Comprehensive genotyping analysis of single nucleotide polymorphisms responsible for beef marbling in Japanese Black cattle.

BACKGROUND: Beef marbling is considered a desirable trait in the meat industry. Therefore, understanding the genetic factors that cause marbling is important. Previously, we performed a genome-wide association study to examine genetic factors associated with beef marbling in Japanese Black cattle and identified a candidate region between 10-30 Mbp on chromosome 7. We verified the effect of the SNPs in this region on beef marbling using linkage disequilibrium block analysis. We narrowed down the candidate region to a range of 15.8-16.1 Mbp. In this study, we comprehensively detected all of the SNPs in this region and verified their effects on beef marbling. RESULTS: Genome resequencing using four animals exhibiting high beef marbling standard (BMS) and four with low BMS revealed a total of 1,846 polymorphisms within the candidate region. Based on the annotation, we selected 13 SNPs exhibiting a moderate impact, as no high-impact SNPs were detected. All of the SNPs represented missense polymorphisms and were located in the following seven genes: RDH8, ANGPTL6, DNMT1, MRPL4, ICAM1, ICAM3, and ICAM5. Finally, we determined the effects of these SNPs on the BMS of a Japanese Black cattle population (n = 529). Analysis of variance revealed that the five SNPs were located in genes encoding the intercellular adhesion molecules (ICAM1, ICAM3, and ICAM5), and showed a highly significant association compared with the remainder (p < 0.01). The lowest p-value was observed for ICAM3_c.739G > A (p = 1.18E-04). Previous studies have suggested that intercellular adhesion molecules (ICAM) may be an upstream factor that regulates adipocyte differentiation. Therefore, considering the polymorphism and putative gene function, we suggest that ICAM1 is potentially responsible for beef marbling. c.470C > G and/or c.994G > A on ICAM1 may be responsible for this quantitative trait locus. CONCLUSIONS: Promising SNP candidates responsible for beef marbling were identified using extensive polymorphism verification in a previously reported QTL region. We aim to elucidate the mechanism of beef marbling in future studies by investigating how these polymorphisms alter protein structure and function.

Estimation of genetic parameters for visceral diseases of fattening Japanese Black cattle in Shimane Prefecture, Japan.

In this study, the genetic parameters of major visceral diseases were estimated using the postmortem inspection records of 9057 fattening Japanese Black cattle in Shimane Prefecture, Japan, and the genetic correlation between visceral diseases and carcass traits was analyzed. There were six visceral diseases with a prevalence of 5% or higher, namely, pleurisy, pneumonia, bovine abdominal fat necrosis (BFN), rumenitis, hemorrhagic hepatitis, and perihepatitis. Variance components were estimated using the Gibbs sampling method, and the heritability of the visceral disease ranged from 0.07 to 0.49 for perihepatitis and BFN, respectively. Significant negative genetic correlations were identified between pleurisy and rib thickness (-0.32), BFN and carcass weight (-0.29), and BFN and rib eye area (-0.22). No significant genetic correlation was observed among the visceral diseases. The least squares analysis of variance suggested that some visceral diseases decrease the value of carcass traits. In particular, carcass weight and rib eye area in individuals with BFN were 11.7 kg and 1.87 cm2 lower than those of healthy cattle, respectively. Thus, it was inferred that genetic factors were involved in the visceral diseases of fattening Japanese Black cattle in Shimane Prefecture.

[Small duct primary sclerosing cholangitis diagnosed after fever and liver disorder: a case report].

A woman in her 10s presented to our hospital with persistent fever and liver disorder and was admitted. It was considered that her fever was due to infectious, hematological, and collagen diseases; however, these diseases were excluded. Upper and lower gastrointestinal endoscopy revealed gastritis and indicated inflammatory bowel disease involvement. Neither bile duct stricture nor bile duct wall thickening was observed in the imaging. Thus, liver biopsy was performed due to worsening liver disorder. A diagnosis of small duct primary sclerosing cholangitis was made based on the findings of edematous enlargement of the portal tracts, neutrophilic infiltration, and destruction of the interlobular bile ducts. Furthermore, liver biopsy is helpful in diagnosing unknown liver disorders, even if no abnormality in the bile duct is observed on imaging.

