the impact of encapsulated savory (satureja hortensis) essential oils versus antibiotics on growth performance, ileal microbiota, and immune response in broiler chickens

This study compared the effects of non-encapsulated (seo) savory essential oils, encapsulated savory essential oils (eseo) and antibiotics (ant) on growth performance, ileal microbiota, and immune responses in broiler chicks. a total of 360 one-day-old male ross 308 broiler chicks was randomly assigned to six treatments, five replicates, and 12 chickens per replicate. the dietary treatments included a control group (con), an antibiotic group (ant, 650 ppm flavophospholipol), and groups receiving seo and eseo at the levels of 150 and 300 ppm. feed intake (fi), body weight gain (bwg), feed conversion ratio (fcr), production efficiency factor (pef), ileal microbiota, and immune response were measured on day 42. results indicated an increase (p<0.01) in bwg for birds receiving 150 ppm seo, while fcr improved (p<0.01) in birds receiving either 150 ppm seo or eseo compared to the control and ant groups. birds that were fed with 150 ppm seo showed significantly higher pef than other treatments except for those fed with eseo150. additionally, both seo and eseo at 150 ppm level positively influenced the ileal microbial population (p<0.05). dietary supplementation with varying levels of savory essential oils (seo or eseo) increased (p<0.05) the relative weight of the bursa of fabricius compared to the ant group. specifically, inclusion of 150 ppm seo led to a notable increase (p<0.05) in anti-srbc antibody levels at both 35 and 42 days of age, and elevated the igg level at 35 days of age, when compared to the control birds. furthermore, supplementation of seo or eseo, particularly at the 150ppm level, was effective in enhancing the populations of beneficial bacteria in the gastrointestinal tract, along with improving the growth performance and antibody response in broilers.