Adhesion of Lactobacillus isolates to intestinal epithelial cells of chicken

Inclusion of Lactobacillus salivarius strain revealed a positive effect on improving growth performance, fecal microbiota and immunological responses in chicken

Probiotics are defined as live microorganisms that when administered in an appropriate amount, provide health benefits to the host. This study aimed to evaluate the effect of the oral administration of Lactobacillus salivarius (L. salivarius) on growth performance, immunological responses, fecal microbial flora and intestinal mucosal morphology in chickens. Chickens were fed with 10⁹ colony-forming units (CFUs) of wild-type (WT) L. salivarius or phosphate-buffered saline (PBS) for 5 weeks. Chickens body weight was significantly increased by administration of L. salivarius groups compared than control group. The microbial taxonomy in the small intestine and cecum was identified via the chicken feces sample. A total of 286,331 bacterial species were obtained from the chicken fecal samples in overall experimental group. From these, 145,012 bacterial species were obtained from oral administration of L. salivarius treatment group, while 141,319 bacterial species were obtained from control group. Almost 98% of all 16S rRNA sequences from the chicken fecal sample of the two groups were classified into known phyla. Firmicutes, Cyanobacteria, Proteobacteria, Bacteroidetes and Actinobacteria were highly abundant in both groups. Compared with the control birds, the chickens orally administered L. salivarius showed no significant differences in villus length and crypt length. Serum concentrations of the cytokines IL-8, TNF-α, IFN-γ, and IL-4 were markedly reduced in the L. salivarius group. In summary, our findings reveal that L. salivarius can act as a potential probiotic to improve performance and overall gut health in of chickens.

Dietary supplementation with avilamycin and Lactobacillus acidophilus effects growth performance and the expression of growth-related genes in broilers

Context The use of antibiotics in poultry production is appropriate; however, it brings a high risk of dissemination of antibiotic-resistant strains of pathogenic and non-pathogenic bacteria and their further transmission to humans via the food chain. Aims The effects of supplementation with Lactobacillus acidophilus (a probiotic) or avilamycin (an in-feed antibiotic growth promoter), on growth performance, digestibility, plasma lipid levels, and the expression of certain growth-related genes were investigated. Methods In total, 135 15-day-old broiler chicks were divided into three groups (n = 45): a control group and two treatment groups. Each treatment group was then further divided into three replicates (15 birds each). The control group was fed a basal diet; the second group received basal diet supplemented with avilamycin (0.1 g/kg); the third group received basal diet plus L. acidophilus (0.1 g/kg). Growth performance (bodyweight, feed intake and feed-conversion ratio) was measured. Digestibility and gene expression were measured at the end of the experiment. Key results Greatest bodyweight gain was achieved in the L. acidophilus-fed chicks, which were significantly (P < 0.05) heavier than the control chicks and the avilamycin-fed chicks. Addition of avilamycin or L. acidophilus to the diet also significantly improved feed efficiency (P < 0.05) compared with the control. Although the digestibility of dry matter, crude protein and crude fibre significantly improved in the two experimental groups compared with the control, ether extract was not affected. In addition, plasma total cholesterol, triglyceride and low-density-lipoprotein cholesterol levels were significantly (P < 0.05) decreased whereas plasma high-density-lipoprotein cholesterol was significantly (P < 0.05) increased in the L. acidophilus group compared with the control. Expression of the genes for growth hormone secretagogue receptor (GHSR), insulin-like growth factor 1 (IGF-1) and insulin-like growth factor 1 receptor (IGF1R) was remarkably upregulated in the skeletal muscles of the two experimental groups. Conclusions Supplementation with L. acidophilus (0.1 g/kg) in the broiler diet had positive effects on growth, feed intake, feed efficiency, digestibility, and plasma lipid levels of the broilers. Implications Lactobacillus acidophilus might be a more useful additive in broiler feed than antibiotic growth promoters such as avilamycin.

Bacillus subtilis Strain DSM 29784 Modulates the Cecal Microbiome, Concentration of Short-Chain Fatty Acids, and Apparent Retention of Dietary Components in Shaver White Chickens during Grower, Developer, and Laying Phases

