Marc Andre Sirard

Marc Andre Sirard
Laval University | ULAVAL · Centre de Recherche en Biologie de la Reproduction (CRBR)

DVM PhD

About

507
Publications
38,096
Reads
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15,899
Citations
Additional affiliations
January 2001 - present
Laval University
Position
  • Canadian Researh Chair in reproduction genomics
January 1995 - present
Laval University
Position
  • Professor (Full)
Description
  • Canadian Research Chair
January 1992 - present
Laval University
Position
  • Professor (Full)
Education
July 1982 - August 1986
Laval University
Field of study
  • reproduction

Publications

Publications (507)
Article
Imprinted genes are inherited with different DNA methylation patterns depending on the maternal or paternal origin of the allele. In cattle (Bos taurus), abnormal methylation of these genes is linked to the large offspring syndrome, a neonatal overgrowth phenotype analogous to the human Beckwith–Wiedemann syndrome. We hypothesized that in bovine oo...
Article
Full-text available
Fatty acids (FA) are one of the substrates that can be oxidized for energy production. The blood concentration of all types of FA varies according to different nutrition conditions, and follicular fluid levels are generally in line with serum levels. Elevated levels of FA, especially non-esterified fatty acids (NEFA), are commonly found in females...
Article
Abstract: Female reproduction depends on the metabolic status, especially during the period of folliculogenesis. Even though it is believed that melatonin can improve oocyte competence, there is still limited knowledge of how it can modulate metabolic processes during folliculogenesis and which signaling pathways are involved in regulating gene exp...
Article
Knowledge on the effects of perfluorohexane sulfonate (PFHxS) on ovarian function is limited. In the current study, we investigated the sensitivity of oocytes to PFHxS during in vitro maturation (IVM), including consequences on embryo development at the morphological, transcriptomic, and epigenomic levels. Bovine cumulus-oocyte complexes (COCs) wer...
Article
In human IVF, the main uncertainty factor impacting on success is oocyte quality, which largely depends on the follicular status at the time of collection. Decades of debate ensued to find the perfect stimulation protocol demonstrated the complexity of the ovarian response to exogenous gonadotropins and the dynamic nature of late folliculogenesis....
Article
Full-text available
Maternal metabolic disorders such as obesity and diabetes are detrimental factors that compromise fertility and the success rates of medically assisted procreation procedures. During metabolic stress, adipose tissue is more likely to release free fatty acids (FFA) in the serum resulting in an increase of FFA levels not only in blood, but also in fo...
Article
In the field of animal reproduction, the environment associated with gametes and embryos refers to the parents’ condition as well as conditions surrounding gametes and embryos in vivo or in vitro. This environment is now known to influence not only the functionality of the early embryo but potentially the future phenotype of the offspring. Using tr...
Article
This paper offers a framework to help animal scientists engage in critical thinking about their own practices. Its objective is to reinforce their ability to participate in debates and discussions about the ethics surrounding the use of modern animal reproductive technologies (ART). This will be achieved first by exploring some of the most importan...
Article
Circulating levels of nonesterified fatty acids (NEFAs) are elevated in some females, which can impair oocyte maturation and embryo development, and may alter the phenotype of the progeny. However, the effects of NEFAs on human embryo development are not clear due to ethical limitations. Thus, we used pig as the model to investigate the impacts of...
Article
Perfluorooctane sulfonate (PFOS) has been added to Stockholm Convention for global phase out, but will continue to contribute to the chemical burden in humans for a long time to come due to extreme persistence in the environment. In the body, PFOS is transferred into to the ovarian follicular fluid that surrounds the maturing oocyte. In the present...
Article
Full-text available
Background Non-esterified fatty acids (NEFAs) are one of the main lipid components of follicular fluid at concentrations that depend on circulating levels. Elevated levels of NEFAs impair oocyte quality, development potential, and may subsequently influence the metabolism and reproductive fitness of offspring. Granulosa cells (GCs) are the follicul...
Article
Genetic improvement of health, welfare, efficiency, and fertility traits is challenging due to expensive and fuzzy phenotypes, the polygenic nature of traits, antagonistic genetic correlations to production traits and low heritabilities. Nevertheless, many organizations have introduced large-scale genetic evaluations for such traits in routine sele...
