Follicular development and preovulatory oocyte maturation in Hungarian Mangalica and Landrace gilts

Preservation of native pig breeds of different values has got increasing pu blic interest. Hungarian Mangalica, likewise other native races, became uni nteresting because of economic reasons or other characteristics, and were r eplaced by modern breeds. Its population decreased rapidly and reached a cr itical level. However, the exceptional taste of the meat, and the robustnes s and motherliness do support the propagation of this breed. Nevertheless, low prolificacy and marked seasonality remains a problem. The aim of the pr esent study was to find possible implications of the physiological basis wi th regard to the law fecundity. Therefore, preovulatory follicular developm ent and intrafollicular oocyte maturation of Mangalica and of Landrace gilt s were compared. A total of 18 pubertal Blond and Swallow Belly Mangalica a nd 19 Landrace gilts (8.5 to 9 month of age, body weight of 120 to 125 kg) were used. Oestrus of gilts was synchronized by feeding Regumate(R) follicu lar growth was stimulated by administering 1,000 IU PMSC 24 h after the las t Regumate(R) feeding and the LH peak simulated witt 750 IU hCG 80 h after PMSG. Cumulus-oocyte-complexes (COCs) were recovered 34 h after hCG by endoscopic Ovum Pick Up. Follicular fluids from follicles per ovary were pooled and t he morphology of COCs was determined. COCs were classified as compact, expa nded or denuded. Thereafter, COCs were prepared for evaluation of nuclear c onfiguration. Based on their nuclear status the oocytes were classified as 1) immature-germinal vesicle (GV), with diplotene chromatin; 2) meiosis res umed-GV breakdown, diakinesis, M-I to A-I; or 3) mature - T-I and M-II. The average number (+/- SD) of preovulatory follicles was 6.8 +/- 1.4 in Ma ngalica and 19.5 +/- 6.6 in Landrace gilts (p<0.05). Differences were Obtai ned concerning the morphology of recovered COCs between breeds. The per cen t of oocytes with compact cumulus was higher in Mangalica compared to Landr ace gilts (31 vs. 16%) but less oocytes possess expanded cumulus (62 vs. 78 %, p<0.05). The meiotic configuration of oocytes was unlike between Mangali ca and Landrace gilts. The rate of oocytes with mature chromatin configurat ion (Telophase 1/Metaphase II) was higher (27 vs. 62 %, <0.05) in Landrace sows. It is assumed that both diminished follicular development and protracted in trafollicular oocyte maturation may be involved in low fecundity in Mangali ca.