Leptina em fêmeas suínas: relação com status reprodutivo e causas de descarte

• Autor(a) principal: Moreira, Fabiana
• Data de Publicação: 2011
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFPel - Guaiaca
• Texto Completo: http://repositorio.ufpel.edu.br/handle/ri/2579
• topic: Leptina; Receptor da leptina; MAPK; Púberes; Pré-púberes; Leptin; Leptin receptor; MAPK; Pubertal; Prepubertal; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA

Leptin is a multifunctional peptidic hormone, primarily produced by the adipose tissue, which has receptors (Ob-Rs) in reproductive organs, hypothalamus and hypophysis, acting in the appetite regulation and energetic expenditure, potentially influencing the expression of the reproductive function, at puberty and lactation. Reproductive failure are the main causes for female culling, representing 30% to 40%,of the total female culling. Thus, post-mortem evaluation of the genital organs at slaughter may have an important diagnostic value, helping on the identification of the stage of female`s estrous cycle and aiding the interpretation of reproductive abnormalities. Its long form receptor (OBR-b) performs signal transduction in several cell types via mitogen- activated protein kinases (MAPK) cascade, such as ERK 1/2 and p38. The first stage of this thesis is aimed to evaluate the presence of leptin and MPAK in oocites of pubertal sows and prepubertal gilts. Ovaries from 10 pubertal sows and 10 prepubertal gilts were collected at a slaughterhouse. Slides were analyzed for the presence of oocites included in primordial/primary (OIPF), secondary (OISF) and tertiary follicles (OITF). Immunohistochemistry (IHC) was performed with polyclonal antibodies anti-leptin and anti-phospho-MAPK (ERK 1/2 and p38). The second stage involved 28 pubertal sows and the analyses were performed in hypothalamic neurons, endometrial glands and oocytes. For IHC, the antibodies were polyclonal anti-leptin and anti-leptin receptor. Responses were compared with reproductive data registered for each female. All images in both stages were analyzed by 16-Bit Histogram application from Image J® software. Immunolabeling for leptin and activated ERK 1/2 MAPK were more intense in sows oocytes (p ≤ 0.05), while the immunolabeling for activated p38 MAPK was more intense in gilts oocytes (p = 0.05). In sows, OIPF were more intensely marked for leptin and p38 MAPK (p <0.05), on the other hand, for gilts there was no difference in the marking of follicular oocytes from the analyzed categories. Hypothalamic neurons were more intensely marked in the sows culled by reproductive problems (p <0.05). The hypothalamus, uterus and oocytes of luteal or follicular phase sows showed more intense immunolabeling for leptin and OBR-b than the females with cystic ovaries. The immunolabeling for leptin was more pronounced in the hypothalamus and uterus of sows from parity order 2 group (PO 2-4) (p <0.05). These results demonstrate that leptin may be a marker for oocyte competence. Also, cyclic females having PO 2-4 presented more intense leptin immunolabeling in the hypothalamus and uterus and for OBR-b in the oocyte and uterus. The OBR-b immunolabeling was more pronounced in primiparous and multiparous females than for nulliparous. Therefore, immunolabeling for leptin and OBR-b can be a marker for reproductive performance in swine females.