New Association of Milk Thistle and Artichoke Extracts Enhance Egg Quality in Caged-Laying Hens

Valentina Serra^1*Francesca Leone²Valeria Harper³Lorenzo Fiorini³Francesca Del Zozzo⁴Thibaut Chabrillat⁵Claire Carlu⁵Ivonne Archetti⁶Grazia Pastorelli¹DORIANA EUROSIA ANGELA TEDESCO²Alessandro Guerrini²

• ¹Department of Veterinary Medicine and Animal Science, University of Milan, Lodi, Italy
• ²Department of Environmental Science and Policy, University of Milan, Milan, Italy
• ³Gruppo Eurovo, Imola, Italy
• ⁴Chemifarma S.p.a., Forlì-Cesena, Italy
• ⁵Phytosynthese, Mozac, France
• ⁶Istituto Zooprofilattico Sperimentale della Lombardia e dell Emilia-Romagna Bruno Ubertini, Brescia, Italy

Introduction: Egg quality is a crucial indicator of productivity and laying hens' health. However, during the production cycle, hens' ageing, oxidative stress, and metabolic disorders (e.g., liver steatosis) can impair egg production and quality. Nutritional interventions may help preserve productivity under these conditions. Among plant extracts, milk thistle (Silybum marianum L.) and artichoke (Cynara scolymus L.) are noteworthy for their bioactive compounds with hepatoprotective, antioxidant properties. This study evaluated the effectiveness of a combined extract of milk thistle and artichoke (PHYTO-LAYER™), standardised in silibinin (2.4 g/L) and chlorogenic acid (2.2 g/L), in maintaining or improving egg quality, lipid oxidation, and antioxidant capacity in caged laying hens exposed to hepatic and metabolic efforts. Methods: A total of 792 Lohmann LSL-White hens (41 weeks old) were randomly assigned to two groups, control and treated (396 hens/each). The treated group received the products by drinking water at a dose of 1 mL/L, intermittently for 7 weeks (7 consecutive days every 2 weeks). Sampling occurred at five time points (T0–T5). At T0, T3, and T5, 60 eggs per group were collected for quality indices evaluation, while 13 hens per group were sampled for serum biochemical investigations. Results: PHYTO-LAYER™ improved egg, yolk, and albumen weight (p < 0.000), eggshell thickness (p < 0.000), as well as the total polyphenol content (p < 0.026), with an enhancement of yolk antioxidant capacity (p < 0.024). However, the Haugh Unit of treated eggs was worsened (p < 0.000). Discussion: Egg quality often deteriorates during late production stages due to oxidative stress and hens' ageing. Given the antioxidant potential of silibinin and chlorogenic acid, their combined intermittent administration supports and maintains the egg quality in caged laying hens exposed to metabolic efforts and after the peak of production. However, further studies could be of interest to