TLRs, such as the specific type I transmembrane receptors and pathogen pattern recognition receptors play very important roles in acute inflammation. To the best of our knowledge, there is no report of the effects of stress on the mRNA expression of TLRs in the gastrointestinal tract of broiler chickens. Corticosterone has been considered as the end product of HPA axis stimulation. In poultry, CORT is the principal glucocorticoid involved in the regulation of fuel metabolism, feed intake, and immune responses. Moreover, in broiler chickens, it has been reported that CORT treatment causes the marked regression of lymphoid tissues. Thus, the present study was undertaken to assess the influence of the dietary energy density of a protein-adequate diet on the immune response of broiler chickens following CORT treatment. It is well known that decreased feed intake is a primary cause of reduced growth rate in broiler chickens. Previous studies have reported that stressful conditions induce reductions in growth rate even when feed intake levels are maintained. In the present study, exposing broiler chickens to CORT decreased the ADG in the absence of a change in feed intake. Physiological and biochemical changes may have been responsible for the lower growth rate of the HU 210 CORT-exposed broiler chickens. Increased energy expenditure and protein oxidation have been suggested as possible reasons for the suppressive effects of GCs on the growth rate of these animals. Furthermore, it has been reported that GCs may IP7e suppress growth by reducing the absorption of feed through the small intestine. In the present study, feeding broiler chickens a high-energy diet did not compensate for the adverse effects of CORT-induced stress on ADG and FCR. Furthermore, the decrease in the growth rate in the absence of a reduction in feed intake of the CORT-exposed broiler chickens fed the LE diet resulted in a higher FCR. Stressors can modify plasma levels of albumin and gamma globulins. Furthermore, previous studies have shown that GCs, as the end product of the activated HPA axis, increase albumin synthesis in vivo and up-regulate albumin gene expression in vitro. In this study, the CORT treatment increased the plasma albumin concentration in the CORT-exposed broiler chickens regardless of the dietary energy level. However, increasing the dietary energy level did not increase the plasma albumin level. Although the effect of the dietary energy level on the plasma IgG level was not significant, the level of plasma IgG in the CORT-exposed broilers fed the high-energy diet significantly increased compared with the other three groups. An effect of the dietary energy level on the immune system of broiler chickens has been reported by Mirzaaghatabar et al.. In this study, broiler chickens fed the HE diet had a higher plasma IgG concentration than those fed the LE diet. However, in the present study, to formulate the HE diet, soybean oil was used as a dense, high-energy ingredient.