Effects Of Dietary Lysine On Growth Performance And Biochemical Indexes Of Caged Egg-Type Ducklings

The effects of dietary lysine levels on growth performance and biochemical indexes were evaluated with five dietary treatments on0-4weeks caged egg-type ducklings and relatively sensitive indicators were analyzed with the curve regression model to investigate the appropriate level of dietary lysine. It can offer the basis to establish the requirements of lysine for egg-type ducklings. Diet based on corn-soybean meal-based diet, which contained ME (12.18MJ/kg), CP (21%), Met (0.46%), Lys (1.03%) was equal for each group. Graded levels of Lysine (0,0.07,0.14,0.21and0.28%) were added to basal diet. A total of180jin ding egg-type ducklings which were one day old, healthy with average weight42.78±1.20g were divided in six replicates of six ducks per treatment, the test period were4weeks. The weight of experimental ducklings and excess stock were measured every week during experiments and average daily gains, average daily feed intake and feed to gain were calculated. One experimental duckling was selected from each reduplicate which had the weight close to the average weight of the reduplicate after the feeding experiment. Jugular vein blood sampling was performed after liveweight on an empty stomach was measured and biochemical indexes were measured after the serum was separated, then liver^thymus^spleen and bursa of fabricius were obtained after slaughtering for determination of antioxidant index and analysis of immune organs index.Results of growth experiment:average daily weight gain of0-4weeks egg-type ducklings was significantly improved and F/G was decreased significantly while daily intake was not influenced significantly when dietary lysine level was1.17%. As lysine level rises, daily weight gain had a tendency that increased first and then decreased and F/G had the reverse tendency. Growth performance of ducklings were not good with neither too high nor too low level of lysine.Immune organs index:immune organs index was improved when the dietary lysine level was1.17%and thymus index and spleen index were significantly influenced, but bursa of fabricius index was not influenced significantly.Serum biochemical immune index:TP, ALB, ALP, IgG and IgM contents in serum were increased significantly, UA, BUN, TG and TC contents were decreased significantly, GLB, GLU, IgA IL-2contents were not influenced significantly when the dietary lysine level was1.17%.Antioxidant index:activity of T-SOD, T-AOC in serum and liver and GSH-Px in liver were significantly improved, activity of MDA was decreased significantly and activity of GSH-Px, T-AOC in serum were not influenced significantly when the dietary lysine level was1.17%.Serum hormone index:GH and Ins contents of serum were increased significantly when the dietary lysine level was1.17%.Variation of growth performance, biochemical index, immune index, metabolic hormone index and antioxidant index showed that in corn-soybean meal based diet, appropriate lysine level improved growth performance, antioxidant and immune functions of egg-type ducklings. All indexes were took into consideration and the appropriate level of lysine(1.179～1.196%) were determined by conic regression model.