Antiparasitic Activity of Enterocin M and Durancin-like from Beneficial Enterococci in Mice Experimentally Infected with Trichinella spiralis.

Beneficial/probiotic strains protect the host from pathogens by competitive displacement and production of antibacterial substances, i.e., bacteriocins. The antiparasitic potential of bacteriocins/enterocins and their producing strains in experimental murine trichinellosis were tested as a new therapeutic strategy. Enterocin M and Durancin-like and their producers Enterococcus faecium CCM8558 and Enterococcus durans ED26E/7 were administered daily to mice that were challenged with Trichinella spiralis. Our study confirmed the antiparasitic effect of enterocins/enterococci, which reduced the number of adults in the intestine (Enterocin M-43.8%, E. faecium CCM8558-54.5%, Durancin-like-16.4%, E. durans ED26E/7-35.7%), suppressed the Trichinella reproductive capacity ex vivo (Enterocin M-61%, E. faecium CCM8558-74%, Durancin-like-38%, E. durans ED26E/7-66%), and reduced the number of muscle larvae (Enterocin M-39.6%, E. faecium CCM8558-55.7%, Durancin-like-15%, E. durans ED26E/7-36.3%). The direct effect of enterocins on Trichinella fecundity was documented by an in vitro test in which Durancin-like showed a comparable reducing effect to Enterocin M (40-60%) in contrast to the ex vivo test. The reducing activity of T.spiralis infection induced by Enterocin M was comparable to its strain E. faecium CCM8558; Durancin-like showed lower antiparasitic activity than its producer E. durans ED26E/7.

Susceptibility to postbiotics - enterocins of methicillin-resistant Staphylococcus aureus strains isolated from rabbits.

There is a major problem with the rising occurrence of highly virulent and multiply-resistant strains, including methicillin-resistant Staphylococcus aureus (MRSA), because of their difficult treatment. This study aimed to evaluate the antibacterial and antibiofilm effect of new enterocins (Ent) against potential pathogenic MRSA strains isolated from rabbits. Staphylococci were identified with PCR and screened for methicillin/oxacillin/cefoxitin resistance (MR) using the disk diffusion method and the PBP2' Latex Agglutination Test Kit. Enzyme production, hemolysis, DNase activity, slime production, and biofilm formation were tested in MRSA strains. The susceptibility of MRSA to eight partially-purified enterocins (Ent) produced by E. faecium and E. durans strains was checked using agar spot tests. The antibiofilm activity of Ents was tested using a quantitative plate assay. Out of 14 MRSA, PBP testing confirmed MR in 8 strains. The majority of MRSA showed DNase activity and ß-hemolysis. Slime production and moderate biofilm formation were observed in all strains. MRSA were susceptible to tested Ents (100-12,800 AU/mL; except Ent4231). The antibiofilm effect of Ents (except Ent4231) was noted in the high range (64.9-97.0%). These results indicate that enterocins offer a promising option for the prevention and treatment of bacterial infections caused by biofilm-forming MRSA.

The effect of enterocin A/P dipeptide on growth performance, glutathione-peroxidase activity, IgA secretion and jejunal morphology in rabbits after experimental methicillin-resistant Staphylococcus epidermidis P3Tr2a Infection.

The increasing frequency of methicillin-resistant (MR) staphylococci in humans and animals need special attention for their difficult treatment and zoonotic character, therefore novel antimicrobial compounds on a natural base against antibiotic-resistant bacteria are requested. Currently, bacteriocins/enterocins present a new promising way to overcome this problem, both in prevention and treatment. Therefore, the preventive and medicinal effect of dipeptide enterocin EntA/P was evaluated against MR Staphylococcus epidermidis SEP3/Tr2a strain in a rabbit model, testing their influence on growth performance, glutathione-peroxidase (GPx) enzyme activity, phagocytic activity (PA), secretory (s)IgA, and jejunal morphometry (JM). Eighty-eight rabbits (aged 35 days, meat line M91, both sexes) were divided into experimental groups S (SEP3/Tr2a strain; 1.0 × 105 CFU/mL; dose 500µL/animal/day for 7 days, between days 14 and 21 to simulate the pathogen attack), E (EntA/P; 50 µL/animal/day, 25,600 AU/mL in two intervals, for preventive effect between days 0 and 14; for medicinal effect between days 28 and 42), E + S (EntA/P + SEP3/Tr2a; preventive effect; SEP3/Tr2a + EntA/P; medicinal effect) and control group (C; without additives). Higher body weight was recorded in all experimental groups (p < 0.001) compared to control data. The negative influence/attack of the SEP3Tra2 strain on the intestinal immunity and environment was reflected as decreased GPx activity, worse JM parameters and higher sIgA concentration in infected rabbits. These results suggest the promising preventive use of EntA/P to improve the immunity and growth of rabbits, as well as its therapeutic potential and protective role against staphylococcal infections in rabbit breeding.

