Abstract
Background: Recently, attention has been paid to using plants with medicinal efficacy as alternates to antibiotics and growth promoters. Garlic is a traditional plants used as a spice and herb in broilers.
Aim: The objective of the current feeding trial was to investigate the effect of garlic powder on broiler performance, carcass characteristics, blood hematology and biochemistry.
Method: A total of 240 one-day-old broiler chicks (Cobb500) were purchased from local hatchery and randomly distributed into four dietary treatments. Each treatment comprised of five replicates with 12 chicks each. Garlic powder (Allium sativum) was supplemented as follows: 0.0%, 0.1%, 0.2% and 0.3%. The diets were formulated to be approximately isocaloric and cover all nutrients requirements for broiler throughout two stages of growth periods, starter diets (1 - 21) and finisher diets (22 - 42) days. At the end of the experiment, one bird was chosen from each replicate to measure the carcass characteristics and blood was collected.
Results: The findings showed that birds fed diet supplemented by 0.3% garlic powder was significantly (P<0.05) better in terms of body weight, body weight gain and feed conversion ratio compared to those birds fed 0%, 0.1% or 0.2% garlic powder. In addition, feeding 0.1% or 0.2% garlic powder significantly increased (P<0.05) packed cell volume (PCV), total white blood cells (WBC), neutrophil, eosinophil, monocyte and lymphocyte compared to the control group. Furthermore, garlic supplementation led to a decrease alanine aminotransferase (ALT), total cholesterol, triglycerides and low density lipoprotein (LDL) compared to the control. At the same time, high density lipoprotein (HDL) was significantly increased (P<0.05) by garlic supplementation.
Conclusion: It can be concluded that supplementation of 0.3% garlic powder as growth promoter lead to reducing the cost of production through improving growth performance and enhance the birds’ health.

Key words: garlic, broiler, growth, carcass characteristics, hematology