Polimorfismos em genes‑candidatos e suas associações com características de carcaça e qualidade da carne em bovinos Nelore

The objective of this work was to estimate the allele polymorphism frequencies of genes in Nellore cattle and associate them with meat quality and carcass traits. Six hundred males were genotyped for the following polymorphisms: DGAT1 (VNTR with 18 nucleotides at the promoter region); ANK1, a new polymorphism, identified and mapped here at the gene regulatory region NW_001494427.3; TCAP (AY428575.1:g.346G>A); and MYOG (NW_001501985:g.511G>C). In the association study, phenotype data of hot carcass weight, ribeye area, backfat thickness, percentage of intramuscular fat, shear force, myofibrillar fragmentation index, meat color (L*, a*, b*), and cooking losses were used. Allele B from the ANK1 gene was associated with greater redness (a*). Alleles 5R, 6R, and 7R from the DGAT1 VNTR gene were associated with increased intramuscular fat, reduced cooking losses and increased ribeye area, respectively. The single nucleotide polymorphism (SNP) of the TCAP gene was not polymorphic, and MYOG alleles were not associated with any of the evaluated characteristics. These results indicate that ANK1 and DGAT1 genes can be used in the selection of Nellore cattle for carcass and meat quality.O objetivo deste trabalho foi estimar as frequências de polimorfismos alélicos em genes de bovinos Nelore e associá‑los às características de carcaça e qualidade da carne. Seiscentos machos foram genotipados quanto aos seguintes polimorfismos: DGAT1 (VNTR com 18 nucleotídeos na região promotora); ANK1, novo polimorfismo, identificado no presente estudo e mapeado na região gênica regulatória NW_001494427.3; TCAP (AY428575.1:g.346G>A); e MYOG (NW_001501985:g.511G>C). No estudo de associação, foram utilizados os dados fenotípicos de massa da carcaça quente, área de olho do lombo, espessura de gordura subcutânea, percentagem de gordura intramuscular, força de cisalhamento, índice de fragmentação miofibrilar, coloração da carne (L*, a*, b*) e perdas por cocção. O alelo B do gene ANK1 foi associado ao aumento da coloração vermelha (a*) da carne. No gene DGAT1, os alelos 5R, 6R e 7R foram associados ao aumento de gordura intramuscular, à redução das perdas por cocção e ao aumento da área de olho de lombo, respectivamente. O SNP (polimorfismo de nucleotídeo único) do gene TCAP não apresentou polimorfismo, e os alelos do gene MYOG não foram associados a nenhuma das características avaliadas. Os resultados indicam que os genes ANK1 e DGAT1 podem ser utilizados na seleção de animais Nelore quanto à qualidade de carne e carcaça

Associação genética entre o perfil de ácidos graxos e outras características da carcaça e carne de bovinos da raça Nelore

