Expression profiles of genes regulating dairy cow fertility: recent findings, ongoing activities and future possibilities

Subfertility has negative effects for dairy farm profitability, animal welfare and sustainability of animal production. Increasing herd sizes and economic pressures restrict the amount of time that farmers can spend on counteractive management Genetic improvement will become increasingly important to restore reproductive performance. Complementary to traditional breeding value estimation procedures, genomic selection based on genome-wide information will become more widely applied. Functional genomics, including transcriptomics (gene expression profiling), produces the information to understand the consequences of selection as it helps to unravel physiological mechanisms underlying female fertility traits. Insight into the latter is needed to develop new effective management strategies to combat subfertility. Here, the importance of functional genomics for dairy cow reproduction so far and in the near future is evaluated. Recent gene profiling studies in the field of dairy cow fertility are reviewed and new data are presented on genes that are expressed in the brains of dairy cows and that are involved in dairy cow oestrus (behaviour). Fast-developing new research areas in the field of functional genomics, such as epigenetics, RNA interference, variable copy numbers and nutrigenomics are discussed including their promising future value for dairy cow fertility

Gene expression patterns in anterior pituitary associated with quantitative measure of oestrous behaviour in dairy cows

Intensive selection for high milk yield in dairy cows has raised production levels substantially but at the cost of reduced fertility, which manifests in different ways including reduced expression of oestrous behaviour. The genomic regulation of oestrous behaviour in bovines remains largely unknown. Here, we aimed to identify and study those genes that were associated with oestrous behaviour among genes expressed in the bovine anterior pituitary either at the start of oestrous cycle or at the mid-cycle (around day 12 of cycle), or regardless of the phase of cycle. Oestrous behaviour was recorded in each of 28 primiparous cows from 30 days in milk onwards till the day of their sacrifice (between 77 and 139 days in milk) and quantified as heat scores. An average heat score value was calculated for each cow from heat scores observed during consecutive oestrous cycles excluding the cycle on the day of sacrifice. A microarray experiment was designed to measure gene expression in the anterior pituitary of these cows, 14 of which were sacrificed at the start of oestrous cycle (day 0) and 14 around day 12 of cycle (day 12). Gene expression was modelled as a function of the orthogonally transformed average heat score values using a Bayesian hierarchical mixed model on data from day 0 cows alone (analysis 1), day 12 cows alone (analysis 2) and the combined data from day 0 and day 12 cows (analysis 3). Genes whose expression patterns showed significant linear or non-linear relationships with average heat scores were identified in all three analyses (177, 142 and 118 genes, respectively). Gene ontology terms enriched among genes identified in analysis 1 revealed processes associated with expression of oestrous behaviour whereas the terms enriched among genes identified in analysis 2 and 3 were general processes which may facilitate proper expression of oestrous behaviour at the subsequent oestrus. Studying these genes will help to improve our understanding of the genomic regulation of oestrous behaviour, ultimately leading to better management strategies and tools to improve or monitor reproductive performance in bovines

Muscle transcriptomes of Duroc and Pietrain pig breeds during prenatal formation of skeletal muscle tissue using microarray technology

Mammalian myogenesis is an exclusive prenatal process regulated by the muscle regulatory factor gene family, which itself is regulated by numerous other genes. We developed a microarray consisting of the clones of two muscle-specific cDNA libraries with the addition of 500 genes with known function in myogenesis and energy metabolism. Tissue samples were collected of Duroc and Pietrain prenatal litters of 14 and 21 days of age (complete embryos) and 35, 49, 63, 77, and 91 days of age (longissimus muscle tissue) and RNA was isolated. Microarrays were hybridised with pools of six RNA samples. For each age comparisons between Duroc and Pietrain breeds were made, and transcriptome profile changes in time were made for Duroc pigs. Comparison of Duroc and Pietrain prenatal muscle transcriptome expression profiles revealed differences in myogenesis regulating genes, suggesting differential timing of myogenesis between the two pig breeds. The differential development of the expression of the muscle structural genes strengthens this conclusion. Furthermore, differences in the expression of the energy metabolism genes were found. The results also suggest that the differential fat content between the Duroc and Pietrain pig breeds already starts to develop during early prenatal development. The changes in the muscle transcriptome expression profiles during Duroc prenatal muscle development shows a profile of waves of expression of (i) myoblast proliferation stimulating genes,(ii) followed by myoblast proliferation inhibiting and differentiation stimulating genes during the primary muscle fibre development, which is repeated with lower magnitude during secondary muscle fibre development. Furthermore, expression of energy metabolism genes reaches a nadir when differentiation of myoblasts into myotubes takes place. Microarray expression profiles were validated with five genes showing differential expression in the Duroc ¿ Pietrain comparison, and in the Duroc development in time studies using 18S rRNA for normalisation. The real time PCR confirmed the microarray result

Winning en cryoconservering van sperma van zeldzame Nederlandse konijnenrassen voor de genenbank

In dit rapport wordt beschreven welke activiteiten CGN in samenwerking met de SZH, KLN en individuele fokkers hebben ondernomen om genetisch materiaal van konijnenrassen veilig te stellen in de genenbank. Op basis van literatuur en praktijkervaringen is een protocol voor spermawinning en spermaverwerking (cryoconservering) vastgesteld. Een dergelijk protocol was niet beschikbaar in de Nederlandse bedrijfsmatige konijnenhouderij omdat daar uitsluitend met vers sperma gewerkt wordt en niet met ingevroren sperma. Het rapport eindigt met een beschrijving van de resultaten van de spermawinning