Article
Scientists are starting to realize that some effects from the animal environment may affect their progeny’s phenotype. These epidemiological evidences of early life programming are very well described in humans and rodents but less documented in bovines, especially in relation to the peri-conceptual period. In fact, as other species the bovine game...
Article
Full-text available
In cattle, several calves born after IVP (“in vitro” embryo production) present similar birthweight to those generated after MOET (multiple ovulation and embryo transfer). However, the underlying molecular patterns in organs involved in the developmental process are unknown and could indicate physiological programming. The objectives of this study...
Article
Full-text available
This study evaluated the hypothesis that the maternal metabolic stressed status could be inherited to their F1 daughters via epigenetic mechanism. The maternal cow blood β-hydroxybutyric acid (BHB) level (≥0.9 mM/L) was used as an indicator of maternal metabolic stress. Eight newborn daughters’ blood cells were used for methylation comparison and a...
Article
Full-text available
Background Morphological evaluation of embryos has been used to screen embryos for transfer. However, the repeatability and accuracy of this method remains low. Thus, evaluation of an embryo’s gene expression signature with respect to its developmental capacity could provide new opportunities for embryo selection. Since the gene expression outline...
Article
Oocyte maturation in culture is still the weakest part of in vitro fertilization (IVF) and coculture with somatic cells may be an alternative to improve suboptimal culture conditions, especially in the pig in which maturation takes more than 44 h. In the present study, we investigated the effect of a coculture system of porcine luteal cells (PLC) d...
Article
Increasing evidence indicate that maternal malnutrition leads to decreased female fertility and dysregulated metabolic homeostasis in offspring. High levels of non-esterified fatty acids (NEFAs) in follicular fluid were reported to be involved in these maternal nutritional effects, but the mechanisms remain unclear. This study explored the mechanis...
Poster
Lipid metabolism provides a potent source of energy and has an important role in the acquisition of oocyte competence. However, there are conflicting reports about how lipid exposure during invitro maturation (IVM) impacts the gamete and further embryo development. In this study, we performed IVM of oocytes in the presence of lipid-rich culture med...
Article
The production of bovine embryos through in vitro maturation and fertilization is an important tool of the genomic revolution in dairy cattle. Gene expression analysis of these embryos revealed differences according to the culture conditions or oocyte donor’s pubertal status compared to in vivo derived embryos. We hypothesized that some of the meth...
Article
Full-text available
Background Sperm miRNAs were reported to regulate spermatogenesis and early embryonic development in some mammals including bovine. The dairy cattle breeding industry now tends to collect semen from younger bulls under high selection pressure at a time when semen quality may be suboptimal compared to adult bulls. Whether the patterns of spermatic m...
Article
Full-text available
The bovine represents an important agriculture species and dairy breeds have experienced intense genetic selection over the last decades. The selection of breeders focused initially on milk production, but now includes feed efficiency, health, and fertility, although these traits show lower heritability. The non-genetic paternal and maternal effect...
Article
Two experiments were performed to determine effects of follicular ablation (FA) and GnRH treatment on conception rate and synchronization in timing of ovulation among Holstein heifers. In Experiment 1, heifers were randomly allocated to four groups: Control (n = 84): prostaglandin F2α (PGF) IM on Day 0; FA-5/GnRH (n = 43): FA 5 days before PGF and...
Article
Global mitochondrial DNA (mtDNA) methylation has been recently described in bovine and showed particular signatures in both gametes and embryos. Here, we investigated the distribution of mtDNA methylation through strand‐specific mapping of methylation sites to gain perspective on how epigenetic mechanisms can be involved in mitochondrial function....
Article
In the dairy industry, the high selection pressure combined with the increased efficiency of assisted reproduction technologies (ART) are leading toward the use of younger females for reproduction purposes, with the aim to reduce the interval between generations. This situation could impair embryo quality, decreasing the success rate of the ART pro...
Article
The patient’s response to the IVF stimulation protocol is highly variable and thus difficult to predict. When a cycle fails, there are often no apparent or obvious reasons to explain the failure. Having clues on what went wrong during stimulation could serve as a basis to improve and personalize the next stimulation protocol. This exploratory study...