As características da carcaça e da carne são muito importantes, pois são elas que determinam o preço e o acesso a novos mercados. Há uma crescente preocupação quanto ao consumo excessivo de gorduras, bem como do tipo de gordura ou perfil de ácidos graxos na carne, e seu impacto sobre a saúde do consumidor. O melhoramento genético para as características de carcaça, carne e perfil de ácidos graxos não vem sendo praticado devido a dificuldades de mensuração e por ser dispendioso. O presente estudo teve como objetivo estudar as associações entre o perfil de ácidos graxos e as características de carcaça e carne em bovinos da raça Nelore. Foram utilizados dados de 1826 machos da raça Nelore terminados em confinamento, provenientes de fazendas que integram três programas de melhoramento genético. O grupo de contemporâneo foi formado por animais nascidos na mesma fazenda e safra, e do mesmo grupo de manejo ao sobreano. Para a determinação do perfil de ácidos graxos foi utilizado para a extração dos lipídeos o método Folch e para a metilação o método Kramer. As características de carcaça e carne foram obtidas através de amostras de 2,54 cm retiradas entre a 12ª e 13ª costelas da meia-carcaça esquerda. O modelo utilizado para a estimação dos componentes de (co)variâncias incluiu o efeito aleatório genético direto, o efeito fixo do GC, e a idade do animal ao abate como covariável (efeito linear). Os componentes de (co)variâncias e parâmetros genéticos foram estimados utilizando inferência Bayesiana, considerando um modelo animal linear em análise multicaracterística com seis características (AOL, EGS, PCQ, SF, Lip e mais um ácido graxo). Os ácidos graxos apresentaram herdabilidades moderadas a alta, variando de 0,32 a 0,82. As estimativas das correlações genéticas entre as caracteríscas de carcaça e carne com os ácidos graxos saturados foram de baixas a moderadas, em sua maioria negativa ...Carcass and meat traits are very important because they determine the price and access to new markets. There is growing concern about the excessive consumption of fats as well as the type of fat or fatty acid composition in meat, and its impact on consumer health. The genetic improvement for carcass traits, meat and fatty acid composition has not been practiced due to measurement difficulties and be expensive. The present study aimed to investigate the associations between fatty acid composition with carcass and meat traits in Nellore cattle. A total of 1,826 Nelore bulls, finished in feedlot, belong to farms that integrate three breeding programs were used. The contemporary group included animals born on the same farm and year, and the same management group at yearling. To determine the fatty acid composition, it was used the Folch method for lipid extraction and for methylation the Kramer method. The carcass and meat traits were obtained from samples of 2.54 cm withdrawn between the 12th and 13th ribs on the left side carcass. The model used to estimate the (co)variance and genetic parameters included the random direct genetic effect, the fixed effect of the GC, and the animal's age at slaughter as a covariate (linear effect). The (co)variances components and genetic parameters were estimated using Bayesian inference, considering a linear animal model in multi-trait analysis with six characteristics (AOL, EGS, PCQ, SF, Lip and another fatty acid). The fatty acids showed moderate to high heritability, ranging from 0.32 to 0.82. The genetic correlations between carcass and meat traits with saturated fatty acids were low to moderate, most of them negative, ranging from - 0.76 to 0.88, whereas with mono and polyunsaturated fatty acids were low in its most of the cases or close to zero, since the HPD estimate included the zero within the interval, varying from -0.86 to 0.74. Thus, the selection for carcass and meat traits can be used ..

Polymorphisms in candidate genes and their association with carcass traits and meat quality in Nellore cattle

The objective of this work was to estimate the allele polymorphism frequencies of genes in Nellore cattle and associate them with meat quality and carcass traits. Six hundred males were genotyped for the following polymorphisms: DGAT1 (VNTR with 18 nucleotides at the promoter region); ANK1, a new polymorphism, identified and mapped here at the gene regulatory region NW_001494427.3; TCAP (AY428575.1:g.346G>A); and MYOG (NW_001501985:g.511G>C). In the association study, phenotype data of hot carcass weight, ribeye area, backfat thickness, percentage of intramuscular fat, shear force, myofibrillar fragmentation index, meat color (L*, a*, b*), and cooking losses were used. Allele B from the ANK1 gene was associated with greater redness (a*). Alleles 5R, 6R, and 7R from the DGAT1 VNTR gene were associated with increased intramuscular fat, reduced cooking losses and increased ribeye area, respectively. The single nucleotide polymorphism (SNP) of the TCAP gene was not polymorphic, and MYOG alleles were not associated with any of the evaluated characteristics. These results indicate that ANK1 and DGAT1 genes can be used in the selection of Nellore cattle for carcass and meat quality.O objetivo deste trabalho foi estimar as frequências de polimorfismos alélicos em genes de bovinos Nelore e associá-los às características de carcaça e qualidade da carne. Seiscentos machos foram genotipados quanto aos seguintes polimorfismos: DGAT1 (VNTR com 18 nucleotídeos na região promotora); ANK1, novo polimorfismo, identificado no presente estudo e mapeado na região gênica regulatória NW_001494427.3; TCAP (AY428575.1:g.346G>A); e MYOG (NW_001501985:g.511G>C). No estudo de associação, foram utilizados os dados fenotípicos de massa da carcaça quente, área de olho do lombo, espessura de gordura subcutânea, percentagem de gordura intramuscular, força de cisalhamento, índice de fragmentação miofibrilar, coloração da carne (L*, a*, b*) e perdas por cocção. O alelo B do gene ANK1 foi associado ao aumento da coloração vermelha (a*) da carne. No gene DGAT1, os alelos 5R, 6R e 7R foram associados ao aumento de gordura intramuscular, à redução das perdas por cocção e ao aumento da área de olho de lombo, respectivamente. O SNP (polimorfismo de nucleotídeo único) do gene TCAP não apresentou polimorfismo, e os alelos do gene MYOG não foram associados a nenhuma das características avaliadas. Os resultados indicam que os genes ANK1 e DGAT1 podem ser utilizados na seleção de animais Nelore quanto à qualidade de carne e carcaça.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Genetic parameter for meat fatty acid profile of Nelore cattle finished in feedlot

