Modulation of Intestinal Histology by Probiotics, Prebiotics and Synbiotics Delivered In Ovo in Distinct Chicken Genotypes

The aim of the study was to determine the effect of probiotics, prebiotics and synbiotics administered in ovo on selected morphological parameters of the small intestine (duodenum, jejunum, ileum) in broiler chickens (Ross 308) and native chickens (Green-legged Partridge, GP). On the 12th day of embryonic development (the incubation period), an aqueous solution of a suitable bioactive substance was supplied in ovo to the egg’s air cell: probiotic—Lactococcus lactis subsp. cremoris (PRO), prebiotic—GOS, galacto-oligosaccharides (PRE) or symbiotic—GOS + Lactococcus lactis subsp. cremoris (SYN). Sterile saline was injected into control (CON) eggs. After hatching, the chicks were placed in pens (8 birds/pen, 4 replicates/group) and housed for 42 days. On the last day of the experiment, all birds were individually weighed and slaughtered. Samples for histological analysis were taken directly after slaughter from three sections of the small intestine. In samples from the duodenum, jejunum and ileum, the height and width of the intestinal villi (VH) were measured and their area (VA) was calculated, the depth of the intestinal crypts (CD) was determined, the thickness of the muscularis was measured and the ratio of the villus height to the crypt depth (V/C) was calculated. On the basis of the obtained data, it can be concluded that the applied substances administered in ovo affect the production parameters and intestinal morphology in broiler chickens and GP. The experiment showed a beneficial effect of in ovo stimulation with a prebiotic on the final body weight of Ross 308 compared to CON, while the effect of the administered substances on the intestinal microstructure is not unequivocal. In GP, the best effect in terms of villi height and V/C ratio was found in the in ovo synbiotic group. Taking into account the obtained results, it can be concluded that chickens of different genotypes react differently to a given substance; therefore, the substances should be adapted to the genotype.

Survival of Microencapsulated Lactococcus Lactis Subsp. Lactis R7 Applied in Different Food Matrices

Survival of Lactococcus lactis subsp. lactis R7 microencapsulated with whey and inulin was analyzed when applied in blueberry juice, milk and cream. For 28 days, cell viability was evaluated for storage (4°C), simulated gastrointestinal tract (GIT) and thermal resistance. All matrices described high cell concentration when submitted to GIT (11.74 and 12 log CFU.mL-1), except for blueberry juice. The thermal resistance analysis proved the need for microencapsulation, regardless of the food matrix. The results indicate that L. lactis R7 microcapsules have potential for application in different matrices and in the development of new probiotic products by thermal processing.

Donkey Milk Fermentation by Lactococcus lactis subsp. cremoris and Lactobacillus rhamnosus Affects the Antiviral and Antibacterial Milk Properties

Background: Milk is considered an important source of bioactive peptides, which can be produced by endogenous or starter bacteria, such as lactic acid bacteria, that are considered effective and safe producers of food-grade bioactive peptides. Among the various types of milk, donkey milk has been gaining more and more attention for its nutraceutical properties. Methods: Lactobacillus rhamnosus 17D10 and Lactococcus lactis subsp. cremoris 40FEL3 were selected for their ability to produce peptides from donkey milk. The endogenous peptides and those obtained after bacterial fermentation were assayed for their antioxidant, antibacterial, and antiviral activities. The peptide mixtures were characterized by means of LC-MS/MS and then analyzed in silico using the Milk Bioactive Peptide DataBase. Results: The peptides produced by the two selected bacteria enhanced the antioxidant activity and reduced E. coli growth. Only the peptides produced by L. rhamnosus 17D10 were able to reduce S. aureus growth. All the peptide mixtures were able to inhibit the replication of HSV-1 by more than 50%. Seventeen peptides were found to have 60% sequence similarity with already known bioactive peptides. Conclusions: A lactic acid bacterium fermentation process is able to enhance the value of donkey milk through bioactivities that are important for human health.

Autochthonous Enterococcus durans PFMI565 and Lactococcus lactis subsp. lactis BGBU1–4 in Bio-Control of Listeria monocytogenes in Ultrafiltered Cheese

Nowadays, consumers are interested in cheese produced without chemical additives or high-temperature treatments, among which, protective lactic acid bacteria (LAB) cultures could play a major role. In this study, the aims were to isolate, identify and characterize antilisterial LAB from traditionally produced cheese, and utilize suitable LAB in cheese production. Among 200 isolated LAB colonies, isolate PFMI565, with the strongest antilisterial activity, was identified as Enterococcus durans. E. durans PFMI565 was sensitive to clinically important antibiotics (erytromicin, tetracycline, kanamycin, penicillin, vancomycin) and had low acidifying activity in milk. E. durans PFMI565 and the previously isolated bacteriocin producer, Lactococcus lactis subsp. lactis BGBU1–4, were tested for their capability to control Listeria monocytogenes in experimentally contaminated ultrafiltered (UF) cheeses during 35 days of storage at 4 °C. The greatest reductions of L. monocytogenes numbers were achieved in UF cheese made with L. lactis subsp. lactis BGBU1–4 or with the combination of L. lactis subsp. lactis BGBU1–4 and E. durans PFMI565. This study underlines the potential application of E. durans PFMI565 and L. lactis subsp. lactis BGBU1–4 in bio-control of L. monocytogenes in UF cheese.