Evaluation of natural and synthetic vitamin E on production performance, egg quality and vitamin E content of yolk in laying hens

Abstract

A total of two hundred 35-week-old (Hy-line brown) layers were randomly assigned to 4 treatments with 10 replications and 5 layers per replicate (1 layer per cage). Dietary treatments were: (1) CON (basal diet); (2) S150, CON + synthetic vitamin E (VE) 150 IU/kg; (3) N50, CON + natural VE 50 IU/kg; and (4) N75, CON + natural VE 75 IU/kg. Dietary VE led to a greater Haugh unit (HU) and VE concentration in yolk (p<0.05) compared with CON group, whereas the egg production, feed intake, egg weight, eggshell strength, yolk height, yolk colour and eggshell thickness were not influenced (p>0.05) throughout the experiment. Blood characteristics were not affected by the administration of VE. Moreover, no difference (p>0.05) was observed on the laying hens’ performance and egg quality between the synthetic and natural VE supplementation. In conclusion, dietary VE improved the VE concentration in yolk and the HU compared with the CON group. VE concentration of yolk and most characteristics were consistent in those birds fed Nat E Ac (50 or 75 IU/kg) compared with those fed Syn E Ac treatment (150 IU/kg), indicating the relative bioavailability of natural VE was two or three times greater than synthetic VE in laying hens.