This study investigated the efficacy of a single strain of Bacillus subtilis (SSB) in modulating the composition of cecal microbiota and its link to the concentration of short-chain fatty acids (SCFA) and apparent retention (AR) of components. A total of 720, 4-week-old Shaver White chicks were allotted to control (CON), 1.1E+08 (low, LSSB), 2.2E+08 (medium, MSSB), or 1.1E+09 (high, HSSB) CFU/kg of diet groups. At grower (10-week), developer (16-week), and laying (28-week) phases, excreta and cecal digesta samples were taken for AR, microbial, and SCFA analyses. Microbial analysis involved high-throughput sequencing of the V3-V4 hypervariable regions of 16S rRNA gene. Bacterial diversity decreased (P < 0.05) at the developer phase as the SSB dose increased; however, a distinct clustering pattern (P < 0.05) of bacterial community was noted. Bacteroides and Faecalibacterium were differentially enriched in the developer for SSB-fed compared to CON-fed birds. Although no differences in microbial diversity were detected in grower and layer phases, different species of Clostridium (XVIII, XIVa, IV, and XIVb)-major butyrate producers-were identified in all phases, with stronger effect sizes for SSB-fed compared to CON-fed birds. Isobutyric acid was elevated in dose response (P = 0.034) in layer phase. In addition, the relative abundances of Alistipes, Lactobacillus, and Bifidobacterium were positively correlated (P < 0.05), with AR of most components for SSB-fed birds in the pullet phase. The results suggested that supplementing chickens' diet with B. subtilis DSM 29784 may selectively enrich beneficial bacterial communities, which in turn are critical in promoting the growth and performance of hens.IMPORTANCE In egg-laying chickens, the trend in the move away from the cage to alternative housing systems and restriction in antimicrobial use requires alternative approaches to maintain health and prevent diseases. There is increased research and commercial interest toward alternative gut health solutions while improving the performance and product safety in poultry production systems. One such approach, in recognition of the importance of the gut microbial community, is the use of microbes as feed supplements (such as probiotics). Unlike meat-type chickens, studies assessing the efficacy of such microbial supplements are limited for egg-laying chickens. Thus, by conducting a comprehensive assessment of the hen microbiota in response to various levels of B. subtilis DSM 29784 during the pullet phase (grower and developer) and the layer phase, the present study demonstrates the importance of direct-fed microbes in modulating gut microbiome, which may relate to improved performance efficiency in the pullet and layer phases.

Effect of dietary supplementation with Lactobacillus acidophilus D2/CSL (CECT 4529) on caecum microbioma and productive performance in broiler chickens

This study examines the effects of the dietary supplementation with Lactobacillus acidophilus D2/CSL (CECT 4529) (LA) on productive performances, incidence of foot pad dermatitis and caecum microbioma in broiler chickens. A total of 1,100 one-day old male Ross 308 chicks were divided into 2 groups of 16 replicates with 25 birds each and reared from 1–41 d. One group was fed a basal diet (CON) and the other group the same diet supplemented with LA. Caecum contents were collected from 4 selected birds at day one and 5 selected birds at the end of the rearing period. Then, they were submitted to DNA extraction and whole DNA shotgun metagenomic sequencing. Overall, the LA supplementation produced a significant beneficial effect on body weight gain between 15–28 d and improved feed conversion rate in the overall period. On the contrary, litter moisture, pH and incidence of the foot pad lesions were not affected by LA. Birds treated with LA showed a lower occurrence of pasty vent at both 14 and 28 d. At the end of the rearing period, Lachanospiraceae were significantly higher in LA birds in comparison to CON (17.07 vs 14.39%; P = 0.036). Moreover, Ruminococcus obeum, Clostridium clostridioforme, Roseburia intestinalis, Lachnospiraceae bacterium 14-2T and Coprococcus eutactus were significantly higher in LA birds in comparison to CON. The relative abundance of Lactobacillus acidophilus was comparable between LA and CON groups. However, a positive effect was observed in relation to the metabolic functions in the treated group, with particular reference to the higher abundance of β-glucosidase. In conclusion, the LA supplementation improved broiler productive performances and metabolic functions promoting animal health.

Effects of two different probiotics on microflora, morphology, and morphometry of gut in organic laying hens

The current study investigated the effects of Lactobacillus acidophilus and Bacillus subtilis, used as probiotics, on the microflora, morphology, and morphometry of the gut in organic laying hens. The birds (180 Hy-Line laying hens) were divided into 3 homogenous groups and received a pre-deposition diet from 16 to 20 wk of age and a deposition diet for the remaining 7 months of the experiment. The control group ( CTR: ) was fed a corn-soybean cake-based diet, the second group ( L: ) received the same diet supplemented with 0.1% of L. acidophilus while in the third group ( B: ) the basal diet was supplemented with 0.05% of B. subtilis At 18 wk of age ( T1: ) and at 5 ( T2: ) and 7 months ( T3: ) from the beginning of deposition, 9 subjects per group were humanely killed for microbiological, morphological and morphometric analyses of the intestinal tract. The 2 probiotic-supplemented diets increased Lactobacillus spp. and Bifidobacterium spp. counts compared with the CTR diet. The lowest viable counts of E. coli, coliforms and staphylococci were observed in the L group (P < 0.001). Clostridium spp. decreased (P < 0.001) in both L and B subjects. The probiotic supplementation appeared to affect the intestinal microbial population, promoting the presence of beneficial bacteria such as Lactobacillus spp. and Bifidobacterium spp. and reducing potential harmful bacteria such as E. coli, clostridia and staphylococci. Morphological and morphometric analyses did not reveal substantial differences among groups. At T3, the plasma cell infiltrate in the villi of the CTR hens was more severe than that observed in the L and B groups (P = 0.009).

