ảnh h-ởng của khẩu phần protein thấp đ-ợc bổ sung d,l-metionin và l-lyzin.hcl đến sức sản xuất của đàn gà đẻ isa brown th-ơng phẩm giai đoạn từ 23 đến 40 tuần tuổi

An experiment was undertaken to determine effects of low-protein diets with supplementation of D, L-methionine and L- lysine on performance of ISA Brown laying hens during the period from 23rd to 40th week of age. Three diets containing 17% (control), 16%, and 15% CP were fed. The lower protein diets were supplemented with D, L-methionine and L-lysine according to the standard of the Commission of Farm Animal Nutrition, Czech Academy of Sciences. Results showed that compared to the control the low-protein diets supplemented with D, L-methionine and L-lysine had the same effects on the laying rate, egg production, egg weight, and egg quality of the hens (P>0.05). There were no differences in feed consumption per 10 eggs among the three groups (P>0.05), but the low-protein diets reduced the cost of feed/10 eggs by 3.9% and 5.1%, respectively, in comparison with the control (P