Soede N M, Bouwman E G, van der Laan I, Hazeleger W, Jourquin J, Langendijk P, Kemp B
Adaptation Physiology Group, Department of Animal Sciences, Wageningen University, Wageningen, The Netherlands.
Reprod Domest Anim. 2012 Oct;47(5):835-41. doi: 10.1111/j.1439-0531.2011.01977.x. Epub 2012 Jan 9.
Progesterone supplementation during early pregnancy may increase embryo survival in pigs. The current study evaluated whether oral supplementation with an analogue of progesterone, altrenogest (ALT), affects embryo survival. A first experiment evaluated the effect of a daily 20-mg dosage of ALT during days 1-4 or 2-4 after onset of oestrus on embryo survival at day 42 of pregnancy. A control group (CTR1) was not treated. The time of ovulation was estimated by transrectal ultrasound at 12-h intervals. Altrenogest treatment significantly reduced pregnancy rate when start of treatment was before or at ovulation: 25% (5/20) compared to later start of treatment [85% (28/33)] and non-treated CTR1 [100% (23/23)]. Altrenogest treatment also reduced (p < 0.05) number of foetuses, from 14.6 ± 2.6 in CTR1 to 12.5 ± 2.5 when ALT started 1-1.5 days from ovulation and 10.7 ± 2.9 when ALT started 0-0.5 days from ovulation. In a second experiment, sows with a weaning-to-oestrous interval (WOI) of 6, 7 or 8-14 days were given ALT [either 20 mg (ALT20; n = 49) or 10 mg (ALT10; n = 48)] at day 4 and day 6 after onset of oestrus or were not treated (CTR2; n = 49), and farrowing rate and litter size were evaluated. Weaning-to-oestrous interval did not affect farrowing rate or litter size. ALT did not affect farrowing rate (86% vs 90% in CTR2), but ALT20 tended to have a lower litter size compared with CTR2 (11.7 ± 4.1 vs 13.3 ± 3.1; p = 0.07) and ALT10 was intermediate (12.3 ± 2.9). In conclusion, altrenogest supplementation too soon after ovulation reduces fertilization rate and embryo survival rate and altrenogest supplementation at 4-6 days of pregnancy reduces litter size. As a consequence, altrenogest supplementation during early pregnancy may reduce both farrowing rate and litter size and cannot be applied at this stage in practice as a remedy against low litter size.
妊娠早期补充孕酮可能会提高母猪的胚胎存活率。本研究评估了口服孕酮类似物烯丙孕素（ALT）是否会影响胚胎存活率。第一个实验评估了在发情开始后的第1 - 4天或第2 - 4天每天给予20毫克ALT对妊娠第42天胚胎存活率的影响。对照组（CTR1）不进行处理。通过经直肠超声每隔12小时估计排卵时间。当治疗开始时间在排卵前或排卵时，烯丙孕素治疗显著降低了妊娠率：25%（5/20），而治疗开始时间较晚时为[85%（28/33）]，未治疗的CTR1为[100%（23/23）]。烯丙孕素治疗还降低了（p < 0.05）胎儿数量，CTR1组为14.6 ± 2.6，排卵后1 - 1.5天开始使用ALT时为12.5 ± 2.5，排卵后0 - 0.5天开始使用ALT时为10.7 ± 2.9。在第二个实验中，对断奶至发情间隔（WOI）为6、7或8 - 14天的母猪，在发情开始后的第4天和第6天给予ALT [20毫克（ALT20；n = 49）或10毫克（ALT10；n = 48）]，或不进行处理（CTR2；n = 49），并评估产仔率和窝仔数。断奶至发情间隔不影响产仔率或窝仔数。ALT不影响产仔率（CTR2为86%，ALT20为90%），但与CTR2相比，ALT20的窝仔数有降低趋势（11.7 ± 4.1对13.3 ± 3.1；p = 0.07），ALT10居中（12.3 ± 2.9）。总之，排卵后过早补充烯丙孕素会降低受精率和胚胎存活率，妊娠4 - 6天补充烯丙孕素会降低窝仔数。因此，妊娠早期补充烯丙孕素可能会降低产仔率和窝仔数，在实践中现阶段不能将其作为解决窝仔数少的补救措施。
