Fat Metabolism And Regulation Of DHEA In Two Broilers During Embryonic Development

In order to research the development pattern of fat metabolism and hepatic fatmetabolism key factors during embryonic development, AA broiler and Sanhuang broilerwith different growth and fat deposition were employed in present study. On the basis ofthe study, Sanhuang was used to investigate the effect of different maternal nutrition andrearing on fat metabolism and hepatic fat metabolism key factors gene expression inoffspring during embryonic development. At the same time, DHEA was injected to AAfertilized eggs before incubation to explore the fat-reducing mechanism of DHEA. Thisresult of this study provided a new rode for the decreasing fat deposition in fat abdomen.1 Fat Metabolism and Hepatic Fat Metabolism Key Genes Expression inBroiler Chickens with Different Fat Deposition during EmbryonicDevelopmentIn order to investigate the difference of fat metabolism during embryonic development,AA broiler and Sanhuang broiler chickens with different growth and fat deposition wereemployed in present study. The liver were gained on days 9,14,and 19 of embryonicdevelopment as well as at hatching. The serum was extracted on 14, 19 of embryonicdevelopment and at hatching. This study showed that embryonic weight, liver weight andserum TC content increased with development proceeding. However, serum TG contentdecreased during embryonic development. Hepatic TG suddenly elevates during day 14 ofembryonic development and with a slight augment and remained relatively constant formE14d to hatching. Insulin and glucagons regulated fat metabolism during embryonicdevelopment. Glucagons mainly play the role at hatching. The mRNA expression of acetylCoA carboxylase (ACC), fatty acid synthase (FAS), malic enzyme (ME), apolipoproteinB100(apoB100), sterol' regulating element binding protein (SREBP-1c), camitinepalmitoyltransferase (CPT-1), peroxisome proliferators-activated receptor(PPARa) andlipoprotein lipase (LPL) genes were determined using RT-PCR. This results showed that expression level of FAS gene in AA broiler and in SH broiler occurred prior to hatchingand at hatching. The expression abundance of the gene was higher in former breed. Theexpression level ACC gene was observed beginning at the earlier development stage. Nobreed and developmental difference was observed in ME and apoB gene expression level.Therefore, this study indicated expression level of lipogenic enzyme genes of liver inbroiler chickens exhibited scheduling during embryogenesis. The ACC gene started toexpress earlier than the FAS gene during embryonic development. The expression level ofCPT-1 and PPARa gene in AA broiler was significantly higher than that in SH broiler athatching. The expression level of LPL gene was very low in AA broiler and SH broiler athatching. This suggested that fat metabolism existed developmental change and breedcharacter and embryonic liver synthesized fatty acid, and showed breed difference prior tohatching.2 Effect of Maternal Effect on Fat Metabolism and Hepatic FatMetabolism Key Genes Expression in Broiler Chickens in Offspringduring Embryonic Development2.1 Effect of Maternal Nutrition on Fat Metabolism and Hepatic Fat Metabolism KeyGenes Expression in Broiler Chickens in Offspring during Embryonic DevelopmentThe laying Sanhuang breeders were divided into treatment and control. The treatmentand control was respectively fed diet containing 18% and 20% CP. The liver were gainedon days 9,14,and 19 of embryonic development as well as at hatching. The serum wasextracted on 14,and 19 of embryonic development and at hatching. The mRNA expressionof acetyl CoA carboxylase (ACC), fatty acid synthasc (FAS), malic enzyme (ME),apolipoprotein B100(apoB100), sterol regulating element binding protein (SREBP-1c),carnitine palmitoyltransferase (CPT-1) and peroxisome proliferators-activatedreceptor(PPARa) genes were determined using real time RT-PCR. This study showed thatembryonic weight, liver weight, serum and hepatic TC concentration, serum TG contentand hormones was not significant between the treatment and control during embryonicdevelopment. Hepatic