An experiment was conducted to determine the effect of diet supplementing with tributyrin (TB) in different levels in diet on egg performance and quality of laying hens from 55-65 weeks age. A total of 960 Hisex Brown laying hens at the 55 weeks of age were randomly distributed in a completely randomized design experiment, with 4 treatments and 3 replicates, each replicate consisted of a line with 20 pens (4 birds/pen). The experimental data was collected during 10 weeks. Treatments used: (1) Control (Cont): Basal diet (B) without any supplementation; (2) TB0.5: B + Tributyrin at 0.5 g/kg feed; (3) TB0.75: B + Tributyrin at 0.75 g/kg feed; (4) TB1.0: B + Tributyrin at 1.0 g/kg feed. The results showed that, average daily feed intake was not affected by tributyrin supplementations in the diets (P>0.05). But a little improvement hen day production, egg mass and egg weight in TB0.75 and TB1.0 compared to TB0.5 and Cont group. Tributyrin supplementation significantly increased eggshell thickness (P < 0.01), and the higher yellow color of egg york was found in chicken eggs fed TB0.75 and TB1.0 treatments. In conclusion, adding tributyrin at 0.75 and 1.0g/kg feed could trend lightly improved hen day production, egg shell thickness, and egg york color and feed conversion ratio compared to control group of laying hen in the late state of laying cycle.

Keywords: Hen- day production, Hisex Brown, laying hen, Tributyrin