In eukaryotes, DNA methylation is an important epigenetic modification involved in gene expression regulation. Meat quality traits are complicated traits that are controlled by many genes. Changes in the methylation levels of certain genes controlling meat quality traits will inevitably affect their expression levels, thereby affecting meat quality. The objectives of this study were to investigate the differences in the DNA methylation level in pectoral muscle tissues using fluorescent-labeled methylation sensitive amplified polymorphism and their relationships with meat quality traits in three-yellow chickens. The results showed that the differences in the DNA methylation level had a highly significant effect on muscle fiber density and drip loss (P<0.01). However, no significant correlations were found between the DNA methylation levels and the other investigated traits (P>0.05).

为了研究TLR7在病毒入侵时是否起到重要的抗原递呈作用,试验采用实时荧光定量PCR技术检测禽流感感染鸡和SPF鸡的免疫器官及发病器官中TLR7的表达水平差异情况.结果表明:TLR7基因在禽流感感染组和SPF组肺脏、气管上、气管下、脾脏、法氏囊、胸腺中均有表达,在不同组织中表达差异极显著,在感染组中的表达量明显高于SPF组.说明TLR7在禽流感病毒感染鸡的过程中表达量发生了改变.

Chickens are susceptible to the highly pathogenic H5N1 strain of avian influenza virus (HPAIV), whereas ducks are not. Here, we used high‐throughput sequencing to analyse the microRNA expression in the spleen, thymus and bursa of Fabricius of H5N1‐HPAIV‐infected and non‐infected chickens and ducks. We annotated the genomic positions of duck microRNAs and we compared the microRNA repertoires of chickens and ducks. Our results showed that the microRNA expression patterns in the homologous immune organs of specific‐pathogen‐free (SPF) chickens and ducks diverge substantially. Moreover, there was larger divergence between the microRNA expression patterns in immune organs of HPAIV‐infected chickens than HPAIV‐infected ducks. Together, our results might help to elucidate the roles of microRNAs in the divergent immunity of chickens and ducks against H5N1 HPAIV.

Interferon, gamma-inducible protein 30(IFI30)plays a key role in MHC classⅡ-restricted antigen processing and MHCⅠ-restricted cross-presentation. In our study, PAMs were infected by PRRSV of three different concentrations, and the levels of IFI30 mRNA expression of different time were detected by qPCR. The results showed that the IFI30 expression differences were not significant when PAMs were infected by three different concentrations,0.08 MOI,0.10 MOI and 0.12 MOI(P 0.05), respectively. The expression of IFI30 infected by PRRSVafter1.5 hwas reduced,butthe difference was not significant(P 0.05), and then the expression of IFI30 was increased, the expression difference was very significantwhen PAMs were infected by PRRSV after 12 h, 24 h and 36 h(P 0.01), but then the expression of IFI30 was reduced(P 0.05). The results indicated that the IFI30 expression change in the process of PRRSV infecting PAM may be one of the mechanisms which interact between PRRSV and host.

To reveal the effect of the infection of avian influenza virus on the genome-wide DNA methylation level of the host,the DNA methylation levels and patterns of CCGG sites in genomes was analyzed among nine different tissues of SPF chicken,and the heart and lung of SPF chicken infected by A/Goose/Guangdong/1/96,H5N1,A/Duck/Anhui/1/2006 and H5N1,respectively.The differences of DNA methylation level were compared between Guangdong group and SPF group,Anhui group and SPF group,respectively.The result indicates that the degrees of DNA methylation are all approximately 53.22%,which the lowest degree is 50.00% in upper part of trachea,and the highest degree is 57.33%.In heart,both of Guangdong group and Anhui group are higher than SPF group in terms of the level of DNA methylation;in lung,the level of DNA methylation of Anhui group is higher than the SPF group,but the level of Guangdong group is lower than SPF group.These results demonstrated that there was difference in the DNA methylation level between the chicken infected by AIV and SPF chicken,which suggested that the infection of avian influenza virus(H5N1) may have effect on the DNA methylation level of healthy hosts.

