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- Author or Editor: Sándor Cseh x
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The mycotoxin T-2 has many harmful effects on mammalian cells and reproductive functions. In the present study, the in vitro effect of T-2 toxin on mouse blastocysts was examined. Embryos were cultured in media supplemented with 0.5, 0.75 and 1 ng/ml T-2. Different exposure times were applied [96 h (treatment I) or 24 h following 72 h in toxin-free media (treatment II)]. Blastomere number, nuclear chromatin status and blastocoel formation were investigated in blastocysts. Our data show that the effect of T-2 toxin may vary depending on the stage of the embryo at the start of exposure. At 96 h of exposure, the blastocysts had blastomeres with normal chromatin quality but their developmental potential was decreased. After 24 h of exposure applied following a 72-h culture, blastomeres had a higher level of chromatin damage, although their developmental potential was the same as in the control embryos. In both cases, decreased mitotic rate was found, which resulted in decreased blastomere number even at low toxin concentration.
Motility is one of the most important characteristics associated with the fertilising ability of spermatozoa indicating their viability and structural integrity. Therefore, the examination of motility constitutes an integral part of semen analysis. Computer-assisted semen analysis (CASA) allows an accurate and objective assessment of different sperm motion characteristics with high repeatability. The aim of this study was to evaluate the different kinematic (velocity) parameters of frozen/thawed bull semen and determine if any of them could be correlated with their fertilising capability after insemination based on the achieved pregnancy rate. Ejaculates from 10 bulls were collected and frozen. The kinematic/velocity parameters of spermatozoa were measured by CASA and compared to the pregnancy results of almost 9,000 females artificially inseminated (AI) with frozen semen of any of the 10 tested bulls. The data of the experiments are summarised mainly with a focus on the effects of individual velocities (curvilinear velocity: VCL, straight-line velocity: VSL, average path velocity: VAP) on fertility rather than on the influence of progressive motility as a whole. We conclude that VAP is the most useful semen motility characteristic which has clinical relevance in the prediction of fertility.
Abstract
The objective of this study was to compare the efficiency of artificial insemination (AI) carried out with frozen and fresh, diluted and chilled semen under field conditions. One hundred and twenty-nine mares of different breeds were included in the study. Eighty-one out of the 107 mares inseminated with fresh, chilled semen got pregnant. Seven pregnant mares aborted and 74 foals were born. Out of the 22 mares inseminated with frozen semen, 17 mares got pregnant. Two mares out of the 17 pregnant mares aborted and finally 15 healthy foals were born. No difference was found between the two groups in the ratio of the foals born (P > 0.05). The comparison of medians for the number of insemination cycles did not show significant differences. However, a significant difference (Kruskal–Wallis test, P = 0.014) was found in the number of the inseminations per conception in favour of frozen semen (2.5 vs. 1.8 with fresh chilled and frozen semen, respectively). The Cox regression revealed that the type of semen has a significant impact (P < 0.001) on the service period (duration of the insemination period): the use of frozen semen prolonged the insemination period. This could be due to management issues, since re-insemination with frozen semen took place after only one/a few missed oestrous cycles not used for AI.
Abstract
The authors aimed to determine the plasma melatonin concentration in mares and their new-born foals in the early post-partum period. Blood samples were collected from the jugular vein of 53 mare-foal pairs within twelve hours after parturition. Plasma melatonin levels were measured by ELISA. The melatonin concentration, adjusted for the moment of parturition using a generalised linear model, was 34.58 pg mL−1 in mares. It was significantly lower (27.63 pg mL−1) in the new-born foals. However, the melatonin concentration declined differently by the end of the twelve hours, it decreased less in the offspring than in the mothers. An artificial light supplementation at the end of gestation reduced the melatonin concentration both in mares and their foals by about 10 pg mL−1, compared to the controls. An elevated melatonin production may be related to preparation of mares for parturition and ensures the chances of survival of offspring, therefore the melatonin may reach its peak at the moment of foaling regardless of its actual time. The effect of low melatonin concentration in new-born foals might be associated with the foal's health and subsequent performance. The need to monitor the melatonin concentration in the offspring justifies further studies.
