In naturally occurring bovine mastitis, effects of infection depend on the host inflammatory response, including the effects of secreted cytokines. Knowledge about the inflammatory and regulatory cytokines in milk cells of free-stall barn dairy cows and in naturally occurring mastitis is lacking as most studies focus on induced mastitis. Hereby, the aim of the study was to determine inflammatory and regulatory cytokines in the milk of dairy cows with subclinical and clinical mastitis. The following examinations of milk samples were performed: differential counting of somatic cells (SCC), bacteriological examination, and immunocytochemical analysis. Mean SCC increased in subclinical and clinical mastitis cases. The number of pathogenic mastitis-causing bacteria on plates increased in subclinical mastitis cases but decreased in clinical mastitis. The inflammatory and regulatory markers in the milk cells of healthy cows showed the highest mean cell numbers (%). In mastitis cases, immunoreactivity was more pronounced for IL-4, IL-6, IL-12, IL-13, IL-17A, TNF-α, and IFN-γ. Data about subclinical and clinical mastitis demonstrate inflammatory responses to intramammary infection driven by IL-1α, IL-4, and IL-17A. Moreover, the host defense response in mastitis is characterized by continuation or resolution of initial inflammation. IL-12 and INF-γ immunoreactivity was recognized to differ mastitis cases from the relative health status.

The aim of the study was (1) to compare the antimicrobial activity of essential oils (EOs) obtained from leaves and inflorescences of Monarda media, Monarda didyma and Monarda citriodora found in different phenological stages of development, (2) to examine the inhibition of microbial growth by Monarda EOs in O/W emulsions. Thymol, p-cymene and carvacrol were the main constituents in Monarda EOs. The strongest antimicrobial activity were obtained from the leaves of Monarda EOs in the flowering phase of the development. M. media EO fulfilled the criterion of the preservative effectiveness test for all tested bacteria and fungi, while M. didyma and M. citriodora EOs does not meet criterion for Gram-negative bacteria. M. media EO can be an effective candidate for a natural cosmetic preservatives and finally create self-preserving system in O/W emulsion, while M. didyma and M. citriodora EOs can only reduce concentration of synthetic preservatives in O/W emulsions.

Microorganisms thriving in poultry bedding materials during their exploitation are involved in the development of several diseases and disfunctions of animals. They can also contaminate food products and pose risks to the environment and human health. This study provides an analysis of dynamics and diversity in microbiological contamination observed during the exploitation of poultry bedding materials containing parts of medicinal plants: Satureja hortensis, Origanum vulgare, Melissa officinalis, Salvia officinalis, and Thymus vulgaris, compared with standard types of beddings: straw chaff and straw pellets. The research was carried out in two 42-day experimental cycles involving in total 2400 broiler chickens. Each week, the total count of mesophilic bacteria, fungi and yeasts, the presumptive presence and count of Staphylococcus sp., Escherichia sp., Listeria sp., Salmonella sp., and Candida sp. were determined by culturing on selective media, along with pH and moisture measurements. After 35 days of the experiment, a reduction of the total count of mesophilic bacteria above 1 log compared to the control (11.86 vs. 13.02 log CFU/g) was observed. As the count of yeasts decreased after 21 days, an increase in the total count of bacteria was reported, which indicates a strong competition between microorganisms. The results improve our understanding of the temporal effects of using materials containing parts of medicinal plants on the microbial contamination in poultry litter.

Common valerian is a medicinal plant. The underground organs of this species are used as a mild sedative and sleeping aid. Poland is one of the largest producers of this raw material in Europe, with local cultivar ‘Lubelski’ as a primary cultivated form. Although valerian is the subject of more or less deliberate selection carried out by farmers, it is still genetically unstable. The aim of this study was to determine the diversity of the ‘Lubelski’ cultivar originating from four regions of Poland (forms: L1–L4) in relation to wild-growing populations of the species. The plants were assessed in terms of the mass of underground organs and the content of valerenic acids and essential oils (EOs). The content of valerenic acids was determined using HPLC, whereas the content of EOs was determined using hydrodistillation. The composition of EOs was assessed using GC-MS GC-FID. The ploidy level of the analyzed objects was determined as well. Wild-growing populations (diploids) were characterized by lower masses of underground organs and lower contents of valerenic acid than cultivated forms (tetraploids). However, they produced higher contents of EOs. All the cultivated forms were strongly diversified with respect to the analyzed traits, including the mass of the roots (CV 49–75%), the content of valerenic acids (CV 18–55%), and the content of EOs (CV 28–57%). A total of 44 compounds were identified in the EOs. The dominant compound of both wild-growing populations and the ‘Lubelski’ forms were: α-fenchene, bornyl acetate, and valerenal. Among ‘Lubelski’ forms, the most interesting seems to be the L2 form, which was characterized by a relatively high yield and high content of valerenic acids and EOs. Thus, it appears to be a promising source of objects for further valerian cultivar improvement.

Monarda fistulosa L. above-ground organs, collected at three phases of plant phenology, were investigated as potential raw materials for application in the food industry. They were evaluated regarding essential oil (EO) content, composition, and antimicrobial activity, as well as characteristics of phenolic fractions and antioxidant properties, which may determine health benefits and potential use in food preservation. The dominant constituent of leaf EO was carvacrol. In the inflorescence EO carvacrol content was especially high at the full flowering phase (45.12%), while during the fruit setting phase its content was lower than that of p-cymene (39.75%) and thymoquinone (25.04%). In the agar dilution test, leaf and inflorescence EOs inhibited the growth of the six tested microorganisms at the concentration range of 0.156–0.625 µL/mL. Leaves collected at the vegetative phase of plant growth were characterised by the highest content of rosmarinic acid and didymin. Inflorescences harvested during the flowering of plants were rich in linarin. Flavonoid content was highly correlated with antioxidant activity of extracts. Due to these properties, M. fistulosa extracts and essential oils could be used in the food industry as natural preservatives or antioxidants, thereby contributing to the development of safer and more sustainable food products.