Effects of high energy-low protein diet on apo A I and lipid metabolism of laying hens.

The experiment was designed to explore the effects of high energy-low protein diet on the apo AⅠ and lipid metabolism of Hy-Line brown laying hens.One hundred and two laying hens at the age of 140 days were randomly divided into 2 groups with 3 replicates each and 17 laying hens in each replicate.The laying hens in the two groups were fed with normal diet(ME 11.51 MJ/kg and CP 15.58%) and high energy-low protein diet(ME 14.47 MJ/kg and CP 12.55%).Six hens from each group were selected on 1st,15th,25th,35th,45th and 55th days to collected samples including serum and liver,respectively.The concentration of serum apo AⅠ,and indexes relevant to fat metabolism in serum and liver were investigated.The results showed that compared with the control group,the concentration of triglycerides(TG) and low-density lipoprotein cholesterol(LDL-Ch) were increased in serum from day 35 and 45(P0.05,P0.01).High-density lipoprotein cholesterol(HDL-Ch) was decreased from day 45(P0.05);the activity of lypase(LPS) in serum and liver of the experimental group were increased significantly from day 25 and 35(P0.05,P0.01),the activity of lipoprotein lipase(LPL) in serum and liver of the experimental group were increased significantly from day 45 and 55(P0.05,P0.01),and content of NEFA in serum and liver of the experimental group were increased significantly from day 25(P0.01);the content of apo AⅠ in serum of the experimental group was decreased significantly from the 35th day(P0.05).The results indicated that high energy-low protein diet could decrease the content of apo AⅠ in serum,promote the accumulation of liver fat and destroyed lipid metabolism balance in laying hens.