I think they are confusing general fatigue with CFS
Yes, it looks like the rats just have general fatigue. They are physically stressed. Physically exhausted at worst.
And I don't really see how it's possible diagnose a rat with CFS anyway, because you can't ask them about muscle and joint pain, headaches, unrefreshing sleep or sore throats etc.
I've never heard 'shilajit' before, so I looked it up on wikipedia:
http://en.wikipedia.org/wiki/Shilajit
It seems like a bizarre substance... It's a naturally occuring mineral substance that "seeps from cracks in mountains"!

It looks like there have been quite a number of research papers on it.