Reproduction in Domestic Animals最新文献

Efficient use of stallion semen in liquid state is limited by its relatively short shelf-life. A chemically defined extender (Beyond) is now available for long-term liquid semen preservation. The objectives of the present study were to compare Beyond with milk extenders for the preservation of semen at two temperatures, and to evaluate fertility of semen cooled for 4-8 days before artificial insemination. Semen was processed using different extenders: milk, cholesterol (BotuSemen Special); milk-based (INRA 96); and Beyond. Sperm motility, membrane and acrosome integrity, and chromatin structure were evaluated in semen stored at 17°C for 7 days or at 5°C for 14 days. Sperm motility decreased in the first few days of storage regardless of extender or storage temperature. Sperm motility continued to decline at relatively constant rates in semen extended in milk extenders, but the rate of decline was substantially reduced with Beyond. Sperm motility in semen extended with Beyond was greater than in semen extended with milk extenders after 4 days of storage at 17°C, or after 7 days of storage at 5°C. Extender did not affect sperm DNA damage during storage, but sperm with intact membrane and intact acrosome were lower with Beyond. Inseminations with semen stored with Beyond at 5°C for an average of 5.5 days resulted in embryos in 61% of cycles (11/18). In conclusion, Beyond extender resulted in greater sperm motility longevity when compared to milk extenders, especially when semen was stored at 5°C. Satisfactory fertility was obtained with semen cooled for 4-8 days before artificial insemination.

The present study was undertaken to assess the effect of kisspeptin supplementation (0.0, 5.0, 10.0, 15.0, 20.0 and 40.0 μM) in cryodiluent on freezability and in vivo fertility of buffalo bull spermatozoa. Twenty-four semen ejaculates were collected using an artificial vagina from four Murrah buffalo bulls. Ejaculates having > 70% sperm motility, < 25% morphological abnormalities and > 500 million/ml concentration were diluted with Tris-egg yolk extender containing 0.0 (control), 5.0, 10.0, 15.0, 20.0 and 40.0 μM kisspeptin and cryopreserved following established protocol. The CASA-based progressive motility and viability were higher (p < 0.05) in cryodiluent containing 20.0 μM of kisspeptin in comparison to other experimental concentrations and control. Addition of kisspeptin at 20.0 and 40.0 μM in extender exhibited higher (p < 0.05) CASA-based total motility and plasma membrane integrity. Regarding CASA-based sperm kinematics, supplementation of kisspeptin (20.0 μM) in extender improved (p < 0.05) VCL and VAP as compared to other tested concentrations and control. The acrosome integrity revealed no difference (p > 0.05) in all the experimental extenders compared to control. The MDA levels were lower (p < 0.05) in cryodiluent supplemented with kisspeptin (20.0 μM) than in other concentrations and control. Sixty artificial inseminations were performed with the post-thaw semen having the most effective dose of kisspeptin (20.0 μM) and control (30 inseminations each). The conception rates were recorded to be higher (p > 0.05) using post-thaw semen containing kisspeptin (20.0 μM; 43.3%) as compared to control (33.3%). In conclusion, complementing the cryodiluent with 20.0 μM kisspeptin improved the quality and in vivo fertility of cryopreserved Murrah buffalo bull semen.

Embryonic diapause is widespread among mammals. This is the first report of successful post-thaw in vivo development of mammalian embryos cryopreserved at the diapause stage using mouse as a model species. Live offspring were obtained after cryopreservation of murine embryos and their transfer to pseudo-pregnant recipients. The sex ratio at birth was male-skewed, and the offspring were fertile. The results may open new possibilities for applying the Genome Resource Banking concept to diapausing mammalian species.

Canine somatic cell nuclear transfer (SCNT) is a powerful technology that can be used to clone beloved companion dogs, produce valuable working dogs, rescue endangered canine breeds, and create genetically engineered dogs. Nevertheless, the application of this technology is hindered by the low developmental efficiency of canine SCNT embryos. It has been shown that in pig and horse cloning using mesenchymal stem cells (MSCs), compared with fibroblasts, as donor cells can enhance the developmental potential of SCNT embryos. Whether this is also true for dog SCNT is unknown. This study aims to evaluate the efficiency of MSCs and fibroblasts as donor cells for canine SCNT. We demonstrated that canine adipose tissue-derived MSCs (cAd-MSCs) have a higher growth rate, lower apoptosis level, and higher expression level of pluripotency genes and HOX family genes than canine ear fibroblasts (cEFs). These features enhance the reprogramming efficiency of cAd-MSCs in canine-porcine interspecies SCNT (iSCNT) embryos, resulting in a higher developmental competence in cAd-MSCs-derived iSCNT embryos than that in cEFs-generated counterparts. This study indicates that cAd-MSC is a better donor cell type than cEF for SCNT.

During the in vitro maturation process of oocytes, oxidative stress is commonly present, and excessive oxidative stress can affect oocyte maturation. Thus, adding antioxidants during maturation is an effective strategy for reducing oxidative stress. N-acetylcysteine (NAC), a derivative of cysteine, participates in glutathione (GSH) metabolism and stimulates glutathione synthesis. However, a clear understanding of the effect of NAC on sheep oocytes remains unknown. In this study, we investigated NAC's impact on the maturation of sheep oocytes, and the results revealed that the maturation rate, and subsequently the cleavage and blastocyst formation, were significantly enhanced by incubation with 1 mM NAC. The GSH and Ca²⁺ levels increased, and the cortical granules were significantly elevated, whereas the reactive oxygen species levels were significantly reduced in the 1 mM NAC-treated group. Additionally, the number of inner cell masses was significantly increased. The findings of this study support the hypothesis that NAC increases oocyte maturation rate by protecting them from oxidative stress damage. These discoveries provide a new approach for improving the efficiency of in vitro production of sheep embryos.

This study evaluated the clinical efficacy of aglepristone for the management of canine pyometra-either as a sole therapy or in combination with different antibiotic regimens-and investigated the association between aglepristone dosing and the occurrence of vaginal hyperplasia during the subsequent estrous cycle. Eighty-seven intact bitches diagnosed with pyometra were enrolled and divided into two experiments. In Experiment I, 57 bitches were randomly assigned to three treatment groups (n = 19/group): (1) AGL, aglepristone alone; (2) AGL-CEF, aglepristone plus ceftriaxone; and (3) AGL-CEF-MET, aglepristone plus ceftriaxone and metronidazole. Clinical examinations and haematological and biochemical profiles were assessed every 48 h for 15 days. In Experiment II, 30 bitches were treated with aglepristone using two protocols: AGL 4X (10 mg/kg s.c. on Days 0, 1, 8 and 15) or AGL 2X (10 mg/kg s.c. on Days 0 and 1). Incidence and severity of vaginal hyperplasia, as well as post-treatment reproductive performance, were evaluated during the subsequent oestrus. All three treatment protocols achieved clinical resolution of pyometra-including the aglepristone-only group-with normalisation of leukocyte counts and serum biochemical markers. In Experiment II, vaginal hyperplasia occurred in 53.3% of bitches in the AGL 4X group versus 7% in the AGL 2X group. Grade III hyperplasia was associated with pyometra recurrence and reduced pregnancy rates. Overall pregnancy rate in Experiment II was 80%. These findings indicate that aglepristone is an effective, fertility-preserving treatment for canine pyometra, even when administered without systemic antibiotics. However, high-dose or prolonged administration may induce oestrogen-mediated adverse effects such as vaginal hyperplasia and disease recurrence. A reduced dosing regimen appears safer while maintaining equivalent clinical and reproductive efficacy.