I wonder what is the earliest occurrence of a TV show or a movie where characters are kidnapped and put into an alien zoo, since I have seen it more than once in TV shows.
Can't say for certain there wasn't an earlier example, but I recall seeing at least one variant of this core plot in The Twilight Zone -- the original black & white episodes individually introduced by Rod Serling -- which ran in the very early 1960s. A quick Google gives the episode title as "People Are Alike All Over", Season 1, Episode 25, aired March 25, 1960.
Given the age of mass market television, this might well be the first example in that medium, but movies might beat it.
There was a show (in the late 50s or early 60s) where a man and a woman (total strangers) were abducted from (as I remember it) the platform of a train station and put in some kind of intergalactic zoo where the aliens were hoping to get them to reproduce. The humans were uncooperative. Eventually, the aliens gave up and returned them to the railroad station platform from which they had been abducted. After the aliens had left, the man looked at the woman and she looked back at him - and you knew that they were reconsidering their previous attitudes towards getting it together.