The purpose of this experiment was to study the effects of dietary different levels of lysine(Lys)on growing performance,serum biochemical indices and whole body composition deposition of Youxian shelducks during 1 to 42 days of age,and to evaluate the lysine requirement.A Total of 525 healthy 1-day-old Youxian shelducks were selected and randomly divided into 5 groups with 7 replicates in each group and 15 ducks in each replicate.The dietary lysine levels were 0.85％,0.95％,1.05％,1.15％and 1.25％,respectively.The experiment lasted for 6 weeks.The results showed as follows:1)the final weight and average daily gain of 1.05％,1.15％and 1.25％lysine level groups were significantly higher than those of 0.85％lysine level group(P＜0.05),and the feed to gain ratio of 1.05％,1.15％and 1.25％lysine level groups was significantly lower than that of 0.85％lysine level group(P＜0.05).2)The serum uric acid content of 1.05％and 1.15％lysine level groups was significantly lower than that of 0.85％and 0.95％lysine level groups(P＜0.05),and the ser-um triglyceride content of 1.25％lysine level group was significantly higher than that of 0.85％,0.95％,1.05％and 1.15％lysine level groups(P＜0.05).3)The whole body crude protein content of 1.05％,1.15％and 1.25％lysine level groups was significantly higher than that of 0.85％lysine level group(P＜0.05).4)Using feed to gain ratio,serum uric acid and triglyceride contents and whole body crude protein content as i-dentification indices,the optimal dietary lysine levels of Youxian shelducks during 1 to 42 days of age estimated by quadratic curve were 1.11％,1.11％,0.99％and 1.16％,respectively.In conclusion,comprehensive all indices,the growth and development needs of Youxian shelducks during 1 to 42 days of age can be met by diet-ary lysine level of 0.95％under the conditions of this experiment,but the dietary lysine level of 0.99％to 1.16％is recommended for better growth performance,serum biochemical indices and body composition depo-sition.[Chinese Journal of Animal Nutrition,2024,36(12):7770-7777]
维普
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