Journal of reproduction and fertility. Supplement最新文献

{"title":"Influence of light and photoperiodicity on pig prolificacy.","authors":"R. Claus, U. Weiler","doi":"10.1530/biosciprocs.12.0014","DOIUrl":"https://doi.org/10.1530/biosciprocs.12.0014","url":null,"abstract":"In the wild pig mating activity is seasonal. The main breeding period is in late autumn but a second period may occur around April. It is known from other species that seasonal variations in breeding activity are mainly regulated by photoperiod. In the domestic pig seasonal influences on prolificacy still exist: for example, AI boars not only show decreased steroid synthesis, sperm counts and libido in summer compared with the optima which occur in winter but also a biphasic pattern with a transient increase in spring. In cyclic sows ovarian function may be affected with anoestrus mainly in summer and occasionally in February/March. Additionally ovulation rate may be lower in summer and the duration of oestrus prolonged compared with that in late autumn and winter. In consequence the interval from weaning to oestrus is prolonged in summer and mating during this season leads to lower conception rates and slightly smaller litters. Light programmes which extend the daily light period to a constant 15-16 h seem to be ineffective in improving reproductive characteristics of the sow but stimulate the sucking frequency of piglets and increase survival of piglets with a low birthweight. Simulation, in summer, of the decreasing photoperiod (naturally occurring in autumn) stimulates the reproductive characteristics of AI boars, optimizing testicular steroid production, libido and semen composition. Similarly, a programme of decreasing light (20 min decrease/week) from May to August removed the seasonal increase (June-August) of the weaning-to-oestrus interval which was 5.7 days (compared with 23.6 days for the controls). An interaction between photoperiod and puberty attainment seems to exist for male and female pigs. Further experiments with appropriate light programmes, however, are necessary to clarify this interaction.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"6 1","pages":"185-97"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74355707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of uterine immune cells in early pregnancy in pigs.","authors":"H. Engelhardt, B. Croy, Gordon J. King","doi":"10.1530/biosciprocs.15.009","DOIUrl":"https://doi.org/10.1530/biosciprocs.15.009","url":null,"abstract":"The immune system discriminates 'self' from 'non-self', and eliminates that which it determines to be non-self. Mammalian pregnancy appears to represent a failure of self-non-self discrimination, yet it is a highly successful reproductive strategy. We present evidence that the immune system of the female pig responds to the challenges of both mating and the presence of conceptuses. Mating induces an influx of inflammatory leukocytes into the endometrial stroma and uterine lumen. This response, while partially under endocrine control, is amplified by as yet unidentified factors in seminal plasma. In addition to preventing microbial infection, this mating-induced immune response may enhance reproductive performance. During the first month of pregnancy when intimate contact between maternal and fetal tissues is being established, the number of uterine lymphocytes decrease in the luminal epithelium and increase in the endometrial stroma at sites of conceptus attachment. The majority of these lymphocytes express the CD2 and CD8 surface markers, consistent with either T or natural killer (NK) cell lineage. Dispersed endometrial cells obtained during early gestation exhibit a pregnancy-specific increase in NK-like lytic activity. Our ongoing efforts to determine whether these NK-like lymphocytes are the ones that localize to sites of conceptus attachment are discussed. We speculate on how the reactions of pig uterine leukocytes to seminal plasma and conceptuses might contribute to successful pregnancy.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"9 1","pages":"115-31"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83047316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanisms mediating the stimulatory effects of the boar on gilt reproduction.","authors":"P. Hughes, G. Pearce, A. Paterson","doi":"10.1530/biosciprocs.13.0023","DOIUrl":"https://doi.org/10.1530/biosciprocs.13.0023","url":null,"abstract":"The major stimulatory effects of boar presence on female pig reproduction are well documented. The boar can stimulate the early appearance of first oestrus in the prepubertal gilt, the lactating sow and the weaned sow. Additionally, boar presence may influence the exhibition and detection of oestrus, together with the sow's receptivity (see Hemsworth & Barnett, 1990). Boar involvement in other aspects of sow reproduction such as the maintenance of cyclicity and pregnancy have also been postulated, although few research data are currently available. In this review the prepubertal gilt is used as the model for response of female pigs to boar stimuli, as most of the research data is to be found in this area. Since the major boar effects have been known for some time it may appear surprising thanhe mechanism controlling them is not well understood. This may be partly due to the variation observed between studies in female response to boar contact, probably reflecting confounding factors such as genotype, climatic and housing environment, nutritional status and the age of the gilt. There is also evidence that the manner of boar exposure will influence the response of the female, since variations in the length and frequency of the exposure period and, possibly, the size of the exposure pen all affect the level of stimulation perceived by the female. These interactions clearly influence the response of gilts to boar exposure. They therefore reeeive early attention in this review. The roles of individual components of the boar in gilt stimulation are then considered. Finally endocrine responses of gilts to boar exposure, or exposure to boar-component stimuli, are evaluated and a tentative mechanism of action of the boar effect is postulated.