If he's a pup its the perfect age to introduce him

If you had the chance I would introduce him to weaners to first, but he will soon get the picture if the pigs dont want him around!

Try going into the enclosures with him on an extended line first? I did this and the dogs now have free access into all my pig pens. Take him in just after you have fed the pigs so they are feeling full and relaxed.. I wouldn't introduce him whilst they are actually eating, may get some stroppy sows!
However, as with yourself... never trust a pig! Ours were introduced to the pigs when they were 1-2 years old and they have great fun racing around with the weaners