Mashen Pigs Research Articles

Transcriptome Analysis Revealed Potential Genes of Skeletal Muscle Thermogenesis in Mashen Pigs and Large White Pigs under Cold Stress.

Pigs are susceptible to cold stress due to the absence of brown fat caused by the partial deletion of uncoupling protein 1 during their evolution. Some local pig breeds in China exhibit potential cold adaptability, but research has primarily focused on fat and intestinal tissues. Skeletal muscle plays a key role in adaptive thermogenesis in mammals, yet the molecular mechanism of cold adaptation in porcine skeletal muscle remains poorly understood. This study investigated the cold adaptability of two pig breeds, Mashen pigs (MS) and Large White pigs (LW), in a four-day cold (4 °C) or normal temperature (25 °C) environment. We recorded phenotypic changes and collected blood and longissimus dorsi muscle for transcriptome sequencing. Finally, the PRSS8 gene was randomly selected for functional exploration in porcine skeletal muscle satellite cells. A decrease in body temperature and body weight in both LW and MS pigs under cold stress, accompanied by increased shivering frequency and respiratory frequency, were observed. However, the MS pigs demonstrated stable physiological homeostasis, indicating a certain level of cold adaptability. The LW pigs primarily responded to cold stress by regulating their heat production and glycolipid energy metabolism. The MS pigs exhibited a distinct response to cold stress, involving the regulation of heat production, energy metabolism pathways, and robust mitochondrial activity, as well as a stronger immune response. Furthermore, the functional exploration of PRSS8 in porcine skeletal muscle satellite cells revealed that it affected cellular energy metabolism and thermogenesis by regulating ERK phosphorylation. These findings shed light on the diverse transcriptional responses of skeletal muscle in LW and MS pigs under cold stress, offering valuable insights into the molecular mechanisms underlying cold adaptation in pigs.

FNDC5 Promotes Adipogenic Differentiation of Primary Preadipocytes in Mashen Pigs.

Fibronectin type III domain-containing protein 5 (FNDC5) plays an important role in fat deposition, which can be cut to form Irisin to promote fat thermogenesis, resulting in a decrease in fat content. However, the mechanism of FNDC5 related to fat deposition in pigs is still unclear. In this research, we studied the expression of FNDC5 on different adiposes and its function in the adipogenic differentiation of primary preadipocytes in Mashen pigs. The expression pattern of FNDC5 was detected by qRT-PCR and Western blotting in Mashen pigs. FNDC5 overexpression and interference vectors were constructed and transfected into porcine primary preadipocytes by lentivirus. Then, the expression of key adipogenic genes was detected by qRT-PCR and the content of lipid droplets was detected by Oil Red O staining. The results showed that the expression of FNDC5 in abdominal fat was higher than that in back subcutaneous fat in Mashen pigs, whereas the expression in back subcutaneous fat of Mashen pigs was significantly higher than that of Large White pigs. In vitro, FNDC5 promoted the adipogenic differentiation of primary preadipocytes of Mashen pigs and upregulated the expression of genes related to adipogenesis, but did not activate the extracellular signal-regulated kinase (ERK) signaling pathway. This study can provide a theoretical basis for FNDC5 in adipogenic differentiation in pigs.

Effects of Low-Ambient-Temperature Stimulation on Modifying the Intestinal Structure and Function of Different Pig Breeds.

Simple SummaryLow ambient temperature resulted in the body’s cold stress response, while local wild boars in the middle-temperate zone performed better than commercial pigs. Therefore, three breeds—Large White (LW) pigs, a local Mashen (MS) pig breed and Jinfen White (JFW) pigs, a hybrid breed from wild boar—were investigated in an artificial climate chamber. The results implicated that low-ambient-temperature stimulation increased trypsin activity in duodenal chyme and promoted inflammatory response in Mashen pigs. The cold-resistance mechanism of MS pigs should be explored to reduce hogs’ stress caused by low-ambient-temperature stimulation.Ambient temperature (Ta) fluctuation is a key factor affecting the growth performance and economic returns of pigs. However, whether the response of intestinal structure and function are related to pig breeds in low Ta has not been investigated yet. In this study, Large White (LW) pigs, Jinfen White (JFW) pigs and Mashen (MS) pigs were raised in artificial climate chambers under normal Ta (25 °C) and low Ta (4 °C) for 96 h. Afterwards, the decrease in body temperature and complete blood counts (CBC) of all pigs were measured. Hematoxylin–eosin, immunohistochemical staining, qPCR and ELISA were used to investigate their intestinal mucosa integrity and inflammatory response. The results showed that MS pigs could maintain a normal body temperature and villus structure after 4 °C stimulation compared with those of LW and JFW pigs. Villus height and villus height/crypt depth of MS pigs were significantly higher than those of LW and JFW pigs at 4 °C. Low-Ta stimulation increased the digestion of carbohydrates of all pigs. Meanwhile, low Ta enhanced the activity of lipase in LW pigs and increased trypsin activity in MS and JFW pigs. Furthermore, low-Ta stimulation significantly downregulated the protein of tight junction and upregulated the mRNA expression of inflammatory cytokines in MS pigs. MS pigs also showed stronger spleen immune function at 4 °C. These results indicated that the local MS pig breed had stronger intestinal function in low Ta by producing a stronger inflammatory response, which lays the foundation for further study on the mechanism of cold tolerance in pigs.