Modulatory Effect of Beneficial Enterococci and Their Enterocins on the Blood Phagocytes in Murine Experimental Trichinellosis.

Bacteriocins (enterocins) represent a new therapeutic strategy in various intestinal and non-intestinal infections. In antiparasitic defence, an oxidative inflammation of phagocytes is effective in destroying new-born Trichinella spiralis larvae. The strains Enterococcus faecium CCM8558 and E. durans ED26E/7 and their enterocins, enterocin M and a durancin-like enterocin, respectively, were administered daily, and mice were then infected with T. spiralis larvae on the seventh day of treatment. Phagotest and Bursttest kits were used to detect the phagocytosis and respiratory burst in blood leukocytes. T. spiralis infection inhibited phagocytosis from day 11 post-infection (dpi) during the migration of new-born larvae into the muscles. E. faecium CCM8558, E. durans ED26E/7, and the durancin-like enterocin increased phagocytic activity from day 11 dpi. Both strains and their enterocins (enterocin M and durancin-like) stimulated the ingestion capability of phagocytes from 18 to 32 dpi. Enterococci/enterocins therapy prevented a reduction in cells with respiratory burst caused by T. spiralis infection from 11 dpi. The enzymatic activity of phagocytes was stimulated on 18 and 25 dpi, particularly by E. faecium CCM8558 and enterocin M. Enterocin M and the durancin-like enterocin were as effective in stimulating phagocytosis as the bacterial strains that produce them. The stimulation of phagocytosis could contribute to decreased larval migration and reduced parasite burden in the host.

Application of Autochthonous Biofilm-Forming Enterococcus hirae Kr8 Strain in Relation with Enterocin M in Broiler Rabbits and Their Effect on the Rabbit Meat Quality: Risk or Protection?

Around weaning, rabbits are sensitive to gastrointestinal diseases, mostly of bacterial origin, including enterococci (Enterococcus hirae), clostridia, and coliforms. Preventive use of postbiotics-enterocins-as feed additives can reduce this problem. Therefore, simulation of spoilage/pathogenic environment applying the autochthonous, biofilm-forming E. hirae Kr8+ strain in rabbits and its influence on rabbit meat quality as well as the protective effect of Ent M on rabbit meat properties and quality in infected animals was tested. Ninety-six rabbits aged 35 days, both sexes, meat line M91 breed were divided into one control (CG) and three experimental (EG1, EG2, and EG3) groups. The rabbits in CG received standard diet, without any additives, rabbits in EG1 received 108 CFU/mL of Kr8+ strain (at a dose of 500 µL/animal/day), to rabbits in EG2 the Ent M (50 µL/animal/day), and in EG3, combination of the Kr8+ and Ent M was applied in their drinking water during 21 days. The experiment lasted 42 days. The Kr8+ strain did not attack the gastrointestinal tract and have any adverse effect on the meat quality of rabbits. Moreover, improved weight gains, carcass parameters, and higher essential fatty acid (EAA) and amino acid (EAA) content of rabbit meat point rather to its possible beneficial potential in rabbit nutrition. Administration of Ent M improved most of the tested parameters: animal weight and meat physicochemical and nutritional properties, with a focus on EFA and EAA. During combination of both additives, their synergistic impact was noted, improving the nutritional quality, mostly the EAA content of rabbit meat.

Enterococcus moraviensis EMo 1-1Nik of horse origin:characteristics and potential bacteriocin-producing strain.

