Myostatin mRNA expression and its association with body weight and carcass traits in Yunnan Wuding chicken.

Myostatin (MSTN) is expressed in the myotome and developing skeletal muscles, and acts to regulate the number of muscle fibers. Wuding chicken large body, developed muscle, high disease resistance, and tender, delicious meat, and are not selected for fast growth. Broiler chickens (Avian broiler) are selected for fast growth and have a large body size and high muscle mass. Here, 240 one-day-old chickens (120 Wuding chickens and 120 broilers) were examined. Twenty chickens from each breed were sacrificed at days 1, 30, 60, 90, 120, and 150. Breast and leg muscle samples were collected within 20 min of sacrifice to investigate the effects of MSTN gene expression on growth performance and carcass traits. Body weight, carcass traits, and skeletal muscle mass in Wuding chickens were significantly (P < 0.05) lower than those in broiler chickens at all time points. Breast muscle MSTN mRNA was lower in Wuding chickens than in broilers before day 30 (P < 0.05). After day 30, breast muscle MSTN expression was higher in Wuding chicken than in broilers (P < 0.05). Leg muscle MSTN mRNA expression was higher in Wuding chicken than in broilers at all ages except for day 60 (P < 0.05). Correlation analysis revealed that breast muscle MSTN expression has a greater effect in slow growing Wuding chickens than in the fast growing broilers. In contract, leg muscle MSTN mRNA level has a greater effect in broilers than in Wuding chickens. MSTN regulates growth performance and carcass traits in chickens.

Comparison and analysis of Wuding and avian chicken skeletal muscle satellite cells.

Chicken skeletal muscle satellite cells are located between the basement membrane and the sarcolemma of mature muscle fibers. Avian broilers have been genetically selected based on their high growth velocity and large muscle mass. The Wuding chicken is a famous local chicken in Yunnan Province that undergoes non-selection breeding and is slow growing. In this study, we aimed to explore differences in the proliferation and differentiation properties of satellite cells isolated from the two chicken breeds. Using immunofluorescence, hematoxylin-eosin staining and real-time polymerase chain reaction analysis, we analyzed the in vitro characteristics of proliferating and differentiating satellite cells isolated from the two chicken breeds. The growth curve of satellite cells was S-shaped, and cells from Wuding chickens entered the logarithmic phase and plateau phase 1 day later than those from Avian chicken. The results also showed that the two skeletal muscle satellite cell lines were positive for Pax7, MyoD and IGF-1. The expression of Pax7 followed a downward trend, whereas that of MyoD and IGF-1 first increased and subsequently decreased in cells isolated from the two chickens. These data indicated that the skeletal muscle satellite cells of Avian chicken grow and differentiate faster than did those of Wuding chickens. We suggest that the methods of breeding selection applied to these breeds regulate the characteristics of skeletal muscle satellite cells to influence muscle growth.

Genetic diversity of local Yunnan chicken breeds and their relationships with Red Junglefowl.

Yunnan is situated in the Southwest China and encompasses regions having high biodiversity, including habitats for several ancestral species of domestic animals such as chicken. Domestic chickens in Yunnan were kept by peoples of varied ethnic and economic backgrounds living in highly varied geographic environments. To identify the genetic background of Yunnan domestic chickens and their relationships with Red Junglefowl, we applied 28 widely used microsatellite DNA markers to genotype 340 birds from 7 chicken breeds and Red Junglefowl indigenous to Yunnan. Among a total of 342 alleles identified, 121 (35.4%) were breed specific, with Red Junglefowl harboring most microsatellite alleles (23). High levels of heterozygosity were observed within populations indicated by a mean unbiased HE value of 0.663, which was higher than the reported for most populations elsewhere. The FIS value of domestic populations ranged from -0.098-0.005, indicating a lack of inbreeding among these populations. A high proportion of significant departures (89) from the 224 HWE tests for each locus in each population reflected an excess of heterozygosity and population substructure. Individual assignment tests, high FST values (0.1757-0.3015), and Nei's DA genetic distances (0.4232-0.6950) indicated clear differentiation among these populations. These observations, along with the close genetic distance between indigenous domestic populations and Red Junglefowl, were consistent with the primitive and ancestral state of Yunnan indigenous chickens. Protecting the unique variants of these indigenous poultry varieties from contamination with commercial breeds might provide values for improving modern agricultural livestock and breeding programs. Thus, the current study may benefit breeding management and conservation efforts.

