Ros-Freixedes R, Reixach J, Bosch L, Tor M, Estany J
Departament de Producció Animal - Agrotecnio Center, Universitat de Lleida, 191 Rovira Roure, 25198 Lleida, Catalonia, Spain
Selección Batallé S.A., Av. Segadors s/n, 17421 Riudarenes, Spain.
J Anim Sci. 2014 Dec;92(12):5417-25. doi: 10.2527/jas.2014-8202. Epub 2014 Nov 17.
There is an increasing interest in including intramuscular fat (IMF) content and fatty acid composition, particularly oleic acid (C18:1) content, in the selection objectives of pig lines for quality pork markets. These traits are costly and can be measured in more than 1 location, so knowing their correlation structure across muscles and with subcutaneous fat (SF) is necessary for developing optimum sampling and recording schemes. We analyzed the genetic and phenotypic correlations of IMF content and composition among 3 of the most relevant muscles (LM, gluteus medius muscle [GM], and semimembranosus muscle [SM]) and with the fatty acid composition of SF. All genetic correlations were positive but variable. For IMF, the genetic correlation between GM and LM was 0.68, and for fatty acids, the genetic correlation ranged from 0.62 for C18:1 to 0.82 for total PUFA. Genetic correlations of GM and LM with SM were much lower: 0.13 to 0.19 for IMF and 0.10 to 0.54 for fatty acids. Correlations for fatty acid composition in SF with GM and LM were moderate to high (0.29-0.53 and 0.43-0.75, respectively) but were null with SM. The expected responses for IMF in the 3 muscles and for C18:1 in each muscle and in SF to selection on records taken from only a single muscle or SF were estimated. Selection for IMF and C18:1 in GM is expected to lead to positive responses in IMF and C18:1 in LM and vice versa, although this can entail genetic lags of 20 to 45% in the muscle not directly selected for. Selection for C18:1 in SF is more effective for C18:1 in LM than in GM and of very limited value for IMF. In conclusion, the genetic correlations of IMF content and fatty acid composition among muscles and with SF, although positive, are variable enough to influence the genetic evaluation scheme for IMF and fat quality. They also indicate that GM and LM can be used alternatively for selection purposes.
在优质猪肉市场的猪品系选择目标中，人们对纳入肌内脂肪（IMF）含量和脂肪酸组成，尤其是油酸（C18:1）含量的兴趣日益浓厚。这些性状测定成本高，且可在多个部位进行测量，因此了解它们在不同肌肉间以及与皮下脂肪（SF）的相关结构，对于制定最优采样和记录方案很有必要。我们分析了3块最相关肌肉（腰大肌[LM]、臀中肌[GM]和半膜肌[SM]）之间的IMF含量和组成，以及与SF脂肪酸组成的遗传和表型相关性。所有遗传相关性均为正，但存在差异。对于IMF，GM与LM之间的遗传相关性为0.68，对于脂肪酸，遗传相关性范围从C18:1的0.62到总多不饱和脂肪酸（PUFA）的0.82。GM和LM与SM的遗传相关性则低得多：IMF为0.13至0.19，脂肪酸为0.10至0.54。SF中脂肪酸组成与GM和LM的相关性为中度至高度（分别为0.29 - 0.53和0.43 - 0.75），但与SM无相关性。估计了仅从单一肌肉或SF获取记录进行选择时，3块肌肉中IMF以及每块肌肉和SF中C18:1的预期反应。在GM中选择IMF和C18:1预计会使LM中的IMF和C18:1产生正向反应，反之亦然，尽管这可能会在未直接选择的肌肉中导致20%至45%的遗传滞后。在SF中选择C18:1对LM中C18:1的效果比对GM中更有效，对IMF的价值非常有限。总之，肌肉间以及与SF的IMF含量和脂肪酸组成的遗传相关性虽然为正，但差异足以影响IMF和脂肪品质的遗传评估方案。它们还表明GM和LM可交替用于选择目的。