Epithelial cell adhesion and gastrointestinal colonization of Lactobacillus in poultry

Administration of probiotic Lactobacillus cultures is an important alternative to the use of antibiotic growth promoters and has been demonstrated to improve animal health, growth performance, and preharvest food safety in poultry production. Whereas gastrointestinal colonization is thought to be critical to their probiotic functionality, factors important to Lactobacillus colonization in chickens are not well understood. In this study we investigate epithelial cell adhesion in vitro and colonization of Lactobacillusin vivo in broiler chickens. Adhesion of Lactobacillus cultures to epithelial cells was evaluated using the chicken LMH cell line. Lactobacillus cultures were able adhere effectively to LMH cells relative to Bacillus subtilis and Salmonella Typhimurium. Epithelial cell adhesion was similar for Lactobacillus crispatus TDCC 75, L. cristpatus TDCC 76, and Lactobacillus gallinarum TDCC 77, and all 3 were more adherent than L. gallinarum TDCC 78. However, when colonization was evaluated in the ileum and cecum of broiler chicks, L. crispatus TDCC 75 and L. gallinarum TDCC 77 were more persistent than L. crispatus TDCC 76 and L. gallinarum TDCC 78. The reduction of growth in medium supplemented with oxgal was greater for L. gallinarum TDCC 78 than L. gallinarum TDCC 77, suggesting that whereas adhesion was similar for the 2 strains, the difference in colonization between L. gallinarum strains may be due in part to their bile sensitivity. This study demonstrates that whereas adhesion to epithelial cells may be important in predicting gastrointestinal colonization, other factors including bile tolerance may also contribute to the colonization of Lactobacillus in poultry. Additionally, the chicken LMH cell line is expected to provide a platform for investigating mechanisms of Lactobacillus adhesion to epithelial tissue and evaluating the probiotic potential Lactobacillus in poultry.

Effects of dietary prebiotics, probiotic and synbiotics on performance, caecal bacterial populations and caecal fermentation concentrations of broiler chickens

BACKGROUND

In view of a worldwide attempt to restrict or ban the use of antibiotics as growth promoters in animal production, probiotics, prebiotics and combinations of both, as synbiotics, have been suggested as potential alternatives. In this study, the effects of a prebiotic (isomalto-oligosaccharides, IMO), a multi-strain probiotic (consisting of 11 Lactobacillus strains), and a combination of these dietary additives as a synbiotic on the performance, caecal bacterial populations and concentrations of caecal volatile fatty acids and non-volatile fatty acids of broiler chickens were evaluated.

RESULTS

Supplementation of 1g kg⁻¹ probiotic (PRO); 5 g kg⁻¹ prebiotic IMO (PRE05); 10 g kg⁻¹ prebiotic IMO (PRE10); synbiotic consisting of 1g kg⁻¹ probiotic + 5 g kg⁻¹ prebiotic IMO (SYN05); or synbiotic consisting of 1 g kg⁻¹ probiotic + 10 g kg⁻¹ prebiotic IMO (SYN10) significantly (P < 0.05) improved weight gain of broiler chickens at 22-42 and 1-42 days of age, and feed conversion rate from 1 to 21, 22-42 and 1-42 days of age. The supplementation of probiotic (PRO), prebiotics (PRE05 and PRE10) or synbiotics (SYN05 and SYN10) also significantly (P < 0.05) increased the caecal populations of lactobacilli and bifidobacteria, and decreased the caecal Escherichia coli at 21 days of age, and increased the caecal VFA at 21 and 42 days of age. In all parameters studied, synbiotics did not show a two-fold synergistic effect, when compared to those of probiotic or prebiotic alone.

CONCLUSION

The results of the study indicated that prebiotic IMO (5 g kg⁻¹ or 10 g kg⁻¹), probiotic and their combinations as synbiotics were effective in improving the performance of broiler chickens and in increasing the caecal beneficial bacteria and fatty acids.

Oral administration of a combination of select lactic acid bacteria strains to reduce the Salmonella invasion and inflammation of broiler chicks

One-day-old chicks are susceptible to infection by strains of Salmonella enterica subspecies. Because multistrain probiotics are suggested to be more effective than monostrain probiotics due to the additive and synergistic effects, in this study, we prepared a multistrain formula A (MFA) consisting of 4 lactic acid bacteria (LAB) strains selected by enhancing the TNF-α production for mouse macrophage 264.7 cells. The antagonistic effect of this MFA against the cecal colonization, viscera invasiveness, as well as the inflammation of 1-d-old chicks challenged with Salmonella Typhimurium were then assayed. One-day-old chicks were fed with MFA from d 1 to d 3, and on d 4, chicks were challenged with Salmonella Typhimurium (200 μL, 10(6) cfu/mL). The livers, spleens, and cecal tonsils of chicks were then removed on d 3 and 6 postinfection. Compared with the multistrain formula B (MFB) which consisted of LAB strains selected at random, the efficacy of MFA to reduce the Salmonella counts recovered from the cecal tonsils, spleens, and livers of chicks were significantly higher. Moreover, when the levels of proinflammatory cytokines, such as IL-1β, IL-6, interferon (IFN)-γ, and anti-inflmmatory cytokine, that is, IL-10, in cecal tonsils were measured by reverse-transcription real-time quantitative PCR; it was found that chicks fed with MFA for 3 d had lower levels of IL-1β, IL-6, IFN-γ and a higher level of IL-10 in the cecal tonsils of chicks as compared with those of the chicks fed with MFB or without LAB. These results suggest that multistrain probiotics consisting of LAB strains selected by immunomodulatory activity and adherence are more effective than those consisting of strains selected at random in antagonistic effect against Salmonella colonization, invasion, and the induced inflammation.

