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

Abstract

Background
Many previous studies
prov e d the ability of Milk thistle ( Silybum marianum ) to treat and immune enhance
against many diseases a n d hepatic dysfunctions w i t h antioxidant activities t o support cells protection in
heat stress conditions
Aims
T
o assess the effects of graded dietary supplementation by milk thistle ( Silybum marianum ) ext ract on
immune responses , hepatic biomarkers and Hematology parameters in pre laying hens under natural Iraqi
summer heat stress.
Methods
One hundred twenty Isa
brown pre laying hens (10 weeks old) were randomly allocated in four groups of
30 birds per group and housed till 18 weeks of age in a closed system using floor pens. The diets included
a basal diet without extract (control, G1), or basal diet supplemented with 0. 5 g m kg hens ration (G2), 1
g m kg hens ration (G3), or 2 g m kg hens ration (G4) of the extracted material. The experimental period
was 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.
Results
Silybum marianum
supplementation resulted in a significant increase in liver function compared to the
control group. In particular, G3 and G4 had considera bly lower ALT and AST levels compared to G1 and
G2. Moreover, compared with control, there were significant reductions in glucose, TG and TC due to the
extract. G4 showed significant improvement in immunity measured as Newcastle disease antibody titers
com pared to all the other groups.
Conclusions
Silybum marianum
extract (2 g m/ kg) modulates glucose, TG, TC, ALT and AST and the blood immune
status as well in pre laying hens under summer heat stress.