Effect of Milk Thistle Seeds Aqueous Extract on The Growth Outcomes, Egg Quality Traits, Cecal Microbiota, and Hemato-Biochemical Markers of Laying Japanese Quails

This study evaluated the effects of milk thistle seeds aqueous extract (MTS) on the growth performance, egg quality traits, cecal microbiota, and hemato-biochemical parameters of laying Japanese quails. A total of 108 quails (8 weeks old) were allotted to three experimental groups: a control group receiving plain drinking water and two treatment groups supplemented with 200 mg/L (MTS1) and 400 mg/L (MTS2) of MTS, respectively. Productive parameters, egg characteristics, fertility, hatchability, carcass traits, blood markers, and cecal microbial populations were assessed. Gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) analyses identified 29 active phytochemical compounds in MTS, including flavonoids and phenolic agents. Results indicated that MTS supplementation improved egg production rates, egg mass, and feed conversion efficiency compared to the control. The highest dose (MTS2) significantly enhanced eggshell thickness, egg shape index, and Haugh unit scores. Fertility rates improved in both MTS groups, while hatchability and embryonic mortality remained unaffected. Carcass traits showed non-significant differences, except for a reduced spleen weight in the MTS2 group. Hematological analysis revealed increased haemoglobin, packed cell volume (PCV), and plasma globulin levels in MTS-treated quails. Additionally, MTS supplementation reduced aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, indicating improved liver function. Cecal microbiota analysis demonstrated a dose-dependent decrease in Escherichia coli and Salmonella counts. Therefore, MTS supplementation positively influenced egg production, quality, immune response, and gut health in laying quails, supporting its potential as a functional feed additive for poultry production.