Transcription networks responsible for early regulation of Salmonella_induced inflammation in the jejunum of pigs

Background The aim of this study was to identify transcription factors/regulators that play a crucial role in steering the (innate) immune response shortly (within a few hours) after the first contact of the intestinal mucosa with an inflammatory mediator, and to test whether the processes regulated by these factors/regulators can be modulated by chemical substances of natural origin. Methods We experimentally induced inflammation by perfusion of surgically applied jejunal loops with Salmonella enterica subspecies enterica serovar Typhimurium DT104 in three pigs. Segments of mock and Salmonella treated loops were dissected after 2, 4 and 8¿hours of perfusion. IL8 and IL1-beta mRNA expression levels were measured in mucosal scrapings of all segments. Furthermore, intra-animal microarray comparisons (isogenic) between Salmonella and mock treated segments after 8¿hours, and inter-animal comparisons between similar Salmonella-treated loops of each pig at 2 and 4¿hours, were performed. Results IL-1beta and IL8 mRNA levels, and intra-animal microarray comparisons at 8¿hours between Salmonella and mock treated segments showed that the response-time and type of response to Salmonella was different in all three pigs. This plasticity allowed us to extract a comprehensive set of differentially expressed genes from inter-animal comparisons at 2 and 4¿hours. Pathway analysis indicated that many of these genes play a role in induction and/or tempering the inflammatory response in the intestine. Among them a set of transcription factors/regulators known to be involved in regulation of inflammation, but also factors/regulators for which involvement was not expected. Nine out of twenty compounds of natural origin, which according to literature had the potential to modulate the activity of these factors/regulators, were able to stimulate or inhibit a Salmonella-induced mRNA response of inflammatory-reporter genes IL8 and/or nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha in cultured intestinal porcine epithelial cells. Conclusions We describe a set of transcription factors/regulators possibly involved in regulation of “very early” immune mechanism which determines the inflammatory status of the intestine later on. In addition, we show that these mechanisms may be modulated by chemical substances of natural origin. Keywords: Transcription regulation; Salmonella-induced inflammation; Pig intestin

Failing to pay heed to health warnings in a food-associated environment

People often fail to adhere to food-related health information. Increasing evidence suggests that environmental stimuli interfere with good intentions by triggering choices relatively automatically. Using a Pavlovian-instrumental transfer (PIT) task, we examined whether food-associated stimuli reduce health warnings’ effectiveness. We expected that people adhere to health warnings in the absence, but not presence, of food-associated stimuli. In addition, we examined timing effects, i.e., whether health warnings are more effective when they are given prior to associative learning rather than afterwards. In the PIT task, participants learned to press keys for two food rewards (instrumental learning) and associations between stimuli and these rewards (Pavlovian learning) in separated phases. Health warnings about one reward were given after associative learning (Study 1), or before versus afterwards (Study 2). During test phase, participants pressed for food outcomes while occasionally food-related stimuli were presented. In absence of food-related stimuli, participants increased responding for rewards perceived as more healthy. However, when stimuli were present, responding was biased towards the signaled outcome, regardless of health warnings or timing. Health messages influence food choice behavior, but are no longer effective when food-associated stimuli are present. This provides important insights why health warning effects might be limited in an obesogenic environment

Effect of urea during in vitro maturation on nuclear maturation and embryo development of bovine cumulus-oocyte-complexes

High concentrations of urea in reproductive tract fluids are detrimental to bovine reproduction. Therefore, in experiment 1, the effect of 6 mM urea on nuclear maturation of cumulus-oocyte-complexes (COC) collected from abattoir ovaries was studied. After 4, 8, 12, 16, 20, and 24 h of in vitro maturation, the nuclear stages of samples of the COC were determined. During the first 8 h of maturation, germinal vesicle breakdown and chromosome condensation, resulting in the metaphase I stage, occurred at higher rates in the presence of urea. Segregation of the chromatids and extrusion of the polar body seemed to be impaired in the presence of urea, resulting in a higher percentage of oocytes arrested in metaphase I or telophase, and a lower percentage of oocytes in metaphase II after 24 h of maturation. Overall, nuclear progression of COC matured in the presence of urea differed from COC matured in control medium. In experiment 2, COC were matured for 24 h either in the presence or absence of 6 mM urea followed by in vitro fertilization and culture. After fertilization, a sample of the COC was fixed and stained to determine the fertilization rate. The cleavage rate was determined 3 d after start of maturation, and the stage of embryonic development was recorded 7 and 9 d after start of maturation. Based on cultured oocytes, urea in the maturation medium decreased the subsequent percentage of fertilization, cleavage, and development on d 7 and 9 (43.2, 56.1, 14.8, and 18.2°respectively for urea vs. 64.1, 68.8, 22.4, and 23.9°respectively for the control group). Embryonic development as a percentage of cleaved oocytes was not significantly affected by urea. Therefore, negative effects of urea were evident primarily during oocyte maturation and fertilization