Effects of Dandelion Flavonoid Extract on the Accumulation of Flavonoids in Layer Hen Meat, Slaughter Performance and Blood Antioxidant Indicators of Spent Laying Hens

This study aimed to investigate the effects of different supplemental amounts of dandelion flavonoid extracts (DFE) in diets on nutrients in chicken, slaughtering performance, blood biochemical indexes and antioxidant capacity of spent laying hens. A total of 180 560-day-old spent Hy-Line Brown laying hens were randomly divided into five groups. The control group was fed the basal diet, while the experimental groups were supplemented with DFE at levels of 1000, 2000, 4000, and 8000 mg/kg (as T1, T2, T3, and T4 group) in the basal diet, respectively. The variables measured included the content of dandelion flavonoids in layer hen thigh meat and breast meat, slaughter performance, blood biochemical indexes, and antioxidant capacity. Data were subjected to a one-way analysis of variance (one-way ANOVA) to assess the impact of DFE supplementation compared to the control group on study outcomes. The results showed that dietary supplementation with DFE can increase the content of dandelion flavonoids in layer hen meat. The contents of rutin in layer hen breast meat of groups T1, T2, T3, and T4 were 1.37, 4.41, 16.26, and 36.03 ng/g, respectively, and the contents of quercetin was 2.58, 1.36, 4.98, 12.48 ng/g. In layer hen thigh meat of groups T1, T2, T3, and T4, the contents of rutin were 11.48, 15.98, 44.43, 122.32 ng/g, and the contents of quercetin were 9.96, 13.14, 23.15, 38.09 ng/g, respectively. The addition of DFE increased the total phenol content of the feed and highly significantly elevated the total phenol content of layer hen meat (<i>p</i> < 0.01), and the total phenol content of chicken meat was strongly and positively correlated with the total phenol content of the feed. DFE supplementation significantly decreased abdominal fat percentage (<i>p</i> < 0.05) and increased crude fat content in chicken (<i>p</i> < 0.05). The addition of DFE reduced aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities (<i>p</i> < 0.05), decreased triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL) cholesterol (LDL-C), glucose (GLU), and malondialdehyde (MDA) contents (<i>p</i> < 0.05), and increased the content of albumin (ALB), total antioxidant (T-AOC) capacity and total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px) activity (<i>p</i> < 0.05). Dietary supplementation of DFE at different concentrations could significantly increase the content of dandelion flavonoids in the muscle of spent laying hens, reduce the abdominal fat rate in hens, effectively reduce blood lipid levels, effectively increase crude fat content in thigh muscle, and enhance the body's antioxidant capacity and liver function.