Dietary unsaturated fatty acids distinctly associate with the early age sleep-wake cycle and gut integrity in aged fruit flies, Drosophila melanogaster.

Obesity is a risk factor for compromised health and a driver for non-communicable diseases. Effects of various fats on health, behavior, and other parameters have been studied using different model organisms, including fruit flies Drosophila melanogaster, by exposing them to dietary fats (saturated and trans fatty acids). However, the long-term and short-term effects of dietary unsaturated fatty acids (USFA) on physiology and sleep-activity behavior are relatively less explored. Hence, the present study hypothesizes that exposure to a USFA-rich diet differentially influences early-life behavioral traits and long-term fitness in fruit flies. The results of our study reveal that the flies exhibit attraction to USFA, with comparable responses to control and the higher doses. We further observed sexual dimorphism in lifespan, with males fed with low-dose (2.5%) and intermediate-dose (10%) USFA outliving females. Further, upon first-time examining the interaction between behavioral changes and fitness of flies fed with USFA, our results reveal that the females under MUFA increased late-night activity, and the female flies fed highest dose of MUFA (20%) exhibited sleep reorganization, by reduced sleep in nighttime and increased in daytime. Further, MUFA-fed flies enhance sleep fragmentation at an early age. In line at late age, flies fed with an intermediate dose of MUFA showed loose gut integrity (Smurf positive). Overall, this study suggests that USFA-fed flies have shorter survival associated with sleep fragmentation in early life and reduced gut integrity of flies at a late age in a sex and dose-dependent manner. Highlighting sleep fragmentation and gut dysfunction may contribute dietary USFA quality to aging-associated fitness.