Nowadays, developed more precisious identification techniques have allowed to validate newer enterococcal species. Among them, the species Enterococcus moraviensis was also validated, at first from surface waters. However, in this study, characteristics and potential to bacteriocin production by the strain E. moraviensis EMo 1-1Nik isolated from buccal mucosa of Slovak warm-blood horse breed has been studied. BLASTn analysis allotted this strain to the species E. moraviensis with percentage identity BLASTn 16S rRNA sequence in the strain up to 100% (99.93% similarity with E. moraviensis NR113937.1). The strain EMo 1-1Nik has been provided with GenBank accession number MW326085. It is hemolysis-negative (γ-hemolysis), deoxyribonuclease-negative and gelatinase-negative; absent of virulence factor genes, low-grade biofilm-positive (0.133 ± 0.36), mostly susceptible to tested antibiotics. Moreover, 60% of EMo1-1Nik colonies were found as bacteriocin-producing against the principal indicator Enterococcus avium EA5. The concentrated substance (CS, pH 4.5) of EMo1-1Nik showed the inhibitory activity against EA5 strain (800 AU/mL); CSs with pH 6.3 and 7.3 reached inhibitory activity 100 AU/mL against EA5 strain. CS was thermo-stable and it does not lost activity after enzymes treatment. Oppositelly, EMo 1-1Nik was susceptible to Mundticin EM 41/3 (800 AU/mL) produced by horse fecal strain E. mundtii EM 41/3 and enterocins (up to 51 200 AU/mL). In spite of the preliminary results, it has been shown a potential to produce bacteriocin substance of the safe strain E. moraviensis EMo1-1Nik. The additional studies are in processing.

Microbiota, Phagocytic Activity, Biochemical Parameters and Parasite Control in Horses with Application of Autochthonous, Bacteriocin-Producing, Probiotic Strain Enterococcus faecium EF 412.

The beneficial influence of bacteriocin-producing, probiotic, mostly non-autochthonous bacteria has already been reported in various animals. However, their use in horses provides limited information, and results with autochthonous bacteria have not been reported. Therefore, the main objective of this model study was to test the effect of autochthonous, bacteriocin-producing faecal strain Enterococcus faecium EF 412 application in horses. One gram of freeze-dried EF 412 strain (109 CFU/mL for 21 days) was applied to horses in a small feed ball. Clinically healthy horses (12), Slovak warm-blood breed of various ages (5-13 years), were involved in a 35-day-long experiment, also functioning as control for themselves. They were stabled in separate boxes (university property), fed twice a day (hay, whole oats or grazed) with water access ad libitum. Sampling was performed at the start of the experiment, i.e. at days 0/1, 21 (3 weeks of EF 412 application) and at day 35 (2 weeks of EF 412 cessation). EF 412 colonized GIT of horses was 3.54 ± 0.75 CFU/g (log 10) at day 21. The eggs of the nematode Strongylus spp. were not found in horses after EF 412 application, and Eimeria spp. oocysts were similarly not found. The other microbiota were not reduced as evaluated by the use of standard method. Using next-generation sequencing, at phylum level, phyla Bacteroidetes and Firmicutes dominated and at family level, they were Bacteroidales BS11 and S24-7 gut goups and Lentisphaerae. In horses, the increasing tendency in phagocytic activity was noted after EF 412 application. Biochemical parameters were in the physiological range. Total protein value was significantly decreased at day 21 compared with day 0/1 as well as with day 35 (P < 0.05). Cholesterol and triglycerides were influenced (decreased) at day 21 compared with day 0/1 and day 35. Neither nematode eggs Strongylus spp. nor Eimeria spp. oocysts were found in faeces after EF 412 application. Autochthonous, faecal strain E. faecium EF 412 showed promising application potential.

Microbiome Associated with Slovak Raw Goat Milk, Trace Minerals, and Vitamin E Content.

