Effect of microencapsulated Minthostachys verticillata essential oil as an antibiotic substitute on broiler performance

This study aimed to evaluate the effects of replacing antibiotics with microencapsulated Minthostachys verticillata essential oil (M-Mv-EO) as a phytogenic feed additive (PFA) on growth performance, liver and intestinal histological changes, serum biochemical parameters, genotoxic activity, and cecal microorganisms in broiler chickens. The Mv-EO was microencapsulated using spray-dried wall material (WM) consisting of Gum Arabic, Maltodextrin, and Whey Protein Concentrate (1:1:1, w/w/w). Forty-eight Cobb broilers aging one-day-old were randomly assigned to four dietary treatments (three replicates per treatment) and fed with a basal diet (CON), a diet supplemented with antibiotics (Bacitracin zinc salt, 7.5 mg/kg) (BZS), a diet supplemented with M-Mv-EO at a concentration of 100 mg/kg, or a diet supplemented with WM only (CON-WM). The results showed that the microcapsules obtained by spray drying remained stable without modifying the composition of Mv-EO. Dietary supplementation with M-Mv-EO increased weight gain and feed intake and improved the feed conversion ratio (FCR; P<0.05) compared to the CON, CON-WM, and BZS groups. Furthermore, M-Mv-EO supplementation did not cause histological changes in the small intestine or the liver. M-Mv-EO supplementation reduced total cholesterol levels and demonstrated non-cytogenotoxic effects in a bone marrow micronucleus test. Moreover, supplementation with M-Mv-EO promoted the growth of Lactobacillus spp., Enterobacteria, and total aerobic bacterial proliferation compared to the BZS group (P<0.05). These findings suggest that M-Mv-EO as a PFA, at a concentration of 100 mg/kg, could replace antibiotics in broiler chicken diets with comparable growth performance and health parameters.