Discrimination of probiotic Lactobacillus strains for poultry by repetitive sequenced-based PCR fingerprinting

BACKGROUND

Four repetitive element sequence-based polymerase chain reaction (rep-PCR) methods, namely repetitive extragenic palindromic PCR (REP-PCR), enterobacterial repetitive intergenic consensus PCR (ERIC-PCR), polytrinucleotide (GTG)₅ -PCR and BOX-PCR, were evaluated for the molecular differentiation of 12 probiotic Lactobacillus strains previously isolated from the gastrointestinal tract of chickens and used as a multistrain probiotic. This study represents the first analysis of the comparative efficacy of these four rep-PCR methods and their combination (composite rep-PCR) in the molecular typing of Lactobacillus strains based on a discriminatory index (D).

RESULTS

Species-specific and strain-specific profiles were observed from rep-PCR. From the numerical analysis of composite rep-PCR, BOX-PCR, (GTG)₅ -PCR, REP-PCR and ERIC-PCR, D values of 0.9118, 0.9044, 0.8897, 0.8750 and 0.8529 respectively were obtained. Composite rep-PCR analysis was the most discriminative method, with eight Lactobacillus strains, namely L. brevis ATCC 14869(T) , L. reuteri C 10, L. reuteri ATCC 23272(T) , L. gallinarum ATCC 33199(T) , L. salivarius ATCC 11741(T) , L. salivarius I 24, L. panis JCM 11053(T) and L. panis C 17, being differentiated at the strain level.

CONCLUSION

Composite rep-PCR analysis is potentially a useful fingerprinting method to discriminate probiotic Lactobacillus strains isolated from the gastrointestinal tract of chickens.

Effects of β-glucanase-producingLactobacillusstrains on growth, dry matter and crude protein digestibilities and apparent metabolisable energy in broiler chickens

The effects of beta-glucanase expressed by transformed Lactobacillus strains on growth performance, apparent digestibilities of dry matter and crude protein, and apparent metabolisable energy were studied. Two hundred and forty 1-d-old chicks (Avian-43) were randomly divided into three dietary treatment groups and fed with the following diets: (i) basal diet (control) (BD); (ii) basal diet with parental Lactobacillus strains (BDP) and (iii) basal diet with transformed Lactobacillus strains (BDT). At 21 d of age, the body weight, body weight gain and feed conversion ratio of the BDT-fed chickens were significantly improved. At 14 and 21 d of age, the proportions of dry matter in the duodenum, jejunum, ileum, caeca and excreta of chickens given the BDT diet were significantly higher than those of chickens given the BD and BDP diets. Apparent metabolisable energy, digestibilities of crude protein and dry matter were also significantly improved (by 3.5, 5.6 and 3.5%, respectively) by the BDT diet. These results showed that the transformed Lactobacillus strains improved digestibility as well as enhanced the growth performance of chickens.

Enhancement of viability of a probiotic Lactobacillus strain for poultry during freeze-drying and storage using the response surface methodology

A rotatable central composite design (CCD) was used to study the effect of cryoprotectants (skim milk, sucrose and lactose) on the survival rate of a probiotic Lactobacillus strain, L. reuteri C10, for poultry, during freeze-drying and storage. Using response surface methodology, a quadratic polynomial equation was obtained for response value by multiple regression analyses: Y = 8.59546-0.01038 X(1)-0.09382 X(2)-0.07771 X(3)-0.054861 X(1)(2)-0.04603 X(3)(2)-0.10938 X(1)X(2). Based on the model predicted, sucrose exerted the strongest effect on the survival rate. At various combinations of cryoprotectants, the viability loss of the cells after freeze-drying was reduced from 1.65 log colony forming units (CFU)/mL to 0.26-0.66 log CFU/mL. The estimated optimum combination for enhancing the survival rate of L. reuteri C10 was 19.5% skim milk, 1% sucrose and 9% lactose. Verification experiments confirmed the validity of the predicted model. The storage life of freeze-dried L. reuteri C10 was markedly improved when cryoprotectants were used. At optimum combination of the cryoprotectants, the survival rates of freeze-dried L. reuteri C10 stored at 4°C and 30°C for 6 months were 96.4% and 73.8%, respectively. Total viability loss of cells which were not protected by cryoprotectants occurred after 12 and 8 weeks of storage at 4°C and 30°C, respectively.

Lactobacillus strain ecology and persistence within broiler chickens fed different diets: identification of persistent strains

Lactobacilli are autochthonous residents in the chicken gastrointestinal tract, where they may potentially be used as probiotics, competitive exclusion agents, or delivery vehicles. The aim of this study was to use an in vivo model to investigate the effect of diet and competing lactic acid bacteria on the colonization of inoculated Lactobacillus strains, with the goal of identifying strains which can consistently colonize or persist for an extended period of several weeks. Chicken-derived Lactobacillus strains were genetically marked with rifampin resistance and administered on day 0 to chickens fed either a normal commercial diet or a specially formulated high-protein diet. Chickens fed the high-protein diet were also coinoculated with two different mixes of additional lactic acid bacteria. Enterobacterial repetitive intergenic consensus sequence-based PCR (ERIC-PCR) was used to identify rifampin-resistant isolates recovered from chickens. Three strains, belonging to the species Lactobacillus agilis, Lactobacillus crispatus, and Lactobacillus vaginalis, were commonly reisolated from the chickens on both diets at days 21 and 42. The ability of these strains to persist was confirmed in a second chicken trial. All three strains persisted throughout the production period in the chickens fed a commercial diet, while only the L. agilis and L. vaginalis strains persisted in the chickens fed the high-protein diet. In both in vivo trials, competing lactic acid bacteria modified representation of the strains recovered, with all three stains capable of competing in the presence of one or both mixes of coinoculated strains. The in vivo model successfully identified three persistent strains that will be characterized further.