Verification of Candidate SNP Effects Reveals Two QTLs on BTA7 for Beef Marbling in Two Japanese Black Cattle Populations.

In our previous study, we used genome resequencing to detect all candidate polymorphisms within a quantitative trait loci (QTL) region for beef marbling reported previously at 10-30 Mbp on bovine chromosome 7, and we selected 6044 polymorphisms as candidate quantitative trait nucleotides (QTNs). In the present study, we aimed to identify quantitative trait genes (QTGs) and QTNs in this QTL region by verifying the effect of SNPs on beef marbling in two Japanese Black cattle populations using a Dynamic Array integrated fluidic circuit. In total, 96 selected SNPs were genotyped in 441 and 529 animals in Hyogo and Miyazaki cattle populations, respectively. The most significant p-values were detected in a SNP in a splice region of ALDH7A1 (SNP93_ALDH7A1; p = 3.46 × 10-5) in Hyogo cattle and a missense polymorphism of intercellular adhesion molecule-1 (ICAM1) (SNP37_ICAM1; p = 3.33 × 10-4) in Miyazaki cattle. Interestingly, SNP93_ALDH7A1 was not significant (p = 0.459) in Miyazaki cattle, and SNP37_ICAM1 showed a weakly significant association (p = 0.043) in Hyogo cattle. Thus, each population would likely have different QTGs and QTNs for beef marbling in the QTL region. In the Hyogo population, it was not possible to determine the accurate range of the linkage disequilibrium (LD) block in LD block analysis because of a strong LD structure throughout the assessed region. In Miyazaki cattle, however, an LD block containing SNP37_ICAM1 had a range of 15.8-16.1 Mbp, suggesting that QTNs would be located within this region. The functions of 19 genes in the LD block were investigated. ICAM1 is known to play an important role in adipocyte differentiation; given this function and the effect of amino acid substitution, SNP37_ICAM1 was identified as a promising candidate QTN for beef marbling. Further research on the effect of SNP37_ICAM1 on adipocyte differentiation is expected to provide insights into the mechanism underlying beef marbling formation.

Chronic Active Epstein-Barr Virus Infection Indistinguishable from Autoimmune Hepatitis: A Case Report.

Chronic active Epstein-Barr virus (CAEBV) infection is a rare disease, mainly affecting children, typically characterized by persistent infectious mononucleosis (IM)-like symptoms. We describe an adult case of CAEBV without IM-like symptoms, which was indistinguishable from autoimmune hepatitis (AIH). A 60-year-old woman with liver damage was diagnosed with AIH (International Diagnostic Score: 16 points). She had been treated with prednisolone for three years; however, her transaminases had never normalized. She was admitted for another liver biopsy due to repeated high fevers and worsening of her liver damage over two months. Her EBV-DNA copy number was 2.9 × 104 copies/µg DNA, and EBV-encoded small RNA1-positive lymphocytic infiltration was observed in both the present and previously collected (three years ago) liver tissue samples. This case implies that hepatic involvement in a CAEBV without IM-like symptoms is difficult to distinguish from AIH and may be misdiagnosed. In some steroid resistant AIH cases, evaluating for CAEBV may be valuable.

Estimation of genetic parameters for carcass grading traits, image analysis traits, and monounsaturated fatty acids in Japanese Black cattle from Hyogo Prefecture.

