I also ran into a Huge-sized galaxy with no minors. This could be a random possibility, since I've started several games since the latest patch and this is the only one which had no minor civs in it.
You can check to see if the minors were present in the game (but conquered before you got to them) or not: either explore the galaxy or talk to the major civs. If you explore the galaxy, you can search for stars with the names of the minor civs: Dark Yor, Jessuins, Carinoids, etc. If you talk to the major civs, look in their planet lists to see if they include the names of minor races' planets. With either method, you should get the answer pretty definitively: if there is no star or planet named "Jessuins" then the Jessuins were not in the game.
By the way, if you start a game and don't encounter one minor race for a long time, there is a good chance that there are none to be found: they tend to explore pretty extensively and you will usually encounter one of their scouts or constructors fairly early on.