Animal Reproduction Science最新文献

The aim of the study was to evaluate the effect of repeated low doses of gonadotropin-releasing hormone (GnRH) agonist buserelin once a day for 5 days on follicle-stimulating hormone (FSH) and luteinizing hormone (LH) release, and ovarian function in dairy cows with anovulation type I. The study was conducted on 10 anovulatory Polish Holstein-Friesian cows. Cows in Group 1 (n = 5) received 4 µg of buserelin intramuscularly. once a day for 5 days. Control cows from Group 2 (n = 5) received saline. Concentrations of progesterone, FSH, and LH in the blood were analysed using radioimmunoassay (RIA). Ovarian structures were monitored weekly after the end of treatment by ultrasound for 4 weeks. Injections of buserelin increased FSH and LH concentrations. Release of FSH and LH was largely variable, but there was significant (P < 0.001) interaction between time and treatment during all treatment days. The number of follicles in the treatment group was significantly greater (P = 0.029) than in the control group on day 5, the diameter of follicles on day 12 was also larger (P < 0.01) in treated than in control cows. Ovulation occurred in 4 of the 5 treated cows, but only in 1 of the control cows in the 40 days after treatment. In conclusion, repeated low doses of GnRH analogue buserelin once a day for 5 days may increase the concentration of FSH and LH in dairy cows with anovulation type I.

The regulation of mammalian ovarian development involves the coordinated processes of autophagy and apoptosis. The autophagy-related gene ATG7 plays a pivotal role in mediating crosstalk between these pathways. Despite its recognized importance, the specific function of ATG7 in ovarian follicular granulosa cells remains poorly understood. This study aimed to explore the effects of ATG7 overexpression on apoptosis and autophagy in porcine ovarian follicular granulosa cells and thereby provide insights into the interplay between these fundamental cellular mechanisms. An ATG7 overexpression vector was introduced into cells, followed by assessment of cell proliferation using the CCK-8 assay, quantification of related gene expression via real-time quantitative PCR and western blotting, and evaluation of apoptosis using TUNEL staining. ATG7 exhibited a predominant cytoplasmic localization and additional nuclear expression in porcine ovarian follicular granulosa cells. The transfection efficiency of the vector was initially verified, indicating that its overexpression notably increased expression of ATG7 protein. Further investigations confirmed that overexpression of ATG7 inhibited cell proliferation, stimulated autophagy, and promoted apoptosis in these cells. In summary, overexpression of ATG7 influences the viability of porcine ovarian follicular granulosa cells by regulating the interplay between autophagy and apoptosis. This study not only broadens the understanding of functional regulation of autophagy and apoptosis by ATG7, but also sheds light on the intricate mechanisms governing ovarian follicular atresia.

Pig production, a vital sector of the meat industry, faces demands for improved quality, efficiency, and sustainability. Advancements in breeding, disease control, and artificial insemination have enhanced production, while biotechnologies such as in vitro embryo production (IVP) and genetic engineering offer further progress. In vitro embryo production could facilitate the global exchange of valuable genetic material, accelerate breeding programs, and improve productivity, and it is essential for generating genetically modified (GM) pigs. These GM pigs have two main applications: first, they allow for targeted modifications aimed at improving production traits relevant to pig production in agriculture, such as meat quality and disease resistance. Second, they serve as valuable biomedical models for human disease research, regenerative medicine, and organ transplantation. Yet, despite notable advancements in recent decades, the efficiency of the current IVP systems for porcine embryos remains a challenge. Compared to the in vivo environment, suboptimal culture conditions lead to issues such as elevated polyspermy, poor embryo development, and the production of low-quality blastocysts. This review provides an overview of the key steps and recent advancements in porcine IVP technology. We will emphasize the promising utilization of oocytes from live females of high genetic value through ovum pick-up and the incorporation of extracellular vesicles and cytokines into IVP media. These innovative strategies hold immense potential to significantly enhance embryo development and overall success rates in porcine IVP, and could open the door for significant progress in both agriculture and biomedicine applications.

In sheep, anatomical characteristics of the cervix and animal value limit application of reproductive technologies; therefore, most breeding is natural service. Rams are selected based on desired physical traits and semen capacity, but their contribution to flock genetics is constrained by expression of sexual behavior. In 1964, it was first reported that approximately one-third of rams expressed limited sexual interest toward ewes in estrus. Therefore, if rams were evaluated for expression of sexual behavior, it is estimated that as many rams would be culled for the lack of behavior as are currently culled for semen quality or physical deficiencies. Sexual behavior is complex, requiring sensory recognition and processing, integration of ram cohorts and social dominance, female mate choice, and a physical response. This review of the literature aims to provide insights into factors influencing expression of ram sexual behavior.