Expression of lipogenic genes during porcine intramuscular preadipocyte differentiation.

Intramuscular fat (IMF) content plays an important role in meat quality. Triglyceride (TG) metabolism in intramuscular adipocytes is strongly associated with the intramuscular fat deposition. To better understand the mechanisms leading to IMF deposition we compared the expression levels of genes related to preadipocyte differentiation and lipogenesis in the intramuscular preadipocytes isolated from the longissimus muscle of Wujin and Landrace pigs. The results showed that the intramuscular preadipocytes could differentiate into mature adipocytes in vitro. Triglyceride content in adipocytes isolated from Wujin pigs was higher than Landrace pigs during the middle and later phases of preadipocyte differentiation. The expression levels of genes related to preadipocyte differentiation such as PPARG and CEBPA showed differential expression between Wujin and Landrace porcine adipocytes during the early stage of differentiation. The expression levels of lipogenic genes such as FASN and SREBF1 were significantly higher in Wujin porcine intramuscular preadipocytes than in Landrace intramuscular preadipocytes at the middle and the later stages of differentiation. This suggests that preadipocyte differentiation and lipogenesis exhibited breed-related scheduling.

Anti-adipocyte scFv-Fc antibody suppresses subcutaneous adipose tissue development and affects lipid metabolism in minipigs.

Anti-adipocyte monoclonal antibody has been shown to reduce body fat mass in animals. Here, we investigated the effects of an anti-adipocyte antibody (single-chain variable fragment and crystallizable fragment, scFv-Fc) on pig subcutaneous adipose tissue development and lipid metabolism. The scFv-Fc antibody did not alter feed intake or body weight of treated pigs. It suppressed subcutaneous adipose tissue development by reducing the percentage of larger adipocytes, which led to a reduction in body fat mass and subcutaneous adipose tissue thickness. Body fat mass was reduced by reducing triglyceride biosynthesis and promoting triglyceride lipolysis in adipose tissue. There was an increase in lipoprotein lipase mRNA expression in adipose tissue and activity in blood and an enhanced transportation of circulating high-density lipoprotein, low-density lipoprotein, and free fatty acids. Blood concentrations of triglyceride, total cholesterol, glucose, insulin, and adiponectin and mRNA expression of adiponectin in adipose tissue remained unaffected. These findings suggest that anti-adipocyte scFv-Fc antibody may have an application for reducing body fat mass in obese subjects.

The polymorphisms of UCP2 and UCP3 genes associated with fat metabolism, obesity and diabetes.

Uncoupling proteins (UCPs) belong to the family of mitochondrial transporter proteins that may uncouple the transport of protons across the inner mitochondrial membrane from electron transport and the synthesis of ATP from ADP, hence generating heat rather than energy. In mammals, more than five family members have been identified, including UCP1, UCP2, UCP3, UCP4 (or BMCP1/UCP5) and UCP5. The UCPs may play an important role in energy homeostasis and have become prominent in the fields of thermogenesis, obesity, diabetes and free-radical biology and have been considered candidate genes for obesity and insulin resistance. They have been as important potential targets for treatment of aging, degenerative diseases, diabetes and obesity. Recently, a series of studies showed the polymorphisms of UCPs gene association with the fat metabolism, obesity and diabetes. This review summarizes data supporting the roles of UCP2 and UCP3 in energy dissipation, as well as the genetic variety association with fat metabolism, obesity and diabetes in humans.

[Cloning, nucleotide sequence and tissue expression profile 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 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 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 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 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, kidney, and almost not expressed in small intestine, large intestine, liver, muscle. The swine RHOG gene was over-expressed 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 over-expressed in fat and spleen, moderately in lung and kidney, weakly in small intestine and large intestine, and almost not expressed in liver and muscle.

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.

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.

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.