A zoo can not replace an African safari park.
But I like a trip to the zoo. You feel nice relaxed when you walk around and look at the animals.
And of course you have your camera with. I usually use my old Olympus e-5 with my 50-200 mm lens with a 1.4 teleconverter. It corresponds to a 140-560 mm full frame. It also happens that you get in touch with other photographers and get a little talk.
You get close to the individual animals and have to find different compositions than in a safari park.
Be sure to isolate the animals as the surroundings in a zoo rarely contribute positively to the image.
So this week I have been to Copenhagen Zoo, got some pictures, but building a new panda plant is a big part of the garden in construction. So I would not recommend a visit right now.