Earticle

Background: Mitochondrial morphological homeostasis is essential for energy production and developmental competence in preimplantation embryos. While epigenetic modifications, particularly histone acetylation, are primarily recognized as regulators of gene transcription, accumulating evidence suggests that acetylation-dependent signaling also governs mitochondrial biogenesis and quality control. However, how PCAF-mediated acetyltransferase activity specifically modulates mitochondrial morphology during early embryonic development remains unknown. Methods: Porcine parthenogenetic embryos were cultured for seven days in PZM-5 medium. Garcinol (5 μM) was applied from the 4-cell stage to inhibit PCAF activity, and mitochondrial ultrastructure was assessed by transmission electron microscopy using a Bio-HVEM system. Results: Ultrastructural analysis of porcine blastocysts revealed morphologically diverse mitochondrial populations, encompassing spherical, hooded, cap-shaped, ringshaped, horseshoe-shaped, elongated, and shell-like configurations. Mitochondrial fusion predominantly occurred in a side-to-side orientation, with tip-to-tip and side-totip contacts observed less frequently, and these combinatorial fusion states collectively contributed to the morphological heterogeneity of the organelle pool. PCAF inhibition disrupted this dynamic equilibrium, inducing aberrant fusion events and the formation of hyperfused clusters containing three or more organelles. Concurrently, mitochondriaderived vesicles, mitochondrial multivesicular body-like structures, and mitophagyassociated autophagy were increased throughout the cytoplasm, reflecting quality-control responses to mitochondrial damage. Conclusions: Collectively, these findings highlight that PCAF-mediated acetyltransferase activity is required for mitochondrial morphostasis, and that its suppression disrupts the fission-fusion balance while activating compensatory quality control responses. These results provide new insight into how epigenetic acetylation signaling is functionally coupled to mitochondrial structural integrity during early embryonic development.

Background: Africa is the fastest-growing continent, with more than half of the global population growth expected to occur in the region by 2050. The increasing population and lifestyle changes translate to high demand for food. However, Africa does not produce enough food to cater to its population. The current study sought to bridge knowledge gaps in the dairy and beef production systems by addressing factors affecting semen production in bulls used for AI at the Kenya Animal Genetic Resources Center. Methods: A total of 88 bulls met the inclusion criteria (> 16 months, healthy, and in active semen collection). The breed breakdown was as follows; Ayrshire (n = 39), Friesian (n = 34), Jersey (n = 7), Boran (n = 3), and Sahiwal (n = 5). Bull characteristics (age, breed, body weight, BCS), testicular attributes (SC and testicular echotexture), and semen parameters (semen volume, forward progressive motility, sperm concentration, and post-thaw motility) were determined, and results were analyzed using R statistical software. Results: Semen volume significantly increased with body weight, age and SC (p < 0.001-0.05). Sperm concentration significantly decreased with increased BCS (p < 0.05). Breed significantly affected semen volume and sperm concentration (p < 0.01- 0.05). Hyperechoic testicular lesions noticed in older bulls did not significantly affect semen quality (p > 0.05). Conclusions: These findings will inform bull selection and culling criteria, highlighting that bulls presumed overdue for culling can still produce high-quality semen (the oldest bull at the time of data collection was aged 140 months). Further studies elucidate the relationship between increased testicular echotexture and semen parameters.

