Study on Myofiber Characteristics during Early Development Stage and Associations with Skeletal Growth and Development in Different Duck Breeds(Anas platyrhynchos domestica)
Abstract：Characteristics of livestock myofiber not only determine meat production but also closely relate to meat quality. The present study was firstly designed to research the characteristics of myofiber during late embryonic and post-hatch development and their associations with skeletal growth and development in two duck breeds(Anas platyrhynchos domestica) (Gaoyou ducks and Jinding ducks) with different growth rate. Gastrocnemius muscles collected from two duck breeds of 21, 25 and 27 embryonic development and 7 day post-hatching were cut at -20℃ using a cryotome and then stained with the method of myosin-ATPase. The results showed that there was no significant difference between two breeds in leg weight, body weight, myofiber diameter, cross-sectional area and density during late embryonic development, but the age effect was significant. The myofiber diameter and cross-sectional area of the two duck breeds increased while the myofiber density decreased throughout the embryonic development. At 7 day post-hatching, leg weight and body weightof Gaoyou duck was significantly higher than that of Jinding duck (P＜0.01), but there was still no significant difference in myofiber diameter, cross-sectional area and density between two breeds (P＞0.05). The myofiber cross-sectional area of two duck breeds decreased slightly (P＞0.05) at 7 day post-hatching while the myofiber density increased significantly (P＜0.05). Gastrocnemius myofibers of two duck breeds could be divided into three types (typeⅠ, typeⅡa and typeⅡb ), and the proportion of type IIb was highest. There existed a trend in duck gastrocnemius muscles that a few of type IIb was switching to type I during late embryo to early hatching period. The correlation analysis showed that in both two duck breeds leg weight and body weight were positively correlated with myofiber diameter and cross-sectional area and negative correlated with myofiber density. These results provide an important reference for studying the development and regulation mechanism of skeletal muscle and meat quality in ducks.
