Effects of Dietary Supplementation of Milk Thistle and Nettle Essential Oils on Performance, Egg Quality, and Hematological Parameters in Layer Hens

This study was conducted to evaluate the effects of dietary levels of milk thistle (MTEO), or nettle essential oils (NEO) on production performance, egg quality and some serum metabolites of white layer hens (Hy-line W-36) aged 60 weeks. A total of 90 birds were randomly assigned to five groups with six replicates of three hens each to study the impact of five dietary treatments consisting of control (as basal diet) and dietary supplementation of different levels of MTEO and NEO (100 and 200 mg/kg). During the experiment period, birds had free accece to feed and water. Dietary supplementation of NEO and 200 mg/kg of MTEO improved egg weight compared to birds that received 100 mg/kg of MTEO (P < 0.05). Also, egg production was greater in 200 mg/kg MTEO treatment than those of birds under control and 100 mg/kg of NEO. Adding MTEO and NEO to the diet exhibited no significant influence on egg mass, feed conversion ratio , and feed intake in laying hens. No change in egg quality characteristics and serum parameters was found in birds fed with MTEO- and NEO-supplemented diets. Diets supplemented with 200 mg/kg of MTEO decreased the percentage of heterophils and heterophil to lymphocyte ratio when compared to control and 200 mg/kg of NEO (P < 0.05). In conclusion, dosage of 200 mg/kg of MTEO could be considered as an dietary feed additive to improve the egg production and immune response in laying hens.