Bioscientifica Proceedings

There is still much we do not understand about the metabolic requirements of oocytes and embryos. Their remarkable metabolic plasticity during in vitro culture has hampered our ability to make significant advances in culture media design that would better support optimal physiology. A new tool, metabolomics, may revolutionize what we know about the interactions between embryos and their culture environment. Armed with this knowledge, we may design more effective culture ...

This review describes effects of variation in the interval between insemination and ovulation on the fertilization process in the sow. Inseminations performed too early or too late relative to ovulation decrease litter size and especially farrowing rate. This effect can be explained to a large extent by the increase in the percentage of non-fertilized eggs, resulting in partial fertilization or no fertilization at all. No effects of variation in the interval from insemina...

Oestrus is the period around ovulation in which sows show a standing response for boars, thus allowing the boars to mate with the sows. The duration of oestrus may vary between sows from 24 h up to 96 h, which is not related to systemic oestrogen concentrations. The moment of ovulation after onset of oestrus may vary from 10 h to 85 h. Consequently, onset of oestrus is not a good predictor for the time of ovulation. A reliable prediction of ovulation time would be worthwh...

A series of integrated, effective techniques is required to produce pig embryos from follicular oocytes in vitro. The failure to form a male pronucleus and polyspermy have been serious problems in efforts to produce embryos efficiently in vitro from pig oocytes. The former problem is now considered to be due to oxidative stress and the latter has been partially solved by reducing the number of capacitated spermatozoa reaching the oocytes. By the use of n...

The formation, normal function and destruction of corpora lutea are essential features of normal reproduction. Although the formation of corpora lutea from follicles is largely dependent on pituitary gonadotrophins, the process of luteolysis is locally regulated and poorly understood. The corpus luteum consists of several steroidogenic and nonsteroidogenic cell types that interact with each other in a paracrine manner. Under cell culture conditions, large luteal cells tha...

Keywords: prolactin; ovarian function; luteal cells; steroidogenesis; pig© 1990 Journals of Reproduction & Fertility Ltd...

During ejaculation in the boar, sperm cohorts emitted in epididymal cauda fluid are sequentially exposed and resuspended in different mixtures of accessory sex gland secretion. This paper reviews the relevance of such unevenly composed fractions of seminal plasma (SP) in vivo on sperm transport and sperm function and how this knowledge could benefit boar semen processing for artificial insemination (Al). The firstly ejaculated spermatozoa (first 10 ml of the spe...

Abstract unavailable© 1995 Journals of Reproduction and Fertility Ltd...

Secreted peptide hormones and components of the steroidogenic machinery are molecules that are expressed usually in high amounts and in a time- and cell-specific fashion within the cells that give rise to the bovine corpus luteum. They thus serve as useful markers for the events occurring within the nuclei of these cells that result in differentiation and the expression of the specific luteal phenotype. We have studied the bovine genes of three such luteal products: oxytocin, ...

Abstract unavailable© 1995 Journals of Reproduction and Fertility Ltd ...