The effects of Silymarin on ovarian activity and productivity of laying hens

In a previous work we evaluated the effects of Silymarin, a natural antioxidant and hepatoprotective polyphenolic compound, on laying hens performances and health status. The aim of the present work was to further confirm the previous results and to investigate the effects of Silymarin on ovarian endocrine activity and productivity of laying hens as well as on egg traits. Eighteen laying hens were randomly allotted into 3 groups and observed for 20 weeks: control hens were fed control diet, while treated groups received supplementations of 200 (S200) and 400 (S400) ppm of Silymarin. S200 group showed improved eggs laying rate (+2.91%), feed conversion rate (-4.52%) and a significant (P<0.05) increase of dry matter content (+0.54%), total lipids (+0.72%) and total sterols (0.02%) of the eggs. Any significant difference was shown for Silymarin at the highest dose (400 mg/kg of feed). At the end of the trial the hens were sacrificed and hierarchical follicles were removed and cultured for 48h. Media were assayed for progesterone (P4) and estradiol-17 beta (E2). Average E2 production in- creased (P<0.05) from F5 (follicles with initial development) to F3 (follicles with intermediate develop- ment), then decreased (P<0.05) from F3 to F1 (pre-ovulatory follicles). Basal P4 production augmented (P<0.05) throughout all follicle growth. Both Silymarin treatment inhibited (P<0.05) steroidogenesis. Silymarin may act as an endocrine-modulating chemical affecting hen performances.