Immune Status and Liver Function for Laying Hens Supplied with Milk Thistle ( Silybum marianum ) as Food Additive under Heat Stress of Iraqi Summer

BackgroundMany previous studiesprov e d the ability of Milk thistle ( Silybum marianum ) to treat and immune enhanceagainst many diseases a n d hepatic dysfunctions w i t h antioxidant activities t o support cells protection inheat stress conditionsAimsTo assess the effects of graded dietary supplementation by milk thistle ( Silybum marianum ) ext ract onimmune responses , hepatic biomarkers and Hematology parameters in pre laying hens under natural Iraqisummer heat stress.MethodsOne hundred twenty Isabrown pre laying hens (10 weeks old) were randomly allocated in four groups of30 birds per group and housed till 18 weeks of age in a closed system using floor pens. The diets includeda basal diet without extract (control, G1), or basal diet supplemented with 0. 5 g m kg hens ration (G2), 1g m kg hens ration (G3), or 2 g m kg hens ration (G4) of the extracted material. The experimental periodwas 8 weeks, from August 24, 2025, to October 26, 2025. Measured variables were alanine aminotrans-ferase ALT )), aspartate aminotransferase AST )), glucose, triglycerides (TG), total cholesterol (TC), het-erophil ratio and lymphocyte ratio and antibody titers against Newcastle disease vaccine.ResultsSilybum marianumsupplementation resulted in a significant increase in liver function compared to thecontrol group. In particular, G3 and G4 had considera bly lower ALT and AST levels compared to G1 andG2. Moreover, compared with control, there were significant reductions in glucose, TG and TC due to theextract. G4 showed significant improvement in immunity measured as Newcastle disease antibody titerscom pared to all the other groups.ConclusionsSilybum marianumextract (2 g m/ kg) modulates glucose, TG, TC, ALT and AST and the blood immunestatus as well in pre laying hens under summer heat stress.