This study investigated 960 Slovak and Czech spotted cattle from four different conventional (non-organic) dairy herds located in Eastern Slovakia and Czechia during early lactation (14–100 days after calving). Dairy cows were examined clinically; milk from fore-stripping of each udder quarter was subjected to sensory examination and assessed by the California mastitis test (CMT), and laboratory analyses of bacterial pathogens in milk, including virulence factors, were conducted. Positive CMT scores (1–3) for one or more quarters were detected in 271 (28.2%) of the examined animals. Out of 230 infected milk samples, representing 24.0% of all dairy cows, staphylococci (59.1% of positive findings) were the most commonly isolated organisms, followed by E. coli (11.3%), streptococci Str. uberis (9.1%) and Str. agalactiae (3.4%), and enterococci (6.1%). From 136 isolates of S. aureus (38 isolates) and non-aureus staphylococci (NAS; 98 isolates), virulence factors and their resistance to 14 antimicrobials were detected using the disk diffusion method, with PCR detection of the methicillin resistance gene, mecA. An increased incidence of clinical and chronic forms of mastitis has been reported in mastitic cows in which staphylococci, especially S. aureus and NAS (S. chromogenes, S. warneri, and S. xylosus), have been detected and compared to other isolated udder pathogens. From those species, S. aureus and isolates of NAS mentioned above showed multiple virulence factors that are more likely to hydrolyze DNA, hemolysis, produce gelatinase and biofilm, and have multi-drug resistance as compared to other less virulent staphylococci. Generally, the isolated staphylococci showed 77.2% resistance to one or more antimicrobials, in particular to aminoglycosides, β-lactams, macrolides, or cephalosporins. Isolates that showed the ability to form a biofilm were more resistant to more than one antimicrobial than isolates without biofilm production. Multi-drug resistance to three or more antimicrobial classes was recorded in 16 isolates (11.7%), and the presence of the mecA gene was also confirmed in two isolates of S. aureus and two species of NAS.

The aim of this study was to compare an improved bedding composition with conventional straw bedding under farm conditions, regarding its effects on the influence of indicator microorganisms on the hygiene levels of cubicle floors and the occurrence of mastitis in dairy cows. Dairy cows were housed in newly built stalls divided into two parts, each with four subsections, and bedded cubicles arranged in three rows. Five stall subsections from each 9-bedded cubicle were selected for study, and 30 dairy cows were monitored according to the time intervals of bedding treatment for cubicles. In the first subsection (control), the cows were housed in bedded cubicles layered with straw up to a height of 20 cm. Sections 2–5 had alternative bedding (AB) as follows: fresh AB, AB 1 month old, AB 2 months old, and AB 3 months old, which were bedded one day before (fresh) and 1–3 months before the actual observation period, respectively. The alternative bedding per one cubicle consisted of ground limestone (100 kg), water (80 L), recycled manure solids (RMS; 15 kg), and straw (25 kg). After laying, the bedding was treated with a concrete selector to provide strength and sufficient resistance. A total of 180 bedding and 600 quarter milk samples were taken simultaneously from all five monitored subsections for microbiological determination. Comparing classical straw bedding with the alternate bedding showed a stabilizing effect by keeping the bedding thickness up to the floor barrier level, which had a beneficial effect by reducing the level of fecal contamination in the rear of the cubicle. Fecal coliforms and fecal streptococci were found to be reduced in one-day-old bedding as well as after the first, second, and third months. By evaluating the health status of the mammary glands, a positive effect was noted in reducing the occurrence of subclinical mastitis, which was reflected in a reduced number of infected quarters in the group of cows housed in cubicles for three months after use of improved bedding.

In this study, we assessed the effect of humic substances, as an organic supplement in feed, on the fattening performance, meat quality and selected lipid and mineral parameters from the blood serum of rabbits. Three groups of the Giant Saris rabbit breed were used (one control and two experimental), with 16 animals per group. The animals in the control group were fed a standard pellet diet, the humic substances group received a basal diet supplemented with 5% humic substances, and the third group received a basal diet with 5% humic–fatty substances preparation during the entire experiment (from 35 to 120 days of age). There were 85 days of fattening; then, the rabbits were slaughtered. In the group supplemented with 5% humic–fatty substances addition, we noticed a higher final weight (p < 0.05) and higher average daily gains compared to the control group at the end of the fattening period, at 120 days of age. On the other hand, a slightly lower final weight (p > 0.05) in the group supplemented with humic substances was found compared to the control group. In the comparison of the individual parameters of the meat quality in rabbits, we observed a positive effect in the reduction in the intramuscular fat content and the lipid parameters as well as a lower total cholesterol from the blood serum in both supplemented groups. Regarding the mineral parameters, we observed elevated blood serum values of calcium and phosphorus in both experimental groups. The addition of humic–fatty substances appears to be the most effective way of supplementing rabbit feed due to the synergistic effect of humates and vegetable oils for their optimal growth development and the production of reduced-fat meat.

