Obesity induction in adult zebrafish leads to negative reproduction and offspring effects

Obesity is a transgenerational epigenetic metabolic disturbance. Although the diet-induced obese (DIO) zebrafish model is well established, reproductive parameters and changes in offspring have not yet been evaluated. Thus, the aim of this study was to evaluate possible changes in reproductive parameters, embryos and offspring (F1) generated by the reproduction of diet-induced obese males and females. The adult zebrafish were divided into two groups: one group receiving a balanced diet (control group) and the other group was overfed (DIO group) . The dietary protocol was maintained for 8 weeks. During this period, males and females in the same group were stimulated through a weekly reproduction protocol. To verify parental obesity, body weight, blood glucose, triglyceride, the hepatosomatic and gonadosomatic index and adipose tissue morphometry evaluations were carried out. Reproductive parameters were evaluated through ovarian and oocyte maturation stage, total spawning, fertility and fertilization index. To verify possible changes caused by parenteral obesity, all offspring were kept in separate groups in correspondence with their parents and were fed a control diet. Plasma glucose, triglycerides, mortality rate, hatching, and deformities were determined. After 8 weeks under the diet protocol, the DIO group exhibited characteristic obesity alterations, displaying significant increases in body mass and hepatosomatic and gonadosomatic indices, hyperglycemia and visceral and subcutaneous adipocyte hypertrophy. In addition, high mortality rates, morphologic deformities and high plasmatic glucose and triglyceride levels, with 100% mortality at 60 dpf, were observed for the offspring. Therefore, obesity induction in adults led to negative effects on their offspring, with a high occurrence of deformities and mortality.