If it's untreated, yes, it should be treated with something.
I used a clear spar urethane. I've seen walnut and pecan colors used and boy are they beautiful! But, I wanted to keep things lighter in color, so went with clear. The wood has gotten a rich orange color to it.
______________________________ The CoTH CYA - please consult w/your veterinarian under any and all circumstances. - ET