Background: Using cell lines to explore the function of organic compounds is fundamental in biotechnology. Evaluating new additives intended to improve animal production is challenging due to the complexity and uncertainty of in vivo testing. This study investigated the action of a compound with antioxidant properties using cells from terrestrial (LMH cells line) and aquatic vertebrates (CHSE-214). Results: The results of our study provide reassuring evidence of the compound's safety for use in animal production. The compound demonstrated no adverse effects on cell viability, indicating its potential for safe application. Furthermore, the compound's antioxidant properties were evident, with a 100% recovery in both cell lines when exposed to hydrogen peroxide 0.1 mM. It also effectively reduced cellular ageing caused by metabolic processes, as measured by the TBARS formation in both cell lines, from 5 MDA lM/ mg protein to 2.5 MDA lM/mg protein when used at 0.05 or 0.5 g/L. Notably, this action did not increase cell membrane oxidation, further supporting its safety profile. Conclusions: These findings indicate that the compound has an antioxidant effect and can be used independently or in combination with metabolic stimulants in the diets of production animals. Applying this additive and its possible synergy with other compounds could help reduce oxidative stress and improve growth in animal production. The data generated in this study provide a solid basis for designing diets incorporating this additive to observe improvements in animal production based on activity observed at the cellular level. How to cite: Olivares- Ferretti P, Maguregui E, Chavez V, et al. Novel antioxidant additive ENTAN molecule for animal production: Evaluation at the cellular level. Electron J Biotechnol 2024;71. https://doi.org/ 10.1016/j.ejbt.2024.07.001. (c) 2024 The Authors. Published by Elsevier Inc. on behalf of Pontificia Universidad Cat & oacute;lica de Valparaiso. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).