Background: Canine mammary tumors are one of the most common tumors in female dogs, and the development of effective therapeutic agents is a critical clinical challenge. Chrysin, a natural flavonoid compound, has been reported to exhibit anticancer activity in various human cancers through the regulation of cell proliferation and apoptosis. However, the anticancer effects of chrysin on canine mammary tumors have not yet been fully elucidated. Therefore, this study investigated the antiproliferative and apoptosis-inducing effects of chrysin on CMT-U27 cells derived from canine mammary tumors. Methods: Antiproliferative activity was confirmed by treating CMT-U27 cells with chrysin at concentrations of 0-10 μM and evaluating cell viability. Cell proliferation capacity was assessed using Ki-67 immunocytochemistry. The expression levels of cell cycle-related proteins, including CDK2, CDK4, cyclin D, and cyclin E, were analyzed by Western blotting. Additionally, apoptosis-related proteins, including phosphorylated p53 and BCL2, were evaluated to investigate the apoptotic activity of chrysin treatment. Results: Chrysin treatment significantly reduced the viability and migration of CMT-U27 cells and decreased the number of Ki-67-positive cells in a dose-dependent manner. Following chrysin treatment, the expression of CDK2, CDK4, cyclin D, and cyclin E was significantly reduced, indicating that cell cycle progression was inhibited. Additionally, chrysin increased the expression of phosphorylated p53 and decreased BCL2 expression. Conclusions: Chrysin exhibited significant anticancer effects in canine mammary tumor-derived CMT-U27 cells through the inhibition of cell proliferation, accompanied by G2/M phase accumulation and downregulation of cyclin-CDK complex components. In addition, chrysin altered apoptosis-related signaling molecules, including p53 and BCL2. These results suggest that chrysin may have potential as a therapeutic candidate for canine mammary tumors.

Background: Sperm cooling is a critical step in cryopreservation, as exposure to temperatures below 15℃ can induce cold shock-associated damage, including phospholipid scrambling and lipid peroxidation. Goat sperm are particularly vulnerable to cooling-induced injury because of their membrane characteristics. This study evaluated the effects of cooling rate and interval agitation during cooling in frozenthawed goat sperm. Methods: The samples were cooled at 0.5℃/min (0.5 Cool) or 0.1℃/min (0.1 Cool) and agitated every 15 min during cooling until 5℃, then, the samples were cryopreserved in liquid nitrogen. After thawing, sperm motility was assessed using computer-assisted sperm analysis (CASA) and plasma membrane integrity, acrosomal integrity, intracellular H2O2 levels, mitochondrial activity, mitochondrial membrane integrity, and mitochondrial membrane potential (ΔΨm) were analyzed by flow cytometry. Results: In results, there were no significant differences in sperm motility, plasma membrane integrity, acrosomal integrity, and mitochondrial function among the treatment groups. However, intracellular H2O2 levels were significantly lower in agitation-treated groups than non-agitated groups both 0.5 Cool and 0.1 Cool treatment groups (p < 0.05), whereas there were no significant differences between cooling rate groups. Conclusions: In conclusion, these results indicate that interval agitation during the cooling process could reduce intracellular reactive oxygen species in frozen-thawed goat sperm.

Background: This pilot study aims to develop an automated, multi-task deep learning system as a proof of concept for both the classification of pregnancy status and gestational day prediction in Korean crossbred goats. Methods: Two 1-year-old goats were followed longitudinally until mid to late gestation. A complete data set containing 11,092 high-resolution image frames (6,647 pregnant and 4,445 non-pregnant) was created from the video sequences. The dataset was segmented at the frame level with 80% allocated to the training partition (n = 8,875), 10% to the validation partition (n = 1,110), and 10% to the test partition (n = 1,107). Multi-task Four convolutional neural networks (ResNet18, EfficientNet-B0, MobileNetV3-Large, and ConvNeXt-Tiny) were trained following a multi-task learning strategy with the AdamW optimizer, OneCycle scheduling, and a hybrid Binary Cross- Entropy and Huber loss function. Results: Accuracy was achieved for the four architectures, with more than 99.5%. The MobileNetV3-Large model performed the best in terms of frame-level classification accuracy, with 100% sensitivity and specificity. For the regression-based task for predicting gestational days, EfficientNet-B0 got the best performance with a framelevel Mean Absolute Error (MAE) of 1.3 days. The video-level MAE of 0.882 days and the competitive video MAE of 1.204 days were the outcomes for the aggregated video sequences using ConvNeXt-Tiny and EfficientNet-B0, respectively. Conclusions: The present pilot study lays the foundation for the methodological feasibility of small optimized deep learning models for accurate monitoring of fetal development and for the automation of reproductive diagnostics.

