Reproduction in Domestic Animals最新文献

The TGF-β/Smad signalling pathway plays a critical regulatory role in mammalian follicular development. Vascular Cell Adhesion Molecule 1 (VCAM1), as a member of the immunoglobulin (Ig) superfamily, is commonly expressed in various cells of the mammalian ovary and affects ovarian development. Previous studies have shown that TGF-β1 is a regulator that down-regulates the expression of VCAM1 in human granulosa cells, but its specific mechanism remains unclear. In this study, we revealed that in porcine follicular granulosa cells, TGF-β1 reduces VCAM1 expression by activating TGF-β receptor type I and through the Smad pathway. This down-regulation can be completely reversed by knockdown of Smad2, but not Smad3, suggesting that Smad2 may exert a non-redundant, specialised function in the regulation of VCAM1 by the TGF-β/Smad signalling pathway. These results enhance the understanding of the regulatory mechanisms of the TGF-β signalling pathway in reproduction and provide a theoretical basis for the regulation of reproductive traits.

Reproductive efficiency in boars partly depends on semen quality. However, it is challenging to predict sperm fertility once acceptable quality endpoints have been met. This study aims to establish a link between different semen quality parameters and farm fertility outcomes in semen doses selected for commercial use. We analysed 105 ejaculates from 15 adult Pietrain boars, extended into 45 mL artificial insemination (AI) doses. A total of 605 sows were inseminated (40.1 ± 7.8 females/boar) and fertility, farrowing rate and prolificacy data were recorded. Sperm evaluation included sperm plasma analysis, kinematics, morphology, viability, acrosome integrity, apoptotic-like changes, mitochondrial activity and DNA damage (DNA fragmentation poly-ADP ribose polymerase 1, PARP1, together with its product PAR and its cleaved form cPARP). The sperm membrane and acrosome were evaluated using the short hypo-osmotic swelling test (sHOST) and the osmotic resistance test (ORT). Fertility and farrowing rates exceeded 94%, with an average of 20.18 ± 2.03 piglets born/litter (average born alive: 87.75% ± 5.61%). Negative correlations were found between damaged acrosomes and ultrasound fertility (ρ = -0.240, p = 0.021), farrowing rate (ρ = -0.244; p = 0.019), and total born (r = -0.304; p = 0.003). Average born alive was positively correlated with plasma seminal concentrations of protein (r = 0.273; p = 0.009), fructose (r = 0.243; p = 0.024) and cathepsine B (ρ = 0.257; p = 0.029) but negatively correlated with apoptosis and DNA damage nuclear markers cPARP (r = -0.295, p = 0.005) and PAR (r = -0.209, p = 0.049). However, regression models only showed significant results for predicting the total born from damaged acrosomes and those born alive from cPARP, although the coefficients of determination were very low. Since semen quality and fertility were good, most parameters did not affect fertility outcomes. In agreement with previous studies, acrosomal damage would be a reliable predictor of reproductive outcomes, whereas cPARP would show potential as a novel biomarker.

The periparturient period represents a critical window of vulnerability in livestock reproduction. Additionally, reproductive performance is often compromised due to a weakened immune system and high oxidative stress. Selenium, an essential micronutrient, emerges as a key element with dual roles in antioxidant defence and immune modulation, making it a cornerstone in maintaining reproductive health in livestock. Selenium exerts its protective effects through incorporation into selenoproteins such as glutathione peroxidase (GPx), which downregulate oxidative stress, support cellular integrity, and regulate inflammation in reproductive tissues. During the periparturient period, selenium deficiency is associated with increased production of β-hydroxybutyric acid (BHBA) and non-esterified fatty acids (NEFA), responsible for triggering lipid mobilisation and activation of the NF-κB (Nuclear Factor kappa-light-chain-enhancer of activated B cells) signalling pathway. This leads to overexpression of pro-inflammatory genes, resulting in uterine infections, mastitis, and other reproductive disorders. Selenium supplementation in organic or nano forms plays a potential role in countering these effects by activating the Nrf2 (Nuclear factor erythroid 2) pathway, boosting antioxidant enzymes, and suppressing the NF-κB pathway. In females, selenium enhances endometrial epithelial repair, hormone regulation, and immune tolerance by regulating the NF-κB signalling pathway. In males, combined supplementation of selenium with vitamin E improves sperm quality, motility, and testosterone levels while preventing lipid peroxidation in spermatozoa. At the epigenetic level, selenium influences histone acetylation to regulate transcription of inflammatory genes such as COX-2 and TNF-α. Recent insights into the role of selenium receptors (LRP8) in ovarian follicular development highlight the applications of selenium in fertility regulation. The efficacy of selenium is highly influenced by its form, dosage, animal species, and physiological state. This review emphasises the need for large-scale, species-specific research trials, nanodelivery strategies, and omics-based biomarkers to improve selenium supplementation strategies and dose rate. Selenium holds significant translational potential in veterinary reproduction, playing a preventative and therapeutic role against reproductive immunopathologies in livestock.

