Publications by authors named "Marc Andre Sirard"

In recent years, biomarkers in granulosa cells (GC) have been determined and associated in several species with oocyte maturation, in vitro fertilization success, and embryo development outcomes. The identification of biomarkers of oocyte competence can aid in improving assisted reproductive technologies (ARTs) in the southern white rhino (SWR). This study aimed to identify biomarkers present in SWR GC associated with oocytes that either did or did not mature in vitro.

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During spermatogenesis, a substantial proportion of histones are substituted by protamine to condense the genome within the sperm head. Studies indicate that a minority of histones, typically ranging from 1 to 15 %, persist in mammalian sperm post-substitution. The persistence of histones in the zygote facilitates chromatin accessibility to transcription factors in regions crucial for early embryonic development.

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Much remains unknown about the reproductive physiology of southern white rhinoceros (SWR) and the effect of ovarian stimulation prior to ovum pickup (OPU) have not been fully elucidated. Granulosa cells (GC) provide valuable insight into follicle growth and oocyte maturation status. The goals of this study were to evaluate transcriptomic changes in GC from three stages of follicle development and to identify biomarkers possibly associated with follicular growth and maturation as a result of ovarian stimulation.

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Cattle farming faces challenges linked to intensive exploitation and climate change, requiring the reinforcement of animal resilience in response to these dynamic environments. Currently, genetic selection is used to enhance resilience by identifying animals resistant to specific diseases; however, certain diseases, such as mastitis, pose difficulties in genetic prediction. This study introduced the utilization of enzymatic methyl sequencing (EM-seq) of the blood genomic DNA from twelve dairy cows to identify DNA methylation biomarkers, with the aim of predicting resilience and susceptibility to mastitis.

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Choline is a vital micronutrient. In this study, we aimed to confirm, and expand on previous findings, how choline impacts embryos from the first 7 days of development to affect postnatal phenotype. Bos indicus embryos were cultured in a choline-free medium (termed vehicle) or medium supplemented with 1.

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Background: DNA methylation has been documented to play vital roles in diseases and biological processes. In bovine, little is known about the regulatory roles of DNA methylation alterations on production and health traits, including mastitis.

Results: Here, we employed whole-genome DNA methylation sequencing to profile the DNA methylation patterns of milk somatic cells from sixteen cows with naturally occurring Staphylococcus aureus (S.

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Sperm small non-coding RNAs (sncRNAs), such as microRNAs (miRNAs) and tRNA-derived small RNAs (tsRNAs), have been found to have implications for male fertility and play a role in the intergenerational transmission of specific phenotypes by influencing the early embryo's physiological processes in various animal species. This study postulates that there exists a correlation between sperm small non-coding RNAs (sncRNAs) and bull fertility, which in turn can influence the fertility of offspring through the modulation of early embryo development. To investigate this hypothesis, we generated comparative libraries of sperm sncRNAs from sires exhibiting high (n = 3) versus low bull fertility (n = 3), as well as high (n = 3) versus low daughter fertility (n = 3), as determined by the industry-standard Bull fertility index and Daughter fertility index.

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Background: maturation (IVM) of germinal vesicle intact oocytes prior to fertilization (IVF) is practiced widely in animals. In human assisted reproduction it is generally reserved for fertility preservation or where ovarian stimulation is contraindicated. Standard practice incorporates complex proteins (CP), in the form of serum and/or albumin, into IVM media to mimic the ovarian follicle environment.

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The current decline in dairy cattle fertility has resulted in significant financial losses for dairy farmers. In the past, most efforts to improve dairy cattle fertility have been focused on either management or genetics, while epigenetics have received less attention. In this study, 12 bulls were selected from a provided 100 bull list and studied (High daughter fertility = 6, Low daughter fertility = 6) for Enzymatic methylation sequencing in the Illumina HiSeq platform according to the Canadian daughter fertility index (DFI), sires with high and low daughter fertility have average DFI of 92 and 112.

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The Resilient Dairy Genome Project (RDGP) is an international large-scale applied research project that aims to generate genomic tools to breed more resilient dairy cows. In this context, improving feed efficiency and reducing greenhouse gases from dairy is a high priority. The inclusion of traits related to feed efficiency (e.

