Lofgren Jennifer L S, Erdman Susan E, Hewes Christine, Wong Catrina, King Rebecca, Chavarria Tony E, Discua Allan R, Fox James G, Maurer Kirk J
Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
J Am Assoc Lab Anim Sci. 2012;51(5):594-9.
Microbiologic surveillance is essential for murine health maintenance. At our institution, female progeny of inhouse-bred CD1 mice are used in both the transgenic facility and health-surveillance program. To reduce overall animal use, the male progeny, otherwise slated for euthanasia due to a lack of utility, also were enrolled as sentinels. However, veterinary technicians noted excessive fighting among cohoused male surveillance mice that was not resolved by environmental enrichment. After review of factors known to influence aggression in male mice, early castration was selected as the most likely approach to eliminate aggressive behavior among cohoused male mice. Male mice were castrated before 1 mo of age and then placed into the surveillance program. Each week, veterinary technicians recorded all incidences of fighting in cages of castrated and noncastrated male surveillance mice to determine differences between groups. Over a 3-mo period, the overall prevalence of fighting in cages of intact male mice was 64% (14 of 22 cages); although all intact male mice were used preferentially for complete necropsy surveillance time points, one of these cages required separation and 4 cages housed mice that incurred severe fight wounds requiring both separation and euthanasia. In comparison, a 0% (0 of 16 cages) prevalence of fighting was observed among castrated male mice. Castration eradicated pain and distress associated with fighting, thereby constituting a refinement, and allowed the use of male mice from the breeding colony for surveillance, thereby reducing the total number of mice bred for surveillance. In conclusion, castration is a minimally invasive, safe, humane, rapid method to eliminate conspecific aggression among male CD1 surveillance mice.
微生物监测对于维持小鼠健康至关重要。在我们机构，内部饲养的CD1小鼠的雌性后代用于转基因设施和健康监测项目。为了减少整体动物使用量，原本因无用而预定安乐死的雄性后代也被纳入作为哨兵。然而，兽医技术人员注意到同笼饲养的雄性监测小鼠之间存在过度打斗，环境丰富化措施未能解决这一问题。在审查了已知影响雄性小鼠攻击行为的因素后，早期阉割被选为最有可能消除同笼饲养雄性小鼠攻击行为的方法。雄性小鼠在1月龄前进行阉割，然后进入监测项目。每周，兽医技术人员记录阉割和未阉割雄性监测小鼠笼内的所有打斗事件，以确定组间差异。在3个月的时间里，完整雄性小鼠笼内打斗的总体发生率为64%（22个笼子中有14个）；尽管所有完整雄性小鼠都优先用于完整尸检监测时间点，但其中一个笼子需要分开，4个笼子里的小鼠因打斗受伤严重，需要分开并实施安乐死。相比之下，阉割雄性小鼠笼内打斗的发生率为0%（16个笼子中有0个）。阉割消除了与打斗相关的疼痛和痛苦，从而构成了一种优化措施，并允许使用繁殖群体中的雄性小鼠进行监测，从而减少了为监测而繁殖的小鼠总数。总之，阉割是一种微创、安全、人道、快速的方法，可消除雄性CD1监测小鼠之间的同种攻击行为。
