I would say that we do not add leucine alone because leucine, isoleucine, and valine go hand in hand.

我认为我们不会单独添加，因为、异和缬是相伴而行的。

Essential amino acids, or EAAs, are amino acids that our body needs but cannot produce on its own, and there are 9 of them: Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

基本基，简称 EAA，是我们体需要但不能自己产生的基，其中有 9 种：组，异，，赖，蛋，苯丙，苏，色和缬。