ACC, FAS, SREBP-1c, ME and apoB gene expression was notsignificant between the treatment and the control during embryonic development. TheCPT-1 and PPARαgenes expression was insignificant between the treatment and controlgroup. This suggested a little change of nutrition level of laying breeder has no effect on fat metabolism and hepatic fat metabolism key genes expression in offspring broiler duringembryonic development.2.2 Effect of Maternal Rearing on Fat Metabolism and Hepatic Fat Metabolism KeyGenes Expression in Broiler Chickens in Offspring during Embryonic DevelopmentThe laying Sanhuang breeders were divided into treatment and control. The treatmentand control was respectively floor-reared and cage-reared with the same diet. The liverwere gained on days 9,14, and 19 of embryonic development as well as at hatching. Theserum was extracted on 14,and 19 of embryonic development and at hatching. The mRNAexpression of acetyl CoA carboxylase (ACC), fatty acid synthase (FAS), malic enzyme(ME), apolipoprotein B100(apoB100), sterol regulating element binding protein(SREBP-1c), carnitine palmitoyltransferase (CPT-1) and peroxisome proliferators-activatedreceptor(PPARa) genes were determined using real time RT-PCR. This result showed thatembryonic weight, liver weight, serum and hepatic TC concentration and serum TGcontent was not significant between the treatment and control during embryonicdevelopment. However, embryonic weight, liver weight, serum and hepatic TCconcentration, serum TG content and serum Leptin of treatment was significantly higherthan that of the control at hatching. Hepatic ACC, FAS, SREBP-1c, ME and apoB geneexpression was not significant between the treatment and the control during E9 and E14development. Hepatic ME gene expression in control group was higher than that intreatment group during E19 development. Hepatic FAS, SREBP-1c, CPT-1 geneexpression in control group was higher than that in treatment group. Therefore, change ofmaternal rearing can regulate fat metabolism and hepatic fat metabolism key genesexpression in offspring broiler during embryonic development especially at hatching.Floor-rearing of laying breeder could decrease fatty acid synthesis in offspring broilerduring embryonic development compared with cage-rearing especially at hatching.3 Regulation of DHEA on Hepatic Fat Metabolism and Fat MetabolismKey Genes Expression in Broiler Chickens during EmbryonicDevelopmentIn order to explore the possible fat-reducing mechanism of DHEA, this study was toinvestigate the effect of in ovo administration of DHEA on fat metabolism and theregulating mechanism of DHEA on fat metabolism in broiler chickens during embryonic development. The control was injected 50μL DMSO. The treatment was injected tofertilized eggs with were injected 50 mg DHEA per kilogram eggs in 50μL DMSO. Theliver were gained on days 9,14,and 19 of embryonic development as well as at hatching.The serum was extracted on 14,and 19 of embryonic development and at hatching. ThemRNA expression of ACC, FAS, ME, ApoB100, SREBP-1c, CPT-1 and PPARa geneswere determined using real time quantitative PCR. This results showed that embryonicweight and liver weight in DHEA group was a little lower than that in control group.Hepatic TG concentration in DHEA group was significantly lower than that in DHEA groupon days 14, 19 of embryonic development and at hatching. Serum TG content in DHEAgroup was significantly lower than that in control group on days 14 of embryonicdevelopment and at hatching. Serum TC concentration in DHEA was lower than that incontrol group at hatching. Serum NEFA content and LPL activity in DHEA group waslower than that in control group at hatching. Compared with control group, serum LEP,GLU and INS of DHEA treatment was insignificant. DHEA decreased hepatic ACC, FAS,ME, SREBP-1c, ApoB, CPT-1 and PPARαgenes expression. This suggested that DHEAdecreased hepatic lipogenetic genes expression, suppressed triglycerols transporting andreduced fatty acid oxidizing so as to decline the deposition of fat in adipose tissue in broilerchicken during embryonic development which could be one of the fat-reducing mechanismsof DHEA.