Bertoldo M, Holyoake P K, Evans G, Grupen C G
Faculty of Veterinary Science, The University of Sydney, Camden, NSW, Australia.
Reprod Domest Anim. 2011 Jun;46(3):489-94. doi: 10.1111/j.1439-0531.2010.01695.x. Epub 2010 Nov 18.
Impaired reproductive performance exhibited by the domestic sow during the late summer and early autumn months is referred to as seasonal infertility. This study was carried out to determine whether there are changes in ovarian morphology and follicular steroidogenesis associated with season, which may be associated with seasonal infertility. Ovaries were collected in pairs from sows sourced from two farms and slaughtered 4 days after weaning during winter and summer. The mean progesterone concentration in follicular fluid (FF) collected from small follicles was lower in summer (701.3 ± 115.54 nm) compared with winter (1235.55 ± 164.47 nm; p<0.001). The mean progesterone concentration in the FF of large follicles was also lower in summer (1469.2 ± 156.51 nm) compared with winter (2470.9 ± 169.13 nm; p<0.001). The number of large surface antral follicles (5-8 mm in diameter) on the ovaries recovered from Farm A sows was higher during summer (17.76 ± 0.56) than in winter (15.38 ± 0.54; p<0.05). Similarly, the number of small follicles (3-4 mm in diameter) on Farm A sow ovaries was higher in summer (8.46 ± 0.66) than in winter (4.63 ± 0.53; p<0.001). In contrast, the number of small follicles on the surface of ovaries recovered from Farm B sows was higher during winter (10.17 ± 1.50) than in summer (6.45 ± 1.00; p<0.01). The number of pre-ovulatory follicles (>8 mm in diameter) was also higher in winter (1.23 ± 1.68) when compared to summer (0.51 ± 0.3; p<0.001) on the ovaries of sows from Farm B. The results suggest that there are seasonal differences in follicular steroidogenesis and ovarian dynamics. These findings add support to the theory that altered follicular steroidogenesis and ovarian morphology may possibly be the mechanism behind reduced reproductive performance during the period of seasonal infertility in sows.
家猪在夏末和初秋期间表现出的繁殖性能受损被称为季节性不育。本研究旨在确定与季节相关的卵巢形态和卵泡类固醇生成是否存在变化，这可能与季节性不育有关。从两个农场获取的母猪断奶4天后成对采集卵巢并屠宰，分别在冬季和夏季进行。夏季从小卵泡采集的卵泡液（FF）中孕酮平均浓度（701.3±115.54纳摩尔）低于冬季（1235.55±164.47纳摩尔；p<0.001）。夏季大卵泡FF中孕酮平均浓度（1469.2±156.51纳摩尔）也低于冬季（2470.9±169.13纳摩尔；p<0.001）。从A农场母猪回收的卵巢上，直径5 - 8毫米的大表面有腔卵泡数量夏季（17.76±0.56）高于冬季（15.38±0.54；p<0.05）。同样，A农场母猪卵巢上直径3 - 4毫米的小卵泡数量夏季（8.46±0.66）高于冬季（4.63±0.53；p<0.001）。相比之下，从B农场母猪回收的卵巢表面小卵泡数量冬季（10.17±1.50）高于夏季（6.45±1.00；p<0.01）。B农场母猪卵巢上排卵前卵泡（直径>8毫米）数量冬季（1.23±1.68）也高于夏季（0.51±0.3；p<0.001）。结果表明卵泡类固醇生成和卵巢动态存在季节性差异。这些发现支持了这样一种理论，即卵泡类固醇生成和卵巢形态改变可能是母猪季节性不育期间繁殖性能下降背后的机制。
