Abstract
This experiment investigated the impact of the blend of microencapsulated essential oils (BMEOs) on performance, economic index, meat fatty acid profile, carcass characteristics, and immune index in broilers. In a completely randomized design, a total of 640 (mixed-sex) one-day-old Ross 308 broilers were divided into 4 treatments with 10 replicates (16 chicks/replicate) for 42 days. Treatments were basal diet supplemented with BMEOs at levels of 0 (control), 300 (BMEOs-300), 600 (BMEOs-600), and 900 (BMEOs-900) mg/kg of diet. BMEOs contain equal ratios of EOs of eucalyptus (compounds: α-pinene, γ-terpinene, 1,8-cineol, limonene, and α-terpineol), oregano (compounds: carvacrol, thymol, ρ-cymene, linalool, ethyl caprate, ledol, and β-bisabolene), rosemary (compounds: 1,8-cineol, α-pinene, borneol, camphor, verbenone, bornyl acetate, limonene, camphene, and β-myrcene), and thyme (main compounds: thymol, carvacrol, ρ-cymene, γ-terpinene, and β-caryophyllene). The result showed that during the whole experimental period, the BMEOs-900 treatment increased (P < 0.05) average daily body weight gain (ADBWG; 69.3 vs. 62.0 g/chick), European production efficiency factor (EPEF) (437.9 vs. 359.9), European broiler index (EBI) (269.8 vs. 221.3), and decreased (P = 0.001) feed conversion ratio (FCR) (1.60 vs. 1.75 g/g) compared to the control and other treatments. The diet containing BMEOs-900 increased the relative weight of the bursa of Fabricius (57.3%), spleen (51.6%), and thymus (123.2%) as immune organs, proventriculus (34.2%), and pancreas (49%) (P < 0.05), as well as lowered the relative weight of the abdominal fat (75.1%, P = 0.001) compared with broilers in the control and other treatments. Broilers in the BMEOs-900 group showed higher (P = 0.001) levels of the total polyunsaturated fatty acids (ΣPUFA; 1.33-fold in breast, 1.26-fold in thigh), Σ(omega-6) n-6 PUFA (1.20-fold in breast, 1.35-fold in thigh), Σ(omega-3) n-3 PUFA (1.45-fold in breast, 1.76-fold in thigh), and PUFA/saturated fatty acid (SFA) ratio (1.74-fold in breast, 1.45-fold in thigh), as well as lower (P = 0.001) levels of ΣSFA (1.30-fold in breast, 1.16-fold in thigh) and n-6 PUFA/n-3 PUFA (1.21-fold in breast, 1.33-fold in thigh) ratio in breast and thigh meat compared to the control and other treatments. Therefore, the active and phenolic components of EOs may have a positive effect on the broiler's body fatty acid profile by increasing its body antioxidant function and the fatty acid β-oxidation process. In conclusion, based on the observations in this trial, BMEOs-900 could serve as a feed additive to enhance growth performance, economic index, meat and carcass quality, and boost immune status in poultry diets.