Effect of some feed supplementation as growth promoters on productive and physiological performance of broilers.

Proscription of synthetic growth promoters (SGP) in poultry production worldwide has encouraged scientists to find natural alternatives, such as herbal additives. This research aimed to investigate the possible impacts of adding garlic, thyme, sage and their combination on performances of broiler chickens. A total of 180 unsexed, one-day-old Cobb 500 chicks were randomly dispensed into five treatments (3 replicates × 12 chicks per replicate). The treatments were: T1: control group; T2: garlic powder (Allium sativum, 5g /kg); T3: thyme powder (Thymus vulgaris L., 5g /kg); T4: sage powder (Salvia officinalis, 5g /kg); T5: garlic + thyme + sage powder (5g /kg from each additive). The productive performance of the groups was evaluated through the experiment, which lasted for 35 days. Following the trial, measurements were made of the carcass's properties. Results obtained revealed that the inclusion of herbal additives suggested in broiler diets promoted productive performances (final body weight (FBW), average gain (AVG), feed conversion ratio (FCR) and carcass yield % with no significant effect on relative weights of carcass cuts and organs. A significant decrease in blood cholesterol and total lipids levels was also noticed. In addition, enhanced immunological indices (H/L ratio and antibody titer against Newcastle disease) and beneficial bacteria count in the small intestine of birds provided by supplemented phytogenics. In respect of the results, it can be concluded that adding 0.5% of additives propositioned into broilers' diets could be utilized as an alternative to SGP due to the affirmative productive performance and immune-system defence of broilers.