Effect Of AMPK On The Regulation Of Appetite In Stressed Broiler Chickens

The experiments were conducted to study the effect of AMPK on the regulation of appetite in stressed broiler chickens.The effect of glucocorticoids on appetite and AMPK signal in broiler chickens.One-day-old male broiler chicks were selected and randomly assigned into 18 cages,each containing 8 chickens.At 7 d of age,the chickens were divided into 3 treament with 6 cages:corticosterone-supplemented diet;Methidone-supplemented diet;basal diet.The treatment lasted for 7 days.At 14 d of age,the hypothalamus,liver,muscle and plasma from 6 chickens per treatment(2 chickens per pen)were individually collected.The result showed that corticosterone treatment significantly reduced BW gain,heart index,spleen index and bursa index,meanwhile increasing liver index and abdominal fat rate.Corticosterone,glucose and triglycerides in plasma were significantly increased by corticosterone treatment.In addition,corticosterone treatment significantly increased the glycogen in breast muscle and liver.Compared with control group,the gene expression of hypothalamic mTOR,GR,AMPKα2,NPY,LKB1,AMPKα1 and FAS were significantly upregulated in corticosterone-challenged chickens.Corticosterone treatment significantly increased the phosphorylation levels of ACC and AMPK protein expression,and also increased total AMPK protein level.The results demonstrated that corticosterone increased the release of neuropeptide Y(NPY)and activated LKB1-AMPK-ACC signaling pathway.The effect of central compound C on regulation of appetite in stressed chickens.Male Arbor Acres chicks(7-d old)were randomly assigned into 24 cages,each containing 2chickens.Each of the following treatment was randomly and separately applied to twelve of the 24 cages of chickens: subcutaneous injection of DEX for three days at a dose of 2.0 mg/kg BW,and sham-treated control for three days(injection of saline).Feed intake and BW gain were recorded.At 10 days,after injection,all chickens were fasted for 3 hours and then icv injected with either compound C(6ug/2 μL)or vehicle(dimethyl sulfoxide,2 μL).The feedintake was recorded thereafter.The experiment was repeated twice.During the second experiment,the chicks were continuously fasted for 1 hour,and then the samples were collected.The result showed that the BW of DEX-treated chickens significantly decreased compared with control chickens.Compared with control group,DEX treatment significantly upregulated the hypothalamic mRNA levels of AMPKα2,LKB1,NPY and m TOR,meanwhile,compound C significantly decreased the gene expression of mTOR and phosphorylation level of AMPK protein expression in stressed chickens.In conclusion,we demonstrated that inhibition of AMPK signaling attenuates hyperphagia in stressed chicks,in some extent,through the activation of the hypothalamic AMPK-mTOR signaling pathway.The effects of glucocorticoids administration and dietary energy level on appetite in broiler chickens.In experiment 1,a total of 216 1-d-old chicks were randomly assigned to 18 pens of 12 birds.Six pens of chicks were provided with a high-energy diet(HE,3500 kcal/kg),six pens of chicks were fed with a low-energy diet(LE,2900 kcal/kg),and the other chicks were provided with basal diet.Each 21-day-old chickens were selected from each treatment group.The result showed that the food intake in LE-fed chickens was significantly higher than HE-fed group and control group in whole period,but the body weight gain revealed the opposite tendency.The hypothalamic gene expression of LKB1,NPY,CCK and GR were significantly decreased in HE-fed chickens compared with control group.LE-fed chickens showed significantly higher levels of gene expression of AMPKα2 compared with control group.In addition,the hypothalamic gene expression of AMPKα1 was significantly increased in LE-fed chickens compared with HE-fed chickens.In conclusion,we demonstrated that LE treatment inhibited LKB1-AMPK signaling pathway and reduced NPY gene expression,conversely,HE diet activated AMPK signaling pathway and promoted appetite.In experiment2,at 1 d of age,216 chickens of similar body weight were divided into three groups,with six replicates per group and twelve chickens per replicate.Chickens were randomly subjected to one of the following three treatments:1)feeding with high-energy diet(HE,3500 kcal/kg),or2)feeding with low-energy diet(LE,2900 kcal/kg),or 3)feeding with basal diet.At 14 d of age and 28 d of age,every replicate was either given a dexamethasone injection(DEX,2mg/kg body weight),or a saline injection(Control,same volume as the DEX group).DEX treatment lasted for three days.The result showed that at 17 days of age,DEX treatmentsignificantly increased the hypothalamic genes expression of LKB1,AMPKα1 and GR,which is not dependent on different energy diet.However,at 31 days of age,DEX treatment significantly increased the hypothalamic genes expression of LKB1 and NPY,in condition of fed with basal diet and high energy diet.In conclusion,we demonstrated that the effect of peripheral GCs injection on AMPK signal pathway is dependent on dietary energy concentration and growing state.In summary,stress had a significant effect on appetite in broiler chicks and activated LKB1-AMPK-ACC signaling pathway;the hypothalamic AMPK signaling pathway took part in the regulation of appetite in stressed chicks.The effect of peripheral GCs injection on AMPK signal pathway is dependent on dietary energy concentration and growing state.