Background: Gold nanoparticles (AuNPs) have several beneficial properties that make them effective as intracellular drug carriers, and their potential for various diagnostic and therapeutic applications is gaining recognition. Depending on their size and shape, AuNPs can cross the central nervous system (CNS) through the blood–brain barrier (BBB). In the CNS, they can exert a variety of influences on neuronal and glial cells, which can be both supportive—promoting cell health and function—and cytotoxic, potentially leading to cellular damage. The hypothalamus (HT) is the first region where nanoparticles (NPs) interact, as this neuroendocrine center is particularly sensitive to factors in the systemic circulation due to its function and location. This area is affected by systemic factors, including pro-opiomelanocortin (POMC) neurons, which regulate metabolic function and maintain homeostasis. The activity of mitochondria within these cells influences their response to both external factors and the presence of AuNPs, thereby facilitating a complex interplay between nanoparticle interactions and cellular metabolism in this vital brain region. Aims: This study investigates how AuNPs, at different concentrations and exposure times under in vitro conditions, affect the mitochondrial activity of POMC neurons, aiming to provide a comprehensive understanding of the mechanisms in the HT. Methods: The study investigates the effect of varying gold nanoparticle concentrations on the mitochondrial activity of POMC neurons over treatment periods of 1, 15, 24, and 48 h. Mitochondrial activity was measured using a Seahorse XFp Analyzer to provide high-resolution insights. Additionally, mitochondrial functionality was assessed through the detection of reactive oxygen species (ROS) and cell viability. Results: The findings indicated that the effects of gold nanoparticles on mitochondrial activity depend significantly on their concentration and exposure time. Specifically, exposure leads to an increase in early response systems, the citric acid cycle, and proton efflux, ultimately resulting in the inhibition of mitochondrial function and ATP production in POMC cells. This disruption may affect hypothalamic regulation and energy metabolism.

This study focuses on the development of antibacterial polymer nanocomposites based on biologically synthesized silver nanoparticles (AgNPs) and polyvinyl alcohol (PVA) as the polymer matrix. Silver nanoparticles were produced using an aqueous extract from dried Lavandula angustifolia (lavender) leaves, which proved to be highly effective in reducing silver ions and stabilizing the resulting nanoparticles. The synthesized AgNPs were characterized by FTIR, UV-Vis, TEM, SEM, and DLS analyses. The nanoparticles were predominantly spherical, with more than 70% having diameters below 20 nm. Subsequently, AgNPs were incorporated into the PVA matrix via an ex situ approach to fabricate nanocomposite fibers and thin films. SEM analysis confirmed successful incorporation and uniform distribution of AgNPs within the polymer structures. The nanocomposites exhibited pronounced antibacterial activity against both Gram-positive (Staphylococcus aureus, Staphylococcus haemolyticus, Streptococcus uberis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria, with nanofibers demonstrating superior performance compared to thin films. These findings highlight the potential of lavender-extract-mediated AgNPs as sustainable functional fillers for the fabrication of eco-friendly antibacterial materials applicable in biomedical and food packaging fields.

The sex of crocodilians is determined by the temperature to which the eggs, and hence the developing embryo are exposed during critical periods of development. Temperature-dependent sex determination is a process that occurs in all crocodilians and numerous other reptile taxa. The study of artificial incubation temperatures in different species of crocodiles and alligators has determined the specific temperature ranges that result in altered sex ratios. It has also revealed the precise temperature thresholds at which an equal number of males and females are generated, as well as the specific developmental period during which the sex of the hatchlings may be shifted. This review will examine the molecular basis of the sex-determination mechanism in crocodilians elucidated during recent decades. It will focus on the many patterns and theories associated with this process. Additionally, we will examine the consequences that arise after hatching due to changes in incubation temperatures, as well as the potential benefits and dangers of a changing climate for crocodilians who display sex determination based on temperature.