Effect of photoperiodic alterations and binge eating on biochemical and metabolic parameters in zebrafish (<i>Danio rerio</i>)

Altered sleep-wake cycles and irregular eating patterns are among the most prominent lifestyle changes observed due to the increasing trend of shift work worldwide. Though circadian rhythm disruptions and unhealthy eating practices are increasingly recognized as contributors to metabolic disorders in humans, the underlying mechanisms remain unclear. The present study investigated the combined effects of binge eating and altered photoperiods on the metabolic and biochemical profiles of zebrafish (Danio rerio), a well-established vertebrate model. Adult zebrafish were subjected to excessive feeding and altered photoperiod (20 h light: 4 h dark) for two weeks, while the age-matched control group were maintained in standard laboratory conditions. Important biochemical indicators, such as blood glucose, nitric oxide, and the activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), were measured in addition to total protein. The present results showed that the blood glucose levels in the experimental group were significantly higher compared to the control group (76.2 ± 1.13 mg/dL vs. 52.9 ± 1.27 mg/dL). The antioxidant enzyme superoxide dismutase activity was significantly higher in the experimental group (56.02 ± 2.14 U/mg) compared to controls (3.18 ± 0.18 U/mg). The enzyme catalase also showed a slight but significant increase in its activity in the experimental group. However, Nitric oxide levels and total protein levels did not significantly change. These results showed that altering photoperiod in conjunction with altered feeding can lead to elevated glucose levels and increased oxidative stress, thereby affecting zebrafish metabolic homeostasis. This work provides a basic framework to understand the intricate relationship between circadian disruption and dietary excess in metabolic dysregulation, potentially impacting overall health.