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.

Development and evaluation of a fish feed mixture containing the probiotic Lactiplantibacillus plantarum prepared using an innovative pellet coating method

Introduction

Due to the intensification of fish farming and the associated spread of antimicrobial resistance among animals and humans, it is necessary to discover new alternatives in the therapy and prophylaxis of diseases. Probiotics appear to be promising candidates because of their ability to stimulate immune responses and suppress the growth of pathogens.

Methods

The aim of this study was to prepare fish feed mixtures with various compositions and, based on their physical characteristics (sphericity, flow rate, density, hardness, friability, and loss on drying), choose the most suitable one for coating with the selected probiotic strain Lactobacillus plantarum R2 Biocenol™ CCM 8674 (new nom. Lactiplantibacillus plantarum). The probiotic strain was examined through sequence analysis for the presence of plantaricin- related genes. An invented coating technology based on a dry coating with colloidal silica followed by starch hydrogel containing L. plantarum was applied to pellets and tested for the viability of probiotics during an 11-month period at different temperatures (4°C and 22°C). The release kinetics of probiotics in artificial gastric juice and in water (pH = 2 and pH = 7) were also determined. Chemical and nutritional analyses were conducted for comparison of the quality of the control and coated pellets.

Results and discussion

The results showed a gradual and sufficient release of probiotics for a 24-hour period, from 10⁴ CFU at 10 mi up to 10⁶ at the end of measurement in both environments. The number of living probiotic bacteria was stable during the whole storage period at 4°C (10⁸), and no significant decrease in living probiotic bacteria was observed. Sanger sequencing revealed the presence of plantaricin A and plantaricin EF. Chemical analysis revealed an increase in multiple nutrients compared to the uncoated cores. These findings disclose that the invented coating method with a selected probiotic strain improved nutrient composition and did not worsen any of the physical characteristics of pellets. Applied probiotics are also gradually released into the environment and have a high survival rate when stored at 4°C for a long period of time. The outputs of this study confirm the potential of prepared and tested probiotic fish mixtures for future use in in vivo experiments and in fish farms for the prevention of infectious diseases.

Feeding-Regime-Dependent Intestinal Response of Rainbow Trout after Administration of a Novel Probiotic Feed

Intensive fish farming is associated with a high level of stress, causing immunosuppression. Immunomodulators of natural origin, such as probiotics or phytoadditives, represent a promising alternative for increasing the immune function of fish. In this study, we tested the autochthonous trout probiotic strain L. plantarum R2 in a newly developed, low-cost application form ensuring the rapid revitalization of bacteria. We tested continuous and cyclic feeding regimes with regard to their effect on the intestinal immune response and microbiota of rainbow trout. We found that during the continuous application of probiotic feed, the immune system adapts to the immunomodulator and there is no substantial stimulation of the intestinal immune response. During the cyclic treatment, after a 3-week break in probiotic feeding and the reintroduction of probiotics, there was a significant stimulation of the gene expression of molecules associated with both cellular and humoral immunity (CD8, TGF-β, IL8, TLR9), without affecting the gene expression for IL1 and TNF-α. We can conclude that, in aquaculture, this probiotic feed can be used with a continuous application, which does not cause excessive immunostimulation, or with a cyclic application, which provides the opportunity to stimulate the immunity of trout, for example, in periods of stress.

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.

Beneficial effects of Enterococcus faecium EF9a administration in rabbit diet

<p>Forty-eight rabbits aged five weeks (Hycole breed, both sexes) were divided into experimental (EG) and control (CG) groups, 24 animals in each, and fed a commercial diet with access to water <em>ad libitum</em>. Rabbits in EG had Enterococcus faecium EF9a probiotic strain added to their drinking water (1.0×10⁹ colony forming units/mL 500 μL/d/animal) for 28 d (between 35 and 63 d). The experiment lasted for 42 d. The animals remained in good health condition throughout the experiment, and no morbidity and mortality was noted. There was a higher live weight at 63 d of age (+34 g; <em>P</em>&lt;0.0001), final live weight at 77 d of age (+158 g; <em>P</em>=0.0483), and average daily weight gain between 63 and 77 d of age in the EG group rabbits than in CG group rabbits (+8 g/d; <em>P</em>&lt;0.0001). No significant changes in caecal lactic acid and total volatile fatty acid concentrations, jejunal morphological parameters and phagocytic activity were noted during the treatment. The tested serum parameters were within the range of the reference values. EF9a strain sufficiently established itself in the rabbit’s gastrointestinal tract. At 63 d of age, a significant decrease in coliforms (<em>P</em>&lt;0.05), coagulase-positive staphylococci (<em>P</em>&lt;0.01), pseudomonads (<em>P</em>&lt;0.01) and coagulasenegative staphylococci (CoNS, <em>P</em>&lt;0.001) was noted in the faeces of the EG group rabbits compared to the CG rabbits. Antimicrobial effects of EF9a strain in the caecum against coliforms (<em>P</em>&lt;0.001), CoNS (<em>P</em>=0.0002) and pseudomonads (<em>P</em>=0.0603) and in the appendix (coliforms, <em>P</em>&lt;0.05) were detected.</p>