Estimation of 16S rRNA gene copy number in several probiotic Lactobacillus strains isolated from the gastrointestinal tract of chicken

The copy numbers of 16S rRNA genes in 12 probiotic Lactobacillus strains of poultry origin were analyzed. Genomic DNA of the strains was digested with restriction endonucleases that do not cut within the 16S rRNA gene of the strains. This was followed by Southern hybridization with a biotinylated probe complementary to the 16S rRNA gene. The copy number of the 16S rRNA gene within a Lactobacillus species was found to be conserved. From the hybridization results, Lactobacillus salivarius I 24 was estimated to have seven copies of the 16S rRNA gene, Lactobacillus panis C 17 to have five copies and Lactobacillus gallinarum strains I 16 and I 26 four copies. The 16S rRNA gene copy numbers of L. gallinarum and L. panis reported in the present study are the first record. Lactobacillus brevis strains I 12, I 23, I 25, I 211, I 218 and Lactobacillus reuteri strains C 1, C 10, C 16 were estimated to have at least four copies of the 16S rRNA gene. In addition, distinct rRNA restriction patterns which could discriminate the strains of L. reuteri and L. gallinarum were also detected. Information on 16S rRNA gene copy number is important for physiological, evolutionary and population studies of the bacteria.

Growth-promoting effects of single-dose intragastrically administered probiotics in chickens

1. Live body weight gain (WG) and food conversion efficiency (FCE) were measured over a 4-week period in chicks (female, Kabir strain), inoculated intragastrically at one week of age with either a single dose (1 ml) of 10(7) live bacterial cells of Lactobacillus fermentum (LBF) or a strain of Lactobacillus spp. (LB), named Autruche 4 (A4), suspended in 1 ml of phosphate-buffered saline (PBS, pH 7.0); controls (n = 10) were inoculated only with PBS. The same commercial chicken feed was used throughout the 4-week experiment. 2. Compared with the control group, WG to 8 and 21 d, and also liver weight, were significantly greater in LBF and A4 treatments and FCE improved in both of the experimental groups. Compared with the A4 treatment group, WG was significantly higher and FCE improved in the LBF-treated group. The effects of A4 treatment on chicks were similar to those in an earlier pilot experiment using the same methodology but with 1-week-old female chicks (Kabir) inoculated with either the A4 strain or strain of LB named Autruche 5. 3. It is concluded that a single dose of Lactobacillus fermentum or Lactobacillus spp. (Autruche 4) administered intragastrically improves WG and FCE of broiler chicks.

Potential competitive exclusion bacteria from poultry inhibitory to Campylobacter jejuni and Salmonella

The objective of this study was to isolate from chickens potential competitive exclusion bacteria (CE) that are inhibitory to Campylobacter jejuni or Salmonella, or to both, for subsequent development of a defined CE product for use in poultry. Adult chickens from family farms, commercial farms, and broiler chicken research centers were sampled to identify and select C. jejuni-free donor chickens. A challenge treatment, which included administering perorally 106 CFU C. jejuni per chicken and determining undetectable cecal shedding of campylobacters at 4 weeks, was important for identifying the best CE donor chickens. Screening of bacterial colonies obtained from nine donor chickens by using selective and nonselective media yielded 636 isolates inhibitory to six C. jejuni strains in vitro, with 194 isolates being strongly inhibitory. Of the 194 isolates, 145 were from ceca, and 117 were facultative anaerobic bacteria. One hundred forty-three isolates were inhibitory to six strains of Salmonella (including five different serotypes) in vitro. Of these, 41 were strongly inhibitory to all C. jejuni and Salmonella strains evaluated, and most were Lactobacillus salivarius. A direct overlay method, which involved directly applying soft agar on plates with discrete colonies from mucus scrapings of gastrointestinal tracts, was more effective in isolating CE than was the frequently practiced isolation method of picking and transferring discrete colonies and then overlaying them with soft agar. The best approach for obtaining bacteria highly inhibitory to Salmonella and C. jejuni from chickens was to isolate bacteria from ceca under anaerobic conditions. Free-range chickens from family farms were better donors of potential CE strongly inhibitory to both Salmonella and Campylobacter than were chickens from commercial farms and broiler chicken research centers.

Effect of Lactobacillus isolates on the adhesion of pathogens to chicken intestinal mucus in vitro

AIMS

The aims of this study were to investigate in vitro the effects of Lactobacillus isolates from a chicken on adhesion of pathogenic Salmonella and Escherichia coli to chicken intestinal mucus obtained from different intestinal regions.