The long non-coding RNA lncMYOZ2 mediates an AHCY/MYOZ2 axis to promote adipogenic differentiation in porcine preadipocytes

Long non-coding RNAs (lncRNAs) play a vital role in regulating adipogenesis. However, the associated regulatory mechanisms have yet to be described in detail in pig. In this study, we demonstrate a critical role for lncMYOZ2 in adipogenesis from porcine preadipocytes. Specifically, lncMYOZ2 was more abundant in the adipose tissue of Mashen (fat-type) pigs than for Large White (lean-type) pigs, and knockdown of this lncRNA significantly inhibited the differentiation of porcine preadipocytes into adipocytes. Mechanistically, we used RNA pull-down and RIP assays to establish that lncMYOZ2 interacts with adenosylhomocysteinase (AHCY). Moreover, lncMYOZ2 knockdown increased promoter methylation of the target gene MYOZ2 and lowered its expression. Finally, we describe a positive regulatory role for MYOZ2 in adipogenesis. Collectively, these findings establish lncMYOZ2 as an important epigenetic regulator of adipogenesis via the aforementioned AHCY/MYOZ2 pathway, and provide insights into the role of lncRNAs in porcine adipose development.

Effect of Different Pig Fecal Microbiota Transplantation on Mice Intestinal Function and Microbiota Changes During Cold Exposure.

Cold stress influences intestinal processes, causing physiological and immunological responses in animals. Intestinal microbiota participates in maintaining the stability of the intestinal environment. However, phenotypic characteristics and the effects of porcine microbiota changes under cold conditions remain poorly understood. Here, the fecal microbiota of cold tolerant breed (Mashen) and cold sensitive breed (Duroc-Landrace-Yorkshire) was transferred to germ-free mice, respectively. After a cold exposure (4°C) for 21 days, intestinal function and microbe changes of mice were explored. The results showed that Mashen pigs microbiota transplantation made the body temperature of the mice stable, in which the fat weight and expression of uncoupling protein 1 (UCP1), carnitine palmitoyltransferase 1B (Cpt1b), and Peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α) were significantly higher (P < 0.05) than those of the control group. The results of intestinal structure and expression of serum inflammatory factors showed that fecal microbiota transplantation (FMT) mice have more intact intestinal structure and high expression of proinflammatory factor such as interleukin-4 (IL-4). The study of mice fecal microbiome characterized via 16S rRNA sequencing found that pig microbiota transplantation changed the abundance of Firmicutes. In addition, it identified discriminative features of Firmicutes in the microbiota between two breeds of pig, in which Clostridiaceae were enriched in the microbiota community of Mashen pig and Coriobacteriales were significantly (P < 0.05) enriched in the Duroc-Landrace-Yorkshire pig microbiota transplantation group based on linear discriminant analysis effect size (LEfSe) analysis. Finally, we found that the content of propionic acid and butyric acid in rectal contents significantly changed and the abundances of Clostridium and Lachnospira showed significant correlations with changes in short-chain fatty acids. The results suggest that pig fecal microbiota transplantation can alleviate the changes in physiological and biochemical indicators in mice caused by cold exposure. Mice have gut microbes altered and improved gut barrier function via fecal microbiota transplantation in pigs.

Effects of Maternal Factors and Postpartum Environment on Early Colonization of Intestinal Microbiota in Piglets.

