Effects of nanoencapsulated aloe vera, dill and nettle root extract as feed antibiotic substitutes in broiler chickens

Aloe vera, nettle and dill are herbs that have been used in the poultry diet as feed additives to utilise their benefits in improving performance, immune response and health of broiler chickens. However, reactive and volatile properties of bioactive compounds in herbal extracts cause limitations on direct usage of them in the diet. The use of chitosan (CS) nanoparticles for the entrapment of active components has gained interest in the last few years due to its mucous adhesiveness, non-toxicity, biocompatibility and biodegradability. This study was an effort to evaluate effects of nanoencapsulated extracts of aloe vera, dill and nettle root used in diet on performance, carcass traits and serum immunoglobulin (IgM and IgY) concentrations in broiler chickens. Chitosan nanoparticles were prepared by using ionotropic gelation principle. After nanogel preparation of herbal extracts, a total of 240 Ross (308) broiler chicks were divided into eight treatments, with three replicates of 10 birds. The eight dietary treatments consisted of control (no additives), antibiotic (bacitracin 500 g t⁻¹), non-encapsulated and nanoencapsulated extracts of aloe vera, dill and nettle root. In each experimental period, non-encapsulated (free extracts) and nanoencapsulated extracts of aloe vera, dill and nettle roots were added in amounts of 0.02, 0.025 and 0.05 % to starter, grower and finisher diets, respectively. Birds in different treatments received the same diets during the experimental periods. Results revealed that increasing both non-encapsulated and nanoencapsulated herbal extracts to 0.05 % in finisher diets improved body weight gain in the time period of 28–42 days and consequently the whole time from 1 to 42 days. However, in these periods, birds fed a diet containing nanoencapsulated dill extract had a significantly (<i>P</i> &lt; 0.05) higher body weight gain compared with the antibiotic group, while non-encapsulated dill extract treatment was intermediate. The addition of nanoencapsulated nettle extract in diet significantly (<i>P</i> &lt; 0.05) improved feed conversion efficiency in the 28–42-day period compared with the antibiotic group. In comparison with the antibiotic group, nanoencapsulation of dill extract could profoundly improve growth performance and can therefore be used as a substitute for antibiotics in the diet of broiler chickens