Studies On Inheritance And Candidate Genes Of Feed Conversion Rate And Fat Deposition Related Traits In Beijing-You Chicken

Chinese local chicken is of good meat-flavor in meat. Its feed conversion rate is low, which affect the economic benefits of local chicken. This study combines quantitative and molecular genetics methods, estimated genetic parameters and associaed analysis of relevant candidate genes with feed conversion rate and fat deposition related traits in Beijing-You chicken, in order to search the inheritance and molecular markers in feed conversion rate and fat deposition related traits, providing the basis for a reasonable selection method for feed conversion rate.This study was conducted to estimate genetic parameters of feed conversion rate and fat deposition related traits. Usingle multiple derivative-free restricted maximum likelihood (MTDFREML) to estimate the heritability, genetic and phenotypic correlation of 610 10~17-week old Beijing-You chickens. Mass SNP technology was applied to genotype 300 male Beijing-You chickens. Using Haploview to analyze the haplotype and SAS 8.0 analyze the associations of these traits. The results showed that estimated heritability of average daily feed intake (ADF), average daily gain (ADG), residual feed intake (RFI), breast meat yield (BMY), leg meat yield (LMY) and body weight (BW) were high (h~2=0.33~0.52), the percentage of intramuscular fat in breast (B-IMF) was low(h~2=0.07) and feed/weight gain(F/G) and the percentage of intramuscular fat in leg (T-IMF) were moderate(h~2=0.28, 0.13). In the term of genetic correlation, F/G showed negative high correlated with ADG, BMY, LMY and BW, and high correlated with B-IMF and T-IMF, RFI high positive correlated with B-IMF and T-IMF. T-IMF positive high correlated with BW and BMY. As to the single locus, the mutation site in IGF2 gene, C6708G, was significantly associated with ADF, ADG, RFI, T-IMF and fat strip wide (FSW) (P<0.05). The mutation site, G2542A, in CAPN1 gene was significant associated with ADF, abdominal fat weight (AFW), abdominal fat weight percentage (AFP) and FSW (P<0.05). One of mutation site in FATP1 gene, G4241A, was significant associated with sebum weight (SW) and sebum weight percentage (SWP) (P<0.05). There was a mutation site, G25602T, in ATGL gene significant associated with AFW, AFP and B-IMF (P<0.05). There were 6 mutation sites in GHSR gene. A672G was significant associated with ADF and feed conversion rate (FCR) (P<0.05 or P<0.01). 4 mutation sites in LEPR gene, A30126G, T30137C, G30394A and A30631G, were significantly associated with ADF, ADG, FSW and AFP (P<0.05 or P<0.01). Haplotype analyses found that H1H3 haplotype in GHSR gene ADG higher than others. H1H2 haplotype in LEPR gene ADF and FSW significantly lower than others and FCR and IMF significantly higher than others.These results demonstrate that FCR could be improved indirectly by BW, BMY and LMY. H1H3 in GHSR gene is best halotype to ADG, carcass traits and sexual maturity. H1H2 in LEPR gene is lower feed intake, higher feed conversion rate and higher IMF, lower FSW. Therefore, the majority genotype and halotype could be used as effective molecular markers in marker assisted selection for FCR and production traits. The up-selection of chicken meat-flavor traits made the feed conversion rate decrease directly or indirectly. The contradiction of quality and yield is a difficult task, need evaluation and the combination of quantitative and molecular genetics methods to realize efficient and quality in chicken.