Document Type : Original Article


1 Animal and Poultry Nutrition Department, Desert Research Center, Cairo, Egypt.

2 Animal and Poultry Physiology Department, Desert Research Center, Cairo, Egypt.


Ninety unsexed one day old Cobb 500 broiler chicks were used in this experiment. The experiment aimed to study the comparative effect of some feed additives as growth promoters such as selenium and zinc in their inorganic form on broiler growth rate, feed intake, feed efficiency, some blood metabolites and carcass traits by adding them in the drinking water. The chicks were randomly distributed into three equal treatments. Each treatment had 30 chicks divided equally into five replicates. The experimental treatments were: The first treatment was served as a control (T1), while the second (T2) was given 0.8 mg sodium selenite / L of drinking water and the third treatment (T3) was given 1 g zinc oxide/ L. Sodium selenite (T2) showed the heaviest body weight (P<0.01), gained more weight consumed more feed and recorded the best value of feed efficiency ratio (P<0.001) compared to the other treatments. There were non-significant differences between control and zinc treatments in body weight and gain and feed efficiency ratio. There was a significant reduction in feed intake from 21 to 35 days of age and from 1 to 35 days of age for zinc treatment compared to the other treatments and significant increase from 1 to 21 days of age for the same treatment. A significant increase in triiodothyronine (T3) (P<0.01) was observed in selenium and zinc treatments (T2 and T3 respectively) compared to the control treatment. About plasma urea, creatinine, ALT and AST, total lipid, cholesterol, triglycerides, total protein, albumin, globulin and their ratio (A/G ratio) and carcass traits, there were nonsignificant (P>0.05) differences among the experimental treatments. Zinc treatment (T3) recorded the lowest percent (3.85%) of mortality. It was concluded that supplementation of selenium in broiler drinking water improved broiler performance and zinc addition did not have adverse effects on growth rate and the functions of blood.