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"1 1","pages":"323-41"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90291248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Local regulatory factors controlling folliculogenesis in pigs.","authors":"S. Tonetta, G. diZerega","doi":"10.1530/biosciprocs.13.0011","DOIUrl":"https://doi.org/10.1530/biosciprocs.13.0011","url":null,"abstract":"Although many excellent reviews have summarized follicular development from the perspective of gonadotrophin-induced follicular differentiation and steroid secretion (Richards, 1980), the process of selection and dominance of ovulatory follicles during each ovarian cycle remains poorly understood. The present review will focus primarily on the role of intragonadal substances in the regulation of follicular maturation. Since previous summaries have considered follicular maturation with respect to prostaglandins (Aksel et at, 1977), insulin, somatomedins (Adashi et at, 1985), relaxin (Bagnell et al., 1987), lipoproteins (Gwynne & Strauss, 1982) and gonadotrophinreleasing hormone (Gn RH) (Knecht et al., 1983), details of these topics will not be repeated here. Rather, we will review the growing body of data from experiments using predominantly follicular tissue and cells from the sow which address the intraovarian regulation of folliculogenesis. Gonadotrophins play a role in initiation and maintenance of follicular growth, selection of dominant follicles and their maturation to preovulatory status. Evidence for this is derived from changes in blood concentrations of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), concomitant alterations in the number and type of gonadotrophin receptors in granulosa and theca cells, and from the secretion of steroidal and non-steroidal products by these cells in response to gonadotrophin stimulation. However, follicular growth cannot be accounted for entirely by the changing concentrations of gonadotrophins. Rather, the developing responsiveness of follicles to stimulation by FSH and LH results from changes in the production of and alterations in follicular sensitivity to intraovarian paracrine and/or autocrine factors (Tonetta & diZerega, 1986). In this context, gonadotrophins are necessary, but not sufficient by themselves, to account for the ovarian cycle. In recent years, several intragonadal regulators have been identified and characterized which can alter follicular maturation. In addition to the well-known paracrine factors discussed below, additional paracrine regulators have been identified but their function is still uncertain (see Tonetta & diZerega, 1989).","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"35 1","pages":"151-61"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91525345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence for and implications of follicular heterogeneity in pigs.","authors":"M. Hunter, T. Więsak","doi":"10.1530/biosciprocs.13.0012","DOIUrl":"https://doi.org/10.1530/biosciprocs.13.0012","url":null,"abstract":"Follicular heterogeneity has been demonstrated in both naturally cyclic and PMSG-stimulated immature gilts in that follicles in the selected ovulatory population differ in size by up to 2 mm and show marked variability in steriod content and gonadotrophin binding ability. This biochemical and morphological asychrony continued into the immediate preovulatory phase and changes in response to the LH surge did not always occur simultaneously even in the same follicle or in all follicles within an ovary. It is suggested that these differences in follicular maturation immediately before ovulation may result in heterogeneity in the population of corpora lutea. Following oestrus or hCG administration, oocyte maturation was again not completely synchronous in all follicles within an animal. It is proposed that follicular heterogeneity has implications for oocyte maturation and early embryonic development.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"13 1","pages":"163-77"},"PeriodicalIF":0.0,"publicationDate":"2020-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84413183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early uterine development in pigs.","authors":"F. Bartol, A. Wiley, Thomas E. Spencer, Jeffrey L. Vallet, R. K. Christenson","doi":"10.1530/biosciprocs.14.007","DOIUrl":"https://doi.org/10.1530/biosciprocs.14.007","url":null,"abstract":"The capacity of pig uterine tissues to recognize and respond to maternal and conceptus signals determines whether pregnancy can be established and defines the environment in which embryonic and fetal growth occur. Limits of uterine capacity may be defined genetically. However, the extent to which functional uterine capacity approaches genetic potential may be determined, in part, by the success of organizational events associated with growth, morphogenesis and cytodifferentiation of uterine tissues. It is important, therefore, that these events be identified and evaluated with respect to their potential effect on adult uterine function. Histogenesis of the pig uterus begins prenatally, but is completed postnatally. Transformation of the uterine wall from histoarchitectural infancy to maturity occurs between birth and day 120. Morphogenetic events characteristic of the first 60 days of neonatal life proceed