The present study aimed to investigate the efficacy of garlic bulb as natural
antimicrobial agents in improving the performance of broiler chicks co pared to that
of other antimicrobial growth promoters, virginiamycin, copper sulfate nd citric acid.
The effect on small intestine thickness, pH value of ileal content, some blood
constituents and some internal organs were also, examined. One hundred and fifty unsexed day old Arbor Acres broiler chic s were fed on
basal diet supplemented with 150 mg/kg copper sulfate, 20 mg/kg vi giniamycin, 6
g/kg citric acid or 15g/kg garlic bulb, while the fifth group was fed th control basal
diet. The result indicated Ihat, average body gain was improved by 13%, 15%, 13%
and 6% due to adding copper sulfate, virginiamycin, citric acid or ga lie bulb to the
diets respectively. Feed consumption values were Significantly affected by including
copper sulfate, virginiamycin or citric acid to the broiler diets. Feed fficiency ratio
wasn't affected significantly by feeding diets supplemented with the different feed
additives, however virginiamycin-supplemented diet tend to enhance eed efficiency
ratio. Small intestine thickness didn't respond to different antimicrobial growth
promoters. Bursa and spleen weights were positively affected by different dietary
treatments. Both of citric acid and garlic bulb have a lowering effect on pH value of
ileal content. Plasma cholesterol and total lipid decreased significanlly Clue to feeding
dietary copper sulfate or garlic. The values of plasma total protein, albumin and globulin were ot affected by
different treatments. It can be concluded that, garlic bulb is less effective than the other three growth
promoters in promoting chicks growth. Virginiamycin, copper sulfate and citric acid
have approximately the same effectiveness in improving poultry growth.