The aims of this study were: To ultrasonographically describe and compare endometrial echogenicity and heterogeneity using digital analysis in normal and bitches suffering from pyometra, cystic endometrial hyperplasia (CEH) and endometritis; and to evaluate the effect of clinical, bacteriological and histopathological uterine parameters on endometrial echogenicity and heterogeneity. Forty-one post pubertal intact bitches were included. According to clinical, ultrasonographic, anatomopathological and histopathological uterine evaluation, the animals were classified as: Pyometra (PYO; n=6); CEH (n=8); Endometritis (END; n=13); Normal group (NG; n=14). Endometrial images were analyzed with ImageJ software to obtain echogenicity and heterogeneity, represented as the mean gray value (MGV) and standard deviation of gray (SDG), respectively. The effect of the group, clinical, bacteriological, ultrasonographic and histological variables on MGV and SDG were analyzed by a generalized linear model. PYO exhibited higher MGV (P<0.01) and SDG (P<0.01) than the other groups. No differences were found among CEH, END and NG for both parameters (P>0.1). Body weight decreased MGV (P<0.01), while increasing degrees of inflammatory reaction (P<0.01), edema (P<0.01), hemorrhages (P<0.01) and vascular congestion (P<0.01) were associated with higher MGV. Inflammatory reaction (P<0.01) and ulceration (P<0.01) increased SDG. Ultrasonographic images evaluated using computer assisted image analysis were useful to differentiate pyometra from other uterine conditions in dogs. However, this technique could not differentiate among CEH, END and NG. Uterine echogenicity and echotexture, which clearly represent the different histopathological patterns, contribute to the diagnosis of the definite diagnosis of some canine uterine diseases.

The objective of this study was to assess the ability of camel spermatozoa to bind in the Hyaluronan Binding Assay (HBA), to determine if conventional sperm quality parameters, in vitro fertilization capacity, and precursor of A-Kinase Anchoring Protein 4 (proAKAP4) values correlate with HBA results. The potential to predict post-thaw fertilization performance from HBA for fresh dromedary camel sperm was also evaluated. Semen samples were collected and assessed both fresh and post thawing, at 0 h and 1.5 h. Conventional semen analysis, HBA, and a proAKAP4 biomarker-test were used to validate sperm quality. A heterologous sperm penetration assay using zona pellucida-free goat oocytes was used to assess in vitro sperm fertilizing capacity. The results showed that dromedary camel spermatozoa bound to hyaluronan with no correlation between results from fresh samples and after thawing. Furthermore, the proAKAP4 test results showed a negative correlation with HBA at 0 h after thawing (r = - 0.62; P = 0.03). In the conventional analysis, only progressive motility (r = 0.65; P = 0.02) and straightness correlated with HBA for fresh semen (r = 0.69; P = 0.01). In the sperm penetration assay, a moderate but non-significant correlation was identified between fresh sperm HBA and penetration (r = 0.52; P = 0.07). In conclusion, results suggested that HBA can be used to assess camel sperm properties, but further investigation is needed to understand its correlation with other sperm quality parameters. The HBA score from fresh dromedary camel sperm was unable to predict post-thaw fertilization performance.

This study evaluated the use of flunixin meglumine to prevent the occurrence of premature corpus luteum (CL) regression in superovulated ewes, improving embryo recovery and viability. Ewes (n=23) submitted to conventional superovulatory protocol and laparoscopic artificial insemination were treated with 2.2 mg/kg/day of flunixin meglumine (FLU, n=12) or 1.5 mL saline solution (CONT, n=11) on Days 2, 3, and 4 (Day 0 = 48 h after device removal). Serum progesterone (P₄) concentrations were measured (Day 1–6). Ultrasound (US, Days 3 and 6) and laparoscopic evaluation (Day 6) were performed to identify luteinized structures. In the US, laparoscopy, and P₄ assessments, the percentage of ewes with premature CL regression differed (P<0.05) between CONT (54.5; 63.6; and 54.5 %) and FLU (0.0; 0.0; and 0.0 %), respectively. The US exams revealed the effect (P<0.05) of treatment on the number of regressing CL between CONT (1.4 ± 0.6) and FLU (0.0 ± 0.0). Greater (P<0.05) number of normal CLs (10.5 ± 1.8 vs. 4.4 ± 1.5), ova/embryos (9.1 ± 2.1 vs. 3.7 ± 1.3), viable embryos (5.1 ± 1.1 vs. 2.6 ± 1.2), and recovery rate (79.5 ± 9.6 vs. 41.3 ± 15.0 %) were observed in FLU compared to CONT, respectively. The embryo viability rate did not differ (P>0.05) between FLU (60.7 ± 10.5 %) and CONT (45.5 ± 16.1 %). In conclusion, the flunixin meglumine protocol was able to prevent the occurrence of premature CL regression in superovulated ewes, increasing the recovery rate and embryo production.

