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

Abstract

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.

Effect of a Single Nucleotide Polymorphism in the Cholecystokinin Type A Receptor Gene on Growth Traits of the Miyazaki Jitokko Chicken

“…Sequential reports from the author's group have shown that a significant difference in allele frequency between low-and high-growth lines was caused by long-term selection for growth perform-ance, and that the A allele of the g.420 C>A SNP in CCKAR improved growth traits within the Hinai-dori breed (Rikimaru et al, 2013(Rikimaru et al, , 2014. A significant association was observed between the g. 420 C>A SNP and growth traits using the Amakusa Daioh cross chicken, an F 1 hybrid between Amakusa Daioh (native to the Kumamoto Prefecture) sires and the Kyushu Rhode dams (Takahashi et al, 2019). This report provides an additional line of evidence that the g.420 C> A SNP is a useful marker and its application is practicable for improving the growth traits of Jidori brand chickens.…”

“…In the Amakusa Daioh cross chickens, no significant differences were observed between the A and C alleles in most intervals of the rearing period (Takahashi et al, 2019). In the Miyazaki Jitokko chickens, the effect of the A allele on ADG in the first half of the rearing period was significantly greater than in the second half.…”

Practical Application of Miyazaki Jitokko Chickens Selected for a Superior Allele at a Single Nucleotide Polymorphism Site in the Cholecystokinin Type A Receptor Gene

“…For example, in the distal region of chromosome 4 where CCKAR is located, the CCKAR SNPs— other than g.420 C>A ( Dunn et al , 2013 ) and the SNPs in other candidate genes ( Lyu et al , 2017 )—have been suggested to affect growth traits by studies on resource populations of White Leghorn×commercial broilers ( Dunn et al , 2013 ) and New Hampshire×White Leghorn ( Lyu et al , 2017 ), respectively. Regardless, without doubt, the g.420 C>A SNP is a quality marker for marker-assisted selection to improve growth traits with a wide application range in chickens, since a significant association is reported between the SNP and growth traits in other commercial slow-growing chickens (Amakusa Daioh cross chicken, Takahashi et al , 2019 ; Miyazaki Jitokko chicken, Horinouchi et al , 2019 ; Hinai-jidori chicken, Rikimaru et al , 2019 ; Okuminokojidori chicken, Ishikawa et al , 2020 ).…”

“…Therefore, we cannot exclude the possibility that the associations that were detected in this study may have resulted from the linkage disequilibrium between the SNP and other linked nuclear DNA polymorphisms that are directly involved in the regulation of growth traits. For example, in the distal region of chromosome 4 where CCKAR is located, the CCKAR SNPs̶ other than g.420 C>A (Dunn et al, 2013) and the SNPs in other candidate genes (Lyu et al, 2017)̶ have been suggested to affect growth traits by studies on resource populations of White Leghorn×commercial broilers (Dunn et al, 2013) the g.420 C>A SNP is a quality marker for marker-assisted selection to improve growth traits with a wide application range in chickens, since a significant association is reported between the SNP and growth traits in other commercial slowgrowing chickens (Amakusa Daioh cross chicken, Takahashi et al, 2019;Miyazaki Jitokko chicken, Horinouchi et al, 2019;Hinai-jidori chicken, Rikimaru et al, 2019;Okuminokojidori chicken, Ishikawa et al, 2020).…”

“…The National Agriculture and Food Research Organization (NARO) and the Akita Prefectural Livestock Experiment Station have reported that a SNP site (AB604331, g.420 C>A in DDBJ; rs313822901 in NCBI dbSNP) in the 5 ′ -untranslated region of the cholecystokinin type A receptor gene ( CCKAR ) is associated with growth traits in the Hinai-dori breed of the Akita Prefecture in Honshu, Japan (Rikimaru et al , 2013). The effectiveness of the g.420 C>A SNP as a selection marker for improved growth traits has been investigated in other commercial slow-growing chickens (Amakusa Daioh cross chicken, Takahashi et al , 2019 ; Miyazaki Jitokko chicken, Horinouchi et al , 2019 ; Hinaijidori chicken, Rikimaru et al , 2019 ; Okumino-kojidori chicken, Ishikawa et al , 2020 ). These studies conclude that the A allele of the g.420 C>A SNP is superior for improving growth traits.…”