The Influence of Feed-Supplementation with Probiotic Strain Lactobacillus reuteri CCM 8617 and Alginite on Intestinal Microenvironment of SPF Mice Infected with Salmonella Typhimurium CCM 7205

Alginite is a non-ore raw material arising by fossilization of accumulated organic (algae) and inorganic material, particularly clay, carbonates, quartz, and amorphous modification of silicic acid in the aqueous environment. Humic acids as a component of organic portion of alginite are known for very good buffering ability which allows them to stabilise pH throughout the digestion system of animals, stimulate receptors of the immune system in intestinal villi against pathogenic bacteria, and support proliferation and activity of beneficial bacteria (lactobacilli, bifidobacteria, and similar). Our investigations focused on the influence of a probiotic strain in combination with alginite on intestinal microenvironment of SPF mice infected with Salmonella Typhimurium. The 66 female mice (BALB/c) used in our study were divided to four experimental groups, control NC1, control NC2 (alginite), IC (alginite + Salmonella Typhimurium CCM 7205_NAL), LAB (Lact. reuteri CCM 8617 + alginite + Salm. Typhimurium CCM 7205_NAL). The group supplemented with Lact.reuteri CCM 8617 and alginite showed significant reduction in growth of Salm. Typhimurium in mice faeces at 24 and 72 h (P < 0.001) post infection. The supplementation of additives affected positively also nitrogen, enzymatic, hepatic and energy metabolism of mice. The demonstrable positive influence of additives alleviated the negative impact of Salm. Typhimurium infection on the morphology investigated in the jejunum and ileum of LAB group of mice. The livers of mice treated with both alginite and Lact.reuteri CCM 8617 showed marked reduction of overall inflammation, hepatocyte necrosis and size of typhoid nodules.

Can Enterocin M in Combination with Sage Extract Have Beneficial Effect on Microbiota, Blood Biochemistry, Phagocytic Activity and Jejunal Morphometry in Broiler Rabbits?

Simple Summary

The weaning period is one of the most critical phases in a rabbit’s life, when rabbits are most sensitive to various spoilage agents, often with fatal outcome. Preventing these post-weaning alimentary disturbances and improving gut health through the use of natural substances has become an area of research activity in rabbit nutrition. The possibilities of “in vivo” administration of bacteriocins in rabbits are often limited. Our study focused therefore on improving rabbits’ health using enterocin M and sage extract, alone and also in combination, mainly to determine their effect on the microbiota, phagocytic activity, serum biochemistry, and morphometry of rabbits. The antibacterial effect of both additives was observed in the gastrointestinal tract of rabbits. Several biochemical parameters (increased in total proteins (TPs) using enterocin (Ent) M, reduction of alanine aminotransferase (ALT) using sage and its hypocholesteremic effect alone and in combination with EntM, and improvement of mineral levels) were optimized. All additives, but mostly EntM, showed a tendency to improve the jejunal morphological parameters.

Abstract

The present study investigated the effects of enterocin (Ent) M and sage extract alone and also in combination on the gut microflora, phagocytic activity, blood biochemistry, and morphometry of rabbits. Sixty-four rabbits (aged five weeks, M91 meatline, both sexes) were divided into three experimental groups: E (EntM; 50 µL/animal/day), S (sage; 10 µL/animal/day), and E + S (EntM + sage) groups and control group (C). The additives were administered in drinking water for a period of 21 days. Dietary supplementation of EntM and sage significantly reduced the coliforms (E: p < 0.001; S: p < 0.001; E + S: p < 0.001) in feces, while simultaneous addition of EntM and sage decreased enterococci (E + S: p < 0.0001), lactic acid bacteria (E + S: p < 0.01), and coagulase-positive staphylococci (E + S: p < 0.0001) in the appendix. Sage addition reduced HDL (S: p < 0.001) and LDL cholesterol (S: p < 0.001; E + S: p < 0.001), LDL/HDL ratio (S: p < 0.001; E + S: p < 0.01), and increased urea (S: p < 0.01; E + S: p < 0.001) and creatinine (S: p < 0.001; E + S: p < 0.001) in serum. EntM and sage application, alone or in combination, improve the jejunal morphometry (p < 0.0001) in rabbits.