Article
The female reproductive function largely depends on timing and coordination between follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Even though it was suggested that these hormones act on granulosa cells via shared signalling pathways, mainly protein kinases A, B, and C (PKA, PKB, PKC), there is still very little information availa...
Preprint
Full-text available
Background Sperm miRNAs were reported to regulate spermatogenesis and early embryonic development in some mammals including bovine. The dairy cattle breeding industry now tends to collect semen from younger bulls under high selection pressure at a time when semen quality may be suboptimal compared to adult bulls. Whether the patterns of spermatic m...
Preprint
Full-text available
Background: Sperm miRNAs were reported to regulate spermatogenesis and early embryonic development in some mammals including bovine. The dairy cattle breeding industry now tends to collect semen from younger bulls under high selection pressure at a time when semen quality may be suboptimal compared to adult bulls. Whether the patterns of spermatic...
Preprint
Full-text available
Background: Sperm miRNAs were reported to regulate spermatogenesis and early embryonic development in some mammals including bovine. The dairy cattle breeding industry now tends to collect semen from younger bulls under high selection pressure at a time when semen quality may be suboptimal compared to adult bulls. Whether the patterns of spermatic...
Article
In the last years many studies focused on the understanding of the possible role of zinc in the control of mammalian oogenesis, mainly on oocyte maturation and fertilization. However, little is known about the role of zinc at earlier stages, when the growing oocyte is actively transcribing molecules that will regulate and sustain subsequent stages...
Article
Cumulus cells have an important role to play in the final preparation of the oocyte before ovulation. During the final phase of follicular differentiation, FSH levels are low and LH maintains follicular growth; however, it is not known if at that time LH has an influence on cumulus cells inside the follicle. In humans, LH is often inhibited to avoi...
Article
Genetic selection for the best suited offspring drives the dairy industry to use young genitors and assisted reproductive technologies (ART) to reduce generation intervals. However, sperm samples collected from peri-pubertal bulls have lower counts and quality compared to samples from adult bulls. Moreover, our previous study identified differentia...
Article
Cows at the beginning of lactation often do not meet their energy needs by feeding and therefore mobilize body fat, which produces ketone bodies, including β-hydroxybutyrate (BHB). They are nevertheless usually inseminated around 60 d postpartum, when they are still in this characteristic period of energy deficit. The aim of this study was to obser...
Article
One of the major challenges of artificial reproductive technologies is to develop new methods for producing greater numbers of embryos. An oocyte fosters the ability to develop into an embryo before oocyte meiotic resumption. The aim of the present study was to assess the effect of adenosine (ADO), a purine nucleoside found in follicular fluid, on...
Article
Full-text available
IVF success depends on hundreds of factors and details but the oocyte quality remains the most important and problematic issue. All antral follicles contain oocytes and all of them have that have reached their full size, can be aspirated, can mature and can be fertilized in vitro. But only a few will make it to embryo unless harvested at a very spe...
Article
Full-text available
Comparison of mitochondrial DNA (mtDNA) methylation patterns in oocytes, blastocysts and ovarian granulosa cells indicates hitherto unsuspected dynamics. Oocytes and blastocysts recovered from cows subjected to ovarian stimulation and from non-stimulated abattoir ovaries were analyzed using bisulphite transformation of DNA followed by whole genome...
Article
Full-text available
Purpose Hormonal stimulation prior to IVF influences the ovarian environment and therefore impacts oocytes and subsequent embryo quality. Not every patient has the same response to the same treatment and many fail for unknown reasons. Knowing why a cycle has failed and how the follicles were affected would allow clinicians to adapt the treatment ac...
Article
Medically assisted reproductive technologies (ARTs), such as in vitro embryo production, are increasingly being used to palliate infertility. Eggs are produced following a hormonal regimen that stimulates the ovaries to produce a large number of oocytes. Collected oocytes are then fertilized in vitro and allowed to develop in vitro until they are e...
Article
Increasing evidence indicates that maternal malnutrition leads to decreased female fertility and deregulated metabolic homeostasis in offspring, and these performances may be related to the high level of non-esterified fatty acids (NEFAs) in the maternal follicular fluid (FF), but the mechanisms remain unclear. This study is aiming to explore the e...
