Observatorio de I+D+i UPM

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Research Publications in journals:
Endocrine and ovarian response after a two-day controlled suckling and eCG treatment in lactating rabbit does
Research Areas
  • Animal production
The use of synchronization methods is necessary when artificial insemination (AI) is applied in lactating rabbit does in order to obtain high fertility results. The most applied methods are the administration of eCG or the temporary doe-litter separation. Nevertheless, it is known the negative side effects of hormonal treatment in the doe or low litter growth due to absence of suckling, respectively. Recently, improved reproductive performance without any visible consequence on young growth has been obtained by applying a 2 days controlled nursing method before AI, by allowing for a 10 min nursing of the litter after 24 hrs of separation. The present study was undertaken to study the pituitary (PRL, LH, FSH) and the ovarian response (follicle size and number) to these methods. A total of 442 lactating does inseminated on day 11 post-partum was distributed in three experimental groups: 2CN (closing of nest box on day 9, controlled nursing on day 10 and 11), eCG (20 UI administered on day 9 post-partum) and CONTROL (without treatment). Blood samples were obtained from 10 does per group at 48 h, 24 h and 0 h before AI, and 1 h after AI. 2CN and eCG treatments similarly improved, in comparison with the CONTROL, sexual receptivity (76.3, 77.5 and 58.2%, respectively; P<0.001) and fertility (63.1, 64.1 and 48.4%, respectively; P<0.05) of lactating does. A similar plasma FSH levels in all groups of does and time of sampling was observed. Due to the absence of suckling, plasma concentration of PRL on day 10 post-partum of 2CN group was lower than the CONTROL group (P<0.05); this endocrine change in PRL levels could explain the better reproductive performances obtained with 2CN treatment. At 1h after exogenous administration of GnRH (at the time of AI) a high LH response was observed in all groups (P<0.001). Ovaries from 20 rabbits treated in the same way but not inseminated (2CN , n=10; eCG, n=5; CONTROL, n=5 does) were obtained on day 11 post-partum in order to check the morphometric status (weight, width and height) and to make histological and immunohistochemical studies to show the presence of Growth Hormone Receptor (GH-R). As a result, synchronization methods did not show any significant difference in relation to CONTROL group. However, a small increase in the number of primary follicles was evidenced in 2CN group with respect to eCG group and similar to CONTROL group (23.0 ± 3.7, 9.4 ± 4.9 and 14.8 ± 4.92 primary follicles, respectively; P=0.1). GH-R immunostaining¿presence was more evident in 2CN and eCG groups, including primordial follicles and oocyte itself. Thus, it would be possible some directs effects of GH on follicular development described in other species. Some of ovarian parameters described open new ways to study intra-ovarian mechanism of follicular development in the post-partum period of rabbit does.
Impact factor JCR
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  • Autor: Maria del Pilar Garcia Rebollar (UPM)
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Producción Animal
  • Departamento: Producción Animal
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