The verses say,
και εγενετο φωνη προς αυτον αναστας πετρε θυσον και φαγε
and became a sound/voice to him arise Peter make-sacrificial-slaughter and eat
While θυσον is used to speak of killing an animal as a sacrifice in other contexts I don't see any reason to see anything here other than killing them. I say this because:
Peter is said to be hungry when he went into a trance but there is no context provided for a sacrificial event
Peter is not a Levitic priest, nor does he protest about not being one while he does protest about not eating unclean foods
Peter would not have any of the required paraphernalia: a temple, an altar, priestly garb, a blood catcher, burning coals, etc.
the word has extant usage for just "killing":
Isa 22:13 (Brenton LXX) And behold joy and gladness, slaying oxen, and killing sheep, eating flesh, and drinking wine: let us eat and drink; for to morrow we shall die.
So I would answer: "None".
Well, not "none" (that's a bit absolutist of me) but nothing significant or germane.
Also, we are not told that the animals were unclean. They should be understood to be unclean seeing that Peter is chastised for calling clean animals unclean.