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1.
Anim. Reprod. (Online) ; 15(supl. 1): 984-995, set. 2018. ilus
Artigo em Inglês | VETINDEX | ID: biblio-1461415

Resumo

The beginning of this century has witnessed great advances in the understanding of ovarian physiology and embryo development, in the improvement of assisted reproductive technologies (ARTs), and in the arrival of the revolutionary genome editing technology through zygote manipulation. Particularly in sheep and goats, the current knowledge on follicular dynamics enables the design of novel strategies for ovarian control, enhancing artificial insemination and embryo production programs applied to genetic improvement. In vitro embryo production (IVEP) has evolved due to a better understanding of the processes that occur during oocyte maturation, fertilization and early embryo development. Moreover, interesting advances have been achieved in embryo and oocyte cryopreservation, thereby reducing the gap between the bench and on-farm application of IVEP technology. Nevertheless, the major breakthrough of this century has been the arrival of the CRISPR/Cas system for genome editing. By joining diverse disciplines such as molecular biology, genetic engineering and reproductive technologies, CRISPR allows the generation of knock-out and knock-in animals in a novel way never achieved before. The innumerable applications of this disruptive biotechnology are challenging the imagination of those who intend to build the animals of the future.


Assuntos
Animais , Ovinos/embriologia , Transferência Embrionária , Transferência Embrionária/veterinária , Técnicas Reprodutivas , Criopreservação , Criopreservação/veterinária
2.
Anim. Reprod. ; 15(supl. 1): 984-995, set. 2018. ilus
Artigo em Inglês | VETINDEX | ID: vti-20558

Resumo

The beginning of this century has witnessed great advances in the understanding of ovarian physiology and embryo development, in the improvement of assisted reproductive technologies (ARTs), and in the arrival of the revolutionary genome editing technology through zygote manipulation. Particularly in sheep and goats, the current knowledge on follicular dynamics enables the design of novel strategies for ovarian control, enhancing artificial insemination and embryo production programs applied to genetic improvement. In vitro embryo production (IVEP) has evolved due to a better understanding of the processes that occur during oocyte maturation, fertilization and early embryo development. Moreover, interesting advances have been achieved in embryo and oocyte cryopreservation, thereby reducing the gap between the bench and on-farm application of IVEP technology. Nevertheless, the major breakthrough of this century has been the arrival of the CRISPR/Cas system for genome editing. By joining diverse disciplines such as molecular biology, genetic engineering and reproductive technologies, CRISPR allows the generation of knock-out and knock-in animals in a novel way never achieved before. The innumerable applications of this disruptive biotechnology are challenging the imagination of those who intend to build the animals of the future.(AU)


Assuntos
Animais , Ovinos/embriologia , Transferência Embrionária , Transferência Embrionária/veterinária , Técnicas Reprodutivas , Criopreservação , Criopreservação/veterinária
3.
R. bras. Reprod. Anim. ; 41(1): 340-344, Jan-Mar. 2017.
Artigo em Inglês | VETINDEX | ID: vti-17232

Resumo

Fixed-time artificial insemination (FTAI) is the most effective method to increase the number offemales inseminated in a single day, eliminating the necessity of estrus detection. Usually the treatments forFTAI in sheep are based on the use of progesterone-releasing devices and equine chorionic gonadotropin (eCG)administration at device removal, with an acceptable pregnancy rate. The current information about the ovarianphysiology supports the idea of shortening the traditional progesterone exposure with intravaginal devices from14 days to 5-7 days (Short-term protocols). These protocols ensure appropriate progesterone concentrations toinduce follicular turnover and ovulation of a non-persistent follicle. One im dose of PGF2alpha is required attime of device removal with eCG administration, ovulation occurs around 60 h later and FTAI is performed at 48or 54 h by cervical or intrauterine route, respectively. Several experiments have been conducted during last yearsto adjust this new protocol. In general, reported pregnancy rate is greater -or at least similar- than traditional 14days protocols, and remaining progesterone in the silicone intravaginal devices may be enough for theirreutilization with interesting results. Several improvements on follicular dynamics, time of ovulation,pharmacological associations, insemination time, sperm dose, among others, are summarized in this review inFTAI protocols facilitate a further adoption of insemination and genetic improvement in this species.(AU)


Assuntos
Animais , Feminino , Ovinos/embriologia , Ovinos/fisiologia , Comportamento Sexual Animal/fisiologia , Ovário
4.
Rev. bras. reprod. anim ; 41(1): 340-344, Jan-Mar. 2017.
Artigo em Inglês | VETINDEX | ID: biblio-1492480

