S. Z. Gao

Impact of dietary protein on lipid metabolism-related gene expression in porcine adipose tissue.

BackgroundHigh dietary protein can reduce fat deposition in animal subcutaneous adipose tissue, but little is known about the mechanism.MethodsSixty Wujin pigs of about 15 kg weight were fed either high protein (HP: 18%) or low protein (LP: 14%) diets, and slaughtered at body weights of 30, 60 or 100 kg. Bloods were collected to measure serum parameters. Subcutaneous adipose tissues were sampled for determination of adipocyte size, protein content, lipid metabolism-related gene expression, and enzyme activities.ResultsHP significantly reduced adipocyte size, fat meat percentage and backfat thickness, but significantly increased daily gain, lean meat percentage and loin eye area at 60 and 100 kg. Serum free fatty acid and triglyceride concentrations in the HP group were significantly higher than in the LP group. Serum glucose and insulin concentrations were not significantly affected by dietary protein at any body weight. HP significantly reduced gene expression of acetyl CoA carboxylase (ACC), fatty acid synthase (FAS) and sterol regulatory element binding protein 1c (SREBP-1c) at 60 kg and 100 kg; however, the mRNA level and enzyme activity of FAS were increased at 30 kg. HP promoted gene and protein expression and enzyme activities of lipoprotein lipase (LPL), carmitine palmtoyltransferase-1B (CPT-1B), peroxisome proliferator-activated receptor γ (PPARγ) and adipocyte-fatty acid binding proteins (A-FABP) at 60 kg, but reduced their expression at 100 kg.Gene expression and enzyme activity of hormone sensitive lipase (HSL) was reduced markedly at 60 kg but increased at 100 kg by the high dietary protein. Levels of mRNA, enzyme activities and protein expression of ACC, FAS, SREBP-1c and PPARγ in both LP and HP groups increased with increasing body weight. However, gene and protein expression levels/enzyme activities of LPL, CPT-1B, A-FABP and HSL in both groups were higher at 60 kg than at 30 and 100 kg.ConclusionFat deposition in Wujin pigs fed high dietary protein for 25 weeks was reduced mainly by depression of lipogenic gene expression. The mechanism of lipid transport, lipolysis and oxidation in adipose tissue regulated by dietary protein appeared to be different at 60 kg and 100 kg body weights.

Molecular characterization of the encoding regions and tissue expression analyses for three novel porcine genes––HNRPA1, YIPF5 and UB2D2

The complete encoding regions of three porcine genes––heterogeneous nuclear ribonucleoprotein A1 (HNRPA1), YIP1 family member 5 (YIPF5) and ubiquitin-conjugating enzyme E2 D2 (UB2D2) were amplified using the reverse transcriptase polymerase chain reaction (RT-PCR) based on the conserved encoding region information of the mouse or other mammals and the referenced highly homologous pig ESTs of these conserved encoding regions. These three novel porcine genes were assigned to GeneID: 768103, 768112, and 780418. The phylogenetic tree analysis revealed that the swine HNRPA1 has closer genetic relationships with the HNRPA1 of mouse and rhesus monkey, but the swine YIPF5 has a closer genetic relationship with the YIPF5 of cattle and the swine UB2D2 shows an evolutional model different with the UB2D2 of other five species. The tissue expression analysis indicated that the swine HNRPA1 gene was moderately expressed in fat, spleen and kidney, weakly expressed in muscle and lung, and hardly expressed in small intestine, large intestine and liver. The swine YIPF5 gene was moderately expressed in fat and spleen, and hardly expressed in small intestine, large intestine, liver, lung, muscle and kidney. The swine UB2D2 gene was weakly expressed in lung, and hardly expressed in small intestine, large intestine, liver, muscle, fat, spleen and kidney. Our experiment established the primary foundation for further research on these three swine genes.

Effects of the Sheep Polyclonal Antibodies Against the Porcine Adipocyte Plasma Membrane Proteins on Porcine Carcass Composition and Meat Quality

To detect the effects of the polyclonal antibodies raised in sheep against porcine adipocyte plasma membranes on the porcine carcass composition and meat quality, 30 pigs assigned into 6 treatment groups were given intraperitoneal injections of sheep antipig adipocyte plasma membrane immunoglobulin (ASIg) or sheep nonimmune serum immunoglobulin (NSIg). At the end of the experiment, the pigs were slaughtered at 90 kg body weight, and carcasses and meat quality were evaluated. The results showed that when pigs intraperitoneally immunized with 20 or 30 mg ASIg at 15 kg body weight, 20 mg purified ASIg twice at 15 and 60 kg body weight, or 20 mg purified ASIg at 60 kg body weight, respectively, their lean meat percentage, fat meat percentage, backfat thickness, loin eye area leaf fat weight, caul fat weight, heart weight, liver weight, and kidney weight were significantly affected. However, the kidney weight, lung weight, dressing percentage, and spleen weight did not remarkably change. Our results indicated that pigs intraperitoneally immunized with 20 or 30 mg ASIg at 15 kg body weight, and 20 mg ASIg twice at 15 and 60 kg body weight, have significantly different drip loss rate, cooked meat ratio, tenderness, storage loss rate, muscle fiber diameter, moisture content, dry matter content, crude protein content, and crude fat content from the control group that received 20 mg NSIg at 15 kg body weight. However, meat pH, meat color value, meat marbling score, inosinate, and myohemoglobin were not significantly affected. Our results indicated ASIg could not significantly affect the content of most muscular amino acids and intramuscular fatty acids.

