Thirstrup J P, Larsen P F, Pertoldi C, Jensen J
Institute for Molecular Biology and Genetics, Faculty of Science and Technology, Aarhus University, 8830 Tjele, Denmark
Kopenhagen Research, Agro Food Park 15, 8200 Aarhus, Denmark.
J Anim Sci. 2014 Dec;92(12):5406-16. doi: 10.2527/jas.2014-7781. Epub 2014 Nov 17.
Crosses between different mink lines from 3 Danish mink farms that use different breeding strategies were studied to estimate heterosis and variance components for litter size. The study was designed to analyze crosses between lines of the same color type, between different color types, and between animals originating from different farms. Effect of heterosis, color type, and variance components were estimated using Average information REML (AI-REML) algorithm implemented in the DMU package for analyzing multivariate mixed models. Females from 7 generations that gave birth to at least 1 offspring were analyzed and the effects of parity and production year were included in the analyses. Genetic trend and the proportions of the total variance explained by the effects of additive genetics (h2), common environment (due to repeated litters from the same female; c2), and dam of the female (granddame of the born litter; d2) were estimated. The results showed that mink of the Black color type potentially produced smaller litters compared to mink of the other studied color types. We found significant general maternal effect of heterosis for litter size. Analyses of specific heterosis showed a significant positive effect of crossing between lines of the same color type. Estimates of variance components revealed h2 levels for farm A, B, and C of 0.15, 0.06, and 0.09, respectively; thus litter size could be selected for in the future. The effect of common environment on litter size was also considerable, with c2 values of 0.005, 0.11, and 0.15 at farms A, B, and C, respectively. In conclusion, we recommend genetic selection as a means of increasing litter size in farmed mink.
对来自3个采用不同育种策略的丹麦水貂养殖场的不同水貂品系进行杂交研究，以估计窝产仔数的杂种优势和方差组分。该研究旨在分析相同毛色类型品系之间、不同毛色类型品系之间以及来自不同养殖场的动物之间的杂交情况。使用DMU软件包中实现的平均信息REML（AI-REML）算法估计杂种优势、毛色类型和方差组分的效应，以分析多变量混合模型。对至少产下一窝后代的7个世代的雌性水貂进行分析，并将胎次和生产年份的效应纳入分析。估计了遗传趋势以及加性遗传效应（h2）、共同环境效应（由于同一雌性的重复产仔；c2）和雌性的母亲（所产仔兽的祖母；d2）效应所解释的总方差比例。结果表明，与其他研究毛色类型的水貂相比，黑色水貂的窝产仔数可能较少。我们发现窝产仔数存在显著的杂种优势一般母体效应。对特殊杂种优势的分析表明，相同毛色类型品系之间杂交有显著的正向效应。方差组分估计显示，农场A、B和C的h2水平分别为0.15、0.06和0.09；因此，未来可以对窝产仔数进行选择。共同环境对窝产仔数的影响也相当大，农场A、B和C的c2值分别为0.005、0.11和0.15。总之，我们建议通过遗传选择来增加养殖水貂的窝产仔数。
