Adults in Response to Probiotic Intervention Revealed by High-Throughput Pyrosequencing

Probiotics are live microorganisms that potentially confer beneficial outcomes to host by modulating gut microbiota in the intestine. The aim of this study was to comprehensively investigate effects of probiotics on human intestinal microbiota using 454 pyrosequencing of bacterial 16S ribosomal RNA genes with an improved quantitative accuracy for evaluation of the bacterial composition. We obtained 158 faecal samples from 18 healthy adult Japanese who were subjected to intervention with 6 commercially available probiotics containing either Bifidobacterium or Lactobacillus strains. We then analysed and compared bacterial composition of the faecal samples collected before, during, and after probiotic intervention by Operational taxonomic units (OTUs) and UniFrac distances. The results showed no significant changes in the overall structure of gut microbiota in the samples with and without probiotic administration regardless of groups and types of the probiotics used. We noticed that 32 OTUs (2.7% of all analysed OTUs) assigned to the indigenous species showed a significant increase or decrease of ≥10-fold or a quantity difference in >150 reads on probiotic administration. Such OTUs were found to be individual specific and tend to be unevenly distributed in the subjects. These data, thus, suggest robustness of the gut microbiota composition in healthy adults on probiotic administration.     

Effect of Probiotic Use on Adverse Events in Adult Patients with Inflammatory Bowel Disease: a Retrospective Cohort Study

Alterations of intestinal microflora are involved in the pathogenesis and natural history of inflammatory bowel diseases (IBDs). Manipulation of human gut microbiota with probiotics may be a therapeutic option. In this retrospective cohort study, the benefits of probiotic use in reducing adverse events were analyzed. Data from clinical charts of IBD patients followed up for at least 36 months were retrieved. The occurrence of adverse events including the need for systemic steroids, hospitalization, and surgery related to IBD was analyzed according to age, gender, body mass index, treatments, IBD phenotype, disease duration, and probiotic use. The amount of probiotic use was calculated as the ratio of time under probiotic treatment to the disease duration starting from the date of the first probiotic administration and expressed as a percentage. Patients were stratified according to the percentage of probiotic use as ≤?24%, 25–74%, and ≥?75%, and the number of adverse events per patient-years was calculated. Results were adjusted for Crohn’s disease (CD) and ulcerative colitis (UC) by multivariate analysis including study variables. Data from 200 patients (78 CD, 122 UC; 117 females; mean age 40.6?±?15.3 years; mean disease duration 12.1?±?8.7 years) were available. CD patients taking probiotics for 25–74% of the disease duration experienced a 64% reduction in total adverse events. The need for systemic steroids, hospitalization, and surgery dropped to zero events per person-year in UC patients and decreased by 93% (p?<?0.001) in CD patients taking probiotics for ≥?75% of the disease duration. Our findings suggest that the use of probiotics may be an additional therapeutic tool in patients with IBD.

     

Synergistic effect of green tea extract and probiotics on the pathogenic bacteria, <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> and <Emphasis Type="Italic">Streptococcus pyogenes</Emphasis>

The aim of this study was to assess the effect of a commercial green tea extract (TEAVIGO™) on the microbial growth of three probiotic strains (Lactobacillus and Bifidobacterium), as well as three pathogenic bacteria. MIC and co-culture studies were performed. The MICs of the green tea extract against Staphylococcus aureus and Streptococcus pyogenes (100 μg ml⁻¹) were considerably lower than those against the probiotic strains tested (>800 μg ml⁻¹) and Escherichia coli (800 μg ml⁻¹). In co-culture studies, a synergistic effect of the probiotic strains and the green tea extract was observed against both Staph. aureus and Strep. pyogenes. Green tea extract in combination with probiotics significantly reduced the viable count of both pathogens at 4 h and by 24 h had completely abolished the recovery of viable Staph. aureus and Strep. pyogenes. These reductions were more significant than the reductions induced by probiotics or green tea extracts used separately. These results demonstrate the potential for combined therapy using the green tea extract plus probiotics on microbial infections caused by Staph. aureus and Strep. pyogenes. As probiotics and the green tea extract are derived from natural products, treatment with these agents may represent important adjuncts to, or alternatives to, conventional antibiotic therapy.     

