Effects Of Energy Level And Glucocorticoids On Regulation Of Feed Intake In Broilers

To investigate the effects and mechanisms of glucocorticoids and insulin on therugulation of the mechanism of food intake in broilers(Gallus gallus domesticus), exogenousinsulin and glucocorticoid were used to treat the chicken and compounding with the differentdiet energy level to observe the broiler feeding behavior and body fat changes, simultaneousanalysis of the hyperthalamic appetite-regulated genes expression to providing the evidenceof theory for energy appetite regulation mechanism of broilers.First, exogenous insulin was Subcutaneous injected into broilers, to Investigate theimpact of insulin on broiler food intake. Trail1,72AA broilers male broilers (Arbor Acres)with similar body weight were divided into2part (part A and part B)at the day of6,36birdsper part,6group, the saline and insulin injection group(1IU,3IU,5IU,10IU,20IU insulin/Kg BW),6birds per group. At the day of8, injection with saline and insulin, before injection,the broilers of part A was in free diet and broilers of part B was fasted3h, food intake wasrecord after the injection of0.5h、1h、2h、3h、4h, at4h all the blood samples were obtained.Trail2,60male broilers (Arbor Acres) with similar body weight at the day of8were dividedinto2groups at random: saline,10IU insulin/Kg BW.3h fasting before injection, At2h and4h after the injection hypothalamus were obtained, and were quick-freezed in liquid nitrogen.The results showed that the subcutaneous injections of five insulin levels have no effect onfood intake and insulin had no significant effect on appetite-regulated genes.Then, the study use different diet energy level Building energy model to study theProduction performance and the mRNA expression of genes rugulated the body’s energybalance. Trail1, the effect of diet energy level on the food intake and fat deposition of broilerswith free diet.200AA male broilers (Arbor Acres) were divided into2part after hantched,100birds per part,4group, one part was feed with high energy diet and the other part was fedwith low energy diet for5weeks, the food intake and body weight were recorded Weekly. Atthe day of35, blood, hypothalamus, liver, kidney and abdominal fat were obtained at8:00,All the fat (abdominal fat, neck fat, leg fat) was weighted. The results showed that highenergy diet improved production performance of broilers, and caused obesity, but have nosignificant effect on the blood index, the reduction of mRNA level of AGRP expression in thehypothalamus may be the cause of low food intake in broilers fed with high energy diet. Trail2, the effect of diet energy level on Glucose tolerance of broilers.80AA male broilers (ArborAcres) were divided into2part after hantched, feed with high energy diet and low energy dietfor5weeks, At the day of35, fast for12h, perfusing GLU(2.5ml/Kg BW,0.8g/ml),collect blood at0.5h,1h and2h. The result showed that high energy diet could decrease Glucosetolerance of broilers. Trail3, the effect of diet energy level on the food intake and fatdeposition in fasting and refeeding broilers refed with different nenrgy diet.180AA malebroilers (Arbor Acres) were divided into2part after hantched, the treatmemt were the same aswhich in trail1, but, before samping, the broilers were fasted for24hours. Then the rest ofbroilers were divided into4groups refeeding for3hours (group1, refeeding with high energydiet of broilers fed with high energy diet originally; group2, refeeding with low energy diet ofbroilers fed with high energy diet originally; group3, refeeding with high energy diet ofbroilers fed with low energy diet originally; group4, refeeding with low energy diet of broilersfed with low energy diet originally). Sample collection were the same as which in trail1. Theresult in trait1also indicate that high energy diet improved production performance ofbroilers, and caused obesity, but have no significant effect on the blood index, the reductionof mRNA level of AGRP expression in the hypothalamus may be the cause of low food intakein broilers fed with high energy diet. The result in trait2indicate that broilers have memorywith the diet type that be fed from the beginning, GLU、UA、TG、VLDL、IGF-1and TNF-ain the blood Play a role in energy regulation, NPY, CRH, AGRP and LEPR in hypothalamus,INS、11HSD in liver, INSR、11HSD in kidney and LEPR in fat play an important role in theregulation of energy balance and food intake. Broilers fed with different energy diet maybehave different genes that can feel the energy change and have different feedback mechanism.Finally, based on the different energy diet, the broilers were subcutaneous injected withDEX, furtherly study the appetite genes of broilers and diet energy level on the regulation ofgenetic changes caused by glucocorticoids. Trail1,80AA male broilers (Arbor Acres) weredivided into2part after hantched, feed with high energy diet and low energy diet for5weeks,At the day of35, divided into4groups, group1, broilers fed with high energy diet originallywere subcutaneous injected with DEX (2.6mg/kg BW) at8:00and20:00erery day for4days,diets at choice; group2, broilers fed with high energy diet originally were subcutaneousinjected with saline, diets at choice; group3, broilers fed with low energy diet originally weresubcutaneous injected with DEX, diets at choice; group4, broilers fed with low energy dietoriginally were subcutaneous injected with saline, diets at choice. During the treatment, recodthe food intake of every diet per day, After4days injection, the blood were collected. Theresults showed that Glucocorticoids may contribute to the restoration of the feed of the effectof memory, When given two diets freedom of choice, the main or only feeding the originaldiet, and high energy diet can enhance the effect. High energy diet can inpove the changes of blood index caused by glucocorticoids. Trail2,80AA male broilers (Arbor Acres) fed withdifferent energy diet were divided into4groups (broilers with high energy diet, DEX; broilerswith high energy diet, saline; broilers with low energy diet,DEX; broilers with low energydiet,saline) at the day of35at8:00and20:00, removed the food.8broilers were collectedeach group at8:00in the second day, blood, hypothalamus were obtained, All the fat(abdominal fat, neck fat, leg fat) was weighted. The rest of broilers injection once again andreefed for3h with40g of erery broiler, then collect the blood and hypothalamus. The resultsshowed that the stimulation of Glucocorticoid on the glucocorticoid receptor and anorexigenicgenes, especially CRH maybe the main reason caused the reduction of food intake. Highenergy diet can improve the change of genes induced by glucocorticoid.