METHODS AND RESULTS

Bacteria were labelled by using methyl-1,2-[(3)H]-thymidine. The bacterial adhesion was assessed by measuring the radioactivity of bacteria adhered to the mucus. The results showed that the abilities of Lactobacillus spp. to bind to the same intestinal mucus were higher than those of pathogenic Salmonella and E. coli. Pretreatment of intestinal mucus with Lactobacillus fermentum and Lactobacillus acidophilus, alone or in combination, reduced the adhesion of the tested pathogens, but the reductive extent of pathogenic adhesion by Lactobacillus spp. in combination was relatively high.

CONCLUSIONS

The tested bacteria had different adhesions to mucus glycoproteins isolated from different intestinal regions of chicken. Lactobacillus acidophilus and Lact. fermentum in combination revealed a better ability to inhibit attachments of Salmonella and E. coli to chicken intestinal mucus than Lactobacillus sp. alone.

SIGNIFICANCE AND IMPACT OF THE STUDY

A mixture of intestinal Lactobacillus spp. from a chicken may play a protective role in excluding pathogenic Salmonella and E. coli from the intestine of chicken.

Influence of β-glucanase-producing Lactobacillus strains on intestinal characteristics and feed passage rate of broiler chickens

Two experiments were conducted to study the effects of beta-glucanase produced by transformed Lactobacillus strains on the intestinal characteristics and feed passage rate of broiler chickens fed barley-based diets. Supplementation of transformed Lactobacillus strains to the diet of chickens significantly (P < 0.05) reduced the intestinal fluid viscosity by 21 to 46% compared with chickens fed an unsupplemented diet or a diet supplemented with parental Lactobacillus strains. The relative weights of pancreas, liver, duodenum, jejunum, ileum, ceca, and colon were reduced (P < 0.05) by 6 to 27%, and the relative length of duodenum, jejunum, ileum, and ceca was reduced (P < 0.05) by 8 to 15%. Histological examination of the intestinal tissues showed that the jejunal villus height of chickens fed a diet supplemented with transformed Lactobacillus strains was significantly (P < 0.05) higher than that of chickens fed other dietary treatments. The transformed Lactobacillus strains were found to reduce (P < 0.05) the time of feed passage rate by 2.2 h. Supplementation of transformed Lactobacillus strains to the diet improved the intestinal characteristics and feed, passage rate of the chickens.

Adherence and colonization properties of Lactobacillus rhamnosus TB1, a broiler chicken isolate

AIMS

Selected lactic acid bacteria (LAB) isolated from intestinal tract of chicken have been studied in order to investigate their ability to adhere in vitro to Basement Membrane Matrigel (BMM). A selected strain showing a good adherence in BMM test was used for in vivo colonization assays.

METHODS AND RESULTS

In vitro assessment of adhesion of broiler chicken isolates was performed using BMM assay. Among LAB strains tested, Lactobacillus rhamnosus TB1 showed a good adherence that was comparable to the one of an Escherichia coli EPEC strain used as positive control. For in vivo colonization assays this strain was fluorescently stained with the carboxyfluorescein diacetate succinimidyl ester (cFDA-SE) thus allowing its detection in different layers of intestinal tract after inoculation in broiler chicken. Further, stained L. rhamnosus were found with a highest value in rectum, jejunum and ileum both 3 and 24 h after administration.

CONCLUSIONS

BMM assay is a quick method to test in vitro adhesion properties of bacterial strains and cFDA-SE-stained bacteria may be considered as an alternative method to test in vivo adhesion and colonization properties.

SIGNIFICANCE AND IMPACT OF THE STUDY

Lactobacillus rhamnosus TB1 was therefore showed to be able to adhere strongly in vitro to BMM and in vivo to intestinal epithelial cells of chicken and may be considered as a potential probiotic for chicken.

Monostrain, multistrain and multispecies probiotics--A comparison of functionality and efficacy

This literature review was carried out to make a comparison of functionality and efficacy between monostrain, multistrain and multispecies probiotics. A monostrain probiotic is defined as containing one strain of a certain species and consequently multistrain probiotics contain more than one strain of the same species or, at least of the same genus. Arbitrarily, the term multispecies probiotics is used for preparations containing strains that belong to one or preferentially more genera. Multispecies probiotics were superior in treating antibiotic-associated diarrhea in children. Growth performance and particularly mortality in broilers could be improved with multistrain probiotics. Mice were better protected against S. Typhimurium infection with a multistrain probiotic. A multispecies probiotic provided the best clearance of E. coli O157:H7 from lambs. Rats challenged with S. Enteritidis showed best post-challenge weight gains when treated with a multispecies probiotic. Possible mechanisms underlying the enhanced effects of probiotic mixtures are discussed. It is also emphasized that strains used in multistrain and multispecies probiotics should be compatible or, preferably, synergistic. The design and use of multistrain and multispecies probiotics should be encouraged.

