This study evaluated the antioxidant ability of Taisung No. 3 mulberry leaf extract (MLE) as well as the potential of mulberry leaf (ML)-based dietary supplementation for modulating the antioxidative status of laying hens. The results showed that the MLE had a total phenolic compound content of 7.4 ± 0.15 mg of gallic acid equivalent/g dry weight (DW) and a total flavonoid content of 4.4 ± 0.19 mg of quercetin equivalent/g DW. The 2, 2-diphenyl-1-picrylhydrazyl free-radical-scavenging ability was 45.9% when 0.1 mg/mL MLE was added. The lipid oxidation inhibition ability was 43.9% when 50 mg/mL MLE was added. We subjected 96 laying hens (Hendrix Genetics) to 4 treatments, namely diets supplemented with dry ML at 0 (control), 0.5, 1, or 2% for 12 weeks. Each treatment involved 8 replicates with 3 hens each. The results indicated that the 0.5% ML-supplemented group exhibited significantly higher mRNA levels of antioxidant-regulated genes, such as Nrf2, HO-1, and GST, and significantly lower ROMO1 gene expression levels at wk 12. The serum malondialdehyde level was lower and the catalase activity and superoxide dismutase activity were higher in all the ML-supplemented groups than in the control group. The egg mass and feed conversion rate significantly improved in the ML-supplemented groups compared with the control group, and, overall, 1% ML supplementation had the most favorable effects at one to 12 weeks. The egg yolk weight, shell weight, shell strength, shell thickness, yolk color, and Haugh unit were increased among all ML-supplemented groups at one to 12 weeks. On the basis of these observations, we conclude that 0.5% ML can be used as a new feed additive to potentially modulate the antioxidative status of laying hens and improve their production performance and egg quality.
Keywords: antioxidant properties; laying hens; mulberry leaf.
© 2016 Poultry Science Association Inc.