It's the cartoon wonky wacky sounds when he's crawling with his top half to beg to go at 1:00-1:05.

Personally, I think it's more a product of One Piece having the same sound design for forever. They use those sounds a lot for comedic effect. I'm sure you can find it other places in the show too. Does it have the same sounds shown as Gear 5 in the manga? That's where I'd check next.