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

Abstract

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 feeding) till the time of oocyte aspiration (Day 6 after Regumate). Follicular growth was stimulated by the administration of 1000 IU equiue choriou gonadotropiu (eCG) 24 h after Regumate treatment, and ovulation was induced by injection of 750 IU human choriou gonadotropiu (hCG) 80 h after eCG administration. 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 I) or matured (telophase I and metaphase II). 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), but not in M (25.3 +/- 2.9 vs 28.8 +/- 7.3, 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 mm 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.

Capacidade reprodutiva dos suínos Mangalica – Qual a realidade?

“…Nevertheless the Mangalica ovaries have the biological potential to grow to a higher number of Graafian follicles. Using various doses of PMSG as an additional gonadotropic source to stimulate follicular growth, number of ovulated follicles similar to commercial breeds was achieved Egerszegi et al 2007).…”

Saving Genetic Resources of Native Pigs in Occidental and Oriental Countries — Practical Examples of the Characterization and Utilization of Native Pigs in Hungary and Laos

“…12.4) was noticed in only one study long ago [19]. However, the potential for a higher number of Graafian follicles was described after PMSG treatment, and the stimulated number of ovulations was comparable to that of commercial breeds [20, 21]. Observing ovarian luteal features at slaughter, gilts showed cycling activity at the age of 12 to 15 months under semi-intensive conditions [22].…”

“…27%). Interestingly, the follicular steroid hormone milieu differed considerably in the two breeds [20]. Almost double the estradiol (E2) concentration (29.6 ± 6.8 vs .…”

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

“…Furthermore, there are crucial differences in the secretion of reproductive hormones. The intrafollicular progesterone (P4) concentration is 5 times higher compared to Landrace pigs (Egerszegi et al, 2007), and despite the lower number of corpora lutea, the concentration of P4 in the circulation near the ovary is 4 times higher. Additionally, the pulsatile secretion of luteinizing hormone is suppressed, which influences follicle recruitment and development and the level of leptin is increased fourfold (Brüssow et al, 2008).…”