normally in gilts ovariectomized at birth. These events include appearance and proliferation of uterine glands, development of endometrial folds, and growth of the myometrium. Endometrial development during this period involves alterations in patterns of epithelial and stromal DNA synthesis, coordinated changes in the distribution and biosynthesis of extracellular matrix glycosaminoglycans and cell surface glycoconjugates, and specific alterations in patterns of uterine protein secretion. The ovary-independent, spatially coordinated nature of these events suggests that neonatal uterine development is regulated locally via dynamic cell-cell and cell-extracellular matrix interactions. The extent to which such potentially critical interactions must be preserved to ensure developmental success remains unknown. However, the normal pattern of ovary-independent cellular and molecular events associated with development of the uterine wall was disrupted by treating neonatal gilts with oestradiol valerate, and daily administration of oestrogen to gilts from birth to day 13 did not affect ovulation rate, but did reduce embryonic survival by 22% on day 45 of gestation in adults that were exposed to oestrogen neonatally. These observations support the idea that some organizational events associated with development of the neonatal uterine wall must be allowed to proceed without interruption to ensure that adult uterine function is not compromised. Efforts to identify specific developmental determinants of uterine capacity may be facilitated by examining the consequences of xenobiotically induced interruption of uterine development on adult uterine function. Such studies may also contribute to identification of uterine factors affecting embryonic survival and fetal growth.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"106 1","pages":"99-116"},"PeriodicalIF":0.0,"publicationDate":"2020-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73648708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal effects on fertility in gilts and sows.","authors":"R. Love, Gareth Evans, C. Klupiec","doi":"10.1530/biosciprocs.14.0013","DOIUrl":"https://doi.org/10.1530/biosciprocs.14.0013","url":null,"abstract":"The ancestral wild pig is a short day length seasonal breeder. The domestic pig appears to have retained some of this seasonality as evidenced by a reduction in fertility during the summer-autumn period. The most important aspect of this seasonality is a reduction in the number of mated sows that farrow. Many of these sows conceive and embryos develop normally for 20-25 days before pregnancy is terminated and the sow returns to oestrus (25-35 days after mating). In other species, transduction of photoperiodic information is achieved by release of melatonin during the dark period. In the pig, the pattern of melatonin secretion and the subsequent hypothalamo-pituitary-gonadal responses appear to be more complex. A relatively high light intensity is required for pigs to generate a distinct diurnal melatonin rhythm and they appear unable to respond appropriately to abrupt changes in photoperiod. Pigs on restricted feeding and maintained under long photoperiods (but not under short photoperiods) have higher concentrations of melatonin than do similarly maintained pigs fed ad libitum. Continuous release melatonin implants have a deleterious effect on farrowing rate, suggesting that the abnormally high melatonin concentrations observed in sows in summer-autumn play a role in the pathogenesis of seasonal infertility. Ad libitum feeding of sows during the first few weeks of pregnancy may prevent the increase in melatonin concentrations and so remove the seasonal influence on fertility. The pituitary response to different photoperiods is also somewhat confusing. Although there is some evidence of increased sensitivity to the negative feedback of ovarian steroids in the prepubertal gilts and weaned sows during summer-autumn, LH concentrations are increased in early pregnant sows. It is proposed that the failure of sows to maintain pregnancy in summer-autumn results from disruption of maternal recognition of pregnancy causing regression of the corpora lutea, loss of pregnancy and return of the sow to oestrus.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"1 1","pages":"191-206"},"PeriodicalIF":0.0,"publicationDate":"2020-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82350351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of nutrition on pregnant and lactating sows.","authors":"S. Einarsson, T. Rojkittikhun","doi":"10.1530/biosciprocs.14.0016","DOIUrl":"https://doi.org/10.1530/biosciprocs.14.0016","url":null,"abstract":"It has been suggested that the long-term reproduction of the sow is best served by minimizing weight and fat loss in lactation. Such a strategy would require only a minimal restoration of weight in the following pregnancy, which would be beneficial, since the greater feed intake and weight gain in pregnancy, the greater the weight loss in lactation. Feeding ad libitum should be practised during lactation while gestation feed intake must be held low. A relationship between feed intake and embryo survival has been demonstrated in several studies, but the data are sometimes difficult to interpret. High energy feeding during the premating period and during early pregnancy, however, are often associated with increased embryo mortality. A short-term starvation in lactation decreased prolactin to post-weaning concentrations, and insulin and glucose to very low concentrations. Prolactin increased very rapidly after refeeding indicating that a neural mechanism might be involved. The increasing levels of cholecystokinin after refeeding and the neural reflex triggered might be related to