1,721,084 research outputs found
Local action of cytokines and immune cells in communication between the conceptus and uterus during the critical period of early embryo development, attachment and implantation – Implications for embryo survival in cattle: A review
Full text linkEarly embryo development, implantation and pregnancy involve a complex dialogue between the embryo and mother. In cattle this dialogue starts as early as days 3–4 when the embryo is still in the oviduct, and it continues to implantation. Immunological processes involving cytokines, mast cells and macrophages form an important part of this dialogue. Amongst the cytokines, interleukin-6 (Il-6) and leukemia inhibitory factor (LIF) are secreted by both the embryo and uterine endometrium and form part of an ongoing and reciprocating dialogue. Mast cells and macrophages populate the uterine endometrium during embryo development and are involved in achieving the correct balance between inflammatory and anti-inflammatory reactions at the uterus that are associated with embryo attachment and implantation. Embryo loss is the major cause of reproductive wastage in cattle, and livestock generally. A deeper understanding of immunological processes during early embryo development will help to achieve the next step change in the efficiency of natural and assisted breeding
Transforming growth factor-β superfamily and interferon-τ in ovarian function and embryo development in female cattle: Review of biology and application
Full text linkSurvival of the embryo and establishment of a pregnancy is a critical period in the reproductive function of female cattle. This review examines how the transforming growth factor-β (TGFB) superfamily (i.e. bone morphogenetic protein (BMP) 15, growth differentiation factor (GDF) 9, anti-Müllerian hormone (AMH)) and interferon-τ (IFNT) affect ovarian function and embryo development. The oocyte in a primary follicle secretes BMP15 and GDF9, which, together, organise the surrounding granulosa and theca cells into the oocyte-cumulus-follicle complex. At the same time, the granulosa secretes AMH, which affects the oocyte. This autocrine-paracrine dialogue between the oocyte and somatic cells continues throughout follicle development and is fundamental in establishing the fertilisation potential and embryo developmental competency of oocytes. The early bovine embryo secretes IFNT, which acts at the uterine endometrium, corpus luteum and blood leucocytes. IFNT is involved in the maternal recognition of pregnancy and immunomodulation to prevent rejection of the embryo, and supports progesterone secretion. Manipulation of BMP15, GDF9, AMH and IFNT in both in vivo and in vitro studies has confirmed their importance in reproductive function in female cattle. This review makes the case that a deeper understanding of the biology of BMP15, GDF9, AMH and IFNT will lead to new strategies to increase embryo survival and improve fertility in cattle. The enhancement of oocyte quality, early embryo development and implantation is considered necessary for the next step change in the efficiency of natural and assisted reproduction in cattle
Peripheral action of kisspeptin at reproductive tissues-role in ovarian function and embryo implantation and relevance to assisted reproductive technology in livestock: A review
Full text linkKisspeptin (KISS1) is encoded by the KISS1 gene and was initially found to be a repressor of metastasis. Natural mutations in the KISS1 receptor gene (KISS1R) were subsequently shown to be associated with idiopathic hypothalamic hypogonadism and impaired puberty. This led to interest in the role of KISS1 in reproduction. It was established that KISS1 had a fundamental role in the control of gonadotropin releasing hormone (GnRH) secretion. KISS1 neurons have receptors for leptin and estrogen receptor α (ERα), which places KISS1 at the gateway of metabolic (leptin) and gonadal (ERα) regulation of GnRH secretion. More recently, KISS1 has been shown to act at peripheral reproductive tissues. KISS1 and KISS1R genes are expressed in follicles (granulosa, theca, oocyte), trophoblast, and uterus. KISS1 and KISS1R proteins are found in the same tissues. KISS1 appears to have autocrine and paracrine actions in follicle and oocyte maturation, trophoblast development, and implantation and placentation. In some studies, KISS1 was beneficial to in vitro oocyte maturation and blastocyst development. The next phase of KISS1 research will explore potential benefits on embryo survival and pregnancy. This will likely involve longer-term KISS1 treatments during proestrus, early embryo development, trophoblast attachment, and implantation and pregnancy. A deeper understanding of the direct action of KISS1 at reproductive tissues could help to achieve the next step change in embryo survival and improvement in the efficiency of assisted reproductive technology
Metabolic health, the metabolome and reproduction in female cattle: a review
Full text linkStudies over the past 30 years have confirmed the important role of metabolic hormones and metabolic substrates in reproductive function in female cattle. The emergence of metabolomics is providing a deeper understanding of the role of specific metabolites, and clusters of metabolites, in reproduction and also health and disease. Dairy cows undergo major fluctuations in metabolic health and metabolomics is helping to better understand the changes in metabolite profiles associated with negative energy balance and ketosis. New knowledge that emerges from this work should lead to improved nutritional management of dairy cows. In reproduction, it is now possible to gain a metabolomic signature of ovarian follicular fluid and of developing embryos. This should likewise lead to improvements in both natural and assisted reproduction in cattle. Systems biology integrates genomics, transcriptomics, proteomics and metabolomics, and contributes to gaining an understanding of complex biological networks.Highlights Metabolic hormones and metabolic substrates have a major influence on reproduction in female cattle. Negative energy balance and ketosis are associated with changes in the systemic and liver metabolome in dairy cows. The metabolome of ovarian follicular fluid influences oocyte quality and embryo development. Systems biology integrates genomics, transcriptomics, proteomics and metabolomics, and provides a deeper understanding of complex biological networks
Lh profile and ovulation rate in superovulated buffaloes treated with gnrh agonist and cidr-b devices (preliminary results)
No full textLh profile and ovulation rate in superovulated buffaloes treated with gnrh agonist and cidr-b devices (preliminary results).
