Sprite rotate becomes a mash of pixels

Hello,
I need some help.
When i rotate a 16*16 sprite in game, it becomes an awfull mash of pixels. What can i do to keep his armonious size while rotating ?

I think it wasn’t complicated but i couldn’t solve this problem.
Thx

Any chance that you are using the pixel-perfect camera? The lack of pixel-snapping could be responsible for that.