Intestinal microbiota significantly influences the intake, storage, and utilization of body nutrients, as well as animal growth and development. The establishment of microbiota is affected by many factors, such as delivery and feeding modes, antibiotics, disease, and the surrounding environment. In this study, we selected Chinese indigenous Mashen and Jinfen White pigs as the study subjects. To explore the source and factors affecting the piglet intestinal microbiota, 16S rRNA gene sequencing was performed to analyze the microbial composition of the feces, saliva, vaginal secretions, and colostrum of parturient sows, feces and saliva of newborn piglets, and surrounding environment samples. The results showed that the microbiota of the saliva of sows and piglets is structurally similar to that of the environment and is dominated by the phylum Proteobacteria, including Acinetobacter, Actinomyces, and Pseudomonas. The core genus in the vaginal secretions and colostrum of sows was Pseudomonas. Among the fecal samples, the core bacterial genera in sows before and after delivery were Clostridium sensu_stricto_1 and Christensenellaceae_R-7_group, while in piglets at 1 d of age, Pseudomonas and Escherichia-Shigella were most abundant. These results indicate that microbiota in feces, colostrum, and vaginal secretions of sows more easily colonized piglet intestines through a symbiotic effect. The environmental and salivary microbiota could also affect the early colonization and succession of the intestinal microbiota of piglets to some extent. This study provides a theoretical basis for sow delivery protection and early nursing of piglets and background for the research and development of microbial agents to improve piglet intestinal health.

Comprehensive analysis of differentially expressed circRNAs and ceRNA regulatory network in porcine skeletal muscle

BackgroundCircular RNA (circRNA), a novel class of non-coding RNA, has a closed-loop structure with important functions in skeletal muscle growth. The purpose of this study was to investigate the role of differentially expressed circRNAs (DEcircRNAs), as well as the DEcircRNA-miRNA-mRNA regulatory network, at different stages of porcine skeletal muscle development. Here, we present a panoramic view of circRNA expression in porcine skeletal muscle from Large White and Mashen pigs at 1, 90, and 180 days of age.ResultsWe identified a total of 5819 circRNAs. DEcircRNA analysis at different stages showed 327 DEcircRNAs present in both breeds. DEcircRNA host genes were concentrated predominately in TGF-β, MAPK, FoxO, and other signaling pathways related to skeletal muscle growth and fat deposition. Further prediction showed that 128 DEcircRNAs could bind to 253 miRNAs, while miRNAs could target 945 mRNAs. The constructed ceRNA network plays a vital role in skeletal muscle growth and development, and fat deposition. Circ_0015885/miR-23b/SESN3 in the ceRNA network attracted our attention. miR-23b and SESN3 were found to participate in skeletal muscle growth regulation, also playing an important role in fat deposition. Using convergent and divergent primer amplification, RNase R digestion, and qRT-PCR, circ_0015885, an exonic circRNA derived from Homer Scaffold Protein 1 (HOMER1), was confirmed to be differentially expressed during skeletal muscle growth. In summary, circ_0015885 may further regulate SESN3 expression by interacting with miR-23b to function in skeletal muscle.ConclusionsThis study not only enriched the circRNA library in pigs, but also laid a solid foundation for the screening of key circRNAs during skeletal muscle growth and intramural fat deposition. In addition, circ_0015885/miR-23b/SESN3, a new network regulating skeletal muscle growth and fat deposition, was identified as important for increasing the growth rate of pigs and improving meat quality.

MyHCs developmental expression patterns and its effect on muscle fibre characteristics in pig

ABSTRACT This study comprehensively explored muscle fibre characteristics and expression patterns of myosin heavy chain (MyHC) family in skeletal muscles of Large White and Mashen pigs exhibiting differences in muscle fibre development in postnatal muscle growth. Muscle fibre density and diameter were analysed using haematoxylin and eosin staining. The expression patterns of MyHCI, MyHCIIa, MyHCIIx and MyHCIIb were detected by quantitative real-time polymerase chain reaction. The muscle fibre diameter increased and density decreased gradually with aging. In individuals of the same age, the muscle fibre diameter was significantly lower and density was significantly higher in Mashen than in Large White pigs. The MyHCI expression increased, whereas that of MyHCIIa first increased and then decreased. The expression of MyHCI and MyHCIIa was significantly higher in Mashen. The expression of MyHCIIx and MyHCIIb decreased with increasing age; their expression was significantly lower in Mashen pigs. Muscle fibre diameter was negatively correlated with MyHCI expression and positively correlated with MyHCIIx and MyHCIIb expression (except the expression of MyHCI in psoas major). Muscle fibre diameter, muscle fibre density, and MyHCs expression follow certain patterns in skeletal muscles. These results provide valuable information for understanding the molecular mechanism responsible for pig growth performance and meat quality.

