Can Apple Superdrive play DVD-Audio discs?

No it cannot. Though many DVD-A disks have 5.1 on the same DVD so it may appear to play as it does, with this non DVD-A audio, in all set top DVD players.

The DVD-Audio demo disk that came with my JVC DVD player plays just fine in my MBP. The playlist appears on the screen and the iTunes controls work properly. I don't know if it would reproduce 5.1 audio if I connected the MBP to my sound system with an optical cable but that is what the JVC DVD player is for so it would not be a problem.

DVD-A often have both the DVD-A material and Dolby 5.1 material so they play on traditional DVD players ( including yours in the macbook) just not the DVD-A material (they play the 5.1 material instead).

The Dolby 5.1 material is not even close to the same thing. Some DVD-A don't have the 5.1 at all. It says if they do on the outer packaging.

NB: SACD are similar. They make hybrid with conventional CD audio that plays if you don't have a SACD player.

The other post about the JVC DVD-A sampler is demonstrating how the non DVD-A material will play. The optical (or coax) digital output on DVD-A and SACD is often muted or downmixed to a lower sampling rate to prevent piracy that could occur through recording the high bitrate material.

This may come as a shock but actually reading the packaging will tell you where it will and won't play.

It plays, just not DVD Audio.

You saved some dough then, though on a good home theatre system the 5.1 versions sound pretty good if mixed well. Not worth it for that. DVD-A and SACD sound quite good andneed a top notch audio system so using a macbook seems kind of pointless anyway.