Suffice it to say: Nepenthes do better, a whole lot better, if you feed them. Exactly how you feed them though is a matter of personal choice in what works best for you and your personal environment and cultural practices. While it is possible to do alot of research on what has and hasn't worked for others, the trial and error to discover exactly which methods are best for each individual, falls on that individuals shoulders and noone elses. Whenever trying something new, that goes beyond the scope of tossing some crawly critters or fish food into the pitchers, it is always best to start slowly and with a few plants that are expendable, followed by careful observation and adjustments as necessary to achieve the results you are looking for.
another thing to keep in mind is there is such a thing as a bad batch.......i had a new bottle of pyrethrins that i normally use for pests fry a hamata.....though i have used pyrethrins on the plant with no ill effects in the past.....same brand, everything......b ut something was off with that batch and not only fried my hamata but also a few much tougher house plants......