Effects of vitamin E and milk thistle powder (Silybum marianum) on liver healthy, serum parameters and production indices in laying hens

The objective of this experiment was to investigate the effects of different levels of milk thistle powder and vitamin E on liver healthy, serum parameters and production indices in laying hens. The 2×3 factorial experiment was managed in a randomized complete design with 72 Hy- Line (W36) laying hens in six treatments and four replicates of three birds each. The experimental period lasted for a total of six weeks. Treatments included different levels of milk thistle powder (0, 100 and 200 mg/kg) and vitamin E (recommended by NRC; 5 mg/kg and more than recommended by NRC; 80 mg/kg). The effect of different levels of milk thistle powder and vitamin E on production indices were not significant in the throughout the experimental period. The best feed conversion ratio was observed in hens fed with rations included 80 mg/kg of vitamin E in the sixth week of experiment (p < 0.05). Laying hens were fed with milk thistle powder (200 mg/kg) had the best feed conversion ratio compared with the control group in the fifth week of experiment (p < 0.05). The effect of different levels of milk thistle powder and vitamin E on egg quality and serum parameters were not significant. Dietary milk thistle powder (200 mg/kg), as compared with the control, decreased serum activity of alanine aminotransferase (p < 0.05). In conclusion, diet supplementation with milk thistle powder (100 and 200 mg/kg) and vitamin E (more than recommended by NRC) had no positive effects on production indices and egg quality in laying hens.