Study on differentiation during embryonic development across selective and ancestral breeds.

Abstract

In order to explore the effect of strain on diverging post-hatch muscle properties, muscle regulation during embryo development was investigated in selected and unselected breeds. Four broiler strains were used: JingNing (JN) chicken (a Chinese native chicken), HuangYu (HY) broiler, BaiYu (BY) broiler and Hyline layer (commercial crossbred chickens). Results showed that the four breeds had almost the same characteristic during different incubation periods. BY broilers moved more than JN and Hyline layers from Hamburger & Hamilton stage (HH)24 to HH31 (P<0.05). HY broilers moved more than JN and Hyline layers from HH27 to HH31 (P<0.01). All the embryos were heavier daily from HH24 to ED18 (P<0.05); broilers presented greater body weights than JN and hyline layers (P>0.05); broilers presented smaller fiber diameter than JN chickens before HH31 (P>0.05). From then on, JN chicken exhibited smaller fiber diameter compared to the broilers (P>0.05). Western blotting indicated all the breeds had continuous insulin-like growth factor-I (IGF-I) expression, with the highest expression level in broilers from HH19 to HH24 and highest expression level in JN chicks from HH27 to HH31. The results indicated that the diverging growth among breeds was already shown in embryonic stages; the different expression patterns of IGF-I may be involved in cell proliferation and differentiation.