Abstract
Background:
Feed additives are products used in poultry nutrition to improve the quality of feed and safety of food byproducts from animal origin. They are promising antibiotic alternatives for production of broilers.
Aim:
This study aimed to investigate the effect of sodium butyrate (SB) and rosemary leaves (RL) on growth performance, biochemical profile, immunity, and carcass traits of broilers.
Methods:
Five hundred-one-day old chicks of Hubbard breed were reared on floor pens in a privet farm, Giza. The chicks were weighed on arrival (each chick weighted 43-45 gm) and randomly assigned into five equal groups, with four replicates each (25 chicks/replicate). Group 1 was fed on a broiler diet without any additions (control). The diets of groups 2 and 3 were supplemented with 500 g/ton SB and 4 kg/ton RL, respectively. In group 4, the diet was enriched with 250g/ton SB plus 2 kg/ton RL. Chicks in group 5 were fed on diet fortified with 500 g/ton SB plus 4 kg/ton RL.
Results:
Supplementation of broiler diet with 500 g/ton SB plus 4 kg /ton RL increased Body weight gain (BWG) and feed efficiency ratio (FER) of birds. It decreased serum levels of aspartate aminotransferase, alanine aminotransferase, total cholesterol triglycerides, malondialdehyde, but increased superoxide dismutase, catalase, and immunoglobulins, phagocytic activity, lysozyme activity, and nitric oxide concentrations. Antibody titers against Newcastle disease virus were also elevated.
Conclusion:
Supplementation of broiler diet with 500 g/ton SB plus 4 kg/ton RL gives the best result regarding productive efficiency and immunity of broiler chickens.

Key words: Sodium butyrate, Rosemary herb, Broiler performance, Biochemistry, Immunity