No abstract

Male subfertility is a global issue in human reproduction as well as in animal reproduction. Bacterial infection and semen contamination are still widely overlooked. As the collection of ejaculates is not a sterile process, it is necessary to add antimicrobial agents to avoid a possible depreciation of semen samples. As traditionally used antibiotics have been questioned because of an ever-increasing bacterial resistance, natural bioactive molecules could offer an alternative because of their antibacterial and antioxidant properties. As such, we decided to compare the effects of selected natural biomolecules (resveratrol-RES, quercetin-QUE and curcumin-CUR) with routinely used antibiotics in animal biotechnologies (penicillin-PEN, gentamicin-GEN and kanamycin-KAN) on the rabbit sperm vitality in the presence of Enterococcus faecalis. Changes in the sperm structural integrity and functional activity were monitored at 0, 2, 4 and 6 h. Computer-assisted sperm analysis (CASA) was used for the assessment of spermatozoa motility. Production of reactive oxygen species (ROS) was evaluated using chemiluminiscence, while the mitochondrial membrane potential (ΔΨm) was examined using the JC-1 dye. Finally, the sperm chromatin dispersion (SCD) test was used to assess DNA fragmentation, and changes to the membrane integrity were evaluated with the help of annexin V/propidium iodide. The motility assessment revealed a significant sperm motility preservation following treatment with GEN (p < 0.001), followed by PEN and CUR (p < 0.01). QUE was the most capable substance to scavenge excessive ROS (p < 0.001) and to maintain ΔΨm (p < 0.01). The SCD assay revealed that the presence of bacteria and antibiotics significantly (p < 0.05) increased the DNA fragmentation. On the other hand, all bioactive compounds readily preserved the DNA integrity (p < 0.05). In contrast to the antibiotics, the natural biomolecules significantly maintained the sperm membrane integrity (p < 0.05). The microbiological analysis showed that GEN (p < 0.001), KAN (p < 0.001), PEN (p < 0.01) and CUR (p < 0.01) exhibited the strongest antibacterial activity against E. faecalis. In conclusion, all selected biomolecules provided protection to rabbit spermatozoa against deleterious changes to their structure and function as a result of Enterococcus faecalis contamination. Therefore, administration of RES, QUE and/or CUR to rabbit semen extenders in combination with a carefully selected antibacterial substance may be desirable.

Metschnikowia pulcherrima is common yeast on grape berries and can grow on special cultivation media with iron (e.g. FeSO4.7H2O) (max. 0.02 g/L) to produce reddish (maroon) pigment pulcherrimin. Many studies confirm that pulcherrimin has antimicrobial activity against postharvest pathogens, microscopic fungi and other yeast species. In this study, two strains of M. pulcherrima, isolated from grapes and identified by MALDI-TOF mass spectrometry, were used : VML and CBS 610NT. Sixteen yeast species: Aureobasidium (1), Candida (5), Hanseniaspora (1), Kregenvanrija (1), Pichia (2), Rhodotorula (2), Saccharomyces (1), Zygosaccharomyces (2) and Wickerhamomyces (1) were selected to test the antimicrobial capacity of these two M. pulcherrima strains. The results showed CBS 610NT had a stronger ability than VML to inhibit the tested yeasts. Among the yeast, Candida spp. and Pichia manshurica were the most sensitive to the pigment pulcherrimin.

The aim of the study was to evaluate the antimicrobial effect of sage and rosemary essential oils (EO) on microbiota of fresh chicken breast. Sample treatments were stored without packaging, vacuum-packaged, vacuum-packaged with EDTA 1.5% v/w, sage and rosemary EO treatment 0.2% v/w. Assessment of food quality was done by anaerobic plate count (APC), and Enterobacteriaceae, lactic acid bacteria (LAB) and Pseudomonas spp. counts a period of 16 days of storage at 4 ± 0.5 °C. Bacterial species were identified with a MALDI TOF MS Biotyper. Antimicrobial activity of isolates against both EO were tested. The APC varied from 2.97 log CFU/g to 6.81 log CFU/g, LAB from 2.35 log CFU/g to 3.36 log CFU/g and Enterobacteriaceae from 0.00 log CFU/g on day 0 to 4.77 log CFU/g with the highest counts on day 16 and in control unpackaged samples. Pseudomonas spp. was found only on days 0, 4, 8, and 12, with counts from 0.00 log CFU/g on day 16 to 2.89 log CFU/g on day 4 in control unpackaged samples. APC were represented by Staphylococcus and Kocuria, LAB with Lactobacillus and Enterobacteriaceae with Buttiauxella, Escherichia, Hafnia, Serratia and Yersinia. The Pseudomonas genus was represented by ten species. The best antimicrobial effect on APC, Enterobacteriaceae, LAB and Pseudomonas was achieved by application of EO. The results suggest the potential use of Salvia officinalis L. and Rosmarinus officinalis L. EOs as natural food preservatives and potential sources of antimicrobial ingredients in the food industry.

* Obtained yield of evaporated ethanolic extracts in g, SSF-Solid state fermentation Test microorganisms Four strains of microorganisms were tested in this research. Two Gram-negative bacteria include Klebsiella pneumoniae CCM 2318, Enterobacter aerogenes CCM 2531, two Gram-positive bacteria include Staphylococcus aureus subsp. aureus ser. a5 CCM 2461, Bacillus thiringiensis CCM 19. All tested strains were collected from the Czech Collection of Microorganisms. The bacterial suspensions were cultured in the nutrient broth (Imuna, Slovakia) at 37 °C, expect Bacillus thiringiensis which was cultivated at 30°C. In this paper the antimicrobial activity of 1 year old crude ethanolic extracts obtained from Cordyceps sinesis, Laricifomes officinalis, Oudemansiella mucida and Coprinus comatus were investigated. The antimicrobial activities of extracts against two Gram-positive bacteria (Bacillus thuringiensis, Staphylococcus aureus) and two Gram-negative bacteria (Klebsiella pneumoniae, Enterobacter aerogenes) were determined by disk diffusion and microbroth dilution method according by EUCAST in 96-well microplates. Microorganisms were obtained from Czech Collection of Microorganisms. Absorbance after and before the experiment were substracted, converted to binary system and obtained values to Probit analysis were used. Not all macromycetes ethanolic extracts showed antimicrobial activity against tested bacteria. Antimicrobial activity determined by MIC methodology showed extracts from Oudemansiella mucida, Cordyceps sinesis, Coprinus comatus in the tested range. Conversely, the best antimicrobial activity tested by disc diffusion methods showed extract from Laricifomes officinalis. Equally, more better studying of antimicrobial activity in these mushrooms will needed. ARTICLE INFO