The objective of this study was to evaluate the effect of premix (PM) supplementation on reproduction and egg quality of Noi crossbred hens from 18 to 30 weeks of age. The experiment was arranged in a completely randomized design with 5 treatments and 9 replicates, with 1 hen for each replicate. The treatments were respectively as follows (1) Control using only the basal diet (KPCS) without premix added, (2) PM2.5 including KPCS supplemented with 2.5mg PM/kg feed, (3) PM5 includes KPCS supplemented with 5mg PM/kg feed, (4) PM7.5 includes KPCS supplemented with 7.5mg PM/kgTA, and (5) PM10 includes KPCS supplemented with 10mg PM/kg feed. The experiment was carried out from November 2020 to February 2021 at Thuan Tien B hamlet, Thuan An commune, Binh Minh town, Vinh Long province. The results showed that the first laying age of Noi crossbred hens ranged of 126 - 129 days, and at 50% of the laying rate in PM5 and PM10 (146 -148 days) were earlier than in the control group (151.5 days). Egg laying rate and total egg yield in PM2.5 (36.51% and 66.44 eggs/hen) tended to be higher than control and the other treatments (P > 0.05). Feed consumption and feed conversion ratio of hens among treatments were not statistically significant (P > 0.05) nor did they affect egg quality of Noi crossbred hens (P > 0, 05). From the above research results, it can be suggested to add 2.5mg of premix/kg of feed to the diet to improve egg performance.

Keywords: premix vitamin mineral premix, egg laying rate, first laying age, he