Genetic parameters for carcass grading traits, image analysis traits, and monounsaturated fatty acid (MUFA) percentages were estimated in 29,942 Japanese Black cattle from Hyogo Prefecture. The analyzed traits included five carcass grading traits, two image analysis traits, fat area ratio and fineness index, and two MUFA traits, one measured in intermuscular fat using near-infrared spectroscopy (NIRS) and the other in intramuscular fat using gas chromatography (GC). The heritability estimates of image analysis traits and MUFA were moderate to high, ranging from 0.395 to 0.740, and it was considered that they could be improved simultaneously with carcass grading traits because no severe genetic antagonism was observed. Although the heritability of the NIRS-based intermuscular MUFA was slightly lower than that of the GC-based intramuscular MUFA, the genetic correlation between the two methods was as high as 0.804. These results indicate that the NIRS method can be used as an alternative evaluation procedure to predict MUFA in intramuscular fat in the longissimus muscle.

Effect of Five Polymorphisms on Percentage of Oleic Acid in Beef and Investigation of Linkage Disequilibrium to Confirm the Locations of Quantitative Trait Loci on BTA19 in Japanese Black Cattle.

Five polymorphisms associated with the percentage of oleic acid (C18:1) in beef fat were previously reported on bovine chromosome 19 in different Japanese Black cattle populations. This study aimed to verify the effects of these five polymorphisms on C18:1 using the same Japanese Black cattle population and conduct linkage disequilibrium (LD) analysis in order to determine the locations of the quantitative trait loci (QTLs). We genotyped the five polymorphisms (SREBP1 c.1065 + 83 (84bp indel), STARD3 c.1187 C > T, GH c.379 C > G, FASN g.841 G > C, and FASN g.16024 A > G) in two populations, which were bred in Hyogo and Gifu Prefectures, Japan (n = 441 and 443, respectively) in order to analyze their effects on C18:1 using analysis of variance (ANOVA). In the Hyogo population, SREBP1 c.1065 + 83 and STARD3 c.1187 C > T were significantly associated with C18:1 (p < 0.001). Meanwhile, FASN g.841 G > C, FASN g.16024 A > G, and GH c.379 C > G were significantly associated with C18:1 (p < 0.01) in the Gifu population. LD analysis was subsequently conducted to detect the range of the QTLs, which ranged from 32.2 to 46.4 Mbp and from 47.8 to 52.1 Mbp in the Hyogo and Gifu populations, respectively. In conclusion, this study confirmed the existence of QTLs on BTA19 and divided the candidate region for each QTL based on LD coefficients. These results could contribute to efficient searches for responsible genes and polymorphisms for fatty acid composition.

Detection of candidate polymorphisms around the QTL for fat area ratio to rib eye area on BTA7 using whole-genome resequencing in Japanese Black cattle.

In our previous study, we performed genome-wide association study (GWAS) to identify the genomic region associated with Fat area ratio to rib eye area (FAR) and detected a candidate in BTA7 at 10-30 Mbp. The present study aims to comprehensively detect all polymorphisms in the candidate region using whole-genome resequencing data. Based on whole-genome resequencing of eight animals, we detected 127,090 polymorphisms within the region. Of these, 31,945 were located within the genes. We further narrowed the polymorphisms to 6,044 with more than five allele differences between the high and low FAR groups that were located within 179 genes. We subsequently investigated the functions of these genes and selected 170 polymorphisms in eight genes as possible candidate polymorphisms. We focused on SLC27A6 K81M as a putative candidate polymorphism. We genotyped the SNP in a Japanese Black population (n = 904) to investigate the effect on FAR. Analysis of variance revealed that SLC27A6 K81M had a lower p-value (p = .0009) than the most significant SNP in GWAS (p = .0049). Although only SLC27A6 K81M was verified in the present study, subsequent verification of the remaining candidate genes and polymorphisms could lead to the identification of genes and polymorphisms responsible for FAR.

Estimation of genetic parameters of defective appearances in Japanese Black heifer calves in Kagoshima.

