Challenges with effective nutrient supplementation for amphibians: A review of cricket studies

Abstract

Over the last 25 years, numerous studies have investigated the impact of insect supplementation on insect nutrient content. In light of recent nutrition related challenges with regards to zoo amphibians fed an insect based diet, this review attempts to comprehensively compile both anecdotal and published data in the context of practical application on this topic. Insects, primarily crickets, used for amphibian diets historically demonstrate low concentrations of key nutrients including calcium and vitamin A. Commonly used practices for supplementation involving powder dusting or gut loading have been shown to improve delivery of calcium and vitamin A, though often not reaching desired nutrient concentrations. The large variety of factors influencing insect nutrient content are difficult to control, making study design, and results often inconsistent. Formulation and availability of more effective gut loading diets, combined with a standardized protocol for insect husbandry and dietary management may be the most effective way to supplement insects for use in amphibian feeding programs. Ideally, the nutritional improvement of feeder insects would begin at the breeder level; however, until this becomes a viable choice, we confirm that supplementation of crickets through both gut-loading and dusting appear necessary to support the nutritional health of amphibians and other insectivores in managed collections.

Evaluation of β‐carotene assimilation in leopard geckos (Eublepharis macularius)

“…This could be due to a different palatability of the supplement, although both are commercialized for cricket gut‐loading. Concentration of vitamin A in crickets prior to gut loading was similar to previous studies (Barker et al., ; Finke, , , ; Livingston, Lavin, Sullivan, Attard, & Valdes, ). Managing food intake of invertebrate preys can be practically challenging without repeated prey analysis.…”

“…The horizontal line at the bottom of each boxplot is the minimum value for each group; the lower limit of each box is the lower quartile; the heavy line inside each box is the sample median; the upper limit of each box is the upper quartile; the horizontal line at the top of each plot is the maximum value. Hepatic vitamin A concentrations are significantly different between groups (p = 0.03) 2003, 2013Livingston, Lavin, Sullivan, Attard, & Valdes, 2014).…”

Complete nutrient content of four species of commercially available feeder insects fed enhanced diets during growth

“…Recently, it has been suggested that in addition to more traditional ways of supplementing the base nutrient content of insects such as dusting and gut‐loading, their nutritional content might be improved by altering the diet used by the supplier to grow the insect. [Ferrie et al, ; Livingston et al, ]. So, the purpose of this study is to provide a nutrient analysis of four species of commercially bred insects fed a special feed designed to enhance their nutrient content.…”

The tonic immobility test: Do wild and captive golden mantella frogs (Mantella aurantiaca) have the same response?

“…Both captive colonies receive a diet of variety of live invertebrates, but Chester Zoo’s colony also received a diet supplementation. There is a lack of knowledge concerning the nutritional necessities and absorption efficiency of amphibians; however, studies have demonstrated that diet supplementation can have a positive impact on frog body condition and general health [35]. This lack of vitamin and mineral supplementation could be causing frogs from Mitsinjo to have a lower body condition.…”

“…The stress response is not inherently detrimental, but rather, is a complex and essential negative-feedback process [47]. The capacity to cope with threatening (acute stress) situations is a vital ability to survival in the wild [35]. Predation, competition and other stressful events are part of the routine in the wild habitats.…”