Jo Bijttebier

Preovulatory follicular fluid during in vitro maturation decreases polyspermic fertilization of cumulus-intact porcine oocytes: In vitro maturation of porcine oocytes

Porcine follicular fluid (pFF), as a supplement of maturation media, has been shown several times to improve the in vitro production (IVP) of porcine embryos. As a transudate of serum, pFF contains locally produced factors in addition to the ones derived from serum. The objective of this study was to determine the additional positive effects of these pFF specific factors on the nuclear and cytoplasmic maturation of porcine oocytes. Follicular fluid and autologous serum were collected from sows in the preovulatory phase of the estrous cycle. Subsequently, oocytes from prepubertal gilts were matured in NCSU23 supplemented with either 10% pFF or 10% autologous serum derived from the same sow. Oocytes were then fertilized and the putative zygotes were cultured for 7 days. Nuclear maturation and cumulus expansion were assessed after the maturation culture. For evaluation of cytoplasmic maturation, oocyte glutathione (GSH) content, fertilization parameters and embryonic development were evaluated. After in vitro maturation (IVM) of the oocytes, both cumulus expansion rate and oocyte GSH content were increased for oocytes matured in pFF (P<0.05). More monospermic penetration was found when cumulus-intact oocytes had been matured in 10% pFF but this effect was lost after fertilization of cumulus denuded oocytes indicating that the pFF was acting through the cumulus. We speculate that the increased cumulus expansion and increased glutathione content, which were prevalent after IVM in pFF, are responsible for the positive effects on fertilization and the pre-implantation development of the embryos.

Short-term exposure to hydrogen peroxide during oocyte maturation improves bovine embryo development

Recent studies have shown that short-term exposure of oocytes to a stressor such as hydrostatic pressure or osmotic stress might induce stress tolerance in embryos. The aim of the present study was to investigate the consequences of short-term hydrogen peroxide (H(2)O(2)) exposure to bovine in vitro matured cumulus-oocyte complexes (COCs) on subsequent preimplantation embryo development and apoptosis. In the first experiment, mature COCs were incubated in H(2)O(2) at concentrations ranging between 0.01 and 100 micromol/l, and subsequently fertilized and cultured. Oocyte incubation with 50-100 micromol/l of H(2)O(2) resulted in a significantly higher blastocyst yield (47.3%) in comparison with control medium (31.8%), while apoptotic cell ratio was inversely related with H(2)O(2) concentration. In the second experiment, we showed that the stress tolerance after H(2)O(2) exposure was not mediated by increased glutathione content in treated oocytes nor by enhanced fertilization or penetration. Further research should concentrate on the potential role of players that have been associated with stress tolerance in somatic cell lines.

Opportunities and barriers to on-farm composting and compost application: A case study from northwestern Europe.

Maintaining and increasing soil quality and fertility in a sustainable way is an important challenge for modern agriculture. The burgeoning bioeconomy is likely to put further pressure on soil resources unless they are managed carefully. Compost has the potential to be an effective soil improver because of its multiple beneficial effects on soil quality. Additionally, it fits within the bioeconomy vision because it can valorize biomass from prior biomass processing or valorize biomass unsuitable for other processes. However, compost is rarely used in intensive agriculture, especially in regions with high manure surpluses. The aim of this research is to identify the barriers to on-farm composting and the application of compost in agriculture, using a mixed method approach for the case of Flanders. The significance of the 28 identified barriers is analyzed and they are categorized as market and financial, policy and institutional, scientific and technological and informational and behavioral barriers. More specifically, the shortage of woody biomass, strict regulation, considerable financial and time investment, and lack of experience and knowledge are hindering on-farm composting. The complex regulation, manure surplus, variable availability and transport of compost, and variable compost quality and composition are barriers to apply compost. In conclusion, five recommendations are suggested that could alleviate certain hindering factors and thus increase attractiveness of compost use in agriculture.

Comparative proteome analysis of porcine follicular fluid and serum reveals that excessive α2-macroglobulin in serum hampers successful expansion of cumulus-oocyte complexes

Porcine follicular fluid (pFF) constitutes the micro‐environment of the maturing oocyte. Although pFF is a transudate of serum, in pigs, it is superior to serum in promoting in vitro expansion of the cumulus cells, a specialized cell population surrounding the oocyte. A comparative proteome analysis of autologous serum and pFF was performed to investigate proteins involved in successful cumulus expansion of porcine oocytes. iTRAQ labeling followed by 2‐D LC ESI‐Q‐TOF MS/MS revealed 63 proteins common to both fluids of which the abundance of 13 proteins was significantly different (p<0.05). Seven proteins were more concentrated in serum whereas six proteins were more abundant in pFF. To investigate the importance of these proteins, the cumulus matrices of COCs were collected after in vitro maturation in media supplemented with either of both biologically fluids and then subjected to 2‐D PAGE analysis. α2‐Macroglobulin and CH4 and secrete domains of swine IgM, which were both less abundant in pFF, were absent from cumulus matrix extracts after in vitro maturation in pFF. Although both proteins were incorporated in the matrices of cumulus‐oocyte complexes matured in serum, depletion of α2‐macroglobulin from serum could significantly compensate for the impaired cumulus expansion of oocytes matured in serum.

Farm level implementation of soil conservation measures: farmers’ beliefs and intentions

Understanding motivating factors for taking soil conservation measures is seen as key to improving on-farm implementation. However, to date only few on-farm conservation measures have been investigated. The objective of this paper is to investigate the influence of farmers’ subjective beliefs on their intention to apply and actual implementation of cover cropping, with the region of Brandenburg (Germany) as a case. An additional objective was to investigate how these insights can contribute to increase farm level implementation of soil conservation measures. Theory of planned behavior provides an approach to understand human behavior by analyzing farmers’ subjective beliefs. Our results, based on a survey of 96 farmers, show that attitudes (ATTs) and perceived difficulty significantly explain variations in intention to apply cover cropping, with ATTs being generally very positive. We discuss that, in this case, the most effective way to increase on-farm implementation is to decrease the farmers’ perception of difficulty. This can be achieved by providing information to farmers on how to overcome barriers to implementation of conservation measures. In-depth insights into belief structures reveal what kind of information is most useful in the case of cover cropping.

Vitronectin and Its Receptor (Integrin αvβ3) During Bovine Fertilization In Vitro

The complex series of molecular interactions between male and female gametes required for successful fertilization has captured the interest of several research groups for many years (Benoff 1997). Even though substantial insights into these interactions have been elucidated in particular in human and mouse (Fusi et al. 1992; 1996a; 1996b; Almeida et al. 1995; Evans et al. 1995; Bronson & Fusi 1996), a clear identification of the underlying mechanisms and molecules implicated in bovine fertilization is still required. The involvement of numerous carbohydrates and glycoproteins in adhesion and binding events during several reproductive processes has been described in ruminants, ranging from roles in spermoviduct adhesion (Revah et al. 2000; Talevi & Gualtieri 2001; Sostaric et al. 2005; Gwathmey et al. 2006; Ignotz et al. 2007), sperm-oocyte interactions (Gougoulidis et al. 1999; Amari et al. 2001; Tanghe et al. 2004a; 2004b) to embryo implantation (Spencer et al. 2004).