Microencapsulation of probiotic strains for swine feeding

An in vitro gastrointestinal model to evaluate the tolerance of encapsulated Lactobacillus and Lactococcus strains with synbiotic containing lactobionic acid via lyophilization technique to harsh gastric conditions during storage time

Probiotics are living microorganisms that have potential health benefits for the host when administered in the correct proportions. However, for these beneficial effects to be produced, viable probiotic cells need to reach the human intestine. This study used a gastrointestinal model to represent the pH variation and gastric enzymes that are involved in the digestion process. Eight Lactobacillus strains and one Lactococcus strain were encapsulated using sodium alginate. The aim of this study was to compare free probiotic bacteria with encapsulated probiotic bacteria and determine the number of viable probiotic cells that might reach the human intestine. Microencapsulation of probiotic organisms followed the extrusion method with an alginate compound. Microencapsulated and free probiotic bacteria were inoculated into 200 ml of MRS (Man, Rogosa, Sharpe) broth. Simulated gastric juice and bile and pancreatic salt were used to test the tolerance of free Lactobacillus and Lactococcus species and microencapsulated bacteria to acid pH and enzymes. To enumerate the microencapsulated probiotic organisms, the bacteria were released from the capsules after total digestion with sodium citrate solution. The number of live bacteria (as CFU/g) was determined using the plate count method on MRS plates incubated at 37 °C for 48 h. Bacterial cell viability was determined on MRS agar duplicate plates at different dilutions. The results indicated that microencapsulation of probiotic bacteria showed improved viability over free cells when given 2 h of exposure to acidic conditions, and also for 2 h of exposure to bile and pancreatic salt. Encapsulation with alginate can protect probiotic bacteria from acidic conditions and bile salts. This study attempted also to produce synbiotic preparations with lactobionic acid using nontoxic encapsulating substances. The microorganisms used were stabilized with protective substances, and their stability during storage was checked under room temperature conditions. The final modification of the method, involving placing the capsules in a solution of skimmed milk with 5 % sucrose and 0.35 % ascorbic acid, resulted in an increase in the survival rate of some strains of microorganisms during microencapsulation and lyophilization and demonstrated stability during storage at room temperature.

Investigation of the Role and Effectiveness of Chitosan Coating on Probiotic Microcapsules

Microencapsulation and coating are preferred methods to increase the viability of the probiotic strains. The effect of microencapsulation technologies and materials used as microcapsule cores on viability is being investigated during development. In the present study, chitosan-coated and Eudragit L100-55-coated alginate microspheres were produced to encapsulate Lactobacillus plantarum probiotic bacteria. After the heat loading and simulated gastrointestinal juice dissolution study, the differences in viability were compared based on the CFU/mL values of the samples. The kinetics of the bacterial release and the ratio of the released live/dead cells of Lactobacillus plantarum were examined by flow cytometry. In all cases, we found that the CFU value for the chitosan-coated samples was virtually zero. The ratio of live/dead cells in the 120 min samples was significantly reduced to less than 20% for chitosan, while it was nearly 90% in the uncoated and Eudragit L100-55-coated samples. In the case of chitosan, based on some published MIC values and the amount of chitosan coating determined in the present study, we concluded the reason for our results. It was the first time to determine the amount of the released chitosan coat of the dried microcapsule, which reached the MIC value during the dissolution studies.

Encapsulating Viability of Multi-strain Lactobacilli as Potential Probiotic in Pigs

Important aspects of the selection of probiotics to be used for mixing in animal feed include host species specificity and probiotic cell survival during production and storage of their products. The research was to screen and investigate some probiotic properties of lactic acid bacteria (LAB) isolated from pig fecal samples. One hundred and thirty-eight representative LAB isolates, which were isolated from 51 pig fecal samples, were tested for acid and bile tolerance, antimicrobial susceptibility, antibacterial activity, potential adhesion to the cell surface, and survival rates when stored in varied microencapsulation forms: freeze-dried, spray-dried, and micro-beads. The antibacterial activity results of the ten LAB isolates, which were acid- (pH 2, 3 h) and bile- (50% (v/v) fresh pig bile, 8 h) tolerant and suitable for resisting the five antibiotics commonly used for treating pig infections with pathogenic indicator strains, showed that three isolates (L21, L80, L103) had strong inhibition to Escherichia coli, Salmonella group B, and Salmonella group D using co-culturing and agar spot assays. The three isolates had high hydrophobicity (65-73%) and did not show antagonistic growth against each other. All three selected isolates had greater than 80% survival in freeze-dried and micro-bead forms at 25-30 °C after 2 days of storage (80.4-86.75%, 7.31-7.89 log CFU/ml). Sequence analysis of the 16S rRNA genes demonstrated that the three isolates belong to Lactobacillus plantarum (strain L21 and strain L80) and L. paraplantarum (strain L103). The single and multiple strains of these bacteria may have potential use as probiotics in pig diets.

