Study On Lysine Requirement Of The Laying Hen In Low Energy Diets

This study Was conducted to determine the influence of dietary lysine levels on the laying performance,egg quality,as well as conventional nutrients digestibility in commercial Hy-line laying hens.The ideal protein pattern of Hy-line hens was established by model fitting.Experiment 1:Effect of different lysine levels on laying performance of laying hens in low energy diets.Seven hundred and twenty 22W laying hens were randomly divided into six groups with five replicates per group and 24 laying hens per replicate. The experiment lasted for 60 days. The diet Was based on corn-soybean meal,energy Was 2600 kcal/kg,There were five lysine levels in different levels(0.65%,0.70%,0.75%,0.80% and 0.85%) respectively .the control group was designed according to GB(2004).The results showed that:there was no significant effect on the laying performance in the peak stage (p>0.05) at the lysine levels 0.70%,The analysis indicated that the Laysine levels 0.70% (energy was 2600 kcal/kg,crude protein was 1 6.5%) was the best among the treatment groups according to the laying performance and economic efficiency.Experiment 2: Effect of different lysine levels on the nutritional composition and quality of eggs in low energy diets.The results showed that:there were no significant effects(P>0.05)on the nutritional composition and quality of eggs when the diets contained lysine 0.65%～0.85%.Experiment 3: This study was conducted to determine the true digestibility of dietary amino acid and the efficiency of the nitrogen retention in commercial Hy—line laying hens.All laying hens were allotted to six treatments in a completely randomized design,every treatment has 5 replicates(4 hens per replicate).The ANOVA showed that:(1) The treatment 2 group was the best on the nitrogen retention and day nitrogen balance,In this regard, the treatment 5 group was inferior to other groups(P<0.05),there were no significant difference with the other treatment groups (P>0.05);The control group was the best on the efficiency of the nitrogen retention, The treatment 2 group was the second(P>0.05), the treatment 5 group was the worst(P<0.01) .(2) The true digestibility of total amino acids of every group was over 85%. The treatment 2 group was the highest (P<0.05) in the true digestibility of total amino acids , The treatment 3 was significant higher(P<0.05)compared with the control group,there were no significant difference with the other treatment groups (P>0.05). That is to say, The diets contained lysine 0.70% can improve day nitrogen balance and amino acids balance, and it can increase efficiency of the nitrogen retention.Experiment 4:The experiment was conducted to determine the requirentments of amino acid in Hy-line laying hens.The ideal protein pattern of Hy-line hens was obtained by analyzing the amino acid content of maintenance,eggs and body growing weight.Assumed the lysine is 100,the optimum pattern of some main amino acids was as follows : Met:Cys:Trp:Thr:Arg:Ile:Val: Phe:His:Leu:Lys = 63:36:26:75:101:94:112:97:54:139:100...