Effect of ethanolic extract of propolis as an alternative to antibiotics as a growth promoter on broiler performance, serum biochemistry, and immune responses

Aim: An in vivo experiment was conducted to investigate the effect of different levels of ethanolic extract of propolis, on growth performance, carcass traits, serum biochemistry, and humoral immune responses of chickens, as compared with the antibiotic flavophospholipol. Materials and Methods: 312 1-day-old as-hatched broiler chicks (Ross 308) were randomly allotted to 6 treatments with 4 replicate pens per treatment. The 6 dietary treatments fed for 42 days consisted of a corn-soybean meal basal diet (control); control plus 4.5 mg/kg flavophospholipol, and control plus 50, 100, 200, and 300 mg/kg ethanol extracts of propolis, respectively. Results: Neither propolis nor antibiotic affected the performance criteria; however, dietary treatments tended to enhance to enhance body weight and daily feed intake of broiler chickens compared with control group (p>0.05). None of the dietary treatments significantly altered feed: Gain though; broilers fed diet supplemented with 200 mg/kg propolis had better feed: gain values compared with other groups in starter, and grower phases as well as the whole experimental period (p>0.05). Carcass yield and internal organ relative weights were not affected by treatments on day 42, except for abdominal fat pad weight that decreased in broilers supplemented with antibiotic. None of the treatments significantly affected humoral immune function. Dietary treatments failed to induce any significant effect on serum biochemistry (p>0.05); though broilers receiving 100 mg/kg propolis had greater high-density lipoprotein-cholesterol and lower triglyceride concentrations compared with other groups. Conclusion: In conclusion, the results indicated that addition of ethanolic extract of propolis to routine dietary components of broilers, such as corn and soybean, seems not to have a positive influence on performance criteria