Institut für Genetik und Biometrie, Leibniz-Institut für Nutztierbiologie (FBN), Dummerstorf, Germany.
Institut für Fortpflanzungsbiologie, Leibniz-Institut für Nutztierbiologie (FBN), Dummerstorf, Germany.
Reproduction. 2021 May 14;161(6):721-730. doi: 10.1530/REP-20-0563.
We recently described two outbred mouse lines that were selected for large litter size at first delivery. However, lifetime fecundity appears to be economically more important for the husbandry of many polytocous species for which mouse lines might serve as bona fide animal models (e.g. for pigs). In the present study, we compared the lifetime fecundities of two highly fertile mouse lines (FL1 and FL2: >20 offspring/litter at first delivery) with those of an unselected control line (ctrl) and two lines that were selected for high body weight (DU6) and high protein mass (DU6P) without selection pressure on fertility. We tested the hypothesis that selection for large litter size at first parturition would also increase lifetime fecundity in mice, and we observed very large differences between lines. Whereas FL1 and ctrl delivered up to nine and ten litters, none of the DU6 and DU6P females gave birth to more than five litters. In line with this observation, FL1 delivered the most pups per lifetime (85.7/female). FL2 females produced the largest average litter sizes (20.4 pups/litter) in the first four litters; however, they displayed a reduced number of litters. With the exception of ctrl, litter sizes declined from litter to litter. Repeated delivery of litters with high offspring numbers did not affect the general health of FL females. The presented data demonstrate that two biodiverse, highly fertile mouse lines selected for large litter size at first delivery show different lifetime reproductive fitness levels. Thus, these mouse lines might serve as valuable mouse models for investigating lifetime productivity and longevity in farm animals.
我们最近描述了两个经选育的远交系小鼠，这些小鼠在首次分娩时具有较大的产仔数。然而，对于许多多胎物种来说，终生繁殖力在养殖方面可能更为重要，这些物种的小鼠品系可能作为真正的动物模型（例如，猪）。在本研究中，我们比较了两个高度肥沃的小鼠品系（FL1 和 FL2：首次分娩时产仔数超过 20 只）与未选择的对照品系（ctrl）以及两个选择高蛋白质量（DU6P）而非产仔数的高体品系（DU6）的终生繁殖力。我们检验了这样一个假设，即首次分娩时选择大产仔数也会增加小鼠的终生繁殖力，并且我们观察到了品系之间的巨大差异。尽管 FL1 和 ctrl 最多产了 9 窝和 10 窝，但没有一只 DU6 和 DU6P 雌性产仔超过 5 窝。与这一观察结果一致，FL1 每只雌性产仔最多（85.7 只）。FL2 雌性在头四窝中产生的平均窝仔数最大（20.4 只/窝）；然而，它们的窝仔数减少了。除了 ctrl 之外，窝仔数从一窝到另一窝减少。反复分娩高窝仔数的窝不会影响 FL 雌性的一般健康状况。所呈现的数据表明，两个具有生物多样性的、高度肥沃的、选择在首次分娩时具有大产仔数的小鼠品系显示出不同的终生生殖适应性水平。因此，这些小鼠品系可能作为研究农场动物终生生产力和寿命的有价值的小鼠模型。