Some factors affecting the adherence of probiotic Propionibacterium acidipropionici CRL 1198 to intestinal epithelial cells

Adhesion to the intestinal mucosa is generally considered an important property of probiotic microorganisms and has been related to many of their health benefits. This study investigated some factors that could affect or be involved in the adherence of Propionibacterium acidipropionici CRL 1198, a dairy strain with suggested probiotic effects and high adherence in vitro and in vivo to intestinal epithelial cells. In vitro adhesion of propionibacteria was decreased by gastric digestion but not affected by bile and pancreatic enzymes. Adherence was also decreased by pretreatment of bacterial cells with protease, sodium metaperiodate, and trichloroacetic acid, revealing that different features of the cell surface, like protein factors, carbohydrates, and teichoic acids, are involved in the process. Adherence to intestinal epithelial cells was enhanced by calcium and was dependent on other divalent cations. Adhesion to intestinal mucus was also demonstrated. The results should explain the metabolic effects in the host previously obtained with this strain and support the potential of Propionibacterium for development of new probiotics.

Adhesion of dairy propionibacteria to intestinal epithelial tissue in vitro and in vivo

Adhesion to the intestinal mucosa is a desirable property for probiotic microorganisms and has been related to many of their health benefits. In the present study, 24 dairy Propionibacterium strains were assessed with regard to their hydrophobic characteristics and their autoaggregation and hemagglutination abilities, since these traits have been shown to be indicative of adherence in other microorganisms. Six strains were further tested for their capacity to adhere to ileal epithelial cells in vitro and in vivo. The results of the study showed that propionibacteria were highly hydrophilic, and hemagglutination and autoaggregation were properties not commonly found among these microorganisms. No relationship was found between surface characteristics and adhesion ability, since hemagglutinating, autoaggregating, and nonautoaggregating bacteria were able to adhere to intestinal cells both in vitro and in vivo. Microscopic examination revealed that autoaggregating cells adhered in clusters, with adhesion being mediated by only a few bacteria, whereas the hemagglutinating and nonautoaggregating strains adhered individually or in small groups making contact with each epithelial cell with the entire bacterial surface. The in vitro assessment of adhesion was a good indication of the in vivo association of propionibacteria with the intestinal epithelium. Therefore, the in vitro method presented here should be valuable in screening routinely adhesive properties of propionibacteria for probiotic purposes. The adhesion ability of dairy propionibacteria would prolong their maintenance in the gut and increase the duration of their provision of beneficial effects in the host, supporting the potential of Propionibacterium in the development of new probiotic products.

Growth performance and immune response of two commercial broiler strains fed diets containing Lactobacillus cultures and oxytetracycline under heat stress conditions

1. Hubbard x Hubbard (HH) and Shaver x Shaver (SS) chicks given a dietary supplement of either 50 mg/kg oxytetracycline (OTC) or 1 g/kg Lactobacillus culture (LC) were exposed to 36 +/- 1 degrees C for 3 h daily from day (d) 21 to 42. 2. Prior to heat treatment, body weight (d 21) and weight gain (d 1 to d 21) of OTC and LC birds were greater than those fed the control diet. Chicks given LC had the best food efficiency followed by OTC and control birds during d 1 to d 21. Body weight (d 1 and d 21) and weight gain (d 1 to d 21) were greater for HH tlhan SS chicks. 3. After 3 weeks of heat exposure, birds receiving the LC diet had greater body weight and weight gain, higher food intake and lower food efficiency than OTC and control chicks. 4. Antibody production against Newcastle discase vaccine on d 21 was not affected by strain or diet. On d 42, while diet had negligible effect on this variable among the SS broilers, HH birds fed LC had higher antibody production than those on the control diet. 5. Neither strain nor diet had a significant effect on mortality.

Digestive and bacterial enzyme activities in broilers fed diets supplemented with Lactobacillus cultures

A study was carried out to investigate the effects of adherent Lactobacillus cultures on 1) amylolytic, lipolytic, and proteolytic enzyme activities in the contents of the small intestine (from the distal end of the duodenum to the ileocecal junction) and 2) bacterial beta-glucuronidase and beta-glucosidase activities in the intestinal contents and feces of broiler chickens. Three dietary treatments were randomly assigned to three groups of chicks, i.e., basal diet only (control group), basal diet + 0.1% dried culture of Lactobacillus acidophilus, and basal diet + 0.1% dried culture of a mixture of 12 Lactobacillus strains. The results showed that supplementation of the adherent Lactobacillus cultures to chickens, either as a single strain of L. acidophilus or as a mixture of 12 Lactobacillus strains, increased significantly (P < 0.05) the levels of amylase in the small intestine. However, the proteolytic and lipolytic activities in the small intestine were not affected by addition of either of the adherent Lactobacillus cultures. Addition of either L. acidophilus or a mixture of 12 Lactobacillus strains was also found to reduce significantly (P < 0.05) the intestinal and fecal beta-glucuronidase and fecal beta-glucosidase but not the intestinal beta-glucosidase at 40 d of feeding.