cDNA Cloning and Tissue Expression Analyses of the Encoding Regions for Three Novel Porcine Genes- MJD1, CDC42 and NECD

The cDNAs for Machado-Joseph disease protein 1 homolog (MJD1), cell division control protein 42 homolog precursor(CDC42) and necdin (NECD) genes of pig were amplified using the reverse transcriptase polymerase chain reaction (RT-PCR) based on the conserved coding sequence information of the MJD1, CDC42, and NECD genes from mouse and other mammals and the referenced porcine EST sequence information. Tissue expression analysis showed the swine MJD1, CDC42, and NECD genes were obviously differentially expressed in different tissues including muscle, heart, liver, backfat, kidney, lung, small intestine, and large intestine. Our experiment established the primary foundation for further research on these three swine genes.

Effects of Monoclonal Antibody Against Adipocyte-Specific Membrane Protein on Lipid Metabolism in Pigs

Abstract This study was to investigate the regulation of monoclonal antibodies against adipocyte membrane proteins (McAb) on lipid metabolism in pigs. Forty Landrace x Saba pigs were randomly divided into eight groups; the control group was given 10 mL saline and the treat groups were given monoclonal antibody against adipocyte-specific membrane protein with 0.1, 0.5, and 1.0 mg kg −1 body weight at 15 and 60 kg body weight, respectively, by intraperitoneal injection. The results showed that McAb could increase, significantly, serum lipoprotein lipase activity and reduce serum nonesterified fatty acid (NEFA) content. Meanwhile, McAb increased content of serum lipid, triglyceride (TG), cholesterol (CHO), high density lipoprotein (HDL), and low density lipoprotein (LDL) both at 15 and 60 kg body weight. However, McAb affected more significantly the lipid metabolism at 15 kg body weight than at 60 kg body weight. Moreover, this effect of McAb on lipid metabolism exhibited dose-dependent effect. These results suggested that this monoclonal antibody increased lipase activity, promoted lipolysis, and utilization of lipid so that McAb could be applied to restrain excessive fat deposition in porcine production through the regulation of fat metabolism.

Molecular Characterization and Tissue Expression of Ovine PSAM6 Gene from Muscle Full-Length cDNA Library of Black-Boned Sheep

An ovine PSMA6 gene was obtained from muscle full-length cDNA library of black-boned sheep. The sequences for the PSAM6 gene of Romney sheep and Yunling black goat were also generated in this study. Sequence analysis revealed that nucleotide sequence of this gene was not homologous to any of the known sheep genes, and its open reading frame encodes a protein that contains the putative conserved domain of proteasome subunit alpha type 6 (PSAM6). The nucleotide sequence had higher identity with other animals. However, one mutation of A to G at the site of 383 bp, leading to an amino acid mutation of Asn to Ser, was found only in the black-boned sheep. Tissue expression analysis indicated that this gene was generally expressed in most tissues and differently expressed in tissues of black-boned sheep. This the first report of the ovine PSAM6 gene.

Isolation, sequence identification and tissue expression distribution of three novel porcine genes—RAB14, S35A3 and ITM2A

The complete coding sequences of three porcine genes—RAB14, S35A3 and ITM2A were amplified using the reverse transcriptase polymerase chain reaction (RT-PCR) based on the conserved sequence information of the mouse or other mammals. The nucleotide sequence analysis of these three genes revealed that porcine RAB14 gene encodes a protein of 215 amino acids that contains the conserved putative Ras-related protein Rab-14 domain and has high homology with the Ras-related protein Rab-14 (RAB14) of four species—human and mouse (99%) and rat (100%), dictyostelium discoideum (71%). The porcine S35A3 gene encodes a protein of 325 amino acids that contains the conserved putative nucleotide-sugar transporter domain and has high homology with the UDP-N-acetylglucosamine transporter (S35A3) of five species—cattle (98%), dog (97%), human (96%), mouse (95%) and rat (94%). The porcine ITM2A gene encodes a protein of 254 amino acids that contains the conserved putative BRICHOS domain and has high homology with the integral membrane protein 2A (ITM2A) of two species—human (89%), and mouse (88%). The tissue expression analysis indicated that the swine RAB14 gene was over-expressed in fat, lung, spleen, and kidney, moderately in large intestine, weakly in small intestine, and hardly expressed in muscle and liver. The swine S35A3 gene was moderately expressed in large intestine, fat, and spleen, weakly in liver and lung, and almost not expressed in muscle, small intestine, and liver. The swine ITM2A gene was over-expressed in fat and spleen, moderately in lung, weakly in muscle, and hardly expressed in liver, small intestine, large intestine, and kidney. Our experiment established the primary foundation for further research on these three swine genes.

