Dietary Supplementation of <i>Ocimum Gratissimum </i>Improves Immune Response without Affecting the Growth Performance and Blood Characteristics in Taiwan Country Chicken

Abstract

Ocimum gratissimum (OG) was investigated in this study to determine its effect on the immune capability of black-feathered Taiwan country chickens. A total of 90 four-week-old male chickens were randomly assigned to a control group, which was fed with basal diet (BD), and two experimental groups, which were fed with a 0.2 and 0.4 g/kg OG-supplemented BD. During the experimental period, feed intake and body weight were recorded every two weeks to determine growth performance and feed efficiency. Blood was collected from the brachial vein of the chicken wing to obtain blood characteristics at 12 weeks of age. OG supplementation yielded no significant difference in growth performance and blood characteristics. The hemagglutination test showed that, compared with the control, the 0.4 g/kg BD group was able to maintain a significantly higher antibody titer level over two weeks after goat red blood cells injection (p<0.05), suggesting that 0.4 g/kg improves humoral immune response. The phytohemagglutinin test showed that wattle swelling in the 0.2-0.4 g/kg BD groups was reduced more significantly than that in the control group (p<0.05), suggesting that OG supplementation reduces cell-mediated immune response. Taken together, these findings suggest that although OG does not enhance growth or blood characteristics, the inverse changes in humoral and cell-mediated immune response may improve the overall health of the chickens.