The A Allele of the Cholecystokinin Type A Receptor Gene g.420 C > A Polymorphism Improves Growth Traits in Amakusa Daioh Cross Chicken

Amakusa Daioh cross chickens are F(1) hybrids of restored Amakusa Daioh sires and Kyushu Rhode dams. In the present study, the association between a single nucleotide polymorphism (SNP; AB604331, g.420 C>A) in the cholecystokinin type A receptor gene and growth traits in Amakusa Daioh cross chicken were investigated. We used 72 male and 72 female birds that had hatched on the same day, were raised in the same chicken house, and were fed the same diet ad libitum from day 0 to 17 weeks (wks) of age. Body weight was recorded at weekly intervals and average daily gain of each week interval was calculated from body weight data. Birds were sacrificed at 17 wks and carcass traits were recorded. SNP genotyping was carried out using the mismatch amplification mutation assay. Associations between the SNP and growth traits were analyzed by a generalized linear model. Body weight from 6 to 17 wks was higher in birds with the A allele than in birds with the C allele, although significant differences in average daily gain traits between birds with A and C alleles were not detected during most of the duration of the experiment. Carcass data showed that birds with the A allele had heavier wings and a smaller proportion of the gizzard than those with the C allele. The g.420 C>A SNP will be useful as a selection marker for parent stock lines to increase the growth performance of Amakusa Daioh cross chickens.