Proteomic comparison of the cytosolic proteins of three <Emphasis Type="Italic">Bifidobacterium longum</Emphasis> human isolates and <Emphasis Type="Italic">B. longum</Emphasis> NCC2705

Background  

Bifidobacteria are natural inhabitants of the human gastrointestinal tract. In full-term newborns, these bacteria are acquired from the mother during delivery and rapidly become the predominant organisms in the intestinal microbiota. Bifidobacteria contribute to the establishment of healthy intestinal ecology and can confer health benefits to their host. Consequently, there is growing interest in bifidobacteria, and various strains are currently used as probiotic components in functional food products. However, the probiotic effects have been reported to be strain-specific. There is thus a need to better understand the determinants of the observed benefits provided by these probiotics. Our objective was to compare three human B. longum isolates with the sequenced model strain B. longum NCC2705 at the chromosome and proteome levels.     

Probiotic Strains and Their Combination Inhibit <Emphasis Type="Italic">In Vitro</Emphasis> Adhesion of Pathogens to Pig Intestinal Mucosa

The aim of this study was to investigate in vitro the protective effect of commercial probiotic strains (Bifidobacterium lactis Bb12 and Lactobacillus rhamnosus LGG) alone and in combination on the adhesion of pathogenic strains as Salmonella, Clostridium, and Escherichia coli to pig intestinal mucus obtained from different intestinal regions. In combination, probiotic strains enhanced each other’s adhesion, mainly in large intestinal mucus. Treatment of intestinal mucus with Bb12 and LGG, alone or in combination, significantly reduced (P < 0.05) the adhesion of the tested pathogens. The ability to inhibit pathogen adhesion appears to depend on the specific probiotics and pathogens and on the mucosal site. B. lactis Bb12 and L. rhamnosus LGG in combination revealed a better ability to inhibit adhesion of all pathogens tested to pig intestinal mucus than probiotic strains. Probiotic combinations could be useful for counteracting disease-associated aberrations in intestinal microbiota. Specific protective probiotics could be selected for particular pig pathogens. Probiotic strains from human origin and intended for human use also adhere to pig intestinal mucus and are able to displace and inhibit pathogens.     

Assessment of the Safety of Lactobacillus casei IMV B-7280 Probiotic Strain on a Mouse Model

Probiotics, in particular Lactobacillus (lactic acid bacteria, LAB) strains, are widely used in clinical practice. Despite that these probiotics have GRAS (generally regarded as safe) and qualified presumption of safety (QPS) statuses, the safety of particular strains still needs to be thoroughly studied. The aim of the study was to evaluate the safety of Lact. casei IMV B-7280 strain by investigating toxicity and the effects on gut microbiota in experimental animal model. Male BALB/c mice (7–8 weeks, weight 20–24 g) were treated with amounts of Lact. casei IMV B-7280 strain: 5 × 10⁶, 5 × 10⁸, or 5 × 10⁹ CFU/animal once per day during 7 days, or in the amount of 1 × 10¹⁰ CFU/animal once per day during 3 days (most of the proposed probiotic doses for humans—from 10⁸ to 10⁹ CFU) and monitored during 14 days. Blood tests and serum biochemistry were conducted; the cecal content from mice of the experimental and control groups were freshly collected and analyzed. At the end of the experiments (15th day), the presence of LAB in the heart, liver, kidney, and mesenteric lymph nodes and peripheral blood was determined; histology of the brain, liver, heart, fragments of the small and large intestine, and mesenteric lymph nodes was conducted. Survival rate of BALB/c mice treated with Lact. casei IMV B-7280 strain in different concentrations in toxicity experiments during 14 days was 100%. We observed no signs of toxicity as changes in gait, lethargy, sleep, somatomotor activity as well as changes in fur, eyes, skin and mucous membranes, tremors, behavior pattern, convulsions, salivation, diarrhea, and local injuries in mice from all experimental groups. After administration of probiotic strain, the number of opportunistic bacteria in cecal contents, such as Staphylococcus spp., Candida spp., Pseudomonas spp., and total aerobic and optionally anaerobic bacteria decreased compared to controls; the population of beneficial bacteria such as lactobacilli increased in cecal contents of these mice. LAB were not detected in the peripheral blood, heart, liver, kidneys, and mesenteric lymph nodes after administration of this strain to intact mice. Lact. casei IMV B-7280 strain is safe at dose up to 10¹⁰ CFU/animal during 3- and 7-day oral administration to mice and has a positive effect on the gut microbiota composition; it could be potentially considered as safe probiotic for humans.

