Abstract
Ricetrienol (RT) is a plant oil produced from rice bran which contains tocopherol (Toc) and tocotrienol (T3). The objective of this study was to investigate the effect of dietary RT contents level on egg yolk Toc and T3 concentrations, yolk antioxidative activities, egg production performance and egg quality of laying hens. Twenty four weeks old 200 laying hens were classified randomly into four groups. Each group was fed layer diets containing RT at 0%, 0.25%, 0.50%, 1.00%, and were defined as CONT, 0.25% RT, 0.50% RT, 1.00% RT, respectively. Each group was fed diets at 24 to 74 weeks old. Yolk Toc and T3 concentrations increased in the dietary RT levels. Toc and T3 concentrations at 1.00% RT increased 4.6 and 7.5 fold, respectively, compared with CONT. Yolk Toc and T3 concentrations increased as α-Toc > γ-Toc > β-Toc > δ-Toc, α-T3 > γ-T3 >, respectively. Simple regression analysis revealed the correlation between feed and yolk vitamin E level, α-Toc (R2 = 0.88, P < 0.01), β-Toc (R2 = 0.89, P < 0.01), γ-Toc (R2 = 0.99, P < 0.01), α-T3(R2 = 0.55, P < 0.01), γ-T3 (R2 = 0.66, P < 0.01). Yolk TBARS decreased in inverse proportion to feed RT concentration. RT diets expanded yolk Metric-Hue angle but did not affect feed intake, egg mass, feed conversion, egg weight and Haugh unit. In conclusion, yolk α-, β-, γ-tocopherol and α-, γ-tocotrienol concentrations increased linearly with dietary ricetrienol concentration level. Ricetrienol diets increased yolk Toc more than T3, but did not affect the laying performance.
