Does somebody knows if there is a chapter before 51 (that is announced in the "Anime Start/End Chapter" part) that wasn't adapted?
Just to know and read 😁

The question is really old but the answer might interest some people :
-> Every chapter from 1 to 51 has been adapted into the anime.

However :

• The order seems to be completly random between the manga version and the anime version
• Special chapters 6 and 8 are not included in the anime (the last special included is special 9)
• Episodes 5/18/28/34/47 are fillers.