Defective appearances, including white spotting (WS), tongue defect (TD), and nipple defect (ND), in Japanese Black cattle potentially lead to economic losses to farmers in Japan. We estimated genetic parameters of defective appearances using 553,433 records of Japanese Black heifer calves housed in the Kagoshima Prefecture. Variance and covariance were estimated using the Gibbs sampling algorithm. The estimated heritability ranged from 0.29 for TD to 0.76 for WS. Percent breeding value (%BV) estimates indicated high variation in WS and ND among sires, reflecting higher heritability. Furthermore, there was a positive linear relationship between the %BV estimate of a sire and the mean incidence rate of each defect in his female offsprings. TD was positively associated with other defects. Therefore, genetic factors strongly affect the incidence of defective appearances in Japanese Black cattle.

Effect of DNA markers on the fertility traits of Japanese Black cattle for improving beef quantity and quality.

Carcass traits have been efficiently improved by recent selection using DNA markers in beef cattle. Additionally, DNA markers might have an effect on other traits such as fertility traits; therefore attention should also be paid to such pleiotropic effects. However, the effects of the markers on both carcass and fertility traits have never been evaluated in the same population, since they are generally measured in different populations. The objective in the current study was to discuss effectiveness of DNA markers developed for carcass traits through investigation of their effects on carcass and fertility traits in a population. We genotyped six markers SCD V293A, FASN g.841G>C, PLAG1 g.49066C>G, NCAPG I442M, DGAT1 K232A, and EDG1 g.1471620G>T in a Japanese Black cattle population ( n = 515 ). To investigate their effects on carcass and fertility traits, we performed statistical analysis (ANOVA and the Tukey-Kramer honestly significant difference (HSD) test). In the results, three of six markers, SCD V293A, NCAPG I442M, and EGD1 g.1471620G>T, were significantly associated with both carcass and fertility traits. Remarkably, the same allele for each marker had positive effects on both traits, suggesting that we would be able to simultaneously improve them using these markers in this population. However, previous studies reported that the effects of DNA markers could differ among populations. Therefore, it is necessary to confirm the effect of the marker in each population before it is used for improvement.

The non-synonymous mutation in bovine SPP1 gene influences carcass weight.

Meat quality in beef cattle is controlled by genetic factors. SPP1 (secreted phosphoprotein 1) gene, coding a multifunctional cytokine with diverse biological functions, is the candidate gene influencing carcass traits. In this study, we tried to discover DNA polymorphisms associated with beef quality in bovine SPP1 gene, so that two SNPs (single nucleotide polymorphisms) in the promoter region and one SNP in the CDS (coding sequence) region were identified. Although the formers were predicted to alter SPP1 expression, they did not show any effects on the traits. On the contrary, statistical analysis revealed that g.58675C > T, a non-synonymous mutation from threonine to methionine in the conservative region, had a significant effect on carcass weight. Carcass weight of the animals with C/T allele (473.9 ± 6.0 kg) was significantly heavier than that of the C/C homozygotes (459.2 ± 2.8 kg). Because SPP1 gene functions in skeletal muscle cells as a positive regulator, the non-synonymous mutation might influence muscle development and remodeling, resulting in increased carcass weight of the C/T animals. Our results indicate that the SNP can be applied as a DNA marker for the improvement of beef cattle.

Whole-genome resequencing to identify candidate genes for the QTL for oleic acid percentage in Japanese Black cattle.

In our previous study, we detected a QTL for the oleic acid percentage (C18:1) on BTA9 in Japanese Black cattle through a genome-wide association study (GWAS). In this study, we performed whole-genome resequencing on eight animals with higher and lower C18:1 to identify candidate polymorphisms for the QTL. A total of 39,658 polymorphisms were detected in the candidate region, which were narrowed to 1993 polymorphisms within 23 genes based on allele differences between the high and low C18:1 groups. We subsequently selected three candidate genes, that is, CYB5R4, MED23, and VNN1, among the 23 genes based on their function in fatty acid metabolism. In each candidate gene, three SNPs, that is, CYB5R4 c.*349G > T, MED23 c.3700G > A, and VNN1 c.197C > T, were selected as candidate SNPs to verify their effect on C18:1 in a Japanese Black cattle population (n = 889). The statistical analysis showed that these SNPs were significantly associated with C18:1 (p < 0.05), suggesting that they were candidates for the QTL. In conclusion, we successfully narrowed the candidates for the QTL by detecting possible polymorphisms located within the candidate region. It is expected that the responsible polymorphism can be identified by demonstrating their effect on the gene's function.

