Amakusa Daioh cross chickens from Kumamoto Prefecture, Kyushu Island, Japan, are F₁ hybrid chickens resulting from a cross between the Amakusa Daioh and Kyushu Rhode breeds. A significant association has been reported between a SNP (AB604331, g.420 C>A) in the cholecystokinin type A receptor gene and growth traits in some Japanese slow-growing chickens. This genetic improvement effect was examined in Amakusa Daioh cross chickens by comparing superior A allele-fixed chickens with conventional ones. Fattening experiments using 436 conventional and 297 improved (A allele-fixed) Amakusa Daioh cross birds were performed over two seasons. In each season, experimental birds of both sexes were hatched on the same day, raised in the same chicken house, and fed the same diet ad libitum for 15 wk for cockerels and 19 wk for pullets, after which they were slaughtered. Body weight (BW), average daily gain (ADG), and carcass weights were measured. SNP genotypes were determined using mismatch amplification mutation assay. Association between the SNP and growth traits was analyzed using GLM, taking into account gender, season, genetic additive and dominance, and test group effects. The improved pullets were significantly heavier than the conventional pullets at slaughter age. Boneless carcasses of the improved pullets were significantly heavier than those of the conventional pullets as well. In the conventional cockerels, significantly positive additive effects of the A allele on BW were detected during the entire experimental period, except at 10 and 11 wk. Significantly positive additive effects of the A allele on thigh weight were detected. We concluded that g.420 C>A is a good selective marker for increased slaughter live weight and meat weight in Amakusa Daioh cross chickens.

来自日本九州岛熊本县的天草大王杂交鸡是由天草大王和九州罗德品种杂交产生的F ₁杂交鸡。据报道，A 型胆囊收缩素受体基因中的 S​​NP（AB604331，g.420 C>A）与一些日本生长缓慢的鸡的生长性状之间存在显着关联。通过将优良的 A 等位基因固定鸡与常规鸡进行比较，在天草大王杂交鸡中检验了这种遗传改良效果。在两个季节中，使用436头常规和297头改良的（由等位基因固定的）Amakusa Daioh杂交鸟进行了育肥实验。每个季节，两性实验鸟在同一天孵化，在同一鸡舍饲养，随意喂食相同的饮食。公鸡 15 ​​周，小母鸡 19 周，之后被屠宰。体重（BW），日均增重（ADG)，并测量胴体重。使用错配扩增突变测定法确定SNP基因型。使用 GLM 分析 SNP 与生长性状之间的关联，考虑到性别、季节、遗传可加性和优势以及测试组效应。改良后的小母鸡在屠宰时明显比传统小母鸡重。改良后备母鸡的无骨胴体也明显比传统后备母鸡重。在常规公鸡中，除10和11周外，在整个实验期间均检测到A等位基因对BW的显着正累加作用。检测到 A 等位基因对大腿重量的显着正累加效应。我们得出的结论是 g.420 C>