this increase in prolactin. No changes in LH release were observed during the periods of starvation or refeeding. The catabolic rate during the first week of lactation is higher in sows with higher backfat thickness than in late gestation. As lactation progresses a more balanced metabolism is achieved regardless of backfat thickness before parturition. High-weight-loss primiparous sows need a longer recovery period from their negative energy balance during lactation than do low-weight-loss primiparous sows or multiparous sows. Several investigations have demonstrated that sows losing excessive amounts of body weight have extended weaning to oestrous intervals and an increase in anoestrus. Sows with low body-weight loss during lactation have higher plasma insulin and lower cortisol around weaning than do sows with high body-weight loss. What remains undefined is the degree of weight or condition loss below which an extension in the remating interval will occur and the level of dietary energy intake required to prevent this extension.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"15 1","pages":"229-39"},"PeriodicalIF":0.0,"publicationDate":"2020-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89507429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cytoplasmic inheritance and its effects on development and performance.","authors":"L. Smith, A. Alcivar","doi":"10.1530/biosciprocs.14.003","DOIUrl":"https://doi.org/10.1530/biosciprocs.14.003","url":null,"abstract":"In contrast to nuclear inheritance, cytoplasmic inheritance in mammals is derived mostly, if not exclusively, from the maternal line. Mitochondria, and their DNA molecules (mtDNA), are the genetic units of this method of inheritance. Mammalian mtDNA codes for 13 enzymes used in the mitochondrial energy-generating pathway, oxidative phosphorylation, 22 tRNAs and two rRNAs. Although all transcripts of mtDNA and their translational products remain in the mitochondria, most proteins used in mitochondria are from nuclear DNA and are imported after synthesis on cytoplasmic ribosomes. Spermatozoa introduce a small number of mitochondria into the cytoplasm of the egg at fertilization, which appear to be digested soon after penetration. Although the paternal contribution of mtDNA to the offspring is not believed to occur in mammals, some interspecific crosses have suggested that it does occur. Experiments with animals derived from reconstituted embryos, using nuclear or cytoplasmic transplantations, suggest that nuclear-mitochondrial interactions are important but not essential in the survival and replication of exogenous mitochondria introduced into the egg. As the levels of heteroplasmy varied in several tissues of animals derived from reconstituted embryos, it is suggested that differential partitioning of mitochondria occurs during embryogenesis. Mitochondrial morphology changes substantially during oogenesis and throughout early cleavage stages. Somatic morphology and normal replication patterns are regained at the blastocyst stage. In pig oocytes and embryos, mitochondria aggregate and are closely associated with endoplasmic reticulum, lipid granules and large vesicles. Although the direct correlation of mitochondrial genes with reproductive traits is still unclear, some human degenerative diseases and performance traits in cattle can be related directly to specific mtDNA polymorphisms. In pigs, reciprocal-cross comparisons have indicated greater offspring parent similarity with dam than sire for lean:fat ratio. A difference was also observed for oxygen consumption and oxidative phosphorylation, but not for anaerobic energy metabolism, in a pig reciprocal-cross experiment. Information on the transmission of mtDNA and its effects on performance will have many implications not only for our understanding of mitochondrial genetics but also for the increased productivity of animals. There are also potential ramifications to the animal cloning industry.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"31 1","pages":"31-43"},"PeriodicalIF":0.0,"publicationDate":"2020-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90904719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Follicle-oocyte-sperm interactions in vivo and in vitro in pigs.","authors":"M. Sirard, A. Dubuc, D. Bolamba, Y. Zheng, K. Coenen","doi":"10.1530/biosciprocs.14.001","DOIUrl":"https://doi.org/10.1530/biosciprocs.14.001","url":null,"abstract":"In vitro culture has provided new information on the mechanisms involved in fertilization where two completely different cells fuse together. At the same time, results obtained in vitro have led to new questions. Does the follicle influence the final maturation process of the oocyte and does the oviduct regulate the normal behaviour of spermatozoa? Recent studies indicate a critical influence of both the follicular compartment and the oviduct on the normal fertilization process. Oocytes matured in vivo are more competent to induce pronuclear formation, but are still susceptible to polyspermy. Oocytes matured in vitro can develop fully after fertilization, but require the presence of follicular factors during culture to enhance their developmental competence. Fresh or frozen spermatozoa can penetrate oocytes in vitro, but their conditioning by differential centrifugation or oviductal cells influences the rate of polyspermy. The understanding of these influences is a prerequisite to enhancing in vitro production of pig embryos.","PeriodicalId":16956,"journal":{"name":"Journal of reproduction and fertility. Supplement","volume":"80 1","pages":"3-16"},"PeriodicalIF":0.0,"publicationDate":"2020-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90914263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}