Obesity and high-fat diet (HFD) consumption are associated with various central nervous system (CNS) disorders as well as behavioural and psychological disorders. Zebrafish (Danio rerio) are considered a valuable organism in investigating the neurobehavioral characteristics of human diseases. The study aimed to verify the influence of a HFD on the CNS by evaluating the effects of short-term HFD on Zebrafish anxiety-like responses, aggression, social preference, and memory. Researchers used 60 male wild-type, 4-6 month old short-fin phenotype Zebrafish to investigate this study. For 16 days, 20 Zebrafish were fed a standard diet of 7.5mg/fish that reached the basal energy requirement of 30 cal/fish with a 6.5% fat content, while another 20 were fed a HFD of 7.5mg/fish receiving 48.7 cal/fish with a 16.9% fat content. The last 20 were fed a HFD of 25mg/fish receiving 73 cal/fish with a 21.1% fat content. Between the 14th and 16th day behavioural tests were performed. Morphometrical measurements were taken throughout the experiment. On day 16, immediately following the final behavioural test, the fish were euthanised. This was done in order to confirm the sex of the fish via gonadal extraction and laterally photograph for final measurements. It was found that HFD impaired memory and heightened aggression and anxiety but did not affect social preference. I believe that this research is ethically sound. Throughout experimentation, a 12 hour dark-light cycle was kept to maintain biological rhythms and minimise psychological stress. Furthermore, water temperature was set at 27 + 2 ?, pH was 7.0-7.2, and conductivity was 1500-1600 uS.cm-1 which aligns with recommended water quality parameters for zebrafish (Lawrence & Mason 2012). Therefore, I believe that every effort was done by researchers to reduce harm to the animals during the experiment. This study was approved by Ethics Committee on the Use of Animals (CEUA) of the University of Brasilia. Therefore, researchers had to follow ethical guidelines stating that death must be by humanitarian means involving, according to the species, minimal physical and psychological distress. Additionally, the resulting research must lead to elucidation of physiological or pathological phenomena. This aligns with the utilitarianism framework where potential benefits from the research must outweigh any harm to the animal. Obesity-induced metabolic disorders are associated with various obesity-related comorbidities, including vulnerability to CNS disorders and neurobehavioral disorders (Cadenas-Sanchez et al. 2020). However, the precise pathways that link these are little known. I believe that researching this gap would ultimately be beneficial to humans. Therefore, I consider this research to be morally important and ethically sound. Throughout this study, researchers may have had temptations to fabricate the data in order to ensure significant results. However, there was no omission of data. The results shows that not all the data was statistically significant and did not support the hypothesis. This leads me to believe that no fabrication is present.
In conclusion, I believe researchers succeeded in undertaking this study in an ethical fashion. References Cadenas-Sanchez, C, Esteban-Cornejo, I, Migueles, J, Labayen, I, Verdejo-Román, J, Mora-Gonzalez, J, Henriksson, P, Maldonado, J, Gómez-Vida,