Lenka Kuželová

Local poultry breeds represent an essential component of agricultural biodiversity and play an important role in ensuring the resilience of livestock production systems under changing environmental conditions. The Slovak national chicken breed Oravka is a dual-purpose genotype adapted to mountain and sub-mountain production environments and classified as an endangered genetic resource. The conservation of this breed therefore requires integration of traditional breeding programmes with modern reproductive biotechnologies. The present literature review summarises the origin, breeding characteristics and adaptive potential of the Oravka breed and provides a comprehensive overview of current ex situ conservation strategies based on cryopreservation of reproductive and stem cells. Special attention is devoted to the cryopreservation of primordial germ cells, mesenchymal stem cells and rooster spermatozoa, which represent key biological material stored within national gene bank infrastructure. Differences in cryosurvival between blastodermal cells and germline stem cells are discussed together with methodological limitations of avian embryo cell preservation. The review highlights the importance of combining in situ and ex situ conservation approaches and emphasises the role of poultry gene banks as strategic tools for safeguarding genetic diversity under climate change conditions. The Oravka breed represents a valuable model for integrated conservation strategies linking biodiversity protection, reproductive biotechnology and sustainable poultry production in Europe.

Capsaicin, the main pungent capsaicinoid of Capsicum species, is often described as either an antioxidant or a pro-oxidant compound. This binary view is useful but does not fully explain its effects on cellular redox homeostasis. The response to capsaicin depends on dose, exposure time, cell type, metabolic state, mitochondrial function, antioxidant capacity, and TRPV1 expression. Capsaicin can modulate reactive oxygen species (ROS) production through TRPV1-dependent calcium signaling, but also through TRPV1-independent effects on plasma and mitochondrial membranes. These mechanisms influence mitochondrial bioenergetics, membrane potential, lipid peroxidation, and redox-sensitive signaling. Moderate ROS formation may support adaptive responses, including Nrf2 activation, mitochondrial quality control, and cellular stress tolerance. In contrast, persistent or excessive ROS accumulation may promote mitochondrial dysfunction, apoptosis, and oxidative cell death. Evidence for capsaicin-associated ferroptosis is emerging, particularly through changes in lipid peroxidation, glutathione availability, GPX4 activity, and SLC7A11 expression or activity, but remains incomplete in many models. This review summarizes current evidence on capsaicin-mediated ROS regulation, mitochondrial stress, TRPV1-dependent and TRPV1-independent mechanisms, ferroptosis-related pathways, and methodological challenges in oxidative stress assessment.

Applicability of?cryopreserved insemination doses is?dependent on?the quality of?the semen after thawing. The aim of?the study was to?check the options of?new markers for the assessment of?sperm quality to?predict their fertilisation ability. ...

Cryopreservation plays a critical role in animal breeding and the conservation of endangered species, but it often compromises sperm characteristics such as morphology, motility, and viability due to oxidative stress. This study explores the antioxidative effect of Mito-Tempo (MT) and Berberine (BER) to enhance post-thaw sperm quality in rabbits. Pooled rabbit sperm samples were supplemented with different concentrations (0.0, 0.5, 5, 10, 50 µmol/L) of MT and BER. Sperm motility was evaluated using computer-assisted semen analysis, while viability, apoptosis, reactive oxygen species (ROS) levels, acrosome integrity, and mitochondrial function were assessed through flow cytometry. The results revealed that MT at 5 and 10 µmol/L and BER at 10 µmol/L significantly improved total and progressive motility, mitochondrial activity, and sperm viability compared to the control group. Furthermore, 10 µmol/L BER enhanced acrosome integrity, while both 5 µmol/L MT and 10 µmol/L BER effectively reduced ROS levels and apoptosis. This study is the first to demonstrate the protective effects of MT and BER on rabbit sperm during cryopreservation. By mitigating oxidative stress and reducing apoptosis, these antioxidants markedly improved post-thaw sperm quality, positioning MT and BER as promising agents for improving sperm cryosurvival.

Plant dietary lipids remain one of the most intriguing and complex classes of biological molecules. Among them, medium-chain triglycerides (MCTs) have garnered recognition for their unique physico-chemical properties and potential health benefits. Despite their classification as saturated fats, they stand apart from other saturated fatty acids due to their distinctive characteristics, positioning them as a valuable component in nutrition. While traditional dietary fats primarily contain long-chain triglycerides (LCTs), MCTs consist of medium-chain fatty acids (MCFAs), naturally found in coconut and palm oils. The structural dissimilarity grants MCTs advantageous attributes, encompassing rapid digestion and absorption, providing a swift source of energy. Importantly, MCT oil derived from coconuts surpasses traditional coconut oil in efficiency and speed of energy conversion due to its higher concentration of readily metabolizable MCTs, making it a superior choice in human nutrition. This comprehensive study delves deeply into the potential of coconut-derived MCT oil, illuminating its chemical constituents, production from coconut oil, distinctive physical and chemical properties, and metabolic characteristics. Additionally, it highlights a range of potential biological activities of the oil, including its efficacy in managing gastrointestinal disorders and promising roles in anticancer, neuroprotective, and antimicrobial effects. The report also discusses the extensive applications of MCT oil across diverse industrial and technological sectors, as well as its utilization in structured lipids, oleogels, and as a carrier for capsaicin. Addressing safety concerns and providing dosage guidelines, this paper emphasizes MCT oil as an alternative to coconut oil in various applications, offering a holistic perspective on its benefits.

Cryopreservation reduces the antioxidant activity of spermatozoa and makes them more sensitive to damage caused by reactive oxygen species (ROS). The addition of antioxidants to the freezing medium could prevent cryo-damage by mitigating the harmful effects of ROS and, thus, protecting the spermatozoa. This study aimed to evaluate the effect of ellagic acid (EA) on the rabbit sperm traits after freezing-thawing. Semen samples collected from New Zealand White rabbit males were cryopreserved in a BotuCrio freezing medium (Nidacon, Sweden) supplemented with different concentrations of ellagic acid (EA at 0, 0.5, 1.5 and 2.5 mM) using the manual slow freezing procedure. After thawing, sperm motility parameters were evaluated by CASA. The parameters of viability (DRAQ7), apoptosis (Yo-Pro-1), acrosome integrity (peanut agglutinin; PNA), intracellular ROS (Cell-ROX) and mitochondrial activity (MitoTracker) were evaluated by flow cytometry. EA added to the freezing medium at all concentrations led to a significant reduction (P < 0.05) in intracellular ROS in frozen-thawed sperm cells. However, this effect was not reflected in motility parameters. Semen supplemented with 1.5 mM EA also yielded a lower proportion of apoptotic cells compared to the control group. In conclusion, EA supplementation of semen extender demonstrated its antioxidative properties protecting spermatozoa against oxidative damage during cryopreservation. Nevertheless, to draw a definitive conclusion regarding the effect of EA on spermatozoa functionality, additional research is necessary.