Semen quality is the most crucial indicator for evaluating the reproductive capacity of boars. Semen traits, including semen volume, sperm density, motility and abnormality rate, exhibit low to moderate heritability, making genetic improvement through conventional breeding challenging. Advances in genome sequencing have enabled GWAS to identify genetic markers for economically important traits. In this study, 172 Large White boars with 56,427 phenotypic records across seven semen quality traits were subjected to 15× whole-genome resequencing. GWAS was performed using the FarmCPU model, identifying 2824 significant SNPs and annotating 573 candidate genes associated with seven semen traits. After linkage disequilibrium (LD)-based clumping (r² < 0.1, 1 Mb window), 916 independent genomic loci were identified as significantly associated with the seven semen quality traits. Functional analysis revealed key biological processes, including growth regulation, extrinsic apoptotic signalling pathway and the TOR signalling pathway. In an expanded population, six SNPs associated with semen quality traits were identified in the SOX6, CACNA1H, FOXP4, EFNA3 and ITGA9 genes. Significant associations were found between SOX6 gene and sperm abnormality rate, CACNA1H gene and semen volume, sperm density, motility, and abnormality rate, FOXP4 gene and sperm density, EFNA3 gene and semen volume, sperm density, ITGA9 gene and semen volume, sperm density, motility, and abnormality rate. These findings enhance understanding of the genetic architecture of boar semen quality and provide molecular markers for genetic selection, facilitating improved breeding strategies.

For approximately 40 years, microencapsulation technology has been utilised across various species due to its ability to release semen gradually after artificial insemination. This study aimed to establish the use of the alginate microencapsulation procedure for goat semen and to investigate whether this method enhances longevity during cold storage compared to the traditional straw method. Semen was collected from Canindé bucks and analysed using Computer-Assisted Semen Analysis (CASA). The semen was then diluted in a commercial extender and packaged either in straws or microcapsules (using 1% sodium alginate). Both groups were refrigerated at 4°C-5°C and assessed at 24, 48 and 72 h after dilution. The evaluation included assessments of sperm viability, abnormalities, membrane integrity, and DNA integrity. Data were analysed using repeated-measures ANOVA at p < 0.05. Concerning the parameters straight line (VSL) and average path (VAP), no statistical differences (p > 0.05) were observed. However, the microcapsule group showed significantly higher results (p < 0.05) for straightness (STR), beat cross frequency (BCF), and wobble (WOB) at 24 and 48 h of storage. Sperm viability was also higher (p < 0.05) in the microcapsule group at 24 and 48 h of storage. In conclusion, this study demonstrates the feasibility of microencapsulating goat semen. Further in vivo and/or in vitro fertility trials are needed to confirm these findings.

Glutathione peroxidase (GPx), a crucial element of anti-oxidative defence, is known to enzymatically ward off lethal free radicals released from redox metabolism within the sperm. However, in vitro semen chilling procedures gravely affect the scavenging capacity of antioxidants to counter reactive oxygen species (ROS) and dismantle the cellular structures. This directs towards the integration of exogenous antioxidants into the semen freezing medium. Japanese quail, not fully exploited yet because of high sensitivity to inbreeding, if propagated via assisted reproduction, could enormously contribute to fulfill the escalating poultry demand. Therefore, the current study aimed at investigating the effect of GPx fortification on the quality, mitochondrial activity, antioxidant potential and lipid peroxidation (LPO) of cryopreserved Japanese quail semen. For this purpose, pooled semen (30 males) was divided and diluted with NaCl extender (1:15) having 5, 10 15 U GPx/mL and control. Samples were cryopreserved and evaluated for the quality and biochemical activity at post-dilution, post-cooling, post-equilibration and post-thaw stages of cryopreservation. The sperm motility (η_p ² = 0.617), plasma membrane integrity (η_p ² = 0.666), viability (η_p ² = 0.691), mitochondrial status (η_p ² = 0.710), total antioxidant potential (η_p ² = 0.674) and free radical scavenging capacity (η_p ² = 0.680) were recorded highest (p < 0.05) in samples containing 5 U GPx/mL compared to other concentrations and control at all the stages of freezing. Moreover, the lowest LPO was recorded in the samples with 5 U GPx/mL followed by 10 U GPx/mL, control and 15 U GPx/mL throughout the stages of cryopreservation. The study concluded that GPx at 5 U/mL maintains the quality and scavenging capacity of cryopreserved Japanese quail semen against ROS accumulation.