Some probiotic properties of chicken lactobacilli

The beneficial effect of lactobacilli has been attributed to their ability to colonize human and animal gastrointestinal tracts. In this work, adhesion assays with three lactobacillus strains and intestinal fragments obtained from chickens were assessed. Lactobacillus animalis and L. fermentum were able to adhere to three kinds of epithelial cells (crop, small and large intestines) with predominance to small intestine. Among the strains considered, L. fermentum subsp. cellobiosus showed the lowest and L. animalis the highest adhesion ability. Scanning electron microphotographs showing L. animalis and L. fermentum adhering to intestinal cells were obtained. The characterization of L. animalis adhesion indicated that lectin-like structure of this strain has glucose/mannose as specific sugars of binding. However, a calcium requirement was not observed. The adhesion of L. fermentum was reduced by addition of sialic acid or mannose (P < 0.01). These carbohydrates can be involved in the interaction between adhesin and epithelial surface. In this case, the dependence on bivalent cations was demonstrated. Lactobacillus fermentum was effective in reducing the attachment of Salmonella pullorum by 77%, while L. animalis was able to inhibit (90%, 88%, and 78%) the adhesion of S. pullorum, S. enteritidis, and S. gallinarum to host-specific epithelial fragments respectively. Our results from this in vitro model suggest that these lactobacilli are able to block the binding sites for Salmonella adhesion.

Lactococci as probiotic strains: adhesion to human enterocyte-like Caco-2 cells and tolerance to low pH and bile

There have been few studies on the probiotic activity of Lactococcus strains although they are commonly used as starter bacteria in manufacturing many kinds of fermented dairy products. Nine strains of the genus Lactococcus were examined for their probiotic properties, such as adherence to human enterocyte-like Caco-2 cells and tolerance to acid and bile. Six strains were adhesive and the highest adhesion was observed with Lactcoccus lactis ssp. lactis NIAI527. This strain adhered to the microvilli of cells as observed by scanning electron microscopy and also tolerated low pH and bile. These properties should make strain 527 a potential new probiotic strain.

Growth performance, intestinal microbial populations, and serum cholesterol of broilers fed diets containing Lactobacillus cultures

A study was conducted to determine the effects of adherent Lactobacillus culture on growth performance, intestinal microbial population, and serum cholesterol level of broilers. Four dietary treatments, consisting of the basal diet (control), basal diet + 0.05, 0.10, or 0.15% Lactobacillus culture (LC), were fed to 2,000 Arbor Acres broiler chicks from 1 to 42 d of age (DOA). The chicks were randomly assigned to 40 cages (50 chicks per cage, 10 cages per diet). The experimental period was 42 d. Body weights and feed to gain ratio were measured at 21 and 42 DOA. The intestinal microbial populations and serum cholesterol levels were determined at 10, 20, 30, and 40 DOA. The results showed that body weights and feed to gain ratios were improved significantly (P < 0.05) when compared to control broilers for broilers fed diets containing 0.05 or 0.10% LC, but not 0.15% LC, at 21 and 42 DOA. Coliform counts in the cecum of birds receiving 0.05% LC at 10, 20, and 30 DOA, and 0.10% at 10 and 20 DOA were significantly lower (P < 0.05) than those of the control birds. The total aerobes, total anaerobes, lactobacilli, and streptococci in the small intestines and ceca of the control birds were not significantly different from those of the treated groups. Serum cholesterol levels were significantly lower (P < 0.05) in broilers fed the three diets containing LC at 30 DOA, and in the birds fed 0.05 or 0.10% LC at 20 DOA.

Effect of adherent Lactobacillus spp. on in vitro adherence of salmonellae to the intestinal epithelial cells of chicken

Single strains of Lactobacillus acidophilus and Lact. fermentum, isolated from chicken intestine, were used to study in vitro interactions with Salmonella enteritidis, Salm. pullorum or Salm. typhimurium in an ileal epithelial cell (IEC) radioactive assay. Exclusion, competition and displacement phenomena were investigated by respectively incubating (a) lactobacilli and IEC together, prior to addition of salmonellae, (b) lactobacilli, IEC and salmonellae together, and (c) salmonellae and IEC, followed by the lactobacilli. Lactobacilli were selected for study because of their strong ability to adhere to IEC and poor aggregation with salmonellae. The results demonstrated that Lact. acidophilus significantly reduced (P < 0.05) the attachment of Salm. pullorum to IEC in the tests for exclusion and competition, but not in the displacement tests. Lactobacillus fermentum was found to have some ability to reduce the attachment of Salm. typhimurium to IEC under the conditions of exclusion (P < 0.08), competition (P < 0.09), but not displacement. However, both Lact. acidophilus and Lact. fermentum were unable to reduce the adherence of Salm. enteritidis to IEC under any of the conditions.

Antagonistic effects of intestinal Lactobacillus isolates on pathogens of chicken

Twelve Lactobacillus strains isolated from chicken intestine, which demonstrated a strong and moderate capacity to adhere to the ileal epithelial cells in vitro, were used to investigate their inhibitory ability against five strains of salmonella, i.e. Salmonella enteritidis 935/79, Salm. pullorum, Salm. typhimurium, Salm. blockley and Salm. enteritidis 94/448, and three serotypes of Escherichia coli, viz. E. coli O1:K1, O2:K1 and O78:K80. The results showed that all the 12 Lactobacillus isolates were able to inhibit the growth of the five strains of salmonella, and the three strains of E. coli in varying degrees. Generally, they were more effective in inhibiting the growth of salmonella than E. coli. Inhibition of the pathogenic bacteria was probably due to the production of organic acids by the Lactobacillus isolates.