Our objective was to evaluate the effect of vaccination with an inactivated virus vaccine (IVV) or modified-live virus (MLV) vaccine on the corpus luteum (CL). On d0, synchronized beef cows were treated with MLV (n = 70; BoviShield Gold FP5VL5), IVV (n = 16; ViraShield 6VL5HB), or were unvaccinated controls (n = 5). Plasma was collected from treated animals on d0 and every other day through d22. Plasma was analyzed for concentrations of progesterone and 15 cytokines. Between d10 and d13, selected females (n = 13) were ovariectomized; controls were slaughtered on d15/16 to obtain CL for histological evaluation. There were reduced numbers of large luteal cells (LLC) in MLV compared to IVV and controls (P < 0.0001), but IVV were similar to controls (P = 0.11). MLV had decreased LLC percentage compared to controls, and IVV were intermediate (P < 0.0001, MLV: 1.57 ± 0.33 %, IVV: 2.99 ± 0.30 %, Control: 6.45 ± 0.33 %). Based on progesterone concentrations, 24 % MLV and 0 % IVV had an abnormal cycle following vaccination. Overall, MLV had reduced progesterone concentrations (P = 0.02; MLV: 3.61 ± 0.22; IVV: 4.81 ± 0.46 ng/mL). The new CL that formed following an abnormal cycle in MLV had the greatest percentage (35.56 ± 5.5 %) of apoptotic cells. Treatment by cycle status interaction, and time significantly affected IFN-γ, IP-10, MIP-1β, and MCP-1 (P < 0.03), with several time points having elevated concentrations in abnormally cycling MLV animals. Collectively, this demonstrates MLV vaccination around estrus negatively influenced LLC, progesterone, and increased luteal apoptosis and pro-inflammatory cytokines.

This study aimed to assess the impact of L-carnitine (LC) supplementation in conventional-slow (CS) and ultra-rapid (UR) freezing media on post-thaw quality and fertilizing ability of dog epididymal spermatozoa. Sperm samples were collected from 60 epididymides obtained from 30 adult orchiectomized dogs via retrograde flushing. Twenty pooled sperm samples were then created (3 epididymal samples/pool). Four treatments were established according to the freezing method (CS and UR) and LC supplementation (5 and 0 mM [control, Co]): CS-LC5, CS-Co, UR-LC5, and UR-Co. The CS freezing involved exposing 0.25 mL straw to liquid nitrogen vapors (LN₂), while UR freezing submerged 30-µL drops of sperm samples directly into LN₂. Sperm kinematics, membrane integrity, and fertilizing ability (by heterologous in vitro fertilization using bovine oocytes) were evaluated for all treatments. Post-thaw results revealed that the CS freezing treatments resulted in significantly higher values (P < 0.05) of curvilinear and average-path velocities, and beat-cross frequency compared to the UR freezing treatments, regardless of LC supplementation. The CS-LC5 and UR-LC5 treatments cryoprotected the sperm by increasing (P < 0.05) the percentage of ‘live-sperm/intact-acrosome’ compared to their controls treatments CS-Co and UR-Co. Regarding fertilizing ability, the CS-LC5 treatment yielded a higher percentage (P < 0.05) of pronuclei formation compared to both UR treatments. The UR-LC5 treatment, however, obtained greater percentage (P < 0.05) than their control UR-Co. In conclusion, supplementation with L-carnitine in conventional-slow and ultra-rapid freezing improved sperm motility, plasma, and acrosome membranes integrity and fertilizing ability of dog epididymal spermatozoa.