ABSTRACT
The gut microbiota has an important effect on poultry health and production. The aim of this study was to evaluate the effect of Colombian oregano (COO), Lippia origanoides Kunth, essential oil supplementation on broiler chicken performance and their cecal bacterial microbiome by 16S-based sequencing. Essential oil was extracted by steam distillation and analyzed by Gas chromatography/mass spectrometry. Two COO levels in feed, 0 ppm control (C) and 100 ppm (O), were evaluated in 2 groups of broilers either unchallenged (U) or challenged (E) with a viable attenuated Eimeria (coccidia) oocyte vaccine. Four treatments, UC, UO, EC, and EO, were distributed among 720 one-day-old male Ross broilers randomly placed in 24 pens. Cecal contents DNA was extracted and pyrosequencing was performed following a standard procedure. Pyrosequencing data were processed, and sequence reads were phylogenetically classified. Similarity of membership and structure in the communities were calculated. At the end of the study, the greatest COO effect was found in coccidia-challenged broilers, with an OE body weight of 1,889 ± 52.4 g with respect to 1,799 ± 36.2 g for CE (P < 0.01). Broiler cecal samples were consistent in that phylum Firmicutes and class Clostridia were highly prevalent; COO had no effect on these taxa levels between the 4 treatments (P > 0.05). A positive correlation (P < 0.01) was observed between the Firmicutes:Bacteriodetes phyla ratio against body weight at 35 D of age. This study provided both positive and negative correlations between broiler body weight against some bacterial groups identified, offering perspectives regarding bacterial groups and their impact on host health and metabolism. Lippia origanoides Kunth high thymol content showed a beneficial effect on body weight and the feed conversion ratio in broilers under coccidia challenge.