Corres do modo Revelação

 when exporting the colors come out more contrasted and saturated, even exporting the file in sRGB.

When viewing in LrC develop module, or when viewed in something other than LrC?

and, perhaps I should ask in advanced, how are you calibrating your monitor?

I take the photo in the camera in sRGB

In the future, especially if you shoot RAW, consider using Adobe RGB in camera. it provides you a larger portion of the color spectrum to work with.

Oh, yes, when you export for say the web, you can (and probably will want to) export to sRGB.  During publishing is when to do that. Their are several pages on the web supporting this (mine would be in English, so your own search would be better)

Incidentally:

• LrC, in the Develop Module uses the  ProPhoto RGB color space  (and that is even bigger than Adobe RGB in terms of color space) not sRGB.
• LrC in Library, MAP, Book, and Print Modules uses the Adobe RGB color space. not sRGB
• As the Develop Module and the Library Module use different color space, some slight perception in the images will appear. Best to evaluate in the Develop Module.

In my Lightroom it is not possible to change the profile of colors because, in the reveal tab in Profile I do not see other color profiles or camera.

From that I assume you are referring to:

and if you clcik on the profile browser (Browse) you see:

 If so, this implies that your original image is a Raster, not a RAW image, probably JPEG.

Correct?