Drosophila melanogaster in nutrition research—the importance of standardizing experimental diets

Abstract

The fruit fly Drosophila melanogaster has been increasingly recognized as an important model organism in nutrition research. In order to conduct nutritional studies in fruit flies, special attention should be given to the composition of the experimental diets. Besides complex diets, which are often based on maize, yeast, sucrose, and agar, Drosophila can be also fed chemically defined diets. These so-called holidic diets are standardized in terms of their macro- and micronutrient composition although the quantitative nutrient requirements of flies have yet not been fully established and warrant further investigations. For instance, only few studies address the fatty acid, vitamin, mineral, and trace element requirements of fruit flies. D. melanogaster may be also of interest in the field of nutritional medicine. Diet-induced diabetes and obesity models have been established, and in this context, often, the so-called high-fat and high-sugar diets are fed. However, the composition of these diets is not sufficiently defined and varies between studies. A consensus within the scientific community needs to be reached to standardize the exact composition of experimental complex and holidic diets for D. melanogaster in nutrition research. Since D. melanogaster is an established valuable model system for numerous human diseases, standardized diets are also a prerequisite to conduct diet-disease interaction studies. We suggest that a comprehensive approach, which combines deep phenotyping with disease-related Drosophila models under defined dietary conditions, might lead to the foundation of a so-called fly clinic.

Drosophila-associated bacteria differentially shape the nutritional requirements of their host during juvenile growth

“…HDs comprise a mixture of pure chemical ingredients that satisfy the different physiological requirements of the Drosophila host [34,35]. By altering the concentration of each or a combination of ingredients, one can exactly tailor the experiments by generating specific nutrient deficiencies or excess [36]. The first development of HDs supporting the growth of Drosophila can be traced back to the 1940s [37], and they were used to assess the direct impact of the nutritional environment on axenic larvae in the 1950s [38,39].…”

Dietary fatty acids promote sleep through a taste‐independent mechanism

“…Alternatively, it is possible that individual macronutrients have differential effects on feeding. Differentiating between these possibilities will require manipulating the macronutrients within flies fed an isocaloric diet . Defined holidic diets provide the opportunity to selectively manipulate specific macronutrients and measure the effects on sleep.…”

Gut bacteria mediate nutrient availabilityin Drosophiladiets

“…Despite the many benefits of using D. melanogaster to investigate a 66 spectrum of biological processes, the range of diets used for fly maintenance Lüersen et al, 2019). Recently, we showed that diet composition between 69 studies varied greatly in both the amounts and types of components used (i.e.…”