It could also be that the lower end brands contain less actual meat. I ran into that problem with my Peke (picky picky picky). I fed him Professional Puppy at first. The first ingredient was Chicken, but then it turned into Chicken By-Products, then Corn, another Corn product, then it was like wheat or some other grain. And so it continued. When I weighed it out, there was more Corn than Chicken. Labels can be deceiving. We switched to Wysong, but that wasn't much better (although Wysong is a Greyt food). We then switched to Wellness Super5Mix. It got a little better, but still not up to the point where he would gladly eat it.
Finally, we're on Innova EVO. IMO, this is one of the the best kibble out there. I love it and so does Lucky. Surprise surprise! Guess what the ingredients list is? All meat and veggies. No grains at all. The taste has got to be different and he actually *likes* to eat dinner. I used to use a good 3 heaping tablespoons of shredded meat to entice him to eat. Now, I barely use 1 tablespoon. The meat is soupmeat-fully cooked, no nutrients, just for taste- so I can add however much I need to