USDA, U.S. Meat Animal Research Center, Clay Center, NE, 68933, USA(1).
USDA, U.S. Meat Animal Research Center, Clay Center, NE, 68933, USA(1).
Anim Reprod Sci. 2021 Mar;226:106711. doi: 10.1016/j.anireprosci.2021.106711. Epub 2021 Jan 26.
The objective of this study was to evaluate placental development during late gestation (day 100) between Chinese Meishan (CM; n = 7) and White crossbred (WC; n = 5) gilts following intrauterine crowding induced by unilaterally hysterectomy-ovariectomy. Gross placental morphology and areolae density as well as histological morphology (i.e., folded bilayer and placental stroma) were analyzed using computer-assisted morphometry for placentas of the smallest and largest fetuses within each litter. There was a breed by fetal size interaction (P < 0.01) for areolae density in which placentas for large CM fetuses had greater areolae density compared to small CM fetuses, but the density of areolae was greater for CM fetuses compared to WC fetuses, irrespective of fetal size. The width of the folded bilayer was greater (P < 0.01) in placentas for WC gilts compared to CM gilts, irrespective of fetal size. Placentas for small fetuses had greater (P < 0.01) folded bilayer width compared to large fetuses, irrespective of breed. The placental stromal width was greater (P < 0.01) in placentas for large fetuses compared to small, irrespective of breed. The difference between stromal width in placentas between divergent-sized littermates, however, was greater (P = 0.05) in WC gilts compared to CM gilts, indicating there was a limited response to intrauterine crowding in CM gilts. These results indicate there is an altered placental development during late gestation in CM compared to WC gilts, thus, there are likely different mechanisms for responding to intrauterine crowding between breeds.
本研究旨在评估单侧子宫卵巢切除术引起宫内拥挤后，中国梅山（CM；n = 7）和白色杂交（WC；n = 5）小母猪在妊娠晚期（第 100 天）的胎盘发育情况。使用计算机辅助形态计量学分析了每个窝中最小和最大胎儿的胎盘的总胎盘形态和胎盘小叶密度以及组织学形态（即折叠双层和胎盘基质）。在胎盘小叶密度方面存在品种与胎儿大小的互作（P < 0.01），即与 CM 小胎儿的胎盘相比，CM 大胎儿的胎盘小叶密度更大，但无论胎儿大小，CM 胎儿的胎盘小叶密度均大于 WC 胎儿。无论胎儿大小，WC 小母猪的胎盘折叠双层宽度均大于 CM 小母猪（P < 0.01）。小胎儿的胎盘折叠双层宽度大于大胎儿（P < 0.01），与品种无关。无论品种如何，大胎儿的胎盘基质宽度均大于小胎儿（P < 0.01）。然而，不同大小窝仔之间基质宽度的差异在 WC 小母猪中大于 CM 小母猪（P = 0.05），表明 CM 小母猪对宫内拥挤的反应有限。这些结果表明，CM 与 WC 小母猪相比，在妊娠晚期胎盘发育发生了改变，因此，两种品种对宫内拥挤的反应可能存在不同的机制。
