Pygmy hippos are mainly herbivores, feeding on all sorts of different vegetation. They also feed on aquatic plants, something that larger hippos don't do. Their digestive track is pretty much the same as a cows which allows them to obtain the most energy they can from the food that they eat. Since plants are very hard to digest, having multiple stomach chambers and longer intestinal tracks allows them more time to absorb as much energy as they possibly can. Imagine have more than one stomach? How crazy would that be. Jenny Craig would make a killing, that's for sure. But since we also eat meat, our digestive tracks don't have to be so specialized.
As for conservation, their biggest threat is habitat destruction. They are sometimes hunted by bush hunters since their meat is said to be of very high quality. But since they are pretty scattered, they aren't such a target. Their tusks also don't have any value, unlike their regular cousins, so they aren't poached as often either. Unfortunately I haven't been able to find any conservation programs we can help out, besides a few zoos. I'm sure there are plenty out there though. In the meantime, try and avoid acts that promote deforestation. For example, try and recycle paper or use recycled paper. Also try to avoid products that use imported lumber which could have been a vital piece of habitat to a pygmy hippo, or any other forest dwelling animal.
Cool Random Fact: The pygmy hippo can be heard eating from up to 150 feet (45 meters) away!