The [Zat-gun](http://en.wikipedia.org/wiki/Goa%27uld_technology_in_Stargate) fullfills very usefull jobs in the Stargate SG1 series, allowing stunning and providing a means to overload (and disable) equipment.
I would have thought they would have brought some to both Atlantis and to the mission ending up on the Destiny.
However, this is (as far as I know) not the case. I also don't recall for them even being mentioned in either spin-off.
Hence the question, is an in universe explanation given for not having Zat-guns on Stargate Atlantis and Stargate Universe?