Pool-based genome-wide association study identified novel candidate regions on BTA9 and 14 for oleic acid percentage in Japanese Black cattle.

Fatty acid composition is an important indicator of beef quality. The objective of this study was to search the potential candidate region for fatty acid composition. We performed pool-based genome-wide association studies (GWAS) for oleic acid percentage (C18:1) in a Japanese Black cattle population from the Hyogo prefecture. GWAS analysis revealed two novel candidate regions on BTA9 and BTA14. The most significant single nucleotide polymorphisms (SNPs) in each region were genotyped in a population (n = 899) to verify their effect on C18:1. Statistical analysis revealed that both SNPs were significantly associated with C18:1 (p = .0080 and .0003), validating the quantitative trait loci (QTLs) detected in GWAS. We subsequently selected VNN1 and LYPLA1 genes as candidate genes from each region on BTA9 and BTA14, respectively. We sequenced full-length coding sequence (CDS) of these genes in eight individuals and identified a nonsynonymous SNP T66M on VNN1 gene as a putative candidate polymorphism. The polymorphism was also significantly associated with C18:1, but the p value (p = .0162) was higher than the most significant SNP on BTA9, suggesting that it would not be responsible for the QTL. Although further investigation will be needed to determine the responsible gene and polymorphism, our findings would contribute to development of selective markers for fatty acid composition in the Japanese Black cattle of Hyogo.

Affinity maturation of humanized anti-epidermal growth factor receptor antibody using a modified phage-based open sandwich selection method.

Affinity maturation is one of the cardinal strategies for improving antibody function using in vitro evolutionary methods; one such well-established method is phage display. To minimise gene deletion, we previously developed an open sandwich (OS) method wherein selection was performed using only phage-displaying VH fragments after mixing with soluble VL fragments. The decrease in anti-EGFR antibody 528 affinity through humanization was successfully recovered by selecting VH mutants using this OS method. However, the affinity was not similar to that of parental 528. For further affinity maturation, we aimed to isolate VL mutants that act in synergy with VH mutants. However, the OS method could not be applied for selecting VL fragments because the preparation of soluble VH fragments was hampered by their instability and insolubility. Therefore, we initially designed a modified OS method based on domain-swapping of VH fragments, from added soluble Fv fragments to phage-displaying VL fragments. Using this novel Fv-added OS selection method, we successfully isolated VL mutants, and one of the Fv comprising VH and VL mutants showed affinity almost equivalent to that of parental 528. This method is applicable for engineering other VL fragments for affinity maturation.

A genome-wide association study for fat-related traits computed by image analysis in Japanese Black cattle.

The objective of this study was to identify genomic regions associated with fat-related traits using a Japanese Black cattle population in Hyogo. From 1836 animals, those with high or low values were selected on the basis of corrected phenotype and then pooled into high and low groups (n = 100 each), respectively. DNA pool-based genome-wide association study (GWAS) was performed using Illumina BovineSNP50 BeadChip v2 with three replicate assays for each pooled sample. GWAS detected that two single nucleotide polymorphisms (SNPs) on BTA7 (ARS-BFGL-NGS-35463 and Hapmap23838-BTA-163815) and one SNP on BTA12 (ARS-BFGL-NGS-2915) significantly affected fat percentage (FAR). The significance of ARS-BFGL-NGS-35463 on BTA7 was confirmed by individual genotyping in all pooled samples. Moreover, association analysis between SNP and FAR in 803 Japanese Black cattle revealed a significant effect of SNP on FAR. Thus, further investigation of these regions is required to identify FAR-associated genes and mutations, which can lead to the development of DNA markers for marker-assisted selection for the genetic improvement of beef quality.

