Abstract
A total of two hundred twenty five day-old Cobb broiler chicks were distributed into five groups (15 birds/ group, three replicates for each treatment). The dietary treatments were designed to fed the chicks of basal diet without supplementation (control), basal diet supplemented with 0.5, 0.75 and 1gm/kg anise seed, and basal diet supplemented with 10g/kg zinc bacitracin (anti-biotic group). Behavioral observation was carried out twice daily (7:00-11:30 am and 13:00-17:30 pm) two days a week for 6 consecutive weeks. Body weight (BW) and feed intake per pen were measured weekly from which body weight gain (BWG) and feed conversion ratio (FCR) were measured. Immune response against NDV was determined at 33th day of age. At the end of experiment, fear responses, differential leucocyte count, Hb concentration, PCV, and some carcass traits were assayed. Dead birds from each treatment were recorded. The obtained results showed that higher proportion of birds supplemented with anise 0.5, 0.75 and 1.0 gm/kg were engaged in more feeding behavior compared to control one. Birds supplemented with anise seed and antibiotics were engaged in significantly more resting behavior compared to birds in control group. Untreated control birds exhibited significantly higher preening behavior and lower wing stretching and/or wing flapping and dust bathing behaviors compared to anise seed fed groups. At the 43th day of age birds supplemented with 0.5, 0.75 and 1.0 gm/kg anise seed had significantly higher BW, BWG, and better FCR and had higher carcass percentage compared to birds in control group, but not significantly differed from birds in antibiotic group. Mortality rate was not differed among different treatments. Percent of live weight of bursa and Hb content were significantly higher in anise seed supplemented groups compared to control and anti-biotic groups. Chicks fed basal unsupplemented diet were more fearful in tonnic immobility test and were more stressed and had a significant increase in heterophil / lymphocyte ratio when compared with those in all supplemented diet groups. In contrast, dietary supplementation had no significant effect on antibody titer against NDV. In conclusion, dietary supplementation of broiler chicks with anise 0.5, 0.75 and 1.0 gm/kg improved feeding and comfort behaviors, improved productive performance and bird's welfare (reduced fear and stress) with no effect on immune response. Anise seed could be used as natural alternatives to feed antibiotics in broilers feed.

Key words: Anise, seed, antibiotic, behavior, performance, stress, fear, immune response