Moura A S, Kaps M, Vogt D W, Lamberson W R
Department of Animal Sciences, University of Missouri, Columbia 65211, USA.
J Anim Sci. 1997 Sep;75(9):2344-9. doi: 10.2527/1997.7592344x.
We conducted a two-way selection experiment in a composite rabbit population to investigate the responses to selection for postweaning ADG and feed conversion (FC). Two generations of crossing, followed by four generations of random pair matings, preceded three generations of selection. Selection was practiced within four lines: high-feed conversion (HFC), low-feed conversion (LFC), high gain (HG), and low gain (LG). Data on 1,446 rabbits from the random mating and selection generations were fitted to an animal model to estimate heritabilities of and the genetic correlation between ADG and FC. The two-trait model included rabbit and common litter random effects and line, generation, and sex fixed effects. Estimates of heritability of ADG and FC were .48 and .29, respectively, and the genetic correlation between them was -.82. Common litter environmental effects accounted for a proportion of .11 and .13 of the phenotypic variation of the two traits, respectively. For ADG (in g/d) the regressions of mean breeding values on generation number during the selection period were 1.23 +/- .12 (P < .01) in the HG line and -.86 +/- .12 (P < .01) in the LG line; the regressions for FC (in g feed/g gain) were -.07 +/- .01 (P < .01) in the HFC line and .03 +/- .01 (P < .05) in the LFC line. Selection for ADG was effective in improving ADG and FC.
我们在一个复合兔种群中进行了一项双向选择实验，以研究对断奶后平均日增重（ADG）和饲料转化率（FC）选择的反应。在三代选择之前，先进行了两代杂交，随后是四代随机配对交配。在四条品系中进行选择：高饲料转化率（HFC）、低饲料转化率（LFC）、高生长速度（HG）和低生长速度（LG）。将来自随机交配和选择代的1446只兔子的数据拟合到一个动物模型中，以估计ADG和FC的遗传力以及它们之间的遗传相关性。双性状模型包括兔子和共同窝仔的随机效应以及品系、代次和性别的固定效应。ADG和FC的遗传力估计值分别为0.48和0.29，它们之间的遗传相关性为-0.82。共同窝仔环境效应分别占这两个性状表型变异的0.11和0.13。对于ADG（单位：g/d），在选择期内，HG品系中平均育种值对代次的回归为1.23±0.12（P<0.01），LG品系中为-0.86±0.12（P<0.01）；对于FC（单位：g饲料/g增重），HFC品系中的回归为-0.07±0.01（P<0.01），LFC品系中为0.03±0.01（P<0.05）。对ADG进行选择有效地提高了ADG和FC。
