Instituto de Ciencia y Tecnología Animal, Universidad Politécnica de Valencia, 46071 Valencia, Spain.
J Anim Sci. 2012 Feb;90(2):439-46. doi: 10.2527/jas.2011-4219. Epub 2011 Sep 16.
The aim of this work was to evaluate the correlated responses on survival rates after 10 generations of selection for ovulation rate (OR). Selection was based on the phenotypic value of ovulation rate estimated at d 12 of second gestation by laparoscopy. Traits recorded were litter size (LS), estimated as total number of rabbits born per litter in up to 5 parities; OR, estimated as the number of corpora lutea in both ovaries; the number of implanted embryos (IE), estimated as the number of implantation sites; the number of right and left IE (RIE and LIE); ovulatory difference (OD), defined as the difference between the right and the left OR, expressed as an absolute value; implantatory difference (ID), defined as the difference between RIE and LIE, expressed as an absolute value; embryonic survival (ES), calculated as IE/OR; fetal survival (FS), calculated as LS/IE; prenatal survival (PS), calculated as LS/OR. A total of 1,081 records were used to analyze ES, and 770 were used to analyze FS and PS. The number of records used to analyze the other traits ranged from 1,079 for ID to 3,031 for LS. Data were analyzed using Bayesian methodology. Genetic parameters of OR, OD, and LS were estimated in a previous paper. Estimated heritabilities of IE, ID, ES, FS, and PS were 0.11, 0.03, 0.09, 0.24, and 0.14, respectively. Estimated repeatabilities of IE, ID, and ES were 0.22, 0.12, and 0.20. Estimated phenotypic correlations of OR with ES, FS, and PS were -0.07, -0.26, and -0.28, respectively. Their estimated genetic correlations with FS and PS were negative (probability of being negative 1.00 and 0.98, respectively). Nothing can be said about the sign of the genetic correlation between OR and ES. Ovulation rate was phenotypically uncorrelated with ID. Their estimated genetic correlation was positive (probability of being positive 0.91). The genetic correlation of ID with PS and LS was not accurately estimated. Phenotypic and genetic correlations between LS and survival rates were positive (probability of being positive 1.00). In 10 generations of selection, FS decreased around 1% per generation. No correlated response in ES was observed. In summary, the decrease in FS in rabbits selected for OR seemed to be responsible for the lack of correlated response observed in LS.
本研究旨在评估 10 代排卵率（OR）选择后存活率的相关反应。选择是基于腹腔镜检查估计的第二次妊娠第 12 天的 OR 表型值进行的。记录的特征包括窝产仔数（LS），估计为每窝出生的兔子总数；OR，估计为两个卵巢中黄体的数量；植入胚胎数（IE），估计为植入部位的数量；左右 IE 数（RIE 和 LIE）；排卵差异（OD），定义为右 OR 与左 OR 之间的差异，以绝对值表示；植入差异（ID），定义为 RIE 和 LIE 之间的差异，以绝对值表示；胚胎存活率（ES），计算为 IE/OR；胎儿存活率（FS），计算为 LS/IE；产前存活率（PS），计算为 LS/OR。共使用了 1081 个记录来分析 ES，使用了 770 个记录来分析 FS 和 PS。用于分析其他特征的记录数量从 ID 的 1079 个到 LS 的 3031 个不等。使用贝叶斯方法分析数据。OR、OD 和 LS 的遗传参数在之前的一篇论文中进行了估计。IE、ID、ES、FS 和 PS 的估计遗传力分别为 0.11、0.03、0.09、0.24 和 0.14。IE、ID 和 ES 的估计重复性分别为 0.22、0.12 和 0.20。OR 与 ES、FS 和 PS 的估计表型相关性分别为-0.07、-0.26 和-0.28。它们与 FS 和 PS 的遗传相关性为负（分别为 1.00 和 0.98 的概率为负）。不能确定 OR 与 ES 之间遗传相关性的符号。排卵率与 ID 在表型上无相关性。它们的估计遗传相关性为正（概率为正 0.91）。ID 与 PS 和 LS 的遗传相关性无法准确估计。LS 与存活率之间的表型和遗传相关性为正（概率为正 1.00）。在 10 代选择中，FS 每代减少约 1%。未观察到 ES 的相关反应。综上所述，OR 选择后 FS 的下降似乎是 LS 中未观察到相关反应的原因。