Genetic admixture in pig population observed by microsatellite markers

Abstract. The aim of presented study was estimation of genetic relationship within and between 3 mentioned pig breeds bred in the Slovak Republic. Genetic variability at 10 microsatellite loci (SW24, SO107, SO068, SW936, sw353, so386, so355, sw72, tnfb, and SO070) was analysed in 412 pigs of Landrace, Yorkshire and Slovak White Improved breeds. Variation amount of each population was measured with average number of alleles per locus, heterozygosities, polymorphism information content (PIC) value were calculated. Phylogenetic trees were constructed by UPGMA. The average number of alleles per locus was 11.5, ranging from 7 (SW72) to 16 (SO068). The Slovak White Improved, Landrace and Yorkshire pig breeds showed out high degree of genetic diversity with mean expected heterozygosities of 0.720, 0.697 and 0.705 respectively. Genetic distance ranged from 0.060 between Yorkshire and Slovak White Improved to 0.203 between Landrace and Slovak White Improved breeds. The scatter diagram from principal component displayed genetic differentiation among all three breeds. A Bayesian method was applied for individual assigning testing. On the base of our results the group of Slovak White Improved population was strongly mixed with Yorkshire breed and the group of all Landrace individuals was presented as enclosed population.

Partial characterization of two ruminal bacteriophages with similar restriction patterns and different capsids morphology

Abstract. Two bacteriophages (F5 and F6) were isolated from lysogenic Streptococcus bovis strains 46/2 and 59/2, respectively, after spontaneous induction. Both bacteriophages produced clear and small plaques (0.1–0.2 mm in diameter) on two host Streptococcus bovis strains (47/3 and 4/1) out of 12 tested. After UV-light induction, clear plaques of 1.0–1.2 mm in diameter were observed. Both bacteriophages were relatively resistant to chloroform, however, their survival in sterilised rumen fluid was not long because their complete inactivation was observed after 18 hours of cultivation in sterilised rumen fluid. Transmission electron microscopy showed great differences in the morphology of particles of these two bacteriophages. The F5 phage had an elongated slightly angular head, of a mean length of 94 nm and width of 50 nm, as well as a 180 nm long and 10–15 nm wide noncontractile flexible tail without a sheath. The bacteriophage F6 had an isometric head of icosahedral shape, 43 nm in diameter, and its noncontractile flexible tail without sheath was about 180–200 nm long and 10–12 nm wide. According to Ackermann's classification both phages belong to Siphoviridae. The genome sizes of both phages, determined by summing the molecular sizes of fragments generated by digestions with EcoRI, PstI, BglII and XbaI, were similar (about 41–43 kb). Restriction analysis of the genomes of these 2 bacteriophages by 8 restriction enzymes showed that SalI, BamHI and BspRI did not cleave the DNAs of these phages. Cleavage of the DNAs with the other five restriction enzymes showed a similar restriction pattern, however, with small differences. It is a curiosity to find two bacteriophages with the same genome size and relatively similar DNA restriction patterns having a different morphology of their capsids.

Effect of monensin sodium on fermentation efficiency in sheep rumen (short communication)

Abstract. The efficiency of rumen fermentation was studied in lambs and wethers using 14 experimental rations with and without monensin sodium. The 7 pairs of rations (the first a control diet, the second a monensin treated one) consisted of hay and concentrate at ratios of 60:40, 40:60, 100:0, 50:50 (lambs), 100:0, 75:25 and 50:50 (wethers), respectively. The molar % of acetic, propionic, butyric and valeric acids were taken into stoichiometric calculations of rumen fermentation. In most of the rations monensin increased rumen fermentation efficiency. Of all lamb and wether rations the highest efficiency was recorded in the monensin treated ones consisting of 40 % hay and 60 % concentrates and 50 % hay and 50 % concentrates, respectively. The high fermentation efficiency was probably due to the lowest methane production observed with these rations. This means that monensin increased the amount of metabolizable energy by decreasing methane energy losses. The increase in fermentation efficiency is associated with a high production of propionic acid and in wethers also with an increase in the gross efficiency of feed conversion.