Opportunities for sheep welfare improvement by silymarin additive a review article

Nadya Bozakova and Veselin Ivanov

Abstract: Under grazing conditions, there are a number of stress factors that significantly impair the welfare of ewes and lambs - high and low temperatures, excessive solar radiation, poisonous plants, various endo-and ectoparasites, snake and insect bites, grazing infections, etc. The purpose of this publication is to summarize and highlight the possibilities of using silymarin and Silybum marianum products as a dietary supplement to improve the welfare of sheep under pasture rearing. A detailed analysis of numerous scientific articles related to the active ingredients, properties, and application of Silybum marianum products has been performed. Data on the antioxidant, hepatoprotective and detoxifying effects of silymarin have been summarized. The dual hepatoprotective effect of silymarin has been emphasized particularly for its antioxidant action, associated with reducing the reactive oxygen species content and malondialdehyde properties, and for stimulating the activity of the antioxidant enzymes- glutathione peroxidase, superoxide, and heat shock protein 70 (HSP70). The anti-stress effect of silymarin for lowering blood cortisol levels in animals is also briefly described, and pathways for silymarin detoxification of various toxins have been investigated. As a result of these mechanisms, the silymarin effect on improving the live weight and milk yield of ruminants is explained. Based on the review of the presented research, it can be concluded that silymarin and Silybum marianum-derivatives can be used successfully to improve sheep welfare under grazing conditions, due to their antioxidant, hepatoprotective, anti-stress, detoxifying activity, and to stimulate growth and milk production.

Keywords: anti-stress; antioxidant; detoxifying activity; sheep welfare; silymarin

Date published: 2022-06-16