Comparative Study on the Antioxidant Potential of Milk Thistle Seeds and Silymarin Extract: Potential Implications in Ruminants

Interest in the use of phytogenic additives in animal nutrition is growing, but it remains uncertain whether standardized extracts offer advantages over whole plants. However, there is limited data on the effectiveness of standardized extracts compared with whole-plant extracts, making it difficult to choose the most effective source for animal feed. This work aimed to compare the nutritional composition and antioxidant activity of milk thistle seeds and silymarin extract to evaluate their effects on oxidative processes. The results showed significant differences between the two sources: the seeds were richer in minerals and fat-soluble compounds (vitamin E, carotenoids), while the extract presented higher contents of polyphenols and flavonoids and a higher total antioxidant capacity. This comparison provides new insights into the selection of optimal phytogenic supplement formulations, highlighting the importance of tailoring the product type (seeds vs. extracts) to the specific needs of the animal species and the nutritional objectives on farms.