No full textLh profile and ovulation rate in superovulated buffaloes treated with gnrh agonist and cidr-b devices (preliminary results).
No full textAdhesion molecules in gamete transport, fertilization, early embryonic development, and implantation—role in establishing a pregnancy in cattle: A review
Full text linkCell–cell adhesion molecules have critically important roles in the early events of reproduction including gamete transport, sperm–oocyte interaction, embryonic development, and implantation. Major adhesion molecules involved in reproduction include cadherins, integrins, and disintegrin and metalloprotease domain-containing (ADAM) proteins. ADAMs on the surface of sperm adhere to integrins on the oocyte in the initial stages of sperm–oocyte interaction and fusion. Cadherins act in early embryos to organize the inner cell mass and trophectoderm. The trophoblast and uterine endometrial epithelium variously express cadherins, integrins, trophinin, and selectin, which achieve apposition and attachment between the elongating conceptus and uterine epithelium before implantation. An overview of the major cell–cell adhesion molecules is presented and this is followed by examples of how adhesion molecules help shape early reproductive events. The argument is made that a deeper understanding of adhesion molecules and reproduction will inform new strategies that improve embryo survival and increase the efficiency of natural mating and assisted breeding in cattle
Plasma leptin levels in Murrah buffalo heifers fed diet with two different energy levels.
No full textRIASSUNTO – Livelli plasmatici di leptina in manze bufaline di razza Murrah alimentate con due differenti
livelli energetici. Scopo del lavoro è stato valutare i livelli plasmatici di leptina ed i loro rapporti con le
variazioni di peso, BCS, insulina, glucagone, IGF-1, glucosio, colesterolo, trigliceridi e NEFA in manze bufaline
in accrescimento, alimentate con diete a differente contenuto energetico. 12 manze di razza Murrah (790 giorni
di età e 400 kg di peso), allevate in S .Paolo (Brasile) sono state alimentate con diete differenti per contenuto in
UFL: 5,8 UFL/giorno (Gruppo H; n=6) vs. 3,6 UFL/giorno (Gruppo L; n=6). Si sono registrate differenze significative
tra i gruppi per il peso a fine prova e per i valori di BCS e di leptina. Sono emerse correlazioni significative
tra leptina e incremento di peso corporeo, BCS nonché insulina, glucosio, colesterolo e glucagone ematici.
La relazione tra leptina ed IGF-1 è risultata significativa solo dopo la 4a settimana. Relazioni differenti sono
emerse analizzando i dati entro i singoli gruppi di alimentazione
Embryo recovery in buffalo with timed ovulation and insemination subsequent to follicle superstimulation.
No full textThe aim of this study was to ascertain ovulation rate and non-surgical embryo recovery in buffalo treated with GnRH agonist-LH protocol, and injected with LH 12 or 24 hours after discontinuation of treatment with FSH. Mixed parity buffaloes (n=18) were randomly assigned to three groups: Groups 1 and 2 were implanted with GnRH agonist on Day -14 and injected with estradiol benzoate (10 mg) + progesterone (100 mg) on Day -6. Group 3 received an intravaginal progesterone device (PRID) with estradiol capsule on Day -6. Follicular growth was stimulated with FSH given as equal doses 2x daily in decreasing amounts from Day 0 to Day 4. On day 3 buffaloes were injected with PGF and PRID was removed from Group 3. Groups 1 and 2 were injected with 25 mg LH 12 h (Day 4, P.M.) and 24 h (Day 5, A.M.), respectively, after FSH. Buffaloes were mated by AI and embryo were recovered on Day 5 after AI. The number of follicles were similar among the groups. Group 1 had fewer ovulations and, consequently, corpora lutea compared to the other groups. Also embryo recovery was higher for Groups 2 and 3 compared to Group 1
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