Generation and Analysis of Expressed Sequence Tags （ESTs） from Muscle Full-Length cDNA Library of Wujin Pig

Abstract Porcine skeletal muscle genes play a major role in determining muscle growth and meat quality. Construction of a full-length cDNA library is an effective way to understand the expression of functional genes in muscle tissues. In addition, novel genes for further research could be identified in the library. In this study, we constructed a full-length cDNA library from porcine muscle tissue. The estimated average size of the cDNA inserts was 1 076 bp, and the cDNA fullness ratio was 86.2%. A total of 1 058 unique sequences with 342 contigs (32.3%) and 716 singleton (67.7%) expressed sequence tags (EST) were obtained by clustering and assembling. Meanwhile, 826 (78.1%) ESTs were categorized as known genes, and 232 (21.9%) ESTs were categorized as unknown genes. 65 novel porcine genes that exhibit no identity in the TIGR gene index of Sus scrofa and 124 full-length sequences with unknown functions were deposited in the dbEST division of GenBank (accession numbers: EU650784-EU650788, GE843306, GH228978-GH229100). The abundantly expressed genes in porcine muscle tissue were related to muscle fiber development, energy metabolism and protein synthesis. Gene ontology analysis showed that sequences expressed in porcine muscle tissue contained a high percentage of binding activity, catalytic activity, structural molecule activity and motor activity, which involved mainly in metabolic, cellular and developmental process, distributed mainly in intracellular region. The sequence data generated in this study would provide valuable information for identifying porcine genes expressed in muscle tissue and help to advance the study on the structure and function of genes in pigs.

Effects of monoclonal antibody against porcine 40-kDa adipocyte-specific membrane protein on endocrine secretion in pigs.

Abstract The present study was to investigate the effect of monoclonal antibody against porcine 40-kDa adipocyte-specific membrane protein on endocrine secretion in pigs, in order to provide the evidence for application of this antibody to reduce excessive fat deposition in pig production. 40 Landrace × Saba pigs were randomly divided into 8 groups: 2 control groups were given saline with 10 mL, respectively, and the 6 treatment groups were given monoclonal antibody against porcine 40-kDa adipocyte-specific membrane protein with 0.1, 0.5, and 1.0 mg kg −1 body weight at 15 or 60 kg body weight, respectively, all treatments were performed by intraperitoneal injection. The results showed that this monoclonal antibody could significantly reduce serum insulin level and increase levels of serum growth hormone (GH), insulin-like growth factor-1 (IGF-1), triiodothyronine (T 3 ), and tetraiodothyronine (T 4 ) either at 15 or 60 kg body weight injection. However, more marked effect was observed at 15 kg body weight treatment. Moreover, the dose-dependent effect of this monoclonal antibody on endocrine secretion was also observed. This result revealed that this monoclonal antibody increased secretion of hormones regulating fat lysis and reduced secretion of hormones regulating fat synthesis, suggests the reduction of porcine excessive fat deposition by this monoclonal antibody was carried out through affecting hormones regulating fat metabolism.

Cloning, sequence characterization, and tissue expression profile analysis of three novel porcine genes—RHOB, RHOG, and PRAF1

The complete coding sequences of three porcine genes—Rho-related GTP-binding proteins RHOB and RHOG and Prenylated Rab acceptor protein 1 (PRAF1) were amplified using the reverse transcriptase polymerase chain reaction (RT-PCR) based on the sequence information of the mouse or other mammals and referenced highly homologous pig ESTs. The nucleotide sequences of these three genes revealed that porcine RHOB gene encodes a protein of 196 amino acids that contains the conserved putative RhoA-like domain and has high homology with the RHOB precursor of three species—human, rat, and mouse (100%).The porcine RHOG gene encodes a protein of 191 amino acids that contains the conserved putative RhoG domain and has high homology with the RhoG precursor (RHOG) of three species—human, mouse, and Cricetus cricetus (98%). The porcine PRAF1 gene encodes a protein of 185 amino acids that contains the conserved putative PRA1 domain and has high homology with the PRAF1 of five species—dog (97%), cattle (97%), human (96%), rat (95%), and mouse (95%). The tissue expression analysis indicated swine RHOB gene was moderately expressed in lung; weakly in fat, spleen, and kidney; and almost not expressed in small intestine, large intestine, liver, and muscle. The swine RHOG gene was overexpressed in small intestine, large intestine, liver, and muscle; moderately expressed in kidney; weakly in spleen; and almost not expressed in fat and lung. The swine PRAF1 gene was overexpressed in fat and spleen, moderately in lung and kidney, weakly in small intestine and large intestine, and almost not expressed in liver and muscle. Our experiment established the primary foundation for further research on these three swine genes.