A Drosophila holidic diet optimised for growthand development

Abstract

Diets composed of chemically pure components (holidic diets) are useful for determining the metabolic roles of individual nutrients. For the model organism Drosophila melanogaster, existing holidic diets are unable to support rapid growth characteristic of the larval stage. Here, we use a nutrient co-optimisation strategy across more than 50 diet variants to design HoldFast, a holidic medium tailored to fast larval growth and development. We identify dietary amino acid ratios optimal for developmental speed but show that they compromise survival unless vitamins and sterols are co-optimised. Rapid development on HoldFast is not improved by adding fatty acids but it is dependent upon their de novo synthesis in the fat body via fatty acid synthase (FASN). HoldFast outperforms other holidic diets, supporting rates of growth and development close to those of yeast-based diets and, under germ-free conditions, identical. HoldFast provides new opportunities for studying growth and metabolism during Drosophila development.