The feasibility of a novel method to improve sow reproductive performance by combining inhibin immunization and hCG treatment was tested using in vivo and in vitro experiments. In the in vivo experiment, 106 sows were administered an inhibin immunogen on day 7 prior to weaning, and 56 non-treated sows served as the controls. Sows exhibiting oestrous behaviour on day 5 after weaning were artificially inseminated. On day 5 post-insemination, a subset of 50 inhibin-immunized sows received an injection of 1 000 IU human chorionic gonadotropin (hCG). Our results showed that pre-weaning immunization against inhibin marginally improved (P=0.068) total litter size and significantly increased (P=0.044) the live litter size. The overall differences in farrowing rates and live litter size tended toward significance (P=0.10) in the three groups, and the differences in total litter size were not significant (P=0.18). In the in vitro experiment, activin and hCG dose-dependently suppressed (P<0.001) and stimulated (P<0.001) progesterone (P4) secretion in cultured pig granulosa cells (GCs), respectively, and the suppression effect of activin was reversed (P<0.001) by hCG. Activin suppressed P4 secretion mainly by downregulating (P<0.001) the expression of StAR, Cyp11a1, and 3β-HSDII, whereas hCG prevented (P<0.001) the suppression effects. These results indicate that the combination of pre-weaning immunization against inhibin and post-insemination hCG treatment provides a novel method for improving sow reproductive performance.

通过体内和体外实验测试了通过结合抑制素免疫和hCG处理来改善母猪生殖性能的新方法的可行性。在体内实验中，在断奶前第7天给106头母猪施用了抑制素免疫原，而56头未处理的母猪用作了对照。断奶后第5天表现出雌性行为的母猪被人工授精。授精后第5天，将50只受抑制素免疫的母猪的一部分注射1 000 IU人绒毛膜促性腺激素（hCG）。我们的研究结果表明，断奶前针对抑制素的免疫力略有提高（P = 0.068），而总产仔数却大大增加了（P= 0.044）。三组产仔率和活产仔数的总体差异趋于显着（P = 0.10），总产仔数的差异不显着（P = 0.18）。在体外实验中，激活素和hCG分别剂量依赖性地抑制（P <0.001）和刺激（P <0.001）孕酮（P4）在培养的猪颗粒细胞（GCs）中的分泌，并且激活素的抑制作用是相反的（P <0.001）。激活素主要是通过下调StAR，Cyp11a1和3β-HSDII的表达（P <0.001）来抑制P4的分泌，而hCG可以抑制P4的分泌（P<0.001）的抑制作用。这些结果表明，针对抑制素的断奶前免疫和授精后hCG处理的结合提供了一种改善母猪生殖性能的新方法。