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This study characterized variations in the methylation profile of mitochondrial DNA (mtDNA) during initial bovine embryo development and correlated the presence of methylation with mtDNA transcription. Bovine oocytes were obtained from abattoir ovaries and submitted to culture procedures. Oocytes and embryos were collected at various stages (immature oocyte, IM; mature oocyte, MII; zygote, ZY; 4-cells, 4C; 16-cells, 16C and blastocysts, BL).

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Article Synopsis
  • - The study focuses on the role of DNA methylation in subclinical mastitis caused by Staphylococcus chromogenes (SC), a common pathogen on dairy farms.
  • - Using advanced sequencing and bioinformatics, researchers compared DNA methylation patterns and gene expression in milk somatic cells from cows with SCM and healthy cows, identifying thousands of differentially methylated sites and their relationship to immune functions.
  • - The findings suggest that DNA methylation changes could regulate responses related to SCM and serve as potential biomarkers for mammary health and production in dairy cows.
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Article Synopsis
  • * A study analyzing milk somatic cells of infected cows revealed over 4,000 genes that were expressed differently between infected and healthy cows, highlighting key immune responses and processes related to disease.
  • * A specific gene module (Turquoise) was significantly associated with subclinical mastitis and included genes linked to immune functions, suggesting these genes might play a crucial role in how cows defend against S. aureus infections.
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In Brief: This review discusses advances in the knowledge of epigenetic mechanisms regulating mitochondrial DNA and the relationship with reproductive biology.

Abstract: Initially perceived simply as an ATP producer, mitochondria also participate in a wide range of other cellular functions. Mitochondrial communication with the nucleus, as well as signaling to other cellular compartments, is critical to cell homeostasis.

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The use of assisted-reproduction technologies such as in vitro fertilization (IVF) is increasing, particularly in dairy cattle. The question of consequences in later life has not yet been directly addressed by studies on large animal populations. Studies on rodents and early data from humans and cattle suggest that in vitro manipulation of gametes and embryos could result in long-term alteration of metabolism, growth, and fertility.

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In Brief: Bull fertility is an important economic trait, this study identified some DNA methylation biomarkers that are associated with bull fertility.

Abstract: Subfertile bulls may cause huge economic losses in dairy production since their semen could be used to inseminate thousands of cows by artificial insemination. This study adopted whole-genome enzymatic methyl sequencing and aimed to identify candidate DNA methylation markers in bovine sperm that correlate with bull fertility.

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Sheep farming plays an important economic role, and it contributes to the livelihoods of many rural poor in several regions worldwide and particularly in Tunisia. Therefore, the steady improvement of ewes' reproductive performance is a pressing need. The gene has been identified as an important candidate gene that plays a key role in sheep reproduction and its sexual inactivity.

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Herd gestation and health management are key aspects of effective dairy farm operations and animal welfare improvement. Unfortunately, very little is known about the developmental divergences induced by assisted reproduction technologies (ART) and their consequences once the animal is mature. Indeed, the gestational and health outcomes of this subset of the Holstein population is yet to be characterized.

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Background: Mastitis caused by different pathogens including Streptococcus uberis (S. uberis) is responsible for huge economic losses to the dairy industry. In order to investigate the potential genetic and epigenetic regulatory mechanisms of subclinical mastitis due to S.

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Melatonin is a known modulator of follicle development; it acts through several molecular cascades via binding to its two specific receptors MT1 and MT2. Even though it is believed that melatonin can modulate granulosa cell (GC) functions, there is still limited knowledge of how it can act in human GC through MT1 and MT2 and which one is more implicated in the effects of melatonin on the metabolic processes in the dominant follicle. To better characterize the roles of these receptors on the effects of melatonin on follicular development, human granulosa-like tumor cells (KGN) were treated with specific melatonin receptor agonists and antagonists, and gene expression was analyzed with RNA-seq technology.

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Unlabelled: 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 with metabolic issues, which are often related to subfertility in many species including humans, pigs, cattle, and mice.

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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 oocytes, some of the methylation patterns on maternally imprinted genes are acquired in the last phase of folliculogenesis.

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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 expression. To investigate the effects of melatonin on metabolic signals during the antral stage of follicular development, human granulosa-like tumor cells (KGN) were treated with melatonin or forskolin, and gene expression was analyzed with RNA-seq technology.

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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 important philosophical conceptualizations of animals in Western philosophy, which are shaping the way humans interact with them.

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