Investigation Of (-)-hydroxycitric Acid On Lipid Metabolism In Broiler Chickens Based On Proteomics And Metabolomics

(-)-Hydroxycitric acid[(-)-HCA]is the principal acid of fruit rinds of Garcinia cambogia.(-)-HCA was shown to be a potent inhibitor of ATP citric lyase,thereby reducing fat.Currently,the research for(-)-HCA on lipid metabolism in broiler chicken has been reported rarely.In this study,a study was carried out to examine the effect of(-)-HCA on lipid metabolism in broiler;though the change in protein profiles of liver by comparative proteomics and metabolite profiles in serum by metabolomics,the purpose in metabolite and protein profiles is to analyse the mechanism of(-)-HCA effects on lipid metabolism in broiler chickens.1 Effect of(-)-hydroxycitric acid with different doses on lipid metabolism in broiler chickensIn order to study the effect of(-)-hydroxycitric acid(HCA)on lipid metabolism in broiler chickens,a total of 120 1-day-old broiler chickens(Ross 308)were randomly allocated to four groups,with each group replicating three times and each replicating involving 10 birds.The birds were received a commercial diet supplemented with(-)-HCA at 0,1,000,2,000 or 3,000 mg/kg of the diet,respectively,for a period of 4 wk ad libitum(from 22 to 49 d).The results showed that body weight(BW)in the 2,000 and 3,000 mg/kg(-)-HCA groups was significantly lower,and a marked decreased in the liver weight was noted in 3,000 mg/kg(-)-HCA group.A significantly decreased of triglyceride(TG)and low density lipoprotein-cholesterol(LDL-C)content were observed in 3,000 mg/kg(-)-HCA group.Broiler chickens fed with 2,000 and 3,000 mg/kg(-)-HCA resulted in a pronounced higher of hepatic lipase(HL)activity,glycogen and non-esterified fatty acid(NEFA)content in liver.Serum free triiodothyronine(FT3)and thyroxin(T4)contents were significantly higher in 3,000 mg/kg(-)-HCA group.The level of ATP-citrate lyase(ACLY)expression was significantly decreased in broiler chickens supplemented with 3,000 mg/kg(-)-HCA.Supplemental(-)-HCA markedly decreased the levels of fatty acid synthase(FAS)and sterol regulatory element binding protein-1c(SREBP-1c)expression,while the mRNA abundance of adenosine 5'-monophosphate-activated protein kinase?2(AMPK?2)was significantly increased.No significant differences was observed in the level of carnitine palmitoyl transferase-?(CPT-?)expression,while the level of peroxisome proliferators-activated receptor a(PPAR-alpha)expression was significantly increased in broiler chickens supplemented with 2,000 and 3,000 mg/kg(-)-HCA.Overall,present results indicated(-)-HCA not only inhibited the de novo lipogenesis but also accelerated lipolysis by induction of relevant gene expression which in turn decreased the abdominal fat deposition in broiler chickens.2 Effects of(-)-HCA on the expressions of serum metabolites profile in broiler chickensThe broiler chickens were selected to study the effects of(-)-HCA on the expressions of serum metabolites profile.Experimental design was same to the first chapte.Experimental use of silylating agent,using gas chromatography mass spectrometry(GC/MS),collected pattern,map database for comparison,identificate the compound.Using SIMCA-P11 software for data analysis,principal component analysis(PCA),partial least squares discriminant analysis(PLS-DA)model to evaluate the similarities and differences between four groups,to identify differences in the compound.The results showed that broiler serum reduced lactose and fructose,rised the glucose levels,indicating that(-)-HCA enables enhanced gluconeogenesis.Citric acid cycle intermediates citric acid and malic acid content increased,suggesting that(-)-HCA may promote the rate of Krebs cycle,improve the body's metabolism,thereby reducing weight.Aliphatic amino acid levels were significantly increased,indicating that(-)-HCA could inhibit the biosynthesis of fatty acids.Uric acid as the end product of metabolism in birds,its content is reduced in the serum,represents(-)-HCA has the ability to promote the body's protein synthesis.The high doses of(-)-HCA treatment group significantly decreased linoleic acid,stearic acid,palmitic acid content of broiler serum.Suggested(-)-HCA treatment can significantly inhibit the synthesis of fatty acids in broilers.Pathway enrichment using differentially metabolites preliminary analysis of metabolic pathways and found that(-)-HCA mainly affects the body's malate-aspartate shuttle,ammonia metabolism,the urea cycle,linoleic acid metabolism and glutathione metabolism,gluconeogenesis and other channels.3 Effects of(-)-HCA on the expressions of liver mitochondrial and cytosolic protein/enzyme in broiler chickensThe broiler chickens were selected to study the effect of(-)-HCA on the expressions of liver mitochondrial and cytosolic lipid metabolism-related protein/enzyme in broiler chickens.The results showed that mitochondrion was separated and purificated efficiently by using this methord in present study.Proteins were isolated by differential centrifugation and were separated by two-dimensional electrophoresis,the differentially displayed spots were obtained by pattern analysis,then the spots were further identified by MALDI-TOF-MS.In liver mitochondrial protein,compared with the control group,1,000mg/kg(-)-HCA treatment group received 21 different proteins,2,000mg/kg(-)-HCA treatment group received 27 different proteins,3,000mg/kg(-)-HCA treatment group received 17 different proteins.In liver cytosolic protein,1,000mg/kg(-)-HCA treatment group received 17 different proteins,2,000mg/kg(-)-HCA treatment group received 17 different proteins,3,000mg/kg(-)-HCA treatment group received 12 different proteins.The result showed that,(-)-HGA upregulated the expression of AC02 which catalytic the citric acid to isocitric acid,improve citric acid cycle efficiency,improve energy metabolism,reduce body weight of broilers.Reduced expression of ME1,result to reduce their produce coenzyme NADPH for fatty acid synthesis,reducing the rate of fatty acid synthesis.(-)-HCA by upregulating the expression of PDHc accelerate the citric acid cycle,improve energy metabolism.