A standardization of the Novelty-Suppressed Feeding Test protocol in rats

Tests based on hyponeophagia phenomena are the most widely used to check the efficacy and efficiency of new-generation chronic antidepressant treatments. Even so, these tests lack strict consensus about their methodology, which reduces their validity, reproducibility and makes translatability difficult. Therefore, after an extensive literature review on this subject, we propose a methodological protocol for the Novelty-Suppressed Feeding Test to normalize this situation. Animals were induced to a reserpine-induced depression model and were then chronically treated with duloxetine, desvenlafaxine or vehicle. After a 14-day treatment, a standardized Novelty-Suppressed Feeding Test was performed. Standardization included three-phase deprivation and the introduction of standard highly palatable food. The duloxetine-treated and desvenlafaxine-treated animals exhibited behavioral improvement of depressive-like symptoms. They took less time to eat from the center of the open-field, and approached food more times per minute than the vehicle-treated animals. This normalization proposal proves effective in measuring the antidepressant effect on chronic treatment. Thus introducing this normalization proposal would reduce inter-laboratory variability and increase the validity and robustness of this behavioral test.