Impact of Preferentially Expressed Antigen of Melanoma on the Prognosis of Hepatocellular Carcinoma.

BACKGROUND: Retinoids, vitamin A and its derivatives, have an antitumor effect on hepatocellular carcinoma (HCC). The function of retinoids is exerted by the complex of retinoic acid (RA) with the heterodimer of retinoid X receptor and the RA receptor. The preferentially expressed antigen of melanoma (PRAME) acts as a dominant repressor of RA signaling by binding to the complex. The significance of PRAME on the prognosis of HCC remains to be clarified. METHODS: PRAME mRNA expression was examined by quantitative real-time polymerase chain reaction in both tumor and non-tumor tissues of 100 HCC patients who received surgical resection. The effect of PRAME knockdown on DR5-mediated RA transcriptional activity was examined. RESULTS: In tumor tissues, there were significant associations among PRAME expression, clinical stage, tumor markers, and tumor numbers. In non-tumor tissues, there were significant associations among PRAME expression, overall survival, and disease-free survival. The knockdown of PRAME caused no reduction in DR5-mediated transcriptional activity of RA, suggesting that PRAME acts via other mechanisms than the DR5 RA-responsive elements. CONCLUSION: Our findings indicate that PRAME expression is a novel prognostic marker in HCC patients.

Falsely Elevated Serum Vitamin B12 Levels Were Associated with the Severity and Prognosis of Chronic Viral Liver Disease.

BACKGROUND: Vitamin B12 is stored primarily in the liver, and highly elevated serum vitamin B12 levels occur in acute hepatitis and severe alcoholic liver disease. We evaluated the relationship between vitamin B12 levels and liver disease severity and long term prognosis in patients with chronic viral hepatitis and cirrhosis. METHODS: We enrolled 90 patients (57 men, 33 women) with chronic viral hepatitis and cirrhosis who admitted to our hospital as a prospective cohort study. Overall, 37 patients had chronic hepatitis and 53 had cirrhosis (Child-Pugh A 33, B 13, and C 7); 57 patients had primary liver cancer. Serum vitamin B12 concentration and holotranscobalamin (holoTC) II (active form of vitamin B12) were determined and followed prospectively for at least 5 years. RESULTS: Mean total serum vitamin B12 concentration was significantly higher in Child-Pugh C (1308 ± 599 pg/mL) compared to those with chronic hepatitis (655 ± 551 pg/mL), Child-Pugh A (784 ± 559 pg/mL), and Child-Pugh B (660 ± 464 pg/mL) (P = 0.036) Presence of primary liver cancer also influenced serum vitamin B12 levels [657 (167-2956) vs. 432 (189-2956); P = 0.015]. Patients were divided into quartiles by vitamin B12 level. Patients without primary liver cancer in quartile 4 (≥ 880 pg/mL) demonstrated significantly poorer prognosis than those in quartiles 1-3 (< 880 pg/mL) (P = 0.023). The percentage of holohaptocorrin (holoHC) [(total vitamin B12 - holoTC II) × 100] was significantly higher in Child-Pugh B and C 86 (80-87)% than chronic hepatitis and Child-Pugh A 77 (31-89)% (P = 0.006) Multivariate analysis indicated serum vitamin B12 levels (HR = 1.001, P = 0.029) as a prognostic factor. CONCLUSION: Falsely elevated serum vitamin B12 levels mainly composed of increased holoHC were associated with severity (Child-Pugh C and primary liver cancer) and prognosis in chronic viral liver disease.

Serum Procalcitonin in Patients with Acute Liver Failure.

