I think humans are fundamentally different from animals; we're sentient, and the animals we generally eat as food aren't (you might make a case for the non-human great apes or for whales and dolphins). That means that while they are capable of suffering (which needs to be minimized), killing an animal is not murder because murder is the killing of a sentient creature. Animals (or, in any case, most animals, including the ones generally eaten) can't comprehend their own existence or their own mortality.
Because we are sentient, though, we can't behave like any ordinary predator (and we are predators--omnivorous ones, but predators still). When my cat catches a mouse, she's not aware of the mouse's suffering. When I eat a steak, I'm well aware that the cow that was slaughtered for that steak might have been exposed to inhumane conditions, and that gives me--unlike my cat--a responsibility to ensure that the animals I eat do not suffer, and that if I kill an animal, directly or indirectly, I must ensure that I do it for a very good reason.
Animal rights, no. Animal welfare, definitely. And human responsibility. You don't get to be the top predator on the planet, with a brain big enough to conceive of the entire universe, without being assigned quite a lot of responsibility.