Bioactive Essential Oil Blend in Broiler Diets: Effects on Performance and Intestinal Morphology

Abstract

ABSTRACT This study evaluated the effects of a commercial blend of cinnamon (Cinnamomum verum) and oregano (Origanum vulgare) essential oils on growth performance and intestinal health indicators of broilers. A total of 385 male chicks were allotted to five dietary treatments: a negative control diet without growth promoters, a positive control diet with an antibiotic growth promoter, and three diets supplemented with 0.05, 0.10 or 0.15 kg/t of the essential oil blend in a completely randomized design up to 42 days of age. Growth performance was recorded by phase, and gastrointestinal organ biometrics, serum biochemical profile and small-intestine histomorphometry were assessed at slaughter. Essential oil supplementation did not consistently affect body weight gain; however, the inclusion level of 0.10 kg/t improved feed conversion ratio and reduced cumulative feed intake compared with the antibiotic control during the grower phase and over the rearing period. At 42 days of age, increasing levels of the blend promoted a linear increase in villus height in the duodenum, jejunum and ileum, whereas gastrointestinal organ weights and serum biochemical variables remained within normal physiological ranges and were not influenced by the treatments. Under the present conditions, the cinnamon and oregano essential oil blend at 0.10 kg/t improved feed efficiency and intestinal villus development without adverse effects on health indicators, supporting its use as a phytogenic additive in broiler nutrition. Further studies including microbiota characterization, digestive enzyme activity, and inflammatory or oxidative stress markers are warranted to clarify mechanisms and to better position this blend within antibiotic-free feeding programs.