Hi guys ,I have a problem with my dog(rottweiler).. he is thin.. he doesn't have any health problems.do you know what I have to give him to eat, additional to the dry food to get 'fatter'?. I try all the dry food...

No need to double post. Be a little patient for the experts to get on the site. I know one who's sleeping right now, and another... well is usually here around this time.

https://www.askmehelpdesk.com/dogs/how-you-make-dog-gain-weight-428539.html

It would be helpful if you could post the age of your dog.
Also any photos would be beneficial so we can see the weight of the dog.

What are you currently feeding? (brand and amount please?)

How did you determine he had no health issues? Did you run bloodwork on him? What about a fecal test?