Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan.
Center for Animal Resources and Collaborative Study, National Institutes of Natural Sciences, Aichi, Japan.
J Vet Med Sci. 2022 Jul 10;84(7):960-963. doi: 10.1292/jvms.22-0111. Epub 2022 May 18.
Reproductive performance affects the efficiency of the production of animals. Therefore, knowing the reproductive properties of each species or strain of animal is important for proper management of breeding stocks. To elucidate the reproductive properties of female F344/N rats, frequently used for longevity and gerontology research, we monitored the breeding duration, number of deliveries, litter size and weaning rate of their pups. The first delivery was observed at 2.9 ± 0.1 (mean ± standard deviation) months of age (M) and the last delivery was at 15.1 ± 1.8 M. The number of deliveries was 10.4 ± 2.8 (range of 7-16) within the life span of the mother (24.7 ± 5.6 M). The litter sizes at the third (10.0 ± 3.0) or fourth (10.3 ± 2.7) deliveries were higher than for other deliveries. The breeding outcome declined after the fifth delivery yielding reduced litter size or weaning rate, number of delivered mother. These results suggests that though female F344/N rats are able to deliver more than 10 times, the reproductive performance lowered after fifth delivery.
繁殖性能影响动物的生产效率。因此，了解每种动物的繁殖特性对于种畜的合理管理非常重要。为了阐明常用于长寿和老年学研究的 F344/N 雌性大鼠的繁殖特性，我们监测了其繁殖持续时间、分娩次数、窝仔数和断奶率。首次分娩发生在 2.9±0.1 月龄（M），最后一次分娩发生在 15.1±1.8 M。母亲的寿命内（24.7±5.6 M）分娩次数为 10.4±2.8（范围为 7-16）。第三（10.0±3.0）或第四（10.3±2.7）次分娩的窝仔数高于其他分娩次数。第五次分娩后，繁殖结果下降，导致窝仔数或断奶率、产仔母鼠数量减少。这些结果表明，尽管 F344/N 雌性大鼠能够分娩超过 10 次，但第五次分娩后繁殖性能下降。
