Cinnamon supplementation in broiler and laying hen diets: benefits, mechanisms, supplementation doses, and limitations - a review

Cinnamon and its derivatives (bark powder, essential oil, extract, and nanoparticles) were used as phytogenic feed additives (PFAs) in the modern poultry industry possibly due to their antioxidant, antimicrobial, anti-inflammatory, and gut-promoting properties. The present review pools recent studies on the effects of cinnamon supplementation on broiler and laying hen performance, focusing on growth performance, carcass and meat quality, egg production, egg quality, and hatchability. Cinnamon bioactive compounds, particularly cinnamaldehyde, has been show to improve nutrient utilization through multiple mechanisms of action: direct stimulation of digestive enzymes, enhancement of intestinal morphology, and selective suppression of pathogenic bacteria and proliferation of non-pathogenic bacteria. In broilers, cinnamon supplementation has been indicated to enhance body weight gain (BWG), feed conversion efficiency (FCE), carcass yield, and meat quality traits, including water holding capacity (WHC), meat tenderness, oxidative capacity, and sensory attributes. In laying hens, studies suggest that cinnamon improve egg production, egg mass, internal egg quality, shelf life, and reduce cholesterol content in egg yolk. Supplementation doses are highly form-and context-dependent: 0.2-0.5% cinnamon bark powder (CBP) and 0.2-0.4% extract for broilers under thermoneutral conditions. For laying hens, evidence suggests an effective range of 0.75% to 1.0% CBP, while cinnamon essential oil (CEO) level remain less defined. Under heat stress conditions, 0.03-0.06% CEO or 0.06% cinnamon nanoparticles indicate superior performance. However, results of the effects of cinnamon supplementation on broiler and laying hen performance were inconsistent due to variation in dosage, cinnamon form, bird strain, age, and environmental conditions. High doses of (exceeding 2-3% CBP or 0.01% cinnamaldehyde) can reduce feed intake, elevate blood aspartate aminotransferase (AST) levels, and disrupt cecal microbiota balance. While cinnamon shows promise as a PFA in poultry nutrition, several challenges, including dose optimization, thermal stability in tropical climates, palatability, and long-term residue safety, require further research. Standardized, region-specific studies are also required to facilitate evidence-based commercial adoption of cinnamon in sustainable poultry production.