Transcriptome profile of skeletal muscle at different developmental stages in Large White and Mashen pigs

From the perspectives of promoting individual growth and development, increasing pork yield, and improving feed utilization, it is desirable to screen candidate genes underlying pig muscle growth and regulation. In this study, we investigated transcriptome differences at 1, 90, and 180 d of age in Large White and Mashen pigs, characterized differentially expressed genes (DEGs), and screened candidate genes affecting skeletal muscle growth and development. RNA-seq was applied to analyze the transcriptome of the longissimus dorsi (LD) in the two breeds. In LD samples from the two breeds at three growth stages, 7215, 6332, 237, 3935, 3404, and 846 DEGs were obtained for L01 vs. L90, L01 vs. L180, L90 vs. L180, MS01 vs. MS90, MS01 vs. MS180, and MS90 vs. MS180, respectively. Significant tendencies in DEG expression could be grouped into eight profiles. Based on the functional analysis of DEGs, 16 candidate genes related to skeletal muscle growth and development were identified, including PCK2, GNAS, ADCY2, PRKAB1, PRKAB2, PRKAG1, PRKAG2, PHKA1, PHKA2, PHKG1, PHKG2, ITPR3, IGF1R, FGFR4, FGF1, and FGF18. The results of this study thus provide a theoretical basis for the mechanisms and candidate genes underlying skeletal muscle development in pigs.

Comparison of carcass traits, meat quality and expressions of MyHCs in muscles between Mashen and Large White pigs

The aim of this study was to evaluate the differences in carcase traits, meat quality and muscle characteristics (mean fibre diameter and MyHCs levels of expression) between Mashen and Large White pigs. A total of 60 pigs (30 Mashen pigs and 30 Large White pigs, half male and half female in each breed) were used in this experiment. Results showed that Mashen pigs exhibited lower slaughter weight, reduced back-fat thickness, reduced loin eye area and lower lean meat ratio than Large White pigs (p < .05). Meat from Large White pigs had higher pH1, greater drip losses, higher Warner-Bratzler shear force values, higher lightness, higher yellowness, and greater mean diameter of muscle fibres. Also, meat from Large white pigs had lower cooked yield, lower redness, and reduced intramuscular fat content than meat from Mashen pigs (p < .05). The contents of 17 amino acids, total amino acids, essential amino acids and umami amino acids in the longissimus dorsi of Mashen pigs were higher than those in Large White pigs (p < .05). Large White pigs had higher monounsaturated fatty acids and lower polyunsaturated fatty acids than Mashen pigs (p < .05). Meanwhile, the expression of MyHCI was significantly higher and the expression of MyHCIIb was lower in Mashen than in Large White pigs (p < .05). The higher MyHCI and lower MyHCIIb found in muscles from Mashen pigs might partially explain meat quality differences found between the two breeds in the present study. These results provide valuable information for meat quality differences between Mashen and Large White pigs.HighlightsCarcase traits and meat quality between Large White and Mashen pigs exhibited significant differences.The total amino acids, essential amino acids and umami amino acids in Mashen pigs were higher than those in Large White pigs.Large White pigs had higher monounsaturated fatty acids and lower polyunsaturated fatty acids than Mashen pigs.The expression of MyHCI was significantly higher and the expression of MyHCIIb was lower in Mashen than in Large White pigs.

Identification of candidate genes of growth traits in pigs using RNA-sequencing

The aim of this research was to screen candidate genes affecting growth traits in pigs by studying the difference expression genes (DEGs) between the longissimus dorsi of Large White (LW) and Mashen (MS) pigs. RNA-sequencing (RNA-seq) technology was applied to analyse the transcriptomes from six longissimus dorsi in two pig breeds (LW and MS). Based on sequencing, the DEGs were screened, and functional annotation and enrichment analysis were performed. The results showed that 697 different significant genes were obtained (p < 0.05, FDR <0.05 and |FC| ≥ 2). The results of Gene Ontology (GO) functional annotation showed that DEGs were mainly related to the growth and development of skeletal muscle, the formation of organelles and the function of protein binding. DEGs were mainly involved in the pathways of Phagosome, Viral myocarditis, Antigen processing and presentation, Allograft rejection, Graft-versus-host disease, Cardiac muscle contraction by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Combined with other livestock genomics studies, SFRP2, KDM6A, OGT may be candidate genes involved in pig growth traits. The results provided a theoretical basis for the improvement of pig growth traits and the study of candidate genes.HighlightsIn this study, three candidate genes (SFRP2, KDM6A, OGT) which affecting growth traits were screened.The experimental animals selected in this study were the local breed Mashen pig and the Western commercial breed Large White pig with obvious growth traits difference.In this study, RNA-Seq technology was applied to analysis the transcriptomes of pig muscle.