In Slovakia, goat milk production for direct consumption and cheese processing has attracted growing interest. However, there is a lack of information regarding the microbial consortium in Slovak raw goat milk analyzed by next-generation sequencing and trace elements and vitamin E as well. A randomly selected samples (G24-G50) of raw goat milk from different animals at farms in Slovakia were analyzed. The phylum Actinobacteria dominated (62.8%), followed by the phyla Firmicutes (20.5%), Proteobacteria (7.4%), and Bacteroidetes (6.4%). The family Microbacteriaceae was detected in the highest percentage (60.2%) followed by Staphylococcaceae, Bacteroidaceae, Streptococcaceae, Lactobacillaceae, Enterobacteriaceae, and others. Regarding the genera, the most prevalent was genus Curtobacterium (47.4%) followed by the genera such as Staphylococcus (8.3%) and Bifidobacterium (4%). The genera Streptococcus, Lactococcus, Enterococcus, Lactobacillus, and Lacticaseibacillus were evaluated in abundance percentage in range 1%-3.2%. The genus Veillonella reached abundance 3.2%. The genera Enterobacter, Pseudomonas (1.3% and 0.5%), and Bacteroides (6.4%) were evaluated in small percentage abundance too. Zinc was detected with the highest mean value (2.561 ± 0.6823 mg/L) in raw goat milk, followed by iron (1.383 ± 0.5087 mg/L). The mean value of copper and manganese was 0.1746 ± 0.0463 mg/L and 0.051 ± 0.0238 mg/L. The vitamin E reached the mean value 0.3783 ± 0.1976 mg/L. This study is an original contribution showing microbial consortium in raw goat milk from Slovak farms. It also contributes to trace elements and vitamin E status in raw goat milk showing it as a nutritionally healthy food.

Natural Feed Additives and Novel Approaches for Healthy Rabbit Breeding.

Rabbit meat offers excellent nutritive and dietetic properties, but digestive disturbances, mainly during the post-weaning period, induce important economic losses for rabbit farmers [...].

Enterocin 7420 and Sage in Rabbit Diet and Their Effect on Meat Mineral Content and Physico-Chemical Properties.

Rabbit meat has outstanding nutritional characteristics­it is a lean meat with low fat, cholesterol and sodium content, with high-biological-value proteins, potassium, phosphorus, selenium, iron and vitamin B12 level. The dietary inclusion of natural bioactive compounds can improve the quality of rabbit meat. The present study evaluated the effect of enterocin 7420 (Ent 7420) and sage (Salvia officinalis) extract on the quality and mineral content of rabbit meat. A total of 96 Hyla rabbits (aged 35 days) were divided into E (Ent 7420; 50 µL/animal/d), S (sage extract; 10 µL/animal/d), E + S (Ent 7420 and sage in combination) and control (C) groups. Additives were administrated in drinking water for 21 days. A significant increase in meat iron (p < 0.01) content was noted; phosphorus and zinc levels were also elevated in experimental groups, compared with control data. Ent 7420 and sage treatment reduced the calcium and manganese (p < 0.01) contents. The physico-chemical traits of rabbit meat were not negatively influenced by treatment. Based on these results, diet supplementation, mostly with Ent 7420 but also in combination with sage, could enhance the quality of rabbit meat mineral, with a focus on its iron, phosphorus and zinc contents.

Enterocin M in Interaction in Broiler Rabbits with Autochthonous, Biofilm-Forming Enterococcus hirae Kr8 Strain.

Young rabbits are susceptible to gastrointestinal diseases caused by bacteria. Enterococcus hirae can be associated with diseases. But enterocins produced by some enterococcal species can prevent/reduce this problem. Therefore, the interaction of enterocin M with a biofilm-forming, autochthonous E. hirae Kr8+ strain was tested in rabbits to assess enterocin potential in vivo. Rabbits (96), aged 35 days, both sexes, meat line M91 breed were divided into four groups, control C and three experimental groups. The rabbits in C received the standard diet, rabbits in experimental group 1 (E1) received 108 CFU/mL of Kr8+, a dose 500 µL/animal/day, E2 received Ent M (50 µL/animal/day), and E3 received both Kr8+ and Ent M in their drinking water over 21 days. The experiment lasted 42 days. Feces and blood were sampled at day 0/1 (at the start of the experiment, fecal mixture of 96 animals, n = 10), at day 21 (five fecal mixtures per group, n = 5), and at day 42 (21 days after additives cessation, the same). At days 21 and 42, four rabbits from each group were slaughtered, and cecum and appendix were sampled for standard microbial analysis. Ent M showed decreased tendency of Kr8+. Using next-generation sequencing, the phyla detected with the highest abundance were Firmicutes, Verrucomicrobia, Bacteroidetes, Tenericutes, Proteobacteria, Cyanobacteria, Saccharibacteria, and Actinobacteria. Interaction of Ent M with some phyla resulted in reduced abundance percentage. At day 21, significantly increased phagocytic activity (PA) was found in E1 and E2 (p < 0.001). Kr8+ did not attack PA and did not stimulate oxidative stress. But Ent M supported PA. The prospective importance of this study lies in beneficial interaction of enterocin in host body.

