Effects of Milk Thistle Extract Supplementation on Performance, Egg Quality, and Liver Pathology of Laying Hens’ Fed Diets Lacking Supplemental Choline Chloride

Abstract

The current study evaluated the effects of milk thistle extract supplementation in laying hens’ fed diets lacking choline chloride addition. A total of 60 Isa-brown laying hens were randomly allocated into T1: control diet, 0% extract supplementation; T2: control diet with 1% extract; T3: control diet with 2.5% extract; and T4: control diet with 4% extract. Egg quality parameters, yolk lipid oxidation, malondialdehyde (MDA) content, and fatty acid profile were assessed. Livers were examined grossly and histologically to evaluate hepatocellular lesions such as vacuolization (lipidosis), reticular stromal architecture, the amount of collagenous connective tissue, and vascular wall changes. Groups T3 and T4 showed darker yolks compared to both control group and T2 (p = 0.001) and redness of the egg yolk (p < 0.001). The MDA was lowest in T2 group which had improved gross appearance with lower degrees of hepatic vacuolization than other groups. Liver discoloration was milder in T3 (43.8%) compared to the T1 and T4 groups (18.8% and 12.5%, respectively, p = 0.013). Reticulin loss was correlated with the degree of hepatic vacuolization (r = 0.751, p < 0.001). Supplementation with MT extract in diets lacking choline chloride may influence certain egg quality indices and liver gross macroscopic lesions in laying hens.