Abstract: 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.

Key words: genes related to egg production, HPA/HPG axis, Shanma duck, rearing model, egg performance