ABSTRACT
This study was conducted to evaluate the influence of supplementing tea polyphenols (TP) in diet of laying hens on yolk cholesterol content and production performance. A total of 1800 Lohmann laying hens aged 48 weeks were randomly allocated to 6 groups. Each group consisted of 6 replicates with 50 layers. The feeding experiment was 4 weeks including one-week acclimatization. Layers fed basal diet supplemented with 0, 150, 200, 250, 300 and 350 mg TP/kg diet, respectively. The results showed that average daily feed intake (ADFI), feed conversion ratio (FCR), average egg weight (AEW), laying rate and the indicators of egg quality were not significantly affected by the diet supplemented with 300 mg/kg TP (p>0.05). However, yolk cholesterol content decreased by increasing TP concentration (p<0.01), with 18.06% reduction in layers fed diet supplemented with 300 mg TP/kg. Also, the diet supplemented with 300 mg/kg TP significantly decreased plasma triglyceride (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) level (p<0.05). The activity of serum glutathione peroxidase (GSH-Px) was enhanced by increasing TP concentration, while the content of serum methane dicarboxylic aldehyde (MDA) was decreased by increasing TP concentration. The highest activity of GSH-Px and the lowest serum MDA content were both determined in 300 mg/kg TP group (p<0.01). In conclusion, this study suggests that the addition of 300 mg TP/kg basal diet had no negative effect on the production performance laying hens, yet decreased the egg yolk cholesterol content and enhanced the antioxidant capacity of laying hens at the same time.
Keywords:
Antioxidant; laying hens; production performance; tea polyphenols; yolk cholesterol content