The aim of this study was to estimate (co)variance components and genetic parameters (heritability and genetic correlations) for meat fatty acid composition in Nellore cattle. The fatty acids analyzed were: conjugated linoleic acid - CLA (C18:2 trans-10 cis-12), palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1 cis-9), linoleic acid (C18:2 cis- 9-12) and linolenic acid (C18:3). A total of 751 Nellore bulls, finished in feedlot for at least 90 days, with average age at slaughter of 24 months were used. The animals belong to eight farms located in the Southeast, Northeast and Midwest regions, of São Paulo State, which comprise three specific genetic breeding programs. The fatty acid determination was carried out at the Laboratory of Meat Science (LCC), Department of Animal Production and Nutrition FMVZ/USP. Samples from theLongissimus muscle were collected 48 hours after slaughter. The determination of meat fatty acid profile was performed by the method of Folch et al. (1957) and Kramer et al. (1997). Fatty acids were quantified by gas chromatography (GC-2010 Plus - Shimadzu AOC 20i auto sampler) using SP-2560 capillary column (100 m × 0.25 mm in diameter with 0.02 mm thickness, Supelco, Bellefonte, PA). To estimate the (co) variance components and genetic parameters, the model included the additive genetic effect as random effect, and the fixed effects of the contemporary group and animal's age at slaughter as a covariable (linear effect). The model used for the estimation of the  included random direct genetic effect, the fixed effect of the GC, and the animal's age at slaughter as a covariate (linear effect).The (co)variance components and genetic parameters were estimated by Bayesian inference with a linear multi-trait animal model, using the GIBBS2F90 program. The convergence of the data was verified using the R software package analyzed with the Bayesian Output Analysis (BOA) of the R 2.9.0 software (The R Development Core Team, 2009). Heritability estimates obtained for the fatty acids analyzed were: 0.52; 0.26; 0.68; 0.57; 0.46 and 0.41 for CLA, palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, respectively. The genetic correlation estimates between the palmitic acid (C16: 0) with stearic acid, oleic acid, linoleic acid, linolenic acid and CLA showed the following values: 0.14; 0.39; -0.09; -0.33; 0.34. The genetic correlation estimates between the stearic acid with oleic acid, linoleic acid, linolenic acid and CLA were 0.24, -0.06, -0.21 and 0.22, respectively. For the oleic acid, the genetic correlation estimates were -0.04, -0.02 and -0.02, with the linoleic acid, linolenic acid and CLA, respectively. The genetic correlation estimated between the linolenic acid and CLA was close to zero. Most of the genetic correlations estimates between fatty acids were low to moderate. The heritability estimates for fatty acids were moderate to high, indicating that these traits would respond rapidly to selection. The genetic correlation estimates between fatty acids with different degrees of saturation suggest that indirect selection to improve the meat fatty acid composition is possible

Estimation of variance components, heritability and standard errors for AFC and W550 using traditional and genomic REML with different proportions of multiple sires.

<p>Estimation of variance components, heritability and standard errors for AFC and W550 using traditional and genomic REML with different proportions of multiple sires.</p

Pedigree structure with different proportions of multiple sires.

<p>Pedigree structure with different proportions of multiple sires.</p

Bias and standard errors using BLUP and ssGBLUP with different proportions of multiple sires.

<p>Bias and standard errors using BLUP and ssGBLUP with different proportions of multiple sires.</p

Means and standard deviations (SDs) for true breeding values (TBV) and breeding values from different traits using BLUP and ssGBLUP with different proportions of multiple sires.

<p>Means and standard deviations (SDs) for true breeding values (TBV) and breeding values from different traits using BLUP and ssGBLUP with different proportions of multiple sires.</p

Accuracies of evaluation for W550 for the ALL, BULL, GEN, FEM, and YOUNG groups using different scaling for the genomic matrix (G) to match the numerator relationship matrix for genotyped animals (A₂₂).

<p>W550—weight at 550 days; S1 –scaling for all genotyped animals; S2—no scaling; S3—scaling only for animals which have known sire and dam; S4—scaling only for animals which have one known parent.</p