Hello
@SILVERKINGS and welcome
Purizon is high in protein and fats (44% protein and 20% fats) so with that many calories you wouldn't want to give them much - just a few pieces a day as treats, if they are having mainly wet food, or they will soon become overweight. Also, for some reason Purizon contains several different kinds of fruit, strange ingredients to add to cat food as fruit is not a normal part of the diet of an obligate carnivore.
Perhaps the fruit is there to acidify the urinary tract, and prevent struvite stones. But diets designed to prevent the formation of struvite stones in the bladder , make cats produce urine that is more acidic than normal, and if urinary acidification is taken too far calcium oxalate stones can occur.
Although Purizon is grain free it contains 18% potatoes, so is very high in carbs. A cat living wild would eat no more than 1% or 2% carbs. 18% would be fattening if your cats ate much of this food.