| Body weight is one of the most important performances in poultry industry.Growth is regulated by various factors such as genes,hormones,nutrition and environment.The GH gene has many physiological functions including promoting muscle,growth regulation of fat content,development of bone and metabolism.The Insulin-like Growth Factors IGF-Ⅰ and IGF-Ⅱ genes are very important for overall body and muscle growth,they considered as mitogenic polypeptides which having similar structural to insulin.The Jinghai yellow chicken was developed by traditional genetic breeding of the local yellow chickens in Nantong city,Jiangsu Province,China,for seven generations.It is considered as a national cultivated meat breed characterized by its adaptability to poor quality feeds and environment.According to previous studies,the Jinghai yellow chicken could be considered as a promising meat breed in terms of growth as many detected single nucleotide polymorphisms(SNPs)were associated with their growth and reproductive traits.In this work,we tried to study the single nucleotide polymorphisms(SNPs)of GH,IGF-Ⅰ and IGF-Ⅱ genes in order to detect some mutations which may affect the growth and reproductive traits in Jinghai yellow chickens,as well as to analysis the interactions among the detected mutations for those target genes in order to detect some interactions which may affect the growth and reproductive traits.The experimental chickens were hatched on the same day,and raised in floor pens with access to water and feed.The data of growth and reproductive traits were recorded as well as the blood samples were collected from female Jinghai yellow chickens.Total RNA was isolated from the target organs of male and female Jinghai yellow chickens for expression profiles analysis,all samples were selected randomly from the same batch at the Jiangsu Jinghai Poultry Industry Group Co.,Ltd.Polymerase chain reaction(PCR),Single-strand conformation polymorphism(SSCP)and Real Time-Polymerase chain reaction(qPCR)were used in this study to analyze the polymorphisms,expression profiles and expression regularity of the candidate genes and its association with growth and reproductive traits in Jinghai yellow chickens.Study of the polymorphisms and expression profiles for the GH gene and its association with growth and reproductive traits showed that,two mutations g.2601T>C and g.3856G>A were detected in GH gene.For mutation g.2601T>C,TT genotype was significantly(P<0.05)superior to CC genotype in 6 week-age-weight,TT and TC genotypes were highly significantly(P<0.01)superior to CC genotype in 2 and 4 week-age-weight for growth traits.No significant differences(P<0.05)were detected in this mutation and associated with reproductive traits.For mutation g.3856G>A,AG genotype was significantly(P<0.05)superior to GG genotype in 4 week-age-weight and highly significantly(P<0.01)superior to GG genotype in 6 week-age-weight for growth traits.AG and GG genotypes were significantly(P<0.05)superior to AA genotype in egg number at day 300 for the reproductive traits.Analysis of interaction among 8 combined genotypes of the two mutations g.2601T>C*g.3856G>A showed that.The TT*AG genotype combination was significantly(P<0.05)superior to combined genotype CC*AA in 2 week-age-weight,TT*AG and TC*AG genotype combinations were significantly(P<0.05)superior to TC*GG genotype combination in 4 week-age-weight.TT*AG genotype combination was also significantly(P<0.05)superior to TC*GG genotype combination in 6 week-age-weight.In contrast,no significant interactions were detected among those mutations for the reproductive traits.GH gene was highly expressed in breast and leg muscles both for male and female chickens.The expression pattern between breast and leg muscle was relatively similar in both male and female chickens with breast muscle being higher to leg muscle in the GH gene.The expression levels of the breast and leg muscle in male chickens were higher than that in females.Study of the polymorphisms and expression profiles for the IGF-Ⅰ gene and its association with growth and reproductive traits showed that,one mutation g.295T>C was detected in IGF-I gene with three genotypes CC,CT and TT with CT and TT genotypes were significantly(P<0.05)superior to CC genotype in 8,10,12,14 and 16 week-age-weight for growth traits and chicken weight at first egg for reproductive traits.Comparison of the expression level between male and female showed that,the expression curve was relatively similar with female chicken being higher to male chicken in all studied