Pre-heat the oven to 350 degrees.
Bring a large pot of water to boiling and cook the jumbo shells according to the package directions. Once the shells are cooked, drain and set aside.
Meanwhile, heat a small non-stick skillet to medium heat. Add the lean ground turkey and the garlic powder, 1 teaspoon salt and the oregano and cook until the meat is cooked through. Set aside.
In a large non-stick wok style skillet, heat the olive oil over medium heat. Add the onion, garlic, red pepper, and zucchini and cook until the vegetables are tender, about 8-10 minutes. Once the veggies are cooked, add the seasoned and drained turkey meat. Then add the drained tomatoes. Mix and add the remaining salt and 3/4 cup of the marinara sauce. Mix to combine.
Using a 9x13 Pyrex, add 1/2 cup of the marinara sauce to the bottom of the pan. Then carefully add the meat and veggie mixture to each cooked shell. Add them to the Pyrex pan one by one. Once the pan is filled, sprinkle with the Italian blend cheese.
Add the pan to the oven and cook for about 20-25 minutes. Enjoy immediately.