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Endocrine and follicular studies in Meishan pigs.
J Reprod Fertil Suppl. 1993; 48:261-70.JR

Abstract

The enhanced early embryonic survival in Chinese Meishan compared with Large-White gilts may be due, in part, to differences in ovarian and endocrine function, particularly during the periovulatory period. The overall patterns of oestradiol, LH and FSH secretion were not different between Meishan and Large-White hybrid controls during this period, although circulating inhibin concentrations were higher in Meishan gilts. Thus, there appeared to be a decreased sensitivity to inhibin feedback on FSH secretion in Meishan gilts. Behavioural oestrus was exhibited earlier relative to the LH surge in Meishan gilts than in Large-White hybrid gilts, but the time interval from the oestradiol peak until the LH surge was similar in both breeds. This finding suggests that Meishan gilts are more sensitive in terms of initiating a behavioural response, but not in terms of positive feedback. Although preovulatory follicular characteristics were as variable in Meishan as in Large-White hybrid gilts, follicles from Meishan gilts were smaller, but contained a higher concentration of oestradiol in the follicular fluid. This was probably due to increased aromatase activity in both granulosa and theca cells of Meishan follicles. The enhanced maturation of the intrafollicular environment in Meishan gilts was reflected in the oocyte population which was at a more advanced stage of development in the period preceding ovulation. In addition to decreasing the time between onset of oestrus and ovulation, advancing the LH surge to coincide with onset of oestrus (via hCG administration) decreased embryo survival at day 30 of gestation. It is concluded that both endocrine and follicular mechanisms have a role in ensuring the prolificacy in the Meishan breed.

Authors+Show Affiliations

Department of Physiology and Environmental Science, University of Nottingham, Loughborough, Leics, UK.No affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't
Review

Language

eng

PubMed ID

8145209

Citation

Hunter, M G., et al. "Endocrine and Follicular Studies in Meishan Pigs." Journal of Reproduction and Fertility. Supplement, vol. 48, 1993, pp. 261-70.
Hunter MG, Biggs C, Faillace LS. Endocrine and follicular studies in Meishan pigs. J Reprod Fertil Suppl. 1993;48:261-70.
Hunter, M. G., Biggs, C., & Faillace, L. S. (1993). Endocrine and follicular studies in Meishan pigs. Journal of Reproduction and Fertility. Supplement, 48, 261-70.
Hunter MG, Biggs C, Faillace LS. Endocrine and Follicular Studies in Meishan Pigs. J Reprod Fertil Suppl. 1993;48:261-70. PubMed PMID: 8145209.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Endocrine and follicular studies in Meishan pigs. AU - Hunter,M G, AU - Biggs,C, AU - Faillace,L S, PY - 1993/1/1/pubmed PY - 1993/1/1/medline PY - 1993/1/1/entrez SP - 261 EP - 70 JF - Journal of reproduction and fertility. Supplement JO - J Reprod Fertil Suppl VL - 48 N2 - The enhanced early embryonic survival in Chinese Meishan compared with Large-White gilts may be due, in part, to differences in ovarian and endocrine function, particularly during the periovulatory period. The overall patterns of oestradiol, LH and FSH secretion were not different between Meishan and Large-White hybrid controls during this period, although circulating inhibin concentrations were higher in Meishan gilts. Thus, there appeared to be a decreased sensitivity to inhibin feedback on FSH secretion in Meishan gilts. Behavioural oestrus was exhibited earlier relative to the LH surge in Meishan gilts than in Large-White hybrid gilts, but the time interval from the oestradiol peak until the LH surge was similar in both breeds. This finding suggests that Meishan gilts are more sensitive in terms of initiating a behavioural response, but not in terms of positive feedback. Although preovulatory follicular characteristics were as variable in Meishan as in Large-White hybrid gilts, follicles from Meishan gilts were smaller, but contained a higher concentration of oestradiol in the follicular fluid. This was probably due to increased aromatase activity in both granulosa and theca cells of Meishan follicles. The enhanced maturation of the intrafollicular environment in Meishan gilts was reflected in the oocyte population which was at a more advanced stage of development in the period preceding ovulation. In addition to decreasing the time between onset of oestrus and ovulation, advancing the LH surge to coincide with onset of oestrus (via hCG administration) decreased embryo survival at day 30 of gestation. It is concluded that both endocrine and follicular mechanisms have a role in ensuring the prolificacy in the Meishan breed. SN - 0449-3087 UR - https://www.unboundmedicine.com/medline/citation/8145209/Endocrine_and_follicular_studies_in_Meishan_pigs_ DB - PRIME DP - Unbound Medicine ER -