Article
Genetic selection for the best suited offspring’s drives the dairy industry to use young genitors with assisted reproductive technologies (ART) to reduce generation intervals. However, sperms collected from peri-pubertal bulls have lower quality compared to adults. Moreover, new evidences suggest that sperm can transfer not only the paternal genome...
Article
Embryo transfer in cattle is performed with blastocysts produced in vivo or in vitro using defined media. However, outdated systems such as those that use serum and co-culture remain of interest for research purposes. Here, we investigated the effect of additional culture time on in vitro-produced embryos. Specifically, we compared embryos that for...
Article
Full-text available
MicroRNAs are potent regulators of gene expression that have been widely implicated in reproduction and embryo development. Recent studies have demonstrated that miR-21, a microRNA extensively studied in the context of disease, is important in multiple facets of reproductive biology including folliculogenesis, ovulation, oocyte maturation and early...
Article
The use of younger gamete donors in dairy cattle genetic selection programs significantly accelerates genetic gains by decreasing the interval between generations. Ovarian stimulation and the practice of follicle-stimulating hormone (FSH) withdrawal, also known as coasting, are intensively used in pre-pubertal heifers without detrimental effects on...
Article
Full-text available
Background Assisted reproductive technologies (ART) are widely used to treat fertility issues in humans and for the production of embryos in mammalian livestock. The use of these techniques, however, is not without consequence as they are often associated with inauspicious pre- and postnatal outcomes including premature birth, intrauterine growth r...
Article
Full-text available
Background: Aberrant DNA methylation patterns of genes required for development are common in in vitro produced embryos. In this regard, we previously identified altered DNA methylation patterns of in vivo developed blastocysts from embryos which spent different stages of development in vitro, indicating carryover effects of suboptimal culture con...
Article
Insulin functions as a regulator of metabolism and plays an important role in reproduction. Hyperinsulinemia is often observed in obesity and diabetes type 2 and is known to impair fertility, but the underlying molecular mechanisms are only partly understood. Metabolic programming through epigenetic mechanisms such as DNA methylation during embryon...
Article
Insulin is a key hormone with important functions in energy metabolism and is involved in the regulation of reproduction. Hyperinsulinaemia is known to impair fertility (for example, in obese mothers); therefore, we aimed to investigate the impact of elevated insulin concentrations during the sensitive period of oocyte maturation on gene expression...
Article
Full-text available
Background: Prolongation of superstimulatory treatment appears to be associated with a greater superovulatory response and with greater oocyte maturation in cattle. A genome-wide bovine oligo-microarray was used to compare the gene expression of granulosa cells collected from ovarian follicles after differing durations of the growing phase induced...
Article
In recent years, exciting progress was made to improve the embryo outcome after ovarian stimulation in domestic animals. The practice of follicle-stimulating hormone (FSH) withdrawal, which is defined as the period of time between the last injection of FSH and oocyte retrieval, resulted in embryo yields significantly superior. Since then, specific...
Article
The development of a complex technology such as in vitro fertilization (IVF) requires years of experimentation, sometimes comparing several species to learn how to create the right in vitro environment for oocytes, spermatozoa, and early embryos. At the same time, individual species characteristics such as gamete physiology and gamete interaction a...
Article
In reproduction, FSH is one of the most important hormones, especially in females, because it controls the number of follicles and the rate of follicular growth. Although several studies have examined the follicular response at the transcriptome level, it is difficult to obtain a clear and complete picture of the genes responding to an increase in...
Article
Human health risk assessment (HHRA) must be adapted to the challenges of the 21st century, and the use of toxicogenomics data in HHRA is among the changes that regulatory agencies worldwide are trying to implement. However, the use of toxicogenomics data in HHRA is still limited. The purpose of this study was to explore the availability, quality an...
Article
The selection of the best dairy heifers is mainly driven by the genetic value of their parents. The phenotype analysis of cows and of the daughters of bulls has been used to identify the best genetic value for decades before being replaced by genomic selection of individuals that are not yet parents. Because it is possible to predict the future val...
Article
Full-text available
Background The timing of the first cell divisions may predict the developmental potential of an embryo, including its ability to establish pregnancy. Besides differences related to metabolism, stress, and survival, embryos with different speeds of development present distinct patterns of gene expression, mainly related to energy and lipid metabolis...