     

Survival,growth and physiological responses of juvenile Japanese flounder (Paralichthys olivaceus,Temminck & Schlegel, 1846) exposed to different dissolved oxygen concentrations and stocking densities

The aim of this study was to determine to what extent juvenile Japanese flounder can adapt to different stocking densities in captivity and to examine whether growth and some physiological parameters critical for welfare might be affected by different dissolved oxygen levels. Japanese flounder (Paralichthys olivaceus) juveniles (initial weight 1.27 ± 0.04 g/fish) were reared at five stocking densities (500, 1,000, 1,500, 2,000, 2,500 ind/m³) and two levels of dissolved oxygen (DO) concentration (5.5 ± 0.5 mg/L or 14 ± 2 mg/L) with duplicate tanks for each treatment in water‐recirculating systems for 40 days. Survival and activity of superoxide dismutase (SOD) were not affected either by stocking density or dissolved oxygen, whereas final body weight, specific growth rate (SGR) and feed conversion efficiency (FCE) of fish under low DO concentration decreased significantly with increasing stocking density. In contrast, growth of fish reared in high DO levels were unaffected by the stocking density. Furthermore, fish in this group had a higher feed intake and, consequently, grew faster (SGR) and achieved a higher final weight than fish reared at the low DO level. A significant reduction in hemoglobin (Hb) concentration and red blood cell (RBC) count of fish were recorded as DO concentration increased. Furthermore, the activity of protease decreased significantly with increasing stocking density and increased significantly with increasing DO concentration. The ventilation frequency results indicate that gill ventilation decreased significantly as DO levels increased. This study demonstrates that stocking density can affect the growth performance and physiological parameters critical for welfare of juvenile Japanese flounder. Also shown is that pure oxygen supplementation is an effective way to improve the growth of juvenile Japanese flounder when reared at a high stocking density.     

Impacts of ship noise on the growth and immunophysiological response in the juveniles of two Sciaenidae species,Larimichthys crocea and Nibea albiflora

The wild stocks of large yellow croaker Larimichthys crocea and yellow drum Nibea albiflora have been depleted since the 1980. Although the Chinese government has put a lot of effort (e.g., implementing fishing ban and releasing artificially bred fish into naturally distributed sea areas) into restoring their natural resources, the restoration still fails to expectation. We speculate that the slow restoration may be related to the increasing ship noise near the spawning grounds of these two species of fish. To test the harmfulness of ship noise on the L. crocea and N. albiflora, in our previous study, we studied the impacts of ship noise on their behaviors, parallelly, in the present study, we focused on the impacts of noise on their immunophysiological responses. We designed two experiments. In the first experiment, the juveniles were exposed to 120 dB ship noise for only once, then the plasma physiological indices were monitored every 1 hr within 4 hr. In the second experiment, the juveniles were exposed to 120 dB noise twice a day for 30 days, afterwards, the growth, plasma immune indices and intestinal microbiota were analyzed. The results showed that stimulated by ship noise, the physiological indices of L. crocea and N. albiflora both increased sharply within 3 hr. After a month noise stimulation, the growth and immune indices decreased significantly, and the proportion of intestinal microbiota was seriously imbalanced, showing Vibrio and Pseudomonas were dominant and other genera's abundance was quite low, especially some common intestinal probiotics. In addition, we also found that N. albiflora may be more sensitive to ship noise than L. crocea in terms of the required duration of physiological indices recovering to unstimulated level, and growth. This study highlights that ship noise negatively affects L. crocea and N. albiflora, which is helpful for some departments taking measures to protect the natural resource of these two species of fish.