Viabilidade e fertilidade do sêmen equino resfriado a 5 °C por 24 horas com dois diluidores

• Autor(a) principal: Pugliesi, Guilherme
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5610
• topic: Inseminação artificial; Garanhões; Criopreservação; Artificial insemination; Stallion; Criopreservation; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::PRODUCAO ANIMAL

The objective of this study was evaluate the effectiveness of the Mangalarga Marchador stallions semen diluted with glycine-yolk egg based extender or milk-based extender and cooled at 5 °C for 24 hours, assessed by in vitro tests and of fertility in vivo. In Experiment 1, were used 5 ejaculated of 3 stallions. Following semen collection, the experimental group was divided into two treatments: 1 - cooling and dilution of semen with the milk-based extender, 2 - cooling and dilution of semen with extender glycine-egg yolk based extender. Semen was packaged in samples containing 12 mL of diluted semen with 30 x 106 viable sperm / mL concentration and then stored in Equitainer® for 24 hours. The sperm quality was evaluated after its dilution and after its cooling. The following seminal characteristics were evaluated: progressive motility, spermatic vigor, sperm morphology, integrity of the plasma membrane integrity by supravital test and epifluorescent using the dyes carboxyfluorescein diacetate (CFDA) and propidium iodide (PI); plasma membrane functionality by hypoosmotic test and progressive motility and spermatic vigor during the spermatic thermo-resistance test (TTR) for 90 minutes. The vigor of semen diluted with Kenney was higher (p <0.05) than T2 in the assessment of fresh diluted semen. No statistical difference was observed in other seminal characteristics from the fresh diluted semen. In the cooled semen, the Kenney extender had a better motility and spermatic vigor after the 24 hours storage, but Foote extender had higher average values for reactive spermatozoa percentage to the hypoosmotic test and the viabity to the epifluorescent test (p<0,05). In Experiment 2, the objective was to evaluate the fertility of cooled semen with both extenders previously described. Seventeen semen samples of stallion 1 and twenty three samples of stallion 2 were collected. Following semen collection, the semen was diluted with two extenders used in Experiment 1, and adjusted to an insemination dose of 500 million viable sperm in a final volume of 15 mL per dose. Semen was packaged in Equitainer® and cooled down to 5° C and storage for at least 24 hours. The following seminal characteristics were evaluated: progressive motility and vigor of the diluted and cooled semen; the sperm morphology of fresh semen and cooled with both extenders. Thirty one estrous cycles of 26 mares were used in the first period and 43 cycles of 28 mares in the second period. After detection 30 mm follicle size, the mares were randomly assigned into two groups: group A (mares inseminated with semen cooled with Kenney extender) and group B (mares inseminated with semen cooled with dilutive Foote). The stallions semen were used randomly among mares. The inseminations were done after a period of at least 24 hours of storage at 5° C. Semen was deposited in the body uterus, after the detection of a 30-40 mm follicle detection throughout ovulation. The inseminations were performed only on fixed days (Tuesday, Thursday and Saturday). The pregnancy diagnosis was performed by transrectal ultrasonography. As results, Kenney extender had higher progressive motility and spermatic vigor maintance after cooling compared to T2 extender. The pregnancy rate was higher from treatment A than treatment B (p<0,05), 55,26% (21/38) and 30,56% (11/36), respectively. With this data, it is possible to conclude that: the integrity and functionality of sperm cell plasma membrane evaluation tests are considered ancillary assessments in predicting the reproductive potential of stallions, but are not yet conclusive. The glycine-egg yolk based extender was not effective in preserving the seminal characteristics, and its fertility rate was not acceptable. The milk based extender proposed by Kenney et al. (1975) is still an excellent option for use in programs of AI with cooled semen from Mangalarga Marchador breed.