A blend of microencapsulated essential oils improves performance, economic index, meat fatty acid profile, carcass characteristics, and immune index of broilers

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.