I say you can, but you would have to come up with a list of reasons why being a DNP is not for you (same thing goes for shadowing a dentist, PA, nurse, etc). Also, you would need to shadow a physician in addition and come up with reasons why you would want to do this.
Doing both of those would show that you have considered many different healthcare fields and that you are making an educated decision about becoming a doctor. However, notice how shadowing a doctor (MD or DO) is still a necessity.
If you were to shadow PA, nurses and other health professionals, I would think it is a positive thing as you can rightly claim on your application that you've researched other health careers and know for a fact that it is being a physician that you want.