The use of additives in the feed industry for producing fish has become the focus of constant change and research. The formulation of a product as a feeding strategy leads to the use of more than one molecule with particular characteristics to seek a synergistic effect when they are administered in the food. The application of taurine and silymarin in the salmon farming industry needs the exploration of the synergistic effects. For this study, we evaluated the effects of various concentrations of additives in the cell line CHSE-214 of Oncorhynchus tshawytscha. The cells were exposed to increasing concentrations of hydrogen peroxide as an oxidizing agent and were then given treatments of taurine, silymarin or both additives together. Our results indicate that the molecules had separate antioxidant effects, and the taurine treatment reached the highest number of cells per area at a dose of 100 ppm. However, if the cells were treated together at 100 ppm, silymarin achieved outstanding effects. However, when the treatment with both molecules was increased to 500 ppm of taurine, the effect was blocked, and the treatment acted as an antagonist. Our data indicate that the formulation of diets must be rigorously carried out, especially for determining the doses to be used to generate synergy among antioxidant additives and to reduce the effect of antagonism between the additives. Likewise, the use of cell lines is a strategy to evaluate the mechanisms of action for additives that are used in the development of diets for the salmon industry.