Preventive Potential of Dipeptide Enterocin A/P on Rabbit Health and Its Effect on Growth, Microbiota, and Immune Response.

The present study investigated the effect of the dipeptide enterocin (Ent) A/P on growth, immune response, and intestinal microbiota in rabbits. Eighty-eight rabbits (aged five weeks, M91 meat line, both sexes) were divided into three experimental groups: E (Ent A/P; 50 µL/animal/day for 14 days; between 0-14 days); S (methicillin-resistant Staphylococcus epidermidis SE P3/Tr2a strain; 500 µL/animal/day for 7 days starting at day 14 to day 21); and E + S (Ent A/P between 0-14 days and SE P3/Tr2a strain between 14-21 days) groups, and the control group (C). The additives were administered in drinking water. Administration of Ent A/P lead to an increase in weight gain, reduction of feed conversion; phagocytic activity was stimulated and gut microbiota were optimized due to reduction of coliforms, total bacterial count, and methicillin-resistant staphylococci. Good health and increased weight gain also showed that methicillin-resistant S. epidermidis SE P3/Tr2a strain did not have any pathogenic effect on rabbits' health status.

The Effect of Enterococcus faecium AL41 on the Acute Phase Proteins and Selected Mucosal Immune Molecules in Broiler Chickens.

Probiotic bacteria, including the Enterococcus faecium strain, can improve intestinal mucosal health by several mechanisms, including modulation of the immune response, as well as by improving the protective function of the epithelial barrier. In this study, we tested the effect of Enterococcus faecium AL41 on the acute phase proteins response (blood), gene expression of selected molecules of mucosal immunity (immunoglobulin A, mucin-2, insulin-like growth factor 2) and mucus production (all parts of the small intestine) in broilers. Eighty broiler chicks were divided into two groups: a control and E. faecium AL41 (birds were inoculated with AL41 for 7 days) group. The whole experiment lasted 11 days. Our results revealed that the administration of E. faecium AL41 had no substantial effect on the concentrations of acute phase proteins, but we recorded a significant increase in ß- and γ-globulin fractions at the end of the experiment, which may indicate an improvement in the immune status. A significant prolonged stimulatory effect of E. faecium AL41 on the relative expression of molecules (immunoglobulin A, mucin-2) as well as on the dynamic of mucus production in the chicken intestine was observed. In addition, AL41 significantly reduced the total number of enterococci in the cecum and faeces.

Bacteriocin-Producing Strain Lactiplantibacillus plantarum LP17L/1 Isolated from Traditional Stored Ewe's Milk Cheese and Its Beneficial Potential.

Stored ewe's milk lump cheese is a local product that can be a source of autochthonous beneficial microbiota, especially lactic acid bacteria. The aim of this study was to show the antimicrobial potential of Lactiplantibacillus plantarum LP17L/1 isolated from stored ewe's milk lump cheese. Lpb. plantarum LP17L/1 is a non-hemolytic, non-biofilm-forming strain, susceptible to antibiotics. It contains genes for 10 bacteriocins-plantaricins and exerted active bacteriocin with in vitro anti-staphylococcal and anti-listerial effect. It does not produce damaging enzymes, but it produces ß-galactosidase. It also sufficiently survives in Balb/c mice without side effects which indicate its safety. Moreover, a reduction in coliforms in mice jejunum was noted. LP17L/1 is supposed to be a promising additive for Slovak local dairy products.

