Ibáñez-Escriche N, Varona L, Magallón E, Noguera J L
1Genètica i Millora Animal,IRTA,Av. Alcalde Rovira Roure 191,25198 Lleida,Spain.
2Unidad de Genética y Mejora Animal,Universidad de Zaragoza,C./ Miguel Servet 177,50013 Zaragoza,Spain.
Animal. 2014 Oct;8(10):1569-76. doi: 10.1017/S1751731114001712. Epub 2014 Jul 14.
An experiment of a 2×2 full diallelic cross between two contemporary Iberian pig strains (Retinto: RR, and Torbiscal: TT) was conducted to estimate the crossbreeding effects for growth and carcass traits. Phenotypic records were obtained under intensive management and consisted of two different data sets. The first set comprised growth traits until weaning and was collected at two different farms (6236 and 1208 records, respectively). Specific data included individual piglet weight at birth and at weaning at 28 days and average daily gain from birth to weaning at 28 days (ADG28) for both RR and TT and their reciprocal crosses. The second set comprised growth data from birth to slaughter (~340 days and ~160 kg) and carcass traits from 349 individuals (randomly) sampled at weaning from the first dataset. Data were analyzed through a Bayesian analysis by using a reparameterization of Dickerson's model that allowed estimation of the posterior distributions of the following crossbreeding effects: average maternal breed effect (gM), average paternal breed effect (gP) and individual heterosis (hI). Results showed that the relative magnitude of crossbreeding effects depends on the trait analyzed. Crosses where Torbiscal strain was used as mother (RT and TT) achieved the greatest performance for all growth traits at weaning, leading to remarkable gM effects. The most outstanding example is the case of ADG28 where the probability of relevance was one. In contrast, TR cross showed the greatest differences from RR cross for all growth at slaughter and carcass traits. These differences were mainly due to hI and gP crossbreeding parameters. In particular, the posterior mean of hI was more noticeable for live weight at slaughter, average daily gain at slaughter and carcass length, while gP was more relevant for hams (kg) and loins (kg) representing from 3% to10% of average performance of traits. Hence, growth traits at weaning did not reveal any notable advantage of the crossbreeding scheme because of the superiority of the Torbiscal strain with respect to its mothering ability and the small hI. However, results from growth and carcass traits at slaughter would support the implementation of a TR crossbred system. It would allow exploitation of both the gP of the Torbiscal strain and the hI between these two Iberian pig strains. Additionally, gP estimates and phenotypic differences between reciprocal crosses might suggest signs of the presence of paternal genetic imprinting in primal cuts traits.
在两个当代伊比利亚猪品系（雷廷托猪：RR，和托尔比卡尔猪：TT）之间进行了一项2×2完全双列杂交试验，以评估杂交对生长和胴体性状的影响。在集约化管理条件下获得了表型记录，包括两个不同的数据集。第一组包括断奶前的生长性状，分别在两个不同的农场收集（分别有6236条和1208条记录）。具体数据包括RR和TT及其正反交仔猪出生时和28日龄断奶时的个体体重，以及出生至28日龄断奶期间的平均日增重（ADG28）。第二组包括从出生到屠宰（约340天和160千克）的生长数据，以及从第一组数据集中断奶时随机抽取的349头猪的胴体性状数据。通过贝叶斯分析对数据进行了分析，使用了迪克森模型的重新参数化，从而能够估计以下杂交效应的后验分布：平均母本品种效应（gM）、平均父本品种效应（gP）和个体杂种优势（hI）。结果表明，杂交效应的相对大小取决于所分析的性状。以托尔比卡尔品系为母本的杂交组合（RT和TT）在断奶时所有生长性状上表现最佳，产生了显著的gM效应。最突出的例子是ADG28，其相关性概率为1。相比之下，TR杂交组合在屠宰时的所有生长和胴体性状上与RR杂交组合表现出最大差异。这些差异主要归因于hI和gP杂交参数。特别是，hI的后验均值在屠宰时的活重、屠宰时的平均日增重和胴体长度方面更为显著，而gP在火腿（千克）和腰肉（千克）方面更为相关，占性状平均表现的3%至10%。因此，由于托尔比卡尔品系在育仔能力方面的优势以及较小的hI，断奶时的生长性状并未显示出杂交方案的任何显著优势。然而，屠宰时生长和胴体性状的结果将支持实施TR杂交系统。这将允许利用托尔比卡尔品系的gP以及这两个伊比利亚猪品系之间的hI。此外，gP估计值和正反交之间的表型差异可能表明在主要切割性状中存在父本遗传印记的迹象。
