Invited review: reproductive physiology in commercial and premium pig breeds – history of 30-year-long cooperation

Cooperation of the Hungarian Research Institute for Animal Breeding and Nutrition (ATK) with the German Leibniz Institute for Farm Animal Biology (FBN) goes back many decades. In 1988 the two departments of reproductive biology began a joint project concerning on ovulation investigation in Landrace pigs. This joint project laid the foundation for further joint projects and has existed for almost 30 years. Over the years, the main focus has always been on the events of the female reproductive tract in pigs, i.e., follicular growth, ovulation, transport of gametes in the oviduct, fertilization and early embryonic development. Nearly all studies were done under in vivo circumstances and using different clinical and endocrinological methods, enabling us to obtain more profound knowledge of the dynamics of reproductive processes. Even results considered to be basic scientific achievements were available for utilization in the daily practice of porcine reproductive management. Since the end of the 1990s, the common projects have been gradually shifted to the physiology of the Hungarian indigenous pig breed Mangalica. Research partners were convinced that modern utilization of indigenous pig breeds would open new doors for premium pork production. In addition to the Mangalica breed, this principal was broadened to non-European fatty-type native pig breeds as well and resulted in long-term, intercontinental scientific cooperation

Superovulatory Ovarian Response in Mangalica Gilts is Not Influenced by Feeding Level

The aim of the study was to compare how different feeding levels affect the ovarian potential of follicular development and oocyte maturation in response to superovulatory treatment in native Mangalica (M, n = 17) compared with Landrace (L, n = 20) pigs. Gilts of both breeds were fed high-energy (HI-2.5 kg) or low-energy (LO - 1.25 kg) feed during oestrus synchronization (15 days of Regumate (R) feeding) till the time of oocyte aspiration (Day 6 after Regumate (R)). Follicular growth was stimulated by the administration of 1000 IU equine choriou gonadotropiu (eCG) 24 h after Regumate (R) treatment, and ovulation was induced by injection of 750 IU human choriou gonadotropiu (hCG) 80 h after eCG adminstration. Ultrasound (US) investigation was done three times (4-10 h before, and 40-44 and 72-74 h after eCG administration) for the observation of follicular development. Oocyte and follicular fluid (FF) were collected endoscopically 34 h after hCG injection. Cumulus-oocyte complexes were evaluated, their morphology determined, and thereafter fixed and stained for chromatin evaluation. Oocytes were classified as meiosis-resumed (germinal vesicle breakdown, diakinesis, metaphase I to anaphase 1) or matured (telophase I and metaphase 11). FF concentrations of oestradiol and progesterone were measured by validated radioimmunoassays. In L gilts, differences were observed between HI and LO in the number of preovulatory follicles (32.3 +/- 10.5 vs 17.1 +/- 12.3, p 0.05). Initial follicular growth was not affected by feeding levels; however, preovulatory follicle size was larger in M (7.1 +/- 0.9 and 6.9 +/- 1.1 turn vs 5.7 +/- 0.7 and 5.5 +/- 0.8 mm; p <0.05). No differences were obtained with relation to mature chromatin configuration in both breeds (L gilts: HI - 70% and LO-67% vs M gilts: HI- 67% and LO - 63%). A twofold higher oestradiol concentration was detected in FF of HI-M and LO-M (29.6 +/- 6.8 and 30.9 +/- 10.3 ng/ml respectively) compared with that of L (16.9 +/- 9.7 and 17.9 +/- 3.6 ng/ml, respectively; p <0.05). The mean FF progesterone level was nearly fivefold higher in M (2020.4 +/- 1056 and 1512.2 +/- 1121.8 ng/ml) compared with L (386.2 +/- 113.7 and 298.8 +/- 125.9 ng/ml, p <0.05). The results indicate an influence of the feeding of altered energy on the number of recruitable preovulatory follicles in modern Landrace but not in native Mangalica breed. Moreover, the follicular steroid hormone milieu differs between Landrace and Mangalica gilts but not depending on feeding levels. Oocyte maturation was not affected by diet