不同饲养方式对蛋鸭产蛋性能的影响及其机制

旨在探讨单笼饲养、双笼饲养、散养和网上平养四种养殖模式对蛋鸭（Anas platyrhynchos）产蛋性能的影响及其影响机制。191羽优质蛋鸭品种山麻鸭被分成单笼、双笼、网上平养、散养四组，记录其产蛋率和日耗料量，研究不同饲养模式对产蛋性能的影响。同时，应用real-time PCR技术检测在不同养殖模式下山麻鸭下丘脑、垂体、卵巢、肾上腺等组织中产蛋相关基因的表达，筛选出其中差异表达基因。结果表明，双笼饲养的山麻鸭产蛋性能和饲料转化率最低，单笼饲养的产蛋性能最佳。产蛋相关基因差异表达检测发现，在不同饲养模式下，促肾上腺激素释放激素（corticotropin-releasing hormone， CRH）基因在下丘脑和垂体组织中，阿黑皮素原（proopiomelanocortin， POMC）基因在垂体组织中的表达无显著差异。在双笼饲养模式下，黑素皮质素受体（melanocortin 2 receptor， MC2R）基因在山麻鸭垂体中的表达量最高，催乳素受体（prolactin receptor， PRLR）基因在卵巢中表达量最高，而骨形态发生蛋白4（bone morphogenetic proteins 4，BMP4）基因在卵巢中表达量最低。结果提示，（1）双笼饲养会导致蛋鸭的产蛋性能下降; （2）双笼饲养的蛋鸭可能长期处于应激状态，诱使垂体中MC2R基因高表达，进而调控HPA轴激素分泌，抑制HPG轴的活性，使得卵巢中的PRLR及BMP4等产蛋相关基因异常表达，两个信号通路交互作用，最终影响了蛋鸭的产蛋性能。

Effect and action mechanism of different feeding models on egg performance in Anas platyrhynchos

This experiment was conducted to explore the effect of the single cage\|rearing， double cage-rearing， net rearing and free-ranged rearing on egg performance in Shanma ducks. 191 Shanma ducks （13 weeks old） with similar body weight （BW） were assigned to different rearing models， to investigate the effects of feeding model on egg performance. The RT-PCR was applied to determine the expression profile of genes related to egg production in hypothalamus， pituitary， ovary and adrenal of laying ducks. The results showed that egg performance and feed conversion of ducks in the double cage-rearing were the lowest in four feeding models. Compared with other three feeding models， the egg performance and feed conversion of ducks in the single cage-rearing were the highest. The feeding models had no significant effect on the mRNA expression levels of CRH， POMC genes in hypothalamus， pituitary of laying ducks. The mRNA expression levels of MC2R gene in pituitary and PRLR gene in ovary of double cage-rearing duck were the highest. These results indicated that two ducks rearing in one cage would lead to decreasing egg-laying rate in the laying duck. The induced expression of MC2R gene in pituitary of double cage-rearing was maybe one of the mechanisms of trigger stress signaling. Maybe the induced expression of PRLR gene and the down-regulation of BMP4 gene in ovary of double cage-rearing duck were two of major genes which regulate ovulation rate in the stress condition.