Induction of obesity by a high-carbohydrate diet in zebrafish modulates genes related to feeding behavior and inflammation

Abstract

Global increase in obesity is correlated with a high-carbohydrate diet. In this context, the present study aimed to investigate the effects of a high-carbohydrate diet on the induction of obesity in adult zebrafish. Animals of both sexes were used and divided into two groups over a 12-week period according to the provided diet. The control group received a nutritionally balanced diet formulated for the species, while the High-Carbohydrate Diet (HCD) group was fed a formulated diet enriched with corn starch as the carbohydrate source, designed as a low-cost and effective strategy to induce obesity.Weekly body weight was monitored to assess the impact of the diets. At the end of the experiment, behavioral testing, histological analysis of adipose tissues, and biochemical and enzymatic evaluations were conducted. Additionally, transcriptional regulation of genes associated with feeding behavior (leptin, orexin, and galanin) and inflammation (il-4, il-10, il-6, and tnf-α) was evaluated in the brain. A significant body weight increase was observed in the HCD group from the fifth week onward. At the end of the protocol, HCD-fed animals exhibited obesity-like phenotypes, including hypertrophy of visceral and subcutaneous adipocytes and elevated plasma glucose and triglyceride levels. Furthermore, animals showed anxiety-like behavior and altered gene expression related to feeding and inflammation. This study establishes a zebrafish model of obesity induced by high-carbohydrate diet consumption. Sex-specific differences were also identified, supporting the use of this model for investigating physiological mechanisms of obesity in both sexes and for the development of therapeutic strategies.