Sex-Specific Effects of Sleep Restriction on Food Intake and Neuropeptide Expression in Zebrafish

Studies in mammal models show that reduced sleep is associated with increased food intake. Zebrafish (Danio rerio) is emerging as a promising model for studying sleep and feeding behaviour due to its similarities with mammals. Our goal was to investigate whether sleep restriction increases food intake in zebrafish, its potential effects on central regulation of feeding, and whether effects are similar in both sexes. Individually housed male and female adult zebrafish were exposed to nighttime (ND) or daytime (DD) vibrations and compared to a control group without vibration (n = 30 males and n = 27 females). ND, but not DD, reduced sleep during the disturbance period, with males showing a significant effect and females exhibiting an altered sleep pattern without a statistically significant reduction. ND also significantly increased food intake in males, as measured by daily milligrammes and number of pellets consumed. In contrast, ND females exhibited a decrease in the time spent feeding, suggesting a sex-specific response to sleep disruption. The whole brain expression of neuropeptide Y (npy), proopiomelanocortin (pomc), and its receptor melanocortin-4 (mc4r) were analysed by RT-qPCR. Males from ND exhibited significantly reduced pomc mRNA levels. Grouped-housed (three male and two female) zebrafish exposed to ND also exhibited increased food intake. In conclusion, sleep restriction affected food intake behaviour and the central regulation in zebrafish, with distinct sex-specific effects.