Chitosan nano-encapsulation improves the effects of mint, thyme, and cinnamon essential oils in broiler chickens

This study was conducted to evaluate the effects of chitosan nano-encapsulating mint (MEO), thyme (TEO) and cinnamon (CEO) essential oils (EOs) used in the diet on performance, immune responses and intestinal bacteria population in broiler chickens. A total of 600 mixed-sex, 1-d-old Ross 308 broiler chicks were used in a 2 × 4 factorial experiment as completely randomised design with 8 experimental groups (diets) with 5 replicates of 15 chicks each (totally 40 pens). The eight experimental diets consisted of no EO and free distiller water (control); no EO and chitosan nano-encapsulated (CNE) distiller water; and other six treatments with free or CNE form of MEO, TEO and CEO (added at 0.025%, 0.04% and 0.055% respectively to starter, grower and finisher diets). Both EOs and the CNE form had significant (P < 0.05) benefits on improving body weight gain, and feed conversion ratio in periods of 29-42 and 1-42 days. The highest effect was (P < 0.05) obtained in birds receiving TEO, which was intensified by nano-encapsulation. Breast percentage was improved by nano-encapsulation (P < 0.05). The EOs (especially TEO and CEO) and CNE form improved (P < 0.05) serum IgY and IgM concentrations (at 35 and 42 days) and intestinal Lactobacillus spp. and E. coli populations (at 42 days) in broilers. Nano-encapsulated EOs, especially TEO and CEO had (P < 0.05) the largest effect on increasing IgY₄₂ concentrations and the microbial populations. The tested EOs, especially TEO, improved more of the evaluated traits in broiler chickens. Also, Chitosan nano-encapsulation because of its ideal properties can be an effective, suitable and inexpensive method for protecting bioactive compounds and improving effects of the herbal EOs especially thyme in broiler chickens.