DNA methylation is one of the main epigenetic modification mechanisms in eukaryotic organisms,playing a crucial role in the regulation of gene expression.In this study,we put F1 hybrid with Laiwu pigs and Yorkshine as research object,used the fluorescence-labeled methylation-sensitive amplified polymorphism(F-MSAP) method and used 16 pairs of selective primers to assess the extent and pattern of cytosine methylation in the muscle.The incidence of DNA methylation was approximately 57.20% in the muscle of direct cross and total of 2 031 sites were found to be methylated at cytosines.53.50% in the reciprocal cross and total of 1 905 sites were found to be methylated at cytosines.As type Ⅱ of methylation status,the reciprocal cross was higher than the direct cross significantly(P0.05).As type Ⅲ of methylation status,the direct cross was higher than the reciprocal cross exthreme significantly(P0.01).

DNA methylation play an important role in gene expression regulation as one of epigenetic modification of the methods. With the rapid development of the number of DNA methylation detection technology,such as high-throughput detection of DNA methylation,study of DNA methylation bioinformatics has become a very active hot spots.In animal genetics and breeding,traits that may affect the expression of genes can be influenced since the degree of DNA methylation changes,and thus change the characteristics of various animals.Therefore,relevant studies have already begun to explore the specific role of DNA methylation in animal genetics and breeding.

HABP4 participates in a variety of important physiological and biochemical processes in mammalian, but only few studies have involved its exact physiological function and mechanism of action. In this study, using real-time quantitative PCR technology detected HABP4 gene expression levels in the muscle tissue of hybrid progeny of Large White and Laiwu pigs. The results showed that HABP4 gene was expressed in all longissimus muscle tissue detec- ted. And the expression level is different of longissimus muscle tissue in the two hybrid generation. HABP4 gene ex- pression in the longissimus muscle of the quadrature generation was significantly higher than anti-cross generation. The test provides the evidence of the molecular genetics basis to improve swine carcass traits, and laid the foundation of later in-depth study on the biological role and mechanism of the HABP4 gene in different pig breeds.

This study was designed to investigate the single nucleotide polymorphism （SNP）of diacylglyeerol acyltransferase 2 （DGAT2） gene in red steppe by PCR RFLP, and analyze the correlation between the polymorphisms and milk performante traits. The result of PCR- RFLP indicated that there were three genotypes（AA, AB and BB）. The correlation analysis showed that polymorphism had a extremely significant effect on milk fat and dry matter, the cows with AA genotype had higher milk fat than the AB and BB genotype （P〈0.01）, but there was no significant difference between AB and BB geno-type（P〉0.05）. For the dry matter, the AA genotype was higher than the AB and BB genotype （P〈0.05）, the AB geno-type was higher than the BB genotype （P〈0.05）. Other milk performance traits of red steppe was not different between different genotypes （P〉0.05）. It could be preliminarily concluded that DGAT2 gene was probably a major gene or a QTL linked gene which is associated with milk fat and dry matter and can be chosen as the molecular markers of choosing low milk fat and high dry matter in red steppe.

This study was designed to investigate the single nucleotide polymorphism(SNP) by PCR-SSCP of PRKAG3 gene in 87 plymouth rock,at the same time the correlation between the polymorphism and meat quality traits.The result of PCR-SSCP showed that there were three genotypes(TT,TG and GG).The correlation analysis revealed that polymorphism had a extremely significant effect on PH,the plymouth rocks with GG genotype had lower PH than the GT and TT genotype(P<0.01),at the same time,the GT genotype lower than the TT genotype(P<0.05).other meat quality traits of plymouth rock were not significant influence on different genotypes(P>0.05).It could be preliminarily concluded that PRKAG3 gene was probably a major gene or a QTL linked gene which associated with PH and can be chosen as the molecular markers of meat quality in plymouth rock.