How can I load animation clips at runtime?

Hi
we have a character with 300 animation clips (main fbx file with @anim1-@anim300). We created animation controller add states for all clips, and assign it to main model animator.
then we encountered the issue, the scene won't run at iOS device, it crashed with out of memory.

It worked on iPad2 if I added only 100 states to animation controller, so I create 3 animation controllers, each added 100 states, and change RuntimeAnimationController by script. but Resources.Unload(RuntimeAnimationController) did not release memory, when I tried to load 3rd animation controller, the game crashed (out of memory).

Is it possible to resolve ? any suggestions will be appreciated.