**7. Conclusions**

Plant extracts can be used as growth promoters in poultry production independent of enzyme supplementation. Dietary PE may maximise the nutritional value of feed through improving gut health by reducing intestinal inflammation. Their mode of action may therefore be associated with improved immune status of the birds. This immune modulating effect of PE may explain improvements in growth performance and dietary NE seen in the present study. However, dietary supplementation with PE may improve bird growth performance without corresponding improvements in dietary ME. Studies that have focused solely on the effect of PE on ME alone, may not have detected their full benefit to improve the efficiency of broiler meat production. More research is needed to study the effect of supplementary PE on immune status of birds in relation to dietary available energy and growth performance of birds in commercial conditions using different practical feed formulations.
