Abstract
Background:
Garlic is considered an important natural additive in poultry nutrition because it acts as an antibacterial and antiviral agent, helps boost immunity, improves digestion, and increases growth and production rates, making it a healthy and economical choice in modern farming.

Aim:
This study aimed to evaluate the effect of dietary garlic powder supplementation on the physiological and biochemical parameters in the blood of broiler chickens.

Methods:
A total of 120 Ross 308 chicks were randomly assigned to two groups: a control group that was fed a basal diet and a second group that received the basal diet supplemented with 0.5% garlic powder. Hematological traits, lipid profiles, protein profiles, Immunoglobulin G (IgG) and Immunoglobulin M (IgM) levels, and liver and kidney functions were assessed over 4 weeks.

Results:
There were no significant changes in hematological parameters, including white blood cells, red blood cells, Hemoglobin, Mean Corpuscular Volume Mean Corpuscular Hemoglobin, and Mean Corpuscular Hemoglobin Concentration. Garlic supplementation significantly reduced total cholesterol levels. Other lipid parameters, including TG, High Density Lipoprotein, Low Density Lipoprotein, and Very Low Density Lipoprotein, showed non-significant changes. The second group, fed with garlic, showed a numerical increase in IgG levels. Changes in protein profiles or IgM levels were not significant. Liver and kidney function indicators, including direct bilirubin, alanine aminotransferase, aspartate aminotransferase, creatinine, Na, K, and Cl, remained within normal levels, with a significant decrease in total bilirubin, supporting hepatoprotective effects of garlic. Urea and uric acid levels showed a non-significant decline.

Conclusion:
Garlic supplementation at 0.5% appears safe and beneficial, offering promising immunomodulatory and lipid-lowering effects without inducing physiological stress. As a natural feed additive, garlic may contribute to sustainable farming practices and reduce the reliance on synthetic antibiotics.

Key words: ALT; AST; Immunity; Lipid profile; Protein profile.