Modulation of lymphocyte subpopulations in the small intestine of mice treated with probiotic bacterial strains and infected with Trichinella spiralis.

AIMS: To study the local intestinal lymphocyte immunity in mice with trichinellosis affected by probiotic bacteria. METHODS AND RESULTS: Enterococcus faecium CCM8558, Enterococcus durans ED26E/7, Limosilactobacillus fermentum CCM7421 and Lactiplantibacillus plantarum 17 L/1 were administered daily (109  CFU ml-1 ) and mice were infected with Trichinella spiralis (400 larvae) on the 7th day of treatment. T. spiralis infection significantly inhibited lymphocyte subpopulations from 5 to 25 days postinfection (dpi). L. fermentum CCM7421 and L. plantarum 17 L/1 restored the CD4+ T cell numbers in the epithelium and lamina propria at the control level from 11 dpi. All strains stimulated the CD8+ T cells numbers in infected mice, which were restored in the lamina propria on 11 dpi and in the epithelium only on 32 dpi. B cells (CD19+ ) inhibition after T. spiralis infection was not affected by treatment till 25 dpi. CONCLUSIONS: The strain-specific immunomodulatory effect of tested bacteria was confirmed. L. fermentum CCM7421 and L. plantarum 17 L/1 showed the greatest immunomodulatory potential on CD4+ and CD8+ T lymphocytes in trichinellosis. E. faecium CCM8558 and E. durans ED26E/7 activated only CD8+ T cells in the lamina propria. SIGNIFICANCE AND IMPACT OF THE STUDY: Positive modulation of the gut lymphocyte immunity in T. spiralis infection with bacterial strains showed their beneficial effect with the host's antiparasitic defence.

Susceptibility to Bacteriocins of Multiresistant, mecA Gene Possessing Staphylococcus pseudintermedius Strains from Lesions on Dogs in Vojvodina (Serbia).

Aims: Staphylococci are considered commensal organisms; however, they can also cause diseases in animals. The species Staphylococcus pseudintermedius was originally isolated from the nares and anal mucosa of healthy dogs; nowadays, the incidence of methicillin-resistant S. pseudintermedius strains in dogs has increased, and this species has also become the most common cause of canine skin lesions. S. pseudintermedius were tested for their susceptibility to bacteriocins to show the potential of bacteriocins to eliminate/reduce S. pseudintermedius as a causative agent. Material and Methods: In this study, S. pseudintermedius were isolated from skin lesions on dogs of various breeds and ages in the Vojvodina region (Serbia) in the framework of our international co-operation. Results: S. pseudintermedius strains were identified using matrix-assisted laser desorption ionization time-of-flight mass spectrometry, and the species allocation was confirmed by genotypization and corroborated using phenotyping tests. The strains were multiresistant, involving methicillin-resistance. In addition, the mecA gene was detected in S. pseudintermedius strains, confirming the presence of a genetic feature for methicillin resistance. S. pseudintermedius strains produced large amounts of the enzymes alkaline phosphatase and acid phosphatase; they were low-grade biofilm forming (0.1 ≤ A570 < 1.0), except S. pseudintermedius SPs1. All strains were susceptible to gallidermin (inhibition activity up to 204,800 arbitrary unit [AU]/mL); however, they were mostly resistant to enterocins. However, biofilm-forming S. pseudintermedius SPs1 was susceptible to enterocins (200 AU/mL). Conclusion: Establishing the susceptibility of multiresistant and mecA gene-possessing S. pseudintermedius strains to gallidermin is an innovative, original result; it provides a new opportunity for preventing/eliminating infection caused by those agents.

Antimicrobial Susceptibility to Natural Substances of Campylobacter jejuni and Campylobacter coli Isolated from Italian Poultry.