Background: Miniature pigs are widely used as biomedical models because of their anatomical and physiological similarities to humans; however, hematologic and serum biochemical data for newly developed or regionally derived populations remain limited. The Jeju miniature pig, derived from Korean Jeju native pigs, is an emerging laboratory animal with potential value in veterinary and translational research. This study aimed to characterize hematologic and serum biochemical profiles in healthy Jeju miniature pigs and to evaluate age- and sex-associated physiological variation. Methods: Blood samples from clinically healthy animals were analyzed for complete blood count and serum biochemical parameters, and animals were stratified by age and sex to assess demographic influences. Results: Age was the primary determinant of variation across most parameters. Juvenile animals exhibited higher lipid-related markers and alkaline phosphatase activity, whereas adults showed increased creatinine and total protein concentrations, consistent with physiological maturation. Sex-related effects were modest and largely confined to erythrocyte-associated indices. Comparative analysis demonstrated that these age-related patterns were broadly consistent with those reported in established miniature pig breeds, including Göttingen and Yucatan pigs. Conclusions: These findings provide baseline physiologic information for Jeju miniature pigs and improve understanding of age- and sex-associated hematologic and biochemical variation in this emerging biomedical animal model, supporting its application in experimental and translational research settings.

Background: Heat stress (HS), driven by global climate change, adversely affects reproductive performance in livestock and mammals by impairing gamete development and reducing fertility. Exposure of oocytes to elevated temperatures during in vitro maturation (IVM) can induce persistent cellular stress that compromises subsequent embryonic development. However, the involvement of ATF5-mediated UPRmt signaling and GRP75-associated ER-mitochondria communication during early bovine embryogenesis under HS remains unclear. Methods: In this study, bovine cumulus–oocyte complexes (COCs) were matured for 22 h at either 38.5℃ (control; Con) or 41.5℃ (HS), followed by in vitro fertilization and embryo culture under standard conditions. Results: HS exposure during IVM significantly reduced cleavage and blastocyst formation rates (p < 0.01). Embryos derived from HS-exposed oocytes exhibited decreased mitochondrial membrane potential (ΔΨm), increased reactive oxygen species (ROS) production, and mitochondrial calcium (Ca2+) accumulation, suggesting disruption of GRP75 (known as HSPA9)-mediated ER-mitochondria communication. These embryos also showed increased expression of HSPA9 and HSPD1 at the cleavage stage, indicating persistence of stress signals beyond fertilization. Immunofluorescence analysis revealed enhanced nuclear localization of ATF5 in blastocysts, while qPCR analysis demonstrated increased expressions of ATF5-mediated UPRmt-related genes, including LONP1, HSPD1, and HSPA9. Conclusions: Collectively, these findings demonstrate that heat stress during oocyte maturation induces persistent mitochondrial dysfunction associated with GRP75- mediated mitochondrial Ca2+ dysregulation and ATF5-mediated UPRmt activation, which may represent an adaptive compensatory response in surviving bovine embryos.

In this case report we describe the clinical condition of a 5-year-old Nelore bull with marked enlargement of the right side of the scrotum. After ultrasound evaluation, a hydrocele involving the right testicle was observed. The right testis and epididymis were surgically removed along with the tunica vaginalis and histological examination of each segment was performed. On macroscopic examination gray nodules were found in the tunica vaginalis and adhesions of the visceral layer with the testis. On histopathological evaluation the nodules consisted of papillary neoplastic cells that had invaded the surrounding tissue. Based on these findings, the tumor was diagnosed as sarcomatoid mesothelioma. This is the first case confirmed of mesothelioma in the tunica vaginalis in a semen donor bull by histopathology in Brazil.