| The liver metabolize of goose was dramatically changed induced by overfeeding,and causing large fats deposited in liver. The sensibility of liver is different among goosebreeds in responses to overfeeding, which resulting in differential fatty liver performance.Up till now, the molecular mechanism of fatty liver forming is still remaining un-clear. Inthis study, mRNA differential display and real-time quantitative PCR were applied toisolate and identify the differentially expressed gene between fatty liver and normal liverof Landes and Xupu goose. The bio-informatics technique was also used in predicting thearchitecture and functions on protein and nucleic acid levels, and the main results asfollows:Ninety primer pairs were used in this study to obtain an understanding of the mRNAlevels in response to overfeeding in the two breeds. The identified genes were confirmedby using real-time quantitative PCR technique. Six genes were confirmed as up regulated,two were confirmed as down regulated, and one gene was confirmed as up regulated inLandes, but down regulated in Xupu goose.The expression level of gene 8216 was confirmed as up regulated in both fatty livers,and its expression level is higher in Landes than in Xupu goose. The complete cDNAsequence of this gene was 1797 bp, and the GenBank accession number was EF488993.By blast in NCBI server, this sequence shows 92％identity with chicken seleniumbinding protein 1 (SELENBP1) mRNA (XM-423397.2). The sequence analysis revealedthat its open reading frame (ORF) of 1413 bp encodes a protein of 471 amino acids,which contains a putative conserved domain of 56 kDa selenium binding protein (SBP56)and has high homology with its homologues-chicken 95％, rat 86％, mouse 84％, human86％, monkey 86％, dog 86％, and cattle 86％. The tissue expression analysis indicatedthat goose SELENBP1 mRNA is higher expressed in liver and kidney, but moderate inspleen, and lowest in ovary, uterus, muscular stomach, and abdominal fat.The expression level of gene 9105 was confirmed as up regulated in both fatty livers.A 1248 bp cDNA fragments which contains the complete CDS was obtained thoughcDNA cloning. The accession number of GenBank is EF541127. By blast in NCBI server,this sequence shows 94％identity with chicken transforming growth factor beta 2(TGFB2) mRNA (NM-001031045.1), and also has high identities with TGFB2 of otherspecies. The sequence analysis revealed that its open reading frame (ORF) of 1239 bpencodes a protein of 412 amino acids, which contains two putative conserved domains ofTGFb-propeptide and TGFβ, and has high homology with its homologues-chicken 99％, Xenopus laevis 96％, rat 87％, human 90％, Monodelphis domestica 91％, cattle 89％,mouse 88％, pig 90％, Ovis aries 89％. The tissue expression analysis indicated that goosegene 9105 is higher expressed in muscular stomach, but moderate in liver, spleen, andovary, and lowest in uterus, abdominal fat, and kidney.The expression level of gene 7501 was confirmed as up regulated in both fatty livers,and its expression level is higher in Landes than in Xupu goose. A cDNA fragment of1446 bp was obtained by cDNA cloning. By blast in NCBI server, this sequence shows93％identity with chicken cytosolic NADP (+)-dependent malic enzyme (ME1) mRNA(NM-204303.1), and also has high identities with ME1 of other species. The tissueexpression analysis indicated that goose gene 7501 is higher expressed in liver, butmoderate in muscular stomach, spleen, ovary, uterus, and kidney, and lowest in abdominalfat.The expression level of gene 8407 was confirmed as down regulated in both fattylivers. A 1269 bp cDNA fragments which contains the complete CDS was obtainedthough cDNA cloning. The accession number of GenBank is EF541128. By blast in NCBIserver, this sequence shows 95％identity with chicken cytosolic NADP-dependentisoeitrate dehydrogenase (IDH1) mRNA (NM-421965), and also has high identities withIDH1 of other species. The sequence analysis revealed that its open reading frame (ORF)of 1248 bp encodes a protein of 415 amino acids, which contains a putative domains ofIcd, which conserved among species, and has high homology with itshomologues-chicken 99％, rat 89％, human 90％, monkey 90％, cattle 88％, mouse 88％.The tissue expression analysis indicated that goose gene 8407 is higher expressed in liver,but moderate in muscular stomach, liver, and spleen, and lowest in ovary, uterus,abdominal fat, lung, and muscle.The expression level of gene 9302 was confirmed as down regulated in both fattylivers. A cDNA fragment of 943 bp was obtained by cDNA cloning. By blast in NCBIserver, this sequence shows 93％identity with chicken cytochrome P450, family 7,subfamily A, polypeptide 1 (CYP7A1) mRNA (XM-419217). The tissue expressionanalysis indicated that goose gene 9302 is highly expressed in liver, but non-expressed inother tested tissues.The expression level of gene 7102 was contrary between these two breeds. It was upregulated in Landes, but down regulated in Xupu goose. A cDNA fragment of 923 bp wasobtained by cDNA cloning. By blast in NCBI server, this sequence shows 95％identitywith chicken malate dehydrogenase 1, NAD (soluble) mRNA (MDH1)(NM-001006395.1), and also has high identities with MDH1 of other species. The tissue expression analysis indicated that goose gene 9302 is highly expressed in liver, but lowerexpressed in other tested tissues. Goose can develops fatty liver though overfeeding with feed which contains high energy concentrations in short-term. In the process of fatty liver developments, the oxidative stress of liver increased correspondingly and the free radical accumulated in liver followed by liver cell damaged and the quality of fatty liver decline. A single factor trial based on the Tea Polyphenols (TP) concentration was designed to study the effects of TP in diets on fat metabolism and the capability of antioxidation in overfeeding goose in this study. Geese were assigned to five groups and treated with feeds which contained different levels of TP using the first group as control. The levels of TP in the rest feed were: 40, 80, 160, and 320 mg/Kg. the performance of slaughter, bio-indexes of serum, and the capability of liver antioxdation were analyzed, and the main results are as follows:After 21d of overfeeding, the average intake was approximately same (13.5±0.23Kg). The analysis results revealed that the dressing percentage, semi-eviscerated carcass percentage, eviscerated carcass percentage, breast muscle weight and leg muscle weight had no significant differences among groups (p>0.05), the weight after overfeeding and weight gain presented a significant down trend (p<0.01); The ratio of abdominal weight to the weight after overfeeding showed an up and then down trend, but the changes did not significant. These results indicated that TP had no effects on hepatic lipogenesis and fat depositing, and also had no effects on the assignments of fat in body. The analysis results about serum bio-index among groups revealed that the alteration of triglyceride (TG) level coincided with fatty liver weight, and the total cholesterol (TC) level in serum showed down in total, but had no significant difference among trial groups (p>0.05) and had significant difference compared with control (p<0.01). The High density lipoprotein cholesterol (HDL-C) level were relatively steady, and had no significant difference among groups (p>0.05). The Low density lipoprotein cholesterol (LDL-C) level in serum was significant down (p<0.01). Others had no significant differences ((p>0.05). These results revealed that the migration of fat between liver and other tissues might affected by TP which were absorbed from diets, but the TP involved in diets had no effects on immune system. The analysis results about antioxidation index of liver among groups revealed that TP which from diets had no effects on the activity of Total superoxide dismutase (T-SOD) and Glutathione peroxidase (GSH-Px) in liver, but the Malonaldehyde (MDA) level were significantly decreased according to the TP level in diets (p<0.01). These results indicated that TP could be absorbed into tissues from diets and finally into cell. The intracellular TP and it metabolites suppressed the oxides reaction of fat, but it protecting function was exerted through some signaling pathway by itself and its metabolites, other than via interacted with some antioxidant system.
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