Encapsulation of Lactobacillus plantarum ATCC 8014 and Pediococcus acidilactici ATCC 8042 in a freeze-dried alginate-gum arabic system and its in vitro testing under gastrointestinal conditions

The aim of this study was to investigate the viability of Pediococcus acidilactici ATCC 8042 and Lactobacillus plantarum ATCC 8014 in a freeze-dried capsules system prepared with sodium alginate and gum arabic using the extrusion technique. The capsules made with alginate 2% (w/v)/gum arabic 2% (w/v) showed higher hardness (7.12 ± 0.71 N), with highly cohesive (0.81 ± 0.02) and elastic (0.99 ± 0.00) features on the Texture Profile Analysis (TPA), as well as higher sphericity with 1.75 ± 0.12 mm y 1.73 ± 0.13 mm diameter axes and regularity in their surface by Scanning Electron Microscopy (SEM). The use of skimmed milk at 10% as a cryoprotector in the freeze-drying process allowed the obtention of high viability percentages (88% a 96%) for both strains. Best results of viability for P. acidilactici encapsulated was with the use of alginate 2% (w/v)/gum arabic 2% (w/v) (92%±2.65), and L. plantarum with the use of alginate 2% (w/v) (84.71%±10.33) during the gastrointestinal environment challenge.

Lactobacillus spp. impair the ability of Listeria monocytogenes FBUNT to adhere to and invade Caco-2 cells

OBJECTIVES

The objective of this study was to evaluate the ability of Lactobacillus curvatus CRL705, CRL1532, and CRL1533 and Lactobacillus sakei CRL1613 to survive under simulated gastrointestinal conditions. Moreover, a microencapsulation approach was proposed to improve gastrointestinal survival. Finally, experiments were performed to demonstrate that Lactobacillus spp. can modulate the ability of Listeria monocytogenes FBUNT to adhere to and invade Caco-2 cells.

RESULTS

Lactobacillus strains were encapsulated in alginate beads to enhance the survival of bacteria under in vitro gastrointestinal conditions. All strains hydrolyzed bile salts using chenodeoxycholic acid as a substrate and adhered to Caco-2 cells. Cell-free supernatants (CFSs) showed antimicrobial activity against L. monocytogenes as demonstrated by agar diffusion assays. The average percentages of L. monocytogenes adhesion decreased from 67.74 to 41.75 and 38.7% in the presence of 50 and 90% (v/v), respectively, for all CFSs tested. The highest concentrations of CFSs completely inhibited the L. monocytogenes invasion of Caco-2 cells.

CONCLUSIONS

The studied Lactobacillus strains have protective effects against the adhesion and invasion of L. monocytogenes FBUNT. Alginate encapsulation of these bacteria improved gastrointestinal tolerance such that they could be further studied as potential probiotics against intestinal pathogenic bacteria.

Probiotics, prebiotics, and microencapsulation: A review

The development of a suitable technology for the production of probiotics is a key research for industrial production, which should take into account the viability and the stability of the organisms involved. Microbial criteria, stress tolerance during processing, and storage of the product constitute the basis for the production of probiotics. Generally, the bacteria belonging to the genera Lactobacillus and Bifidobacterium have been used as probiotics. Based on their positive qualities, probiotic bacteria are widely used in the production of food. Interest in the incorporation of the probiotic bacteria into other products apart from dairy products has been increasing and represents a great challenge. The recognition of dose delivery systems for probiotic bacteria has also resulted in research efforts aimed at developing probiotic food outside the dairy sector. Producing probiotic juices has been considered more in the recent years, due to an increased concern in personal health of consumers. This review focuses on probiotics, prebiotics, and the microencapsulation of living cells.

