| A body of evidences have suggested that metformin could activate AMP-activated protein kinase(AMPK) in experimental animals and activated AMPK cut down the anabolism of cholesterol and lipid. Whether metformin could activate AMPK and the relationship between AMPK and lipid metabolism in laying hens needs to be further studied. This research aimed at studying whether metformin could activate AMPK and the optimal dose for activating AMPK in order to establish an activation model in live birds for further studying the relationship between AMPK and lipid metabolism in laying hens in a short time.The whole study consists of experiment 1 and experiment 2.The study lasted for five days.In experiment 1, 40 New Roman laying hens of similar age, weight and laying performance were divided into four groups of five replicates with two hens each to find out the optimal dose for activating AMPK. The control group were fed the basal diet without metformin,while others were fed diet containing 0.6% , 0.8%and 1% metformin respectively. On the second and fourth day morning, five laying hens from each group were selected to collect blood through wing vein and and the liver and ovary (including different size of ovary blastulas ) after a general anaesthesia with chlorpromazine. In experiment 2, 20 New Roman laying hens of similar age,weight and laying performance were divided into two groups of five replicates with two hens each with the purpose of excludeing different food intake.The experiental group were fed diet containing 0.8% metformin ,while control group were fed the same basal diet without metformin to the same amount as experimental group.On the third and fifth day morning, five laying hens from control group were selected to collect blood through wing vein and and the liver and ovary (including different size of ovary blastulas ) after a general anaesthesia with chlorpromazine.The result of the experiment 1 showed that addition of various levels of metformin markedly reduced the food intake of laying hens, 1% has the most evident effect,the weight gain of laying hens tended to be decreased. AMPK activity in the ovary was lower than that in the liver by 46.89% (P=0.124). At the terminal time ,compared with control group, AMPK activity in the liver of the 0.6%, 0.8%and 1% group was increased by 13.83%(P=0.216), 25.90%(P=0.162), 31.10% (P=0.170) respectively. AMPK activity in the ovary of the 0.8% group was increased by 32.73% (P<0.05) . TG and TCcontents in the liver of experimental group were lower than the control, those of 0.6% and l%group were decreased by 31.79% (P=0.126) and 34.41% (P<0.01) .The observed result at the second day suggested that TG> TC> VLDL-C hi the serum of the 0.6% group were decreased by 53.88%(P=0.222) , 22.76%(P=0.380) s 53.88%(P=0.223) respectively compared with control group , the cholesterol content in the ovary blastula with the diameter at 0.5cm was lower than that of control group and that of other diameter has not significant difference.The observed result at the forth day suggested that .compared with control group ,TG and VLDL-C in the blood serum of the 1% group were decreased by 27.1%(P=0.256) and 26.75%(P=0.220).the cholesterol contents in the ovary blastula with the diameter at 2, 1, 0.5cm were decreased by 18.91% (P<0.01)> 17.43% (P<0.0lX 34.23% (P<0.01) respectively. Insulin content in the serum was markedly decreased and estrogen content had the tendency of decreasing and the l%group had the most evident effect.The result of the experiment 2 showed that at the terminal time,compared with control group,the AMPK activity in the liver and ovary of the experimental group was increased by 24.82% (P=0.202) and 10.13% (P=0.541) respectively.TG and TC content in the liver were decreased by 13.61%(F=0.098)and 5.56%(P=0.583)? The observed result at the second day suggested that,compared with control group,TG, TC\ VLDL-C in the blood serum of the experimental group were decreased by 53.88%(P=0.222)> 22.76%(P=0.380)^ 53.88%(P=0.223) respectively. Insulin and estrogen content in the serum were decreased by 42.80% (P<0.01) and 20.75%(P=0.074). Cholesterol contents in the ovary blastula with the diameter at 2^ 0.5cm were decreased by 2.76%n 3.43%, 8.28% (P<0.01). The result at the forth day suggested that .compared with control group, VLDL-C in the blood serum of the experimental group was decreased by 12.66% (P=0.513) . Insulin and estrogen contents in the serum were decreased by 19.42% (P<0.05) and 24.44%(P=0.476). Cholesterol contents in the ovary blastula with the diameter at 2> 1, 0.5cm were decreased by 9.18% (P<0.01)> 9.72% (P<0.01)> 17.04% (P<0.05) respectivelyoThe study suggested that feeding diet with 0.6%~l% metformin for five days could activate AMPK of laying hens and the activated AMPK had an effect on the lipid metabolism in laying hens. |
PDF Full Text Request