Essential Oils as a Dietary Additive for Laying Hens: Performance, Egg Quality, Antioxidant Status, and Intestinal Morphology: A Meta-Analysis

This meta-analysis aimed to evaluate the effects of dietary supplementation with essential oils (EOs) on egg production and quality, antioxidant status in blood serum, intestinal morphology laying hens. The data used were obtained from 38 peer-reviewed publications. effect size was evaluated by weighted mean differences (WMD) between experimental treatments (diets added EOs) control without EOs). EO increased (p < 0.001) (WMD = 2.171%), weight 0.636 g), mass 1.679 g/d), decreased feed conversion ratio −0.074 g/g; p 0.001). In addition, greater 0.05) eggshell thickness 14.262 mm), strength (0.080 kg/cm2), albumen height 0.201 Haugh unit 1.102), yolk color 0.071) observed response supplementation. inclusion EOs levels superoxide dismutase 1.147 U/mL), glutathione peroxidase 879.553 total capacity 1.163 U/mL). duodenum, jejunum, ileum, a higher villus (VH), crypt depth (CD), width, VH/CD conclusion, can be as nutritional strategy improve