Mitchell R D, Burke W H
Department of Poultry Science, University of Georgia, Athens 30602, USA.
Growth Dev Aging. 1995 Spring-Summer;59(1-2):31-44.
The influence of sex and genotype on growth of chick embryos was studied using eggs from commercial broiler hens mated with broiler strain males (BrBr) or with bantam males (BaBr) and using eggs from bantam females mated to bantam males (BaBa) or to broiler strain males (BrBa). Male BrBr embryos were first significantly heavier than females at 9 days of incubation. The influence of sire's genotype was expressed between 6 and 16 days of incubation but not at 20 days. Dam's genotype, and the associated difference in egg weight, significantly affected embryo weight by 12 days of incubation and by 20 days it alone influenced embryo weight. Plasma insulin-like growth factor-I (IGF-I) levels of BrBr and BaBr embryos did not differ at 8, 10, 12, or 14 days of incubation, nor were there sex differences. There were no genotype differences in whole body protein concentration, DNA concentration or protein:DNA ratios at 4 or 8 days of incubation. At 12 days the pectoralis major DNA concentration of BaBa embryos was significantly higher than that of all other groups. Pectoralis muscle protein concentration of BrBa embryos was significantly lower than those of BaBr embryos at 12 days of incubation, but by 16 days it was highest. The protein:DNA ratios of embryos developing in bantam eggs were significantly lower than those in broiler eggs at 12 days. In summary, genotypic and sex differences in body weight and muscularity that develop after hatching appear to be predetermined by differences in embryonic growth patterns, but there is no clear relationship between embryonic growth, plasma IGF-I concentration or the concentration of DNA or protein in pectoralis muscle.
利用来自商业蛋鸡的鸡蛋研究性别和基因型对雏鸡胚胎生长的影响，这些蛋鸡与肉种鸡雄性（BrBr）或矮脚鸡雄性（BaBr）交配，以及来自矮脚鸡雌性的鸡蛋与矮脚鸡雄性（BaBa）或肉种鸡雄性（BrBa）交配。雄性BrBr胚胎在孵化9天时首次显著比雌性重。父本基因型的影响在孵化6至16天之间表现出来，但在20天时没有。母本基因型以及相关的蛋重差异在孵化12天时显著影响胚胎重量，到20天时单独影响胚胎重量。BrBr和BaBr胚胎在孵化8、10、12或14天时的血浆胰岛素样生长因子-I（IGF-I）水平没有差异，也没有性别差异。在孵化4天或8天时，全身蛋白质浓度、DNA浓度或蛋白质：DNA比率没有基因型差异。在12天时，BaBa胚胎的胸大肌DNA浓度显著高于所有其他组。在孵化12天时，BrBa胚胎的胸肌蛋白质浓度显著低于BaBr胚胎，但到16天时最高。在孵化12天时，在矮脚鸡蛋中发育的胚胎的蛋白质：DNA比率显著低于肉种鸡蛋中的胚胎。总之，孵化后出现的体重和肌肉发育的基因型和性别差异似乎由胚胎生长模式的差异预先决定，但胚胎生长、血浆IGF-I浓度或胸肌中DNA或蛋白质浓度之间没有明确的关系。
