Evaluating gut-loading diets and dusting to improve the calcium concentration of pin-head and adult crickets (Acheta domesticus)

Citation

Schlegel ML, Renjifo A, Valdes EV. 2005. Evaluating gut-loading diets and dusting to improve the calcium concentration of pin-head and adult crickets (Acheta domesticus). In Graffam W, Hellinga D, Maslanka M, Ward A, Eds. Proceedings of the Sixth Conference on Zoo and Wildlife Nutrition, AZA Nutrition Advisory Group, Omaha, NE.

Abstract

Four experiments were conducted to evaluate the effectiveness of dusting crickets with calcium carbonate versus feeding a custom or commercial high-calcium diet on the calcium and phosphorus concentration of pin-head (13.7 mg) and juvenile (320.9 mg) crickets. Crickets were housed in 37.9 L aquariums, provided with water and egg crates for hiding, maintained on a 12 h light: 12 h dark cycle, and temperatures ranging from 18.1 to 33.3 °C. Experiments 1 and 2 demonstrated that dusting crickets with calcium carbonate, applied at a rate of 10% of the cricket weight, increased (P < 0.05) Ca concentration and Ca:P ratio of the crickets more than 27 times. The commercial diet fed for 48 h increased (P < 0.05) the Ca content of pin-head crickets 4.4 times and both the custom and commercial diets fed for 48 h increased (P < 0.05) Ca content and the Ca:P ratio 3 to 4 times in adult crickets. Experiment 3 evaluated extending feeding time of the custom diet to 96 and 168 h. Extending feeding time increased (P < 0.05) cricket Ca content and Ca:P ratio 58% over control crickets, but the increase was less than demonstrated in Experiment 1 and 2. In experiment 4, the use of the custom or commercial high-Ca diets ground through a 1 mm screen increased (P < 0.05) the Ca and Ca:P ratio more than 7 times in juvenile crickets. Although both dusting and feeding high-calcium diets increased Ca content of pin-head and juvenile crickets, only dusting increased the Ca:P ratio above 1:1. However, unless dusted crickets are consumed shortly after dusting, the added Ca may be lost. It appears that factors such as palatability, temperature, particle size, or additional nutrients may be impacting consumption of the high calcium diets by the crickets.

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