The objective of this study was to compare the reproductive traits of heifers and the development characteristics of their calves following artificial insemination (AI) with sexed and non-sexed semen. The analysed characteristics included conception rate, gestation length, calf birth weight, calf vigour, stillbirth rate, and twinning rate. Data of 530 calves produced with sexed and 1,163 calves produced with non-sexed semen were analysed. The General Linear Model (GLM) was applied to assess the influence of semen type, farm, season of insemination, the calf’s sex and the inseminating sire on gestation length and calf birth weight. With the exception of gestation length (P > 0.05), all other traits studied were significantly (P < 0.01) influenced by the type of semen. The conception rate was 55% for conventional and 44% for sexed semen, and the average gestation length was 274.6 and 274.9 days, respectively. The mean calf birth weight was 37.47 kg for non-sexed and 36.75 kg for sexed semen. The stillbirth rate was 6.19% for conventional and 7.54% for sexed semen, while the twinning rate was 3.78% for conventional and 1.13% for sexed semen. The calves produced with non-sexed and sexed semen differed significantly in viability (P < 0.001), the latter having a lower calf vigour score. The use of conventional semen did not affect the ratio of female and male calves (52.7:47.3%; P > 0.05); however, artificial insemination with X-sorted sexed semen significantly altered the sex ratio of calves (85.1:14.9%, P < 0.01). The results obtained in this investigation are in agreement with the majority of studies which compared the fertility traits, sex ratio and calf characteristics depending on the application of artificial insemination with sexed or conventional semen.
Artificial insemination (AI) can undoubtedly be regarded as the oldest and most widely used assisted reproductive technique/technology (ART) applied in livestock production and it is one of the most important ARTs. The three cornerstones of its application are that it is simple, economical and successful. Artificial insemination offers many well-known benefits for producers. Fresh, fresh + diluted + chilled and frozen semen can be used for AI in small ruminants. To ensure its successful use, the AI technique must be selected on the basis of the type of semen planned to be used. This review paper gives a detailed overview of semen processing and its effects on semen quality, as well as of the AI techniques applied in small ruminants and their success rates.
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with widespread occurrence and diverse functions. It occurs in high levels in the gonads suggesting a potential central role in reproduction. The aim of our study was to assess the effect of PACAP treatment during embryo vitrification on the developmental rate and the expression of the heparin-binding EGF-like growth factor gene (Hbegf). Mouse embryos, obtained from superovulated females were allocated into the four treatment groups. In EM1 and EM2, the embryos were prepared for vitrification in an Equilibration Solution that was supplemented with 1 or 2 μM PACAP1-38, respectively. The embyos in groups CM1 and CM2 were not treated prior to vitrification but were cultured in a medium supplemented with 1 or 2 μM PACAP1-38 after thawing. The Vitrified Control group consisted of embryos vitrified and thawed then cultured without PACAP1-38 treatment. A non-vitrified, non-treated Fresh Control group was also used. After 24 h of culture, the developmental rate of the embryos, as well as the relative expression level of the Hbegf gene, as determined by qPCR, were compared among groups. Higher developmental rate and Hbegf gene expression level were found in the embryos treated with a higher concentration of PACAP. These results indicate that PACAP treatment has a beneficial effect on the survival and development of vitrified/thawed mouse embryos.
Abstract
Equine grass sickness (also known as dysautonomia) is a life-threatening polyneuropathic disease affecting horses with approx. 80% mortality. Since its first description over a century ago, several factors, such as the phenotype, intestinal microbiome, environment, management and climate, have been supposed to be associated with the increased risk of dysautonomia. In this retrospective study, we examined the possible involvement of genetic factors. Medical and pedigree datasets regarding 1,233 horses with 49 affected animals born during a 23-year period were used in the analysis. Among the descendants of some stallions, the proportion of animals diagnosed with dysautonomia was unexpectedly high. Among males, the odds of dysautonomia were found to be higher, albeit not significantly, than among females. Significant familial clustering (genealogical index of familiality, P = 0.001) was observed among the affected animals. Further subgroups were identified with significant (P < 0.001) aggregation among close relatives using kinship-based methods. Our analysis, along with the slightly higher disease frequency in males, suggests that dysautonomia may have a genetic causal factor with an X-linked recessive inheritance pattern. This is the first study providing ancestry data and suggesting a heritable component in the likely multifactorial aetiology of the disease.
The objective of this study was to evaluate the effect of long-term melatonin treatment applied during the non-breeding season on semen characteristics, endocrine function of testicles and baseline level of insulin-like growth factor-I (IGF-I) in Awassi rams kept in the temperate continental zone of Europe and used as semen donors in an artificial insemination (AI) programme. On 23 February (day 0), slow-release melatonin implants were inserted subcutaneously into rams (n = 8). Control animals (n = 8) received no treatment. In both groups, basic semen parameters (concentration, total motility, fast and slow forward motility, morphology), GnRH-induced testosterone response and basal IGF-I concentration were evaluated on days 0, 47 and 71. No differences were found in concentration of spermatozoa, total motility, and numbers of spermatozoa with fast and slow progressive motility and normal/abnormal morphology between the melatonin-treated and the control group. However, in melatonin-treated animals, basal and GnRH-induced testosterone levels were slightly elevated on day 47 and became significantly higher on day 71 (P < 0.05) as compared to controls. There was no difference in plasma IGF-I levels between the groups. In conclusion, slow-release melatonin applied during the non-breeding season improves testicular testosterone production but does not influence the semen characteristics and the IGF-I level of semen donor Awassi rams used in an AI programme and kept in the temperate continental zone of Europe.