In mammals, the corpus luteum (CL) is an endocrine gland whose function and survival are limited in scope and time. Although the CL produces progesterone to maintain pregnancy, regression of the CL is necessary for initiating the estrous cycle. A previous study showed that prostaglandin F2α (PGF2α) is a luteolysis hormone that causes CL regression by inducing luteal cell apoptosis. Although much is known about the role of PGF2α during luteolysis, the functions of endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in PGF2α-induced CL regression are unclear. In this study, goat luteal cells were treated with PGF2α to trigger apoptosis. We found that ER stress was induced by PGF2α treatment. Additionally, the ER stress-mediated UPR was activated through its three sensors (IRE1, ATF6 and PERK) in goat luteal cells. By applying different ER stresses, we revealed the role of ER stress in PGF2α-induced apoptosis in goat luteal cells. Further, IRE1 knockdown inhibited mitochondrial pathway-mediated apoptosis in luteal cells. Together, our results indicate that the ER stress-mediated UPR promotes goat luteal cell apoptosis, which is related to IRE1 activation in mitochondrial pathway-mediated apoptosis. This present work may provide new insight into the mechanistic pathways of regulating regression of goat CL.

Post-mortem oocyte collection serves to preserve the genetic material of valuable mares and to obtain recipient oocytes for cloning purposes. Therefore, the number of oocytes retrieved per ovary is a critical factor in increasing the likelihood of obtaining a viable embryo. This study evaluated the efficiency of two post-mortem oocyte retrieval techniques: follicular scraping (Scraping) and ultrasound-guided follicular aspiration (OPU). The comparison was based on several parameters, including the number of follicles aspirated per ovary, oocyte recovery rate (ORR), number of oocytes obtained per ovary, processing time, oocyte searching time, and the volume of medium used. A total of 22 replicates were performed (11 for each group), processing 28 ovaries in the Scraping group and 22 ovaries in the OPU group. Oocytes were searched by the same operator, who was blinded to the treatment group. The results demonstrated that the OPU technique was significantly more efficient than Scraping in most evaluated parameters: number of follicles aspirated per ovary (13.6 ± 3.8 vs. 9.5 ± 3.5), oocytes recovered per ovary (9.1 ± 3.0 vs. 4.7 ± 2.1), processing time per oocyte (1.8 ± 0.8 min vs. 4.1 ± 1.6 min), and ORR (66.7% vs. 50%) (p < 0.05). No significant difference was found in the volume of medium used (19.6 ± 10.4 vs. 21.6 ± 11.0 mL). However, the OPU technique resulted in more denuded oocytes (37.5%) than the Scraping technique (18.6%; p < 0.05). In conclusion, ultrasound-guided follicular aspiration yielded a higher number of oocytes per ovary compared to the standard scraping technique.

This study evaluated the effects of cholesterol, pentoxifylline and casein, with or without skim milk, added to extenders during pre-centrifugation on equine sperm cryosurvival. Seven ejaculates from four stallions (n = 28) were divided into four groups: SM (skim milk), SMP (SM + pentoxifylline), SMCho (SM + cholesterol) and ChoCa (cholesterol + casein). After centrifugation and freezing, sperm kinematics and plasma membrane integrity were assessed immediately and 30 min post-thaw. SMCho and ChoCa showed superior results compared with SM and SMP. These findings indicate that cholesterol-based extenders improve post-thaw sperm quality when added before cryopreservation.

Cattleyak is a hybrid between cattle and yak; the underlying mechanism for its spermatogenic arrest is still unclear, and it's a typical male sterile mammal. In this work, we cloned the OTUD6A gene of cattleyak and analyzed it by bioinformatics. The expression level of OTUD6A in testicular tissues and undifferentiated spermatogonia of cattleyak was significantly lower than that in yak (p < 0.05). Overexpression of OTUD6A in cattleyak promoted the viability and proliferation activity of cattleyak undifferentiated spermatogonia (p < 0.05). Furthermore, OTUD6A overexpression resulted in significant upregulation of genes associated with proliferation (p < 0.05). Therefore, the aberrant expression of OTUD6A in undifferentiated spermatogonia of cattleyak impaired its proliferation and decreased its growth potentiality, thereby affecting the development of undifferentiated spermatogonia. This study provided a new theoretical basis for further elucidation of the molecular mechanism of spermatogenesis arrest in cattleyak.