Many general vets don't keep up with recent studies, they usually recommend what they sell in the office. Like lolonurse said, there are a lot of different views out there, you'll just need to read the studies, and go with what you feel comfortable with.
I'm not a fan of Purina, way to many fillers. Also, who knows what chemicals are getting pumped into the animals going into the kibble, what pesticides are on the veggies, and preservatives going in there. It's scary when you find out what is really
in kibble. I've had good luck with Solid Gold, simply because I can get it locally, and they know where the animals come from that go into it. There are so many kibbles out there to choose from thou.
In regards to the omega 3, the fish meal in the chicken/rice puppy formula would have some in there, provided the fish is not farm raised and fed corn. Omega 3 is important, but it has to be balanced with omega 6 to be as effective. When livestock is corn fed, and not raised on grass/bugs/etc. the omega 6 content goes too high, and omega 3 is decreased, the ratio is out of wack. According to purina's site, Natural Turkey and Barley Formula - Products - Purina® Pro Plan®
, the turkey one has Omega 3. Do your research on corn to form an opinion thou. It's the 3rd ingredient. After my own reading, I won't feed my dogs anything with corn in it, that is just my opinion thou.
You'll feel good about whichever kibble you go with after reading around, the internet is great resource
Not knowing is uncomfortable. Purina Pro Plan Dog Food (Dry) Rating and Review