Expression analysis for candidate genes associated with eggshell mechanical property

Damaged eggshells result in losses of eggs. The genetic mechanism of variable eggshell strength is still unclear. The current study was conducted to verify whether the eggshell calcification related genes, CALB1, SPP1, DMP4, BMP2 and SLIT2, were associated with eggshell mechanical property. For this purpose quantitative PCR (q-PCR) analysis was performed to detect gene expression between two groups of hens laying strong and weak eggs. The hens were selected from 360 White Leghorn layers at 60 wk to ensure that the strong and weak eggs differed significantly in breaking strength but not in eggshell thickness and weight. Using this special strong/weak eggshell model, we found that the expression of CALB1 in the uterus of strong shell group was about 3-fold higher (P<0.05) than that in weak shell group. The DMP4 expression was significantly higher (2-fold, P<0.05) in the uterus of weak shell group than that in strong shell group. However, no difference was observed for genes of SPP1, SLIT2 and BMP2 between these two groups. The current study provides a new insight to investigate the association of candidate genes with eggshell mechanical property.