Microencapsulated Blend of Thyme, Oregano, and Ajwain Essential Oils Enhances Broiler Productivity by Modulating Gut Morphology and Nutrient Digestibility

The global poultry industry seeks sustainable alternatives to antibiotic growth promoters due to concerns regarding antimicrobial resistance and chemical residues. This trial examined the physiological and productive impacts of a microencapsulated blend of thyme, oregano, and ajwain essential oils (TOA-EOs) in broiler chickens. A total of 360 male Ross 308 broilers were assigned to four dietary treatments: a basal diet (NC), a basal diet with 50 mg/kg bacitracin (PC), and diets supplemented with either 0.75 or 1.5 g/kg of TOA-EOs. Results demonstrated that TOA-EO supplementation significantly reduced feed intake (p < 0.05) and improved feed conversion ratio (p < 0.05), particularly in the 0.75 g/kg group compared to NC. However, pairwise comparisons for body weight gain showed no significant differences among treatments based on Tukey’s HSD test, despite a significant overall ANOVA (p < 0.05). These performance benefits were linked to enhanced jejunal morphology, characterized by significantly increased villus height, surface area, and villus height to crypt depth ratio (p < 0.05). Furthermore, the apparent ileal digestibility of crude protein was significantly enhanced (p < 0.05), although serum antioxidant status and immune response against Newcastle disease virus were not significantly influenced (p > 0.05). In conclusion, microencapsulated TOA-EOs effectively promote broiler growth performance by refining intestinal structure and enhancing nutrient digestibility, serving as a potent and sustainable alternative to traditional antibiotics.