Novel alternatively spliced isoforms of MEF2A and their mRNA expression patterns in pigs

The present study aimed to identify the alternatively spliced isoforms of pig MEF2A gene and to determine theirmRNA expression patterns. Four alternatively spliced isoforms of pig MEF2A gene (i.e. MEF2A1, MEF2A2, MEF2A3 and MEF2A4) were cloned according to the results of transcriptome sequencing. The fifth to eighth exons of MEF2A1 were normally spliced. In MEF2A2, the fifth exon was missing; the sixth exon had an extra 138 bp at its 5' end, and the seventh exon had an extra 102 bp at its 3' end. In MEF2A3, the fifth exon was missing, and the sixth exon had an additional 138 bp at its 5' end. In MEF2A4, the seventh exon had an extra 102 bp at its 3' end. Quantitative real-time polymerase chain reaction (qPCR) analysis indicated that the expression profiles of the four alternatively spliced transcripts in the longissimus dorsi differed between the Mashen and Large White pigs. MEF2A1 and MEF2A2 expression levels were the highest at 90 days of age and lowest at 180 days of age. MEF2A3 and MEF2A4 expression levels increased with age (in days). The four alternatively spliced isoforms of MEF2A were also expressed in the small intestine, cerebellum, pancreas, heart and lung. The discovery of new alternatively spliced transcripts of the MEF2A gene may be utilized in understanding its biological functions.

Novel splice isoforms of pig myoneurin and their diverse mRNA expression patterns.

ObjectiveThe aim of this study was to clone alternative splicing isoforms of pig myoneurin (MYNN), predict the structure and function of coding protein, and study temporal and spatial expression characteristics of each transcript.MethodsAlternative splice isoforms of MYNN were identified using RNA sequencing (RNA-seq) and cloning techniques. Quantitative real-time polymerase chain reaction (qPCR) was employed to detect expression patterns in 11 tissues of Large White (LW) and Mashen (MS) pigs, and to study developmental expression patterns in cerebellum (CE), stomach (ST), and longissimus dorsi (LD).ResultsThe results showed that MYNN had two alternatively spliced isoforms, MYNN-1 (GenBank accession number: KY470829) and MYNN-2 (GenBank accession number: KY670835). MYNN-1 coding sequence (CDS) is composed of 1,830 bp encoding 609 AA, whereas MYNN-2 CDS is composed of 1,746 bp encoding 581 AA. MYNN-2 was 84 bp less than MYNN-1 and lacked the sixth exon. MYNN-2 was found to have one C2H2 type zinc finger protein domain less than MYNN-1. Two variants were ubiquitously expressed in all pig tissues, and there were significant differences in expression of different tissues (p<0.05; p<0.01). The expression of MYNN-1 was significantly higher than that of MYNN-2 in almost tissues (p<0.05; p<0.01), which testified that MYNN-1 is the main variant. The expression of two isoforms decreased gradually with increase of age in ST and CE of MS pig, whereas increased gradually in LW pig. In LD, the expression of two isoforms increased first and then decreased with increase of age in MS pig, and decreased gradually in LW pig.ConclusionTwo transcripts of pig MYNN were successfully cloned and MYNN-1 was main variant. MYNN was highly expressed in ST, CE, and LD, and their expression was regular. We speculated that MYNN plays important roles in digestion/absorption and skeletal muscle growth, whereas the specific mechanisms require further elucidation.

LncRNA profiling of skeletal muscles in Large White pigs and Mashen pigs during development.

Long noncoding RNA (lncRNA) has been increasingly implicated in the regulation of muscle development. Large White pigs have a higher muscle growth rate than do Mashen pigs. In the present study, the lncRNA expression profiles in skeletal muscle of these 2 pig breeds were compared at 1, 90, and 180 d of age using RNA sequencing. We obtained 2,718 million clean reads and identified a total of 5,153 novel lncRNA. We found 1,407 differentially expressed lncRNA that showed consistent expression patterns between the 2 breeds at all the 3 sampling points. Ten lncRNