I looked up some info on ornate frogs, and was just curious about their stomach contents. After checking out AmphibiaWeb, something popped up:

"Ceratophrys ornata consumes primarily vertebrates; stomach content analysis of thirty-four specimens from Uruguay included 78.5% anurans, 11.7% passerine birds, 7.7% rodents, and 0.3% snakes, leaving only 1.8% as "other" (Basso 1990)."

Of course the invertebrate that we "gut load" and feed our frogs provide them with enough nutrition to maintain health, but since invertebrates aren't natural prey for these frogs as much as other frogs/toads/birds/rodents might be, wouldnt it's natural prey promote optimal growth?