Abstract
Phytogenic compounds and enzymes represent promising strategies to modulate gut microbiota and improve nutrient absorption in poultry. The study was conducted to investigate the effects of oregano essential oil and lauric acid (OEA) as well as complex enzyme preparation (CEP) on laying performance, egg quality, nutrient apparent metabolism, and intestinal morphology of Dagu breeder hens. A total of 288 38-wk-old Dagu breeder hens with similar body weight and condition procured, were randomly divided into 4 groups with 6 replicates of 12 hens. Diet feed additives supplement strategies were as follows: a basal diet as control (CON), while the experimental treatment groups received basal diet containing 200 mg/kg of OEA (LCO), 200 mg/kg of CEP (LCE), and 200 mg/kg of OEA + CEP (LOE). The experiment lasted 40 d. Data were analyzed by one-way ANOVA followed by Duncan's multiple range test using SPSS software, with statistical significance declared at P < 0.05. The results showed that OEA + CEP supplementation significantly increased the laying rate to 69.56%, improved the feed-egg ratio to 3.31, and increased the monthly total egg weight to 18.86 kg/bird, and the OEA supplementation had significant reduced the broken-soft egg ratio by 85.19% than the CON group (P < 0.05). Additionally, dietary supplementation with OEA and OEA + CEP increased eggshell strength (7.66%) and Haugh unit (2.01%) level (P < 0.05). Notably, OEA + CEP significantly improved the antioxidant performance of total antioxidant capacity (7.02%), glutathione peroxidase (11.31%), total superoxide dismutase (5.02%), and malondialdehyde (7.93%) on Dagu breeder hens (P < 0.05), and OEA supplemental in diet significantly increased the level of total antioxidant capacity (6.66%) and glutathione peroxidase (7.97%). Compared to the CON group, the apparent metabolizable energy (4.33%), dry matter (4.15%), crude protein (94.92%), calcium (4.83%), and phosphorus (2.53%) levels in the treatment groups significantly increased (P < 0.05). The dietary supplementation with OEA +CEP improved the α-amylase (9.23%), lipase (12.86%), and trypsin (9.99%) activities and the villus to crypt ratio in jejunum and ileum (P < 0.05). These findings characterize that the dietary treatment with OEA and CEP alone or in combination improves production performance and health status in Dagu breeder hens. Furthermore, combination OEA and CEP demonstrates the potential value to poultry industry.