The best gut-loading technique is to supply a high calcium diet within 72 hours before being fed-off to the predator. It would basically be identical for crickets, too.



Generally, feed: greens(collard, turnip, mustard)-which has minerals, enzymes, moisture & calcium; laying-chicken mash--(Non-medicated) which is high in calcium & protein; and the "shake-N-bake" method of calcium/mineral coating with reptile-calcium products--which according to studies, will provide the most quantity of calcium/minerals to insectivorous reptiles.



When raising roaches & crickets, having a variety of food & moisture sources are important. In addition you can use either dog or cat chow (protein)-preferably without dyes; vegetables and fruits, and fats such as olive or other vegetable oils--(lightly sprayed on the chow) for egg production.



There are many good recipe formulations on the internet for this. Below is a link to an excellent gut-loading recipe:
Link

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