Efeito da colheita fracionada sobre a cinética e viabilidade espermáticas do sêmen refrigerado e congelado de garanhões
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Data
2016-05-03
Autores
Oliveira, Sidnei Nunes de [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O pênis é o órgão copulador e no garanhão é classificado como sendo músculo cavernoso, em que os espaços cavernosos são preenchidos de sangue durante a ereção. Nos testículos que ocorre a produção espermática, que são transportados pela rete testis até o epidídimo, onde sofrerão maturação, capacidade fertilizante e armazenados até a ejaculação. As glândulas sexuais acessórias são responsáveis pelos fluidos expelidos durante a ejaculação, denominado de plasma seminal, que se misturam às células espermáticas e formam o ejaculado. Cada uma dessas glândulas são responsáveis por uma determinada secreção que vai direcionar o ejaculado equino a ser dividido em três distintas frações: fração pré-espermática, produzida pelas glândulas bulbouretrais e próstata; fração rica em espermatozoides, produzida pelas secreções do epidídimo e por líquidos das ampolas dos ductos deferentes; fração pós-espermática ou fração pobre, formada por espermatozoides remanescentes no canal uretral e líquidos produzidos pelas vesículas seminais, o gel. Durante o processo fisiológico de cópula, ocorrem vários eventos denominados de ereção, em que o garanhão se excita por estímulos, emissão que caracteriza-se pela liberação de espermatozoides dentro da uretra pélvica, seguido da ejaculação com a expulsão do sêmen, o relaxamento e recolhimento do pênis. Normalmente, as colheitas de sêmen equino são realizadas de forma convencional, com vagina artificial fechada, em que todas as frações se misturam. Cada garanhão possui características individuais com relação à manutenção das células espermáticas durante a criopreservação, essas características podem estar relacionadas à produção do plasma seminal, assim como os vários componentes que os compõem. Sabe-se que existe um efeito deletério desempenhado pelos componentes do plasma seminal produzido principalmente pelas vesículas seminais, aos espermatozoides durante o processo de criopreservação, porém, esses fatores ainda são desconhecidos. Várias hipóteses são sugeridas, tais como, a redução na produção de lipídeos e os tipos de proteínas e íons presentes em cada uma das frações do ejaculado. Sabendo disso, a colheita fracionada pode trazer benefícios aos espermatozoides, de forma que as primeiras frações não tenham contato com o plasma seminal produzido pelas vesículas seminais. O presente trabalho objetiva revisar a colheita fracionada de sêmen em garanhões, assim como, seus benefícios para as células espermáticas que serão submetidas à criopreservação.
The penis is the copulatory organ and in the stallion it is classified as cavernous muscle and the cavernous spaces are filled with blood during erection. In the testicles occurs sperm production, that are transported through the rete testis to the epididymis, where they will suffer maturation, fertilizer capacity and will be stored until ejaculation. The accessory sex glands are responsible for the expelled fluids during ejaculation, named seminal plasma that are mixed with sperm cells and form the ejaculate. Each of these glands are responsible for a certain secretion that will divide equine semen into three distinct fractions: pre-sperm fraction, produced by the prostate and bulbourethral glands; rich fraction in sperm, produced by epididymal secretions and liquids from ampoules of the vas deferens; post-sperm fraction or poor fraction, consisting of sperm remaining in the urethral canal and liquids produced by the seminal vesicles, the gel. During the physiological process of mating, several events occur named erection, in which the stud is excited by stimuli emission which is characterized by the release of sperm into the pelvic urethra followed by ejaculation with the expulsion of semen, relaxation and gathering the penis. Typically, horse semen collections are performed in the conventional way, with a closed artificial vagina, where all the fractions are mixed. Each stud has individual characteristics related to the maintenance of sperm cells during the cryopreservation, these characteristics may be related to production of seminal plasma and to the components that form it as well. What is known is that there is a negative effect played by the seminal plasma components mainly produced by the seminal vesicles, to the sperm during cryopreservation process, however, these factors are still unknown. Several hypotheses are suggested such as the production’s reduction of lipids and proteins and the types of ions present in each fraction of the ejaculate. Knowing this, the fractional collection may be beneficial to sperm, considering that the first fractions do not have contact with seminal plasma produced by the seminal vesicles. This work aims to review the semen fraction harvest in stallions, as well as its benefits for the sperm cells to be submitted to cryopreservation.
The penis is the copulatory organ and in the stallion it is classified as cavernous muscle and the cavernous spaces are filled with blood during erection. In the testicles occurs sperm production, that are transported through the rete testis to the epididymis, where they will suffer maturation, fertilizer capacity and will be stored until ejaculation. The accessory sex glands are responsible for the expelled fluids during ejaculation, named seminal plasma that are mixed with sperm cells and form the ejaculate. Each of these glands are responsible for a certain secretion that will divide equine semen into three distinct fractions: pre-sperm fraction, produced by the prostate and bulbourethral glands; rich fraction in sperm, produced by epididymal secretions and liquids from ampoules of the vas deferens; post-sperm fraction or poor fraction, consisting of sperm remaining in the urethral canal and liquids produced by the seminal vesicles, the gel. During the physiological process of mating, several events occur named erection, in which the stud is excited by stimuli emission which is characterized by the release of sperm into the pelvic urethra followed by ejaculation with the expulsion of semen, relaxation and gathering the penis. Typically, horse semen collections are performed in the conventional way, with a closed artificial vagina, where all the fractions are mixed. Each stud has individual characteristics related to the maintenance of sperm cells during the cryopreservation, these characteristics may be related to production of seminal plasma and to the components that form it as well. What is known is that there is a negative effect played by the seminal plasma components mainly produced by the seminal vesicles, to the sperm during cryopreservation process, however, these factors are still unknown. Several hypotheses are suggested such as the production’s reduction of lipids and proteins and the types of ions present in each fraction of the ejaculate. Knowing this, the fractional collection may be beneficial to sperm, considering that the first fractions do not have contact with seminal plasma produced by the seminal vesicles. This work aims to review the semen fraction harvest in stallions, as well as its benefits for the sperm cells to be submitted to cryopreservation.
Descrição
Palavras-chave
Equino, Refrigeração, Congelação, Colheita de sêmen, Equine, Cooler, Freezer, Collection sperm