Digestibility and mineral availability of phoenix worms, Hermetia illucens, ingested by mountain chicken frogs, Leptodactylus fallax.

摘要

Soldier fly, Hermetia illucens, larvae have been introduced to the herpetoculture market as an alternative, palatable, high-calcium (Ca) foodstuff that minimizes or alleviates the need for additional gut-loading or dust supplements. Long-term successful breeding programs with insectivorous lizards and amphibians fed these larvae have been anecdotally reported; other observations suggest that whole larvae may pass intact and poorly digested through the gastrointestinal tract unless the cuticle is pierced. Feed intake and digestibility trials were conducted with 25 mountain chicken frogs, Leptodactylus fallax, housed in groups of five animals fed either crickets, or intact or mashed solider fly larvae to investigate nutrient availability. Diet significantly influenced the digestibility of dry matter, protein, fiber fractions, and all minerals (Ca, phosphorus [P], magnesium, sodium [Na], potassium [K], copper, iron, manganese, molybdenum, and zinc) measured in these trials (P<0.01 for all nutrients), with intact soldier fly larvae lowest in availability. Pureeing the worms increased availability of all nutrients except K and Na compared with intact worms. Both Ca and P digestibilities were approximately doubled in the mashed worms (~90 versus 45-50%) and were similar to values measured in supplemented cricket-based diets. This study suggests that soldier fly larvae can supply high levels of dietary minerals without a need for additional external Ca supplementation, provided target species "chew" their food or in some manner worms are processed to break the exoskeleton.