Resumo

Fixed-time artificial insemination (FTAI) is the most effective method to increase the number offemales inseminated in a single day, eliminating the necessity of estrus detection. Usually the treatments forFTAI in sheep are based on the use of progesterone-releasing devices and equine chorionic gonadotropin (eCG)administration at device removal, with an acceptable pregnancy rate. The current information about the ovarianphysiology supports the idea of shortening the traditional progesterone exposure with intravaginal devices from14 days to 5-7 days (Short-term protocols). These protocols ensure appropriate progesterone concentrations toinduce follicular turnover and ovulation of a non-persistent follicle. One im dose of PGF2alpha is required attime of device removal with eCG administration, ovulation occurs around 60 h later and FTAI is performed at 48or 54 h by cervical or intrauterine route, respectively. Several experiments have been conducted during last yearsto adjust this new protocol. In general, reported pregnancy rate is greater -or at least similar- than traditional 14days protocols, and remaining progesterone in the silicone intravaginal devices may be enough for theirreutilization with interesting results. Several improvements on follicular dynamics, time of ovulation,pharmacological associations, insemination time, sperm dose, among others, are summarized in this review inFTAI protocols facilitate a further adoption of insemination and genetic improvement in this species.


Assuntos
Feminino , Animais , Comportamento Sexual Animal/fisiologia , Ovinos/embriologia , Ovinos/fisiologia , Ovário
5.
R. bras. Reprod. Anim. ; 41(1): 217-221, 7. 2017. 2017.
Artigo em Português | VETINDEX | ID: vti-17302

Resumo

This review summarizes the main achievements with the use of transgenesis and genome editingtechnologies in sheep and goats. Transgenesis, also referred to as recombinant DNA (rDNA) technology, madepossible by the first time 30 years ago the addition of novel traits from a given species into a different one. Onthe other hand, more recently genome editing appears a much more precise method of making changes to thegenome of a plant, animal, or other living organism, allowing for the addition, substitution, or deletion ofspecific nucleotides in an organisms genome. With transgenesis, the introduction of new DNA into anorganisms genome was generally without control of the site of the genome in which the insertion of that rDNAconstruct would occur. With genome editing in contrast, researchers and developers of products can makespecific changes in precise locations of the genome. This concept was absolutely improved with the novelCRISPR/Cas system, making genome edition cheaper, more efficient, easier and affordable for every Laboratoryaround the world. This revolution that originally emerged from molecular biology and passed to biomedicine,has recently been applied to livestock and agriculture. In addition, the application of this technology in sheep,goats, pigs and cattle, also has been possible by the advance of assisted reproductive technologies for embryoproduction, micromanipulation, cryopreservation and transfer. In general, multidisciplinary approaches includingbasic research and technical improvements, participation of private actors and adequate regulation should bemerged to take advantage of this potent biotechnology in different countries.(AU)


Assuntos
Animais , Ruminantes/genética , Animais Geneticamente Modificados/genética , Biotecnologia , Micromanipulação/veterinária
6.
Rev. bras. reprod. anim ; 41(1): 217-221, Jan-Mar. 2017.
Artigo em Português | VETINDEX | ID: biblio-1492463

Resumo

This review summarizes the main achievements with the use of transgenesis and genome editingtechnologies in sheep and goats. Transgenesis, also referred to as recombinant DNA (rDNA) technology, madepossible by the first time 30 years ago the addition of novel traits from a given species into a different one. Onthe other hand, more recently genome editing appears a much more precise method of making changes to thegenome of a plant, animal, or other living organism, allowing for the addition, substitution, or deletion ofspecific nucleotides in an organism’s genome. With transgenesis, the introduction of new DNA into anorganism’s genome was generally without control of the site of the genome in which the insertion of that rDNAconstruct would occur. With genome editing in contrast, researchers and developers of products can makespecific changes in precise locations of the genome. This concept was absolutely improved with the novelCRISPR/Cas system, making genome edition cheaper, more efficient, easier and affordable for every Laboratoryaround the world. This revolution that originally emerged from molecular biology and passed to biomedicine,has recently been applied to livestock and agriculture. In addition, the application of this technology in sheep,goats, pigs and cattle, also has been possible by the advance of assisted reproductive technologies for embryoproduction, micromanipulation, cryopreservation and transfer. In general, multidisciplinary approaches includingbasic research and technical improvements, participation of private actors and adequate regulation should bemerged to take advantage of this potent biotechnology in different countries.


Assuntos
Animais , Animais Geneticamente Modificados/genética , Biotecnologia , Micromanipulação/veterinária , Ruminantes/genética
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