Comparison of follicular and oocyte development and reproductive hormone secretion during the ovulatory period in Hungarian native breed, Mangalica, and landrace gilts
2005
Ratky, J.(Research Inst. for Animal Breeding and Nutrition, Herceghalom (Hungary)) | Bruessow, K.P. | Egerszegi, I. | Torner, H. | Schneider, F. | Solti, L. | Manabe, N.
Only a very-small amount of physiological data is available about the low fertility (mean litter size is 5.7 +- 0.8) of Hungarian native breed, Mangalica (M), sows. The aim of the present paper is to reveal the differences in preovulatory follicle development and intrafollicular oocyte maturation between M and Landrace (L) gilts, wlth special reference to the peri- and postovulatory secretion and peripheral concentrations of estradiol-17 beta (E2), progesterone (P4), and luteinizing hormone (LH). The number of preovulatory follicles was 6.8 +- 1.4 and 19.6 +- 6.6 in M and L gilts, respectively. A lower degree of cumulus expansion and a lower percentage of mature oocytes (TI/M II) was noted in M. Higher LH and E2 peak levels, a longer E2 to LH peak interval, and lower embryo survival was confirmed. Interestingly, despite the lower number of corpora lutea, a higher peripheral blood level of P4 was shown in M than in L gilts. Both diminished follicuiar development and protracted oocyte maturation may be involved in low fecundity in M, and the present findings may explain these reproductive phenomena.
اظهر المزيد [+] اقل [-]