Hi,
It's not HikaShop which should include bootstrap, it's the template job.
We have in HikaShop 2.1.0 (released today) an option to use or not the bootstrap html code. So, if your template does not use bootstrap, you can use J2.5 html content and if in a J2.5 website you have bootstrap, you can use it in HikaShop.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.