Meat tenderness and water holding capacity are associated with a 959 A G mutation in the MyoG gene of Chinese indigenous cattle

Myogenin (MyoG) gene has mapped at 25 to 73 cm interval on BTA 16 where several quantitative trait loci for carcass weight and marbling are located. In this study, we determined the associations between gene-specific single nucleotide polymorphisms (SNP) in MyoG gene, to investigate whether this polymorphism affected meat quality characteristics and to evaluate the allelic and genotypic frequencies of six native Chinese cattle breeds. The breeds were Jiaxian red (JXR), Luxi (LX), Nan-yang (NY), Qinchuan (QC), Xia-Nan (XN) and Xue long (XL). Our results suggested a transition of A → G at position 959 in exon 1 of the MyoG gene in cattle that caused the substitution (959Serine/959Cysteine). The A959G SNP was significantly associated with water holding capacity and meat tenderness (P < 0.05), while no effect of genotype on back fat thickness, rib area, loin eye height, eye muscle width and marbling was disclosed (P > 0.05). The x2-test revealed that the genotype distributions among the five cattle breeds (JXR, LX, NY, QC and XL) agreed with Hardy-Weinberg equilibrium (P > 0.05), although, one breed (XN) was not in Hardy-Weinberg equilibrium (P < 0.01). We concluded that, A959G SNP can be used as an efficacious genetic marker for meat quality traits in native Chinese cattle breeds but a much large number of animals are required for Marker assisted selection.Key words: Cattle, genotypic frequencies, myogenin (MyoG) gene, meat quality, single nucleotide polymorphism

A novel polymorphism of resistin gene and its association with meat quality traits in Chinese Bos taurus

Searching for candidate gene polymorphisms and their relationship with meat quality traits is an important issue for Bos taurus industry. In this study, we evaluated polymorphism of resistin (RETN) gene involved in energy metabolism. Using the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technology, a novel missense substitution single-nucleotide polymorphism (SNP) g.2528T>C was identified in the exon 2 region of the RETN gene. Allele frequencies, gene heterozygosity, effective allele number and polymorphism information content of the bovine RETN SNP in six populations were investigated and calculated by the χ2 test. The distribution of the polymorphism from the studied six B. taurus breeds was not uniform. Our results suggested that Qinchuan, Luxi and Luxi × Simmental were not in Hardy-Weinberg equilibrium. Moreover, the polymorphism and its association with meat quality traits were analyzed in 369 Qinchuan and 73 Nanyang individuals. The analyzed SNP in the RETN revealed a significant association with marbling and intramuscular fat (p < 0.05). We observed that TT genotype was associated with a heightened marbling score when compared with the TC and CC in Qinchuan and Nanyang breeds. In Qinchuan breed, we also found that TT genotype was associated with an increased intramuscular fat content when compared with the TC. Such associations were not observed on backfat thickness, loin-muscle area and loin-muscle depth. This study showed that polymorphism of the RETN gene is potentially associated with B. taurus meat quality traits.Key words: Bos taurus, meat quality traits, polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP), resistin gene, single nucleotide polymorphism (SNP)

Novel polymorphism of the bovine fat mass and obesity-associated (FTO) gene are related to backfat thickness and longissimus muscle area in five Chinese native cattle breeds

In this study, genetic variation of the fat mass and obesity-associated gene (FTO) was detected by PCRSSCP and DNA sequencing in 618 individuals from five Chinese indigenous cattle breeds, and their genetic effects on meat quality traits were evaluated. The results showed that a novel single nucleotide polymorphism C1071T was detected in exon 5 and the allelic frequencies for the C and T alleles of the five breeds were 0.666/0.334, 0.583/0.417, 0.631/0.369, 0.653/0.347 and 0.689/0.311, respectively. Animals with CT genotype had higher mean values for backfat thickness than those with CC or TT genotypes (P < 0.01). Individuals with CC or CT genotypes had higher longissimus muscle area than those with TT genotype (P < 0.05). The FTO gene may be a candidate gene for identifying differences in meat quality traits and therefore, could be applied to marker-assisted selection of native Chinese cattle breeds.Key words: Cattle, fat mass and obesity-associated (FTO) gene, single nucleotide polymorphism (SNP), meat quality traits

Effect of sex on meat quality characteristics of Qinchuan cattle

A total of 18 Qinchuan cattle, six intact males (IM), six castrated males (CM) and six females (FM), were used to investigate the effect of sex on the physicochemical characteristics (PCC) and fatty acid (FA) composition of the Longissimus dorsi muscle (LDM). Obvious sex differences were found in the PCC of LDM: the IM group had higher shear value, pH, drip and cooking losses, and contents of ash and hydroxyproline (Hyp) than the CM and FM groups, as well as lower ether extract content and lightness. Both the IM and CM groups had lower water content and higher protein content than the FM group. Sex differences were also observed in contents of C14:0, C14:1, C18:1, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and unsaturated fatty acids (UFA) between the IM and both the CM and FM groups but not between the CM and FM groups. The results indicated that sex is an importantsource of differences in meat quality of Qinchuan cattle because the castration and the meat characteristics of the CM group were more similar to the FM than the IM group