Campylobacter spp. isolated from poultry are a major public health concern. Antimicrobial resistance is increasing in general, which is associated with limited treatment of diseases in animal husbandry and in human as well. The use of natural substances (enterocins and phytoadditives) seems to be a promising alternative, either in the prevention or treatment of the gastrointestinal tract infections. A total 28 broiler carcasses from Italian poultry were sampled and 39 Campylobacter strains were isolated. Twenty-four isolates were identified as Campylobacter jejuni and 15 strains were identified as Campylobacter coli by polymerase chain reaction. All Campylobacter strains were determined to be resistant to nalidixic acid, ciprofloxacin, tetracycline (E-test), cefotaxim, and ampicillin using the disk diffusion method. Interestingly, the study revealed multidrug resistance of the Campylobacter strains; however, the strains were susceptible to natural substances, such as enterocins, oregano, and sage. Eighty-five percent of the Campylobacter strains were susceptible to at least one enterocins, and 77% of the strains were susceptible to enterocin (Ent) 9296, 69% were susceptible to Ent EM41, and 69% were susceptible to Ent A(P). Sage inhibited the growth of 38% of C. jejuni strains and 53% C. coli strains, whereas oregano inhibited the growth of 50% of the C. jejuni strains and up to 67% C. coli strains. Owing to the One health concept, application of enterocins and herbal extracts is a more ecological approach for preventing bacterial contamination during production and processing of poultry, which also leads to the protection of human health.

Thymol in fattening rabbit diet, its bioavailability and effects on intestinal morphology, microbiota from caecal content and immunity.

To our knowledge, no study has been carried out to evaluate the effects of thymol sustained administration on gut health and immune response in terms of its bioavailability in the rabbit organism. A total of 48 rabbits were randomly divided at 35 days of age into two dietary treatment groups (C/control or T/thymol at 0.025% addition). Thymol was added for 21 days and then withdrawn for 7 days. Thymol content in faeces (p < 0.001) and caecal content (p < 0.05) was significantly higher than in plasma during the thymol addition and withdrawal (2442 ± 451.4, 881.9 ± 231.3 ng/g DM and 46.2 ± 28.4 ng/ml, respectively; 149.5 ± 40.54, 45.76 ± 12.44 ng/g DM and 2.73 ± 0.45 ng/ml, respectively). Increasing of villi height to crypt depth ratio in small intestinal wall (p < 0.01), phagocytic activity in blood (p < 0.0001) and lactic acid bacteria in caecal appendix (p < 0.01) and faeces (p < 0.05) was still presented after withdrawn of thymol. The thymol at this concentration demonstrated its biological properties and was able to positively affect gut health and immune response of rabbits.

Effect of enterocin M and durancin ED26E/7 supplementation on blood parameters, immune response and jejunal morphometry in rabbits.

Natural feed additives application in rabbit nutrition can help to control and prevent digestive disturbances and improve gut health and immunity around the critical weaning period. While probiotics are frequently used in rabbits, in vivo administration of bacteriocins is often limited. Therefore, the present study evaluates the effect of enterocin EntM, durancin EntED26E/7 and their combination on serum biochemistry, phagocytic activity and jejunal morphometry of rabbits. Eighty rabbits (aged 35 days, meat line M91, both sexes) were divided into experimental groups E (EntM; dose 50 µl/animal/day, activity 25,600 AU/ml), D (EntED26E/7; 50 µl/animal/day, 12,800 AU/ml), E + D (50 µl EntM + 50 µl EntED26E/7 /animal/day) and control group (C). Additives were administrated in drinking water for 21 days. Both enterocins positively influenced tested serum parameters, with emphasis on durancin EntED26E/7 administration, alone and/or in combination with EntM. Increased total proteins (E, D: p < 0.001), urea (D: p < 0.001), albumin (D: p < 0.05) and triglycerids (E, D, E+D: p < 0.001) were found. Hypocholesterolaemic effect of both additives was recorded (p < 0.001), with the lowest HDL concentration in E + D. The most of tested hepatic enzymes were positively influenced by enterocins combination (E + D; p < 0.001). The lowest AST was noted in group D (p < 0.001). Mineral profile was also improved (p < 0.001), with the highest values in D. Oxidative stress, was not evoked during enterocins application. Both additives showed a tendency to improve phagocytic activity (prolonged effect of EntED26D/7; D, E+D: p < 0.05) and jejunal morphometry parameters (increased villus cut surface; E, D, E+D; p < 0.001). Diet supplementation with EntM and mostly with EntED26E/7 can improve serum biochemistry, phagocytic activity and jejunal morphometry.