He's found that when they're under stress, their endocrine systems react by reducing the amount of hormones such as corticosterone into their blood.

他发现当它们面临压力的时候，它们的内分泌系统会通过降低进入血液荷尔蒙的量来做出反应，比如说皮质酮。

Levels of corticosterone, a stress hormone, were markedly lower in the bacteria-fed mice than they were in the control group when both groups were exposed to stressful situations.

当两组小鼠进行应激实验时，喂食李糖乳杆菌的小鼠体内的应激激素皮质 甾酮含量比那些对照组的小鼠体内要明显低地多。

By giving a modest dose of corticosterone to nestlings twice a day for a week, we were able to show that the corticosterone-treated nestlings had a larger repertoire.

通过让鹦鹉幼崽摄入适量的皮质酮，每日两次，持续一周，我们能够证明，接受皮质酮处理的幼鸟掌握了更广的曲目。

By giving a modest dose of corticosterone to nestlings twice a day for a week, we were able to show that the corticosterone-treated nestlings had a larger repertoire.

Berg：通过每天两次给雏鸟服用适量的皮质酮，持续一周，我们能够证明经过皮质酮处理的雏鸟具有更大的曲目。