tissues in the IGF-Ⅰ gene.The expression pattern between breast and leg muscle was relatively similar in both male and female with leg muscle being higher to breast muscle in the IGF-Ⅰ gene.Study of the polymorphisms and expression profiles for the IGF-Ⅱ gene and its association with growth and reproductive traits showed that,two mutations were detected in IGF-Ⅱ gene.For mutation g.6421G>A,GG genotype was significantly(P<0.05)superior to other genotypes in 8,12 and 14 week-age-weight,and very significantly(P<0.01)superior to other genotypes in 16 week-age-weight for growth traits.GG genotype also was significantly(P<0.05)higher to other genotypes in weight of first egg and chicken weight at day 300 for reproductive traits.For mutation g.13056C>G,GG genotype was significantly(P<0.05)superior to other genotypes in 8,10,12 and 14 week-age-weight and very significantly(P<0.01)superior to other genotypes in 16 week-age-weight for growth traits.GG genotype also was significantly(P<0.05)higher to other genotypes in chicken weight at first egg and weight of first egg for reproductive traits.Analysis of interaction among 9 combined genotypes of two mutations g.6421G>A*g.13056C>G showed that,the AA*DD genotype combination was significantly(P<0.05)superior to all other genotypes in 12 and 16 week-age-weight whereas AA*GG,AG*GG and GG*CC genotype combinations were significantly(P<0.05)superior in 14 week-age-weight.In contrast,no significant interactions were detected among those mutations for the reproductive traits.IGF-II gene was highly expressed in the liver both for male and female and the breast and leg muscles for the female chickens.The expression pattern between breast and leg muscle was relatively similar in both male and female with leg muscle being higher to breast muscle in the IGF-Ⅱ gene.The analysis of interaction among the detected mutations for the GH,IGGF-Ⅰ and IGF-Ⅱ genes were studied and the results showed some significant differences among the combined genotypes were associated with growth and reproductive traits.The analysis of interaction effect between GH and IGF-I genes showed that,the interaction between the mutations g.2601T>C*g.295T>C and g.3856G>A*g.295T>C were associated with growth and reproductive traits.TC*CC,AA*TT,AG*CT,AG*TT,GG*CC and GG*CT genotype combinations were significantly(P<0.05)superior to other genotypes for growth traits.TC*CC genotype combination was also being high significantly(P<0.01)superior to other genotypes for growth traits.TT*CC genotype combination was also being significantly(P<0.05)superior to other genotypes for reproductive traits.The analysis of interaction effect between GH and IGF-II genes showed that,the interaction between the mutations g.2601T>C*g.6421G>A,g.2601T>C*g.13056C>G and g.3856G>A*g.13056C>G were associated with growth traits and no association with reproductive traits were detected.CC*GG,TC*GG TC*CC,TT*CC,TT*CG,TT*GG and AG*GG genotype combinations were significantly(P<0.05)superior to other genotypes for growth traits.TC*GG,TT*AA and TT*GG genotype combinations were high significantly(P<0.01)superior to other genotypes for growth traits.For the interaction between the mutations g.3856G>A*g.6421G>A showed that,no significant differences were associated with both growth and reproductive traits.The analysis of interaction effect between IGF-I and IGF-II genes showed that,the interaction between the mutations g.295T>C*g.6421G>A were associated with growth traits and no association with reproductive traits were detected.CT*GG and CC*CC genotype combinations were high significantly(P<0.01)superior to other.For the interaction between the mutations g.3856G>A*g.13056C>G showed that,no significant differences were associated with both growth and reproductive traits.The comparison of expression level between the GH,IGF-Ⅰ and IGF-Ⅱ genes showed that,the expression level of the GH was higher than IGF-Ⅰ and IGF-Ⅱgenes for most studied tissues in both male and female of Jinghai yellow chickens.The comparison of expression level between the IGF-Ⅰ and IGF-Ⅱ genes showed that,the expression level of the IGF-Ⅰ was higher than IGF-Ⅱ for most studied tissues in both male and female of Jinghai yellow chickens.The results indicated that,single nucleotide polymorphisms(SNPs)of the candidate genes have effects on some growth and reproductive traits,which can be used to provide a theoretical basic as well as marker-assisted selection to upgrade the progress of chicken genetic in the future especially for the Jinghai yellow chickens. |
PDF Full Text Request