BACKGROUND: Procalcitonin (PCT) is a known diagnostic marker of bacterial infection. There are no previous reports of PCT concerning acute liver failure (ALF). We evaluated the clinical value of serum PCT levels in patients with ALF. METHODS: Forty-four patients with acute hepatitis (19 men and 25 women; median age, 40 years; range, 20-79 years) were retrospectively enrolled from January 2001 and June 2015. PCT levels were measured by saved serum samples obtained within 3 days after admission. ALF was defined as prothrombin time (PT) < 40% regardless of hepatic encephalopathy. RESULTS: Serum PCT levels were significantly higher in the patients with ALF (n = 16) than in those with non-ALF (n = 28) [0.25 (0.13-2.66) ng/mL vs. 0.165 (0.03-1.08), P = 0.00967]. Creatinine, total bilirubin, and direct bilirubin were positively correlated, and PT was negatively correlated with PCT. Receiver operating characteristic curve analysis showed an area under the curve of 0.74 for detecting ALF. With a PCT cut-off value of 0.5 ng/mL, the presence of ALF could be demonstrated with low sensitivity (37.5%) and high specificity (96.5%) with high positive (85.7%) and negative (72.9%) predictive value. Multivariate analysis showed that PCT was an independent factor associated with the presence of ALF. The cumulative survival rate was also significantly lower in patients with PCT ≥ 0.5 ng/mL (P = 0.0314), but it was not an independent prognostic factor. CONCLUSION: Serum PCT level was significantly higher in patients with ALF.

Identification of leptin gene polymorphisms associated with carcass traits and fatty acid composition in Japanese Black cattle.

Previous studies have indicated that some leptin gene polymorphisms were associated with economically important traits in cattle breeds. However, polymorphisms in the leptin gene have not been reported thus far in Japanese Black cattle. Here, we aimed to identify the leptin gene polymorphisms which are associated with carcass traits and fatty acid composition in Japanese Black cattle. We sequenced the full-length coding sequence of leptin gene for eight Japanese Black cattle. Sequence comparison revealed eight single nucleotide polymorphisms (SNPs). Three of these were predicted to cause amino acid substitutions: Y7F, R25C and A80V. Then, we genotyped these SNPs in two populations (JB1 with 560 animals and JB2 with 450 animals) and investigated the effects on the traits. Y7F in JB1 and A80V in JB2 were excluded from statistical analysis because the minor allele frequencies were low (< 0.1). Association analysis revealed that Y7F had a significant effect on the dressed carcass weight in JB2; R25C had a significant effect on C18:0 and C14:1 in JB1 and JB2, respectively; and A80V had a significant effect on C16:0, C16:1, C18:1, monounsaturated fatty acid and saturated fatty acid in JB1. The results suggested that these SNPs could be used as an effective marker for the improvement of Japanese Black cattle.

Genetic relationships between meat quality traits and fatty acid composition in Japanese black cattle.

Genetic parameters were estimated to investigate the relationships between meat quality traits and fatty acid composition from 11 855 Japanese Black cattle. The meat quality traits included beef marbling score (BMS), beef color score, firmness of beef (FIR), texture of beef (TEX) and beef fat color score (BFS). The data on fatty acid composition included oleic acid and monounsaturated fatty acids (MUFA) contents, the ratio of MUFA to saturated fatty acids (MUS) and the ratio of elongation. The heritability estimates for meat quality traits ranged from moderate (0.30) to high (0.72). The strong genetic correlations between them were useful for simultaneous genetic improvement. In addition, high heritability estimates of fatty acid composition, ranging from 0.60 to 0.63, indicated that they could also be improved genetically. The genetic correlations of fatty acid composition with BMS, FIR and TEX were weak and negative. In contrast, positive and stronger genetic correlations were found between BFS and fatty acid composition, in particular, related to the level of unsaturation (0.77 and 0.79 for MUFA and MUS, respectively). This implies that improving the level of unsaturation makes fat darker (more yellow) and thus requires balancing with BFS.