A consideration, is that in nature, shrimp and other live foods, have not yet deteriorated .
But as soon as shrimp is fished out of the ocean, or lake, or if it sits, or is frozen, it starts to deteriorate, fish that eat market shrimp, market Tilapia and etc etc are not getting he full gamut of nutrients.
And in nature...... a fish usually eats the entire animal, guts, brains, "whatever algae " or food source inside he digestive tract.
If just fed the shrimp tail meat, or tilapia fillet, the predator doesn't get the full compliment nutrients and vitamins it would get in nature.