RESUMEN
The treated groups were as follows: 1) the control, 2) the antibiotics (8 mg of avilamycin kg-1 of diet) and 3) the pitamin (70 mg of pitamin kg-1 of diet) groups. Body weight gain, feed intake, and feed efficiency were significantly higher in the pitamin group than in the antibiotics and control groups (p<0.05). Carcass weight, dressing percentage, and the weight of breast and thigh muscle recorded significantly higher levels in the pitamin group as compared to the other groups (p< 0.05). The addition of pitamin to the diets for broilers reduced abdominal fat by 23.35% and stimulated the growth of the thymus, the spleen, and the bursa of Fabricius. TAG levels of the pitamin group declined by 12.03 and 10.45% as compared to the control and antibiotics groups, and their TC levels were reduced by 15.17 and 14.39%, and LDL.C levels were reduced by 10.56 and 11.24%, respectively. Serum IgG was increased significantly by 137.43 and 36.80% in the pitamin group as compared to the control and antibiotics groups, respectively (p< 0.05). The numbers of Bifidobacterium and Lactobacillus on the cecum digesta were significantly higher in the pitamin group than in the antibiotics and control groups and the numbers of Escherichia coli and Salmonella tended to be reduced (p<0.05). In conclusion, when Korean red pine bark extract, pitamin, was added to the broiler diets at a concentration of 70 mg of pitamin kg-1 of diet, it resulted in better growth performance as compared to the antibiotics by improving immunity and the cecal beneficial microfloral population.