Effects of microencapsulated essential oils and seaweed meal on growth performance, digestive enzymes, intestinal morphology, liver functions, and plasma biomarkers in broiler chickens

Globally, poultry production has increased to meet the demand for animal protein. Traditionally, antibiotic growth promoters have been used to enhance growth performance and prevent infections in commercial poultry practices. However, concerns regarding antimicrobial resistance have triggered interest in alternative solutions, such as essential oils (EOs) and seaweed additives. The aim of the current study was to assess the impact of a microencapsulated blend of EOs (cinnamaldehyde, eugenol, and thymol) and Ascophyllum nodosum seaweed meal on growth performance, intestinal function, blood biomarkers, and hepatic gene expression in broiler chickens. A total of 440 Arbor Acres chicks were randomly assigned to either a control (CON) or treatment (NEX) group. Each treatment was divided into 11 replicates (20 birds per replicate). NEX chicks were supplemented with 100 mg/kg feed containing a microencapsulated blend of EOs (cinnamaldehyde, eugenol, and thymol) and Ascophyllum nodosum seaweed meal. Data were analyzed using the UNIVARIATE procedure in SAS software. Each replicate was considered an experimental unit. Over a 35-d period, NEX supplementation improved the feed conversion ratio (P = 0.02), reduced mortality rate (P = 0.01), and increased the European performance efficiency factor. No differences in carcass traits were observed between the 2 treatments (P > 0.05). Jejunal digestive enzyme activities, particularly those of amylase and lipase, were higher in NEX birds (P < 0.05) and correlated with morphometric parameters, such as villus height (P = 0.04) and muscular layer thickness (P < 0.01). Gene expression analysis revealed the upregulation of key genes related to nutrient transporters (solute carrier family 5 member 1 gene (SLC5A1), solute carrier family 1 member 1 gene (SLC1A1), solute carrier family 15 member 1 gene (SLC15A1)) in the jejunum (P < 0.05) and lipid metabolism (peroxisome proliferator-activated receptor alpha gene (PPARA) and microsomal triglyceride transfer protein gene (MTTP)) in the liver (P < 0.05) of NEX-supplemented birds. NEX treatment altered plasma biomarkers, including increased glucose (P < 0.01), insulin (P < 0.01), and protein profiles (P < 0.05) but decreased low-density lipoprotein cholesterol (P = 0.03), suggesting enhanced metabolic health. NEX supplementation improved growth performance, economic efficiency, intestinal morphology, digestive enzyme activity, liver function, and metabolic biomarkers in broiler chickens.