Enhancement of Lactobacillus reuteri KUB-AC5 survival in broiler gastrointestinal tract by microencapsulation with alginate-chitosan semi-interpenetrating polymer networks

AIMS

To evaluate an alginate-chitosan microcapsule for an intestinal probiotic delivery system for broilers.

METHODS AND RESULTS

Lactobacillus reuteri KUB-AC5 was successfully microencapsulated with alginate and chitosan mixtures using an emulsion cross-linking method with high microencapsulation efficiency. Scanning electron microscopy revealed a large number of the bacteria entrapped in the semi-interpenetrating network. The microcapsule effectively protected the cells against strong acids. The in vitro study showed that the 8 log CFU g(-1) was released at the jejunum and ileum. For the in vivo study, the number of probiotics was detected by a polymerase chain reaction-based random amplified polymorphic DNA technique. From provision of 10 log CFU, cell numbers of 5-8 log CFU were observed in the intestine.

CONCLUSIONS

The alginate-chitosan microcapsule can serve as a potential intestine-targeted probiotic delivery system.

SIGNIFICANCE AND IMPACTS OF THE STUDY

To the best of our knowledge, this is the first comparison study of the in vitro and in vivo gastrointestinal profiles of microencapsulated probiotics used as feed additives for broilers. This study reveals the similarities and differences of the in vitro and in vivo probiotic profiles and provides convincing evidence of the potential use of the alginate-chitosan microcapsule as a probiotic delivery system.

Fatty acid profile of pig meat after probiotic administration

The aim of this work was to study the fatty acid profile of pig meat after probiotic administration. Thirty postweaned pigs (25 day old) were distributed into 2 groups: control (n = 15) and probiotic (n = 15). Each experimental group was fed ad libitum on a commercial diet for 35 days. Lactobacillus amylovorus and Enterococcus faecium mixed culture (10(8) CFU/ml)was daily orally delivered to the probiotic group. At the end of the assay, six pigs randomly selected from each group were slaughtered and muscle samples (Longissimus dorsi) were taken for fatty acid analysis. Tissues from the probiotic group animals exhibited an increase in monounsaturated and polyunsaturated fatty acids; furthermore, linoleic acid (C18:2), linolenic acid (18:3), and cis-9,trans-11 conjugated linoleic acid (CLA) concentrations were significantly higher (p < 0.05) compared to the control group. These results suggest probiotic administration could be useful to modify and improve the fatty acid profile of pig meat.

Association of beta-glucan endogenous production with increased stress tolerance of intestinal lactobacilli

The exopolysaccharide beta-glucan has been reported to be associated with many health-promoting and prebiotic properties. The membrane-associated glycosyltransferase enzyme (encoded by the gtf gene), responsible for microbial beta-glucan production, catalyzes the conversion of sugar nucleotides into beta-glucan. In this study, the gtf gene from Pediococcus parvulus 2.6 was heterologously expressed in Lactobacillus paracasei NFBC 338. When grown in the presence of glucose (7%, wt/vol), the recombinant strain (pNZ44-GTF(+)) displayed a "ropy" phenotype, while scanning electron microscopy (SEM) revealed strands of polysaccharide-linking neighboring cells. Beta-glucan biosynthesis was confirmed by agglutination tests carried out with Streptococcus pneumoniae type 37-specific antibodies, which specifically detect glucan-producing cells. Further analysis showed a approximately 2-fold increase in viscosity in broth media for the beta-glucan-producing strain over 24 h compared to the control strain, which did not show any significant increase in viscosity. In addition, we analyzed the ability of beta-glucan-producing Lactobacillus paracasei NFBC 338 to survive both technological and gastrointestinal stresses. Heat stress assays revealed that production of the polysaccharide was associated with significantly increased protection during heat stress (60-fold), acid stress (20-fold), and simulated gastric juice stress (15-fold). Bile stress assays revealed a more modest but significant 5.5-fold increase in survival for the beta-glucan-producing strain compared to that of the control strain. These results suggest that production of a beta-glucan exopolysaccharide by strains destined for use as probiotics may afford them greater performance/protection during cultivation, processing, and ingestion. As such, expression of the gtf gene may prove to be a straightforward approach to improve strains that might otherwise prove sensitive in such applications.