Feitosa Fabieli Loise Braga, Olivieri Bianca Ferreira, Aboujaoude Carolyn, Pereira Angélica Simone Cravo, de Lemos Marcos Vinicius Antunes, Chiaia Hermenegildo Lucas Justino, Berton Mariana Piatto, Peripolli Elisa, Ferrinho Adrielle Matias, Mueller Lenise Freitas, Mazalli Mônica Roberta, de Albuquerque Lucia Galvão, de Oliveira Henrique Nunes, Tonhati Humberto, Espigolan Rafael, Tonussi Rafael Lara, de Oliveira Silva Rafael Medeiros, Gordo Daniel Gustavo Mansan, Magalhães Ana Fabrícia Braga, Aguilar Ignacio, Baldi Fernando
Department of Animal Science, Faculty of Agrarian and Veterinarian Sciences, Sao Paulo State University, Jaboticabal, SP, Brazil.
Department of Animal Science, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Pirassununga, SP, Brazil.
J Appl Genet. 2017 Feb;58(1):123-132. doi: 10.1007/s13353-016-0360-7. Epub 2016 Jul 30.
The objective of this study was to estimate the genetic-quantitative relationships between the beef fatty acid profile with the carcass and meat traits of Nellore cattle. A total of 1826 bulls finished in feedlot conditions and slaughtered at 24 months of age on average were used. The following carcass and meat traits were analysed: subcutaneous fat thickness (BF), shear force (SF) and total intramuscular fat (IMF). The fatty acid (FA) profile of the Longissimus thoracis samples was determined. Twenty-five FAs (18 individuals and seven groups of FAs) were selected due to their importance for human health. The animals were genotyped with the BovineHD BeadChip and, after quality control for single nucleotide polymorphisms (SNPs), only 470,007 SNPs from 1556 samples remained. The model included the random genetic additive direct effect, the fixed effect of the contemporary group and the animal's slaughter age as a covariable. The (co)variances and genetic parameters were estimated using the REML method, considering an animal model (single-step GBLUP). A total of 25 multi-trait analyses, with four traits, were performed considering SF, BF and IMF plus each individual FA. The heritability estimates for individual saturated fatty acids (SFA) varied from 0.06 to 0.65, for monounsaturated fatty acids (MUFA) it varied from 0.02 to 0.14 and for polyunsaturated fatty acids (PUFA) it ranged from 0.05 to 0.68. The heritability estimates for Omega 3, Omega 6, SFA, MUFA and PUFA sum were low to moderate, varying from 0.09 to 0.20. The carcass and meat traits, SF (0.06) and IMF (0.07), had low heritability estimates, while BF (0.17) was moderate. The genetic correlation estimates between SFA sum, MUFA sum and PUFA sum with BF were 0.04, 0.64 and -0.41, respectively. The genetic correlation estimates between SFA sum, MUFA sum and PUFA sum with SF were 0.29, -0.06 and -0.04, respectively. The genetic correlation estimates between SFA sum, MUFA sum and PUFA sum with IMF were 0.24, 0.90 and -0.67, respectively. The selection to improve meat tenderness in Nellore cattle should not change the fatty acid composition in beef, so it is possible to improve this attribute without affecting the nutritional beef quality in zebu breeds. However, selection for increased deposition of subcutaneous fat thickness and especially the percentage of intramuscular fat should lead to changes in the fat composition, highlighting a genetic antagonism between meat nutritional value and acceptability by the consumer.
本研究的目的是评估内洛尔牛牛肉脂肪酸谱与胴体及肉质性状之间的遗传定量关系。总共使用了1826头在饲养场条件下育肥并平均在24月龄时屠宰的公牛。分析了以下胴体和肉质性状：皮下脂肪厚度（BF）、剪切力（SF）和总肌内脂肪（IMF）。测定了胸最长肌样本的脂肪酸（FA）谱。由于对人类健康的重要性，选择了25种脂肪酸（18种个体脂肪酸和7组脂肪酸）。使用牛HD基因分型芯片对动物进行基因分型，在对单核苷酸多态性（SNP）进行质量控制后，仅保留了来自1556个样本的470,007个SNP。模型包括随机遗传加性直接效应、当代组的固定效应以及动物的屠宰年龄作为协变量。使用REML方法估计（协）方差和遗传参数，考虑动物模型（单步GBLUP）。总共进行了25次多性状分析，涉及四个性状，考虑了SF、BF和IMF以及每种个体脂肪酸。个体饱和脂肪酸（SFA）的遗传力估计值在0.06至0.65之间，单不饱和脂肪酸（MUFA）的遗传力估计值在0.02至0.14之间，多不饱和脂肪酸（PUFA）的遗传力估计值在0.05至0.68之间。Omega 3、Omega 6、SFA、MUFA和PUFA总和的遗传力估计值低至中等，在0.09至0.20之间。胴体和肉质性状，SF（0.06）和IMF（0.07），遗传力估计值较低，而BF（0.17）为中等。SFA总和、MUFA总和和PUFA总和与BF之间的遗传相关估计值分别为0.04、0.64和 -0.41。SFA总和、MUFA总和和PUFA总和与SF之间的遗传相关估计值分别为0.29、 -0.06和 -0.04。SFA总和、MUFA总和和PUFA总和与IMF之间的遗传相关估计值分别为0.24、0.90和 -0.67。在内洛尔牛中选择改善肉的嫩度不应改变牛肉中的脂肪酸组成，因此有可能在不影响瘤牛品种牛肉营养品质的情况下改善这一特性。然而，选择增加皮下脂肪厚度尤其是肌内脂肪百分比的沉积应会导致脂肪组成的变化，突出了肉的营养价值与消费者可接受性之间的遗传拮抗作用。
