Abstract
Encapsulated phytochemicals with augmented therapeutic and nutritional characteristics have become promising alternatives to antimicrobials in the poultry industry. Hence, our key target was to explore the efficacy of liposomal encapsulation, as a novel carrier, for essential oils (LEOs) on growth, digestibility, intestinal microbiota, and bacterial metabolites of broiler chickens. Moreover, the impact of encapsulated EOs on transcription mechanisms targeting the genes encoding digestive enzymes, gut barrier functions and antioxidant potential of broiler chickens was evidenced. Four equal broiler groups were fed 4 basal diets fortified with LEOs (oregano, cinnamon, and clove) at the levels of 0, 200, 300, and 400 mg/kg diet. Our findings revealed significant improvement in body weight gain and feed conversion ratio of birds fed higher levels of LEOs. These results came concurrently with increasing the activities of digestive enzymes at both serum and molecular levels and consequently nutrient digestibility (dry matter, ether extract, crude protein, and crude fiber) in these groups. Remarkably, the abundance of beneficial bacteria as well as the bacterial metabolites (valeric acid, butyric acid, propionic acid, acetic acid, and total short-chain fatty acids) was increased, while that of pathogenic ones was reduced following dietary inclusion of LEOs. Of note, the mRNA expression of genes encoding antioxidant stability [catalase (CAT), superoxide dismutase 1 (SOD-1), glutathione peroxidase 1 (GPX-1), nuclear factor erythroid 2-related factor 2 (NRF2), NAD(P)H dehydrogenase quinone 1 (NQO1), and heme oxygenase-1 (HO-1)] as well as barrier functions [mucin-2 (MUC-2)] and tight junction proteins, TJP [junctional adhesion molecule-2 (JAM-2) and occludin] were noticeably upregulated in broilers fortified with 400 mg/kg diet of LEOs. Overall, the present work recommended dietary inclusion of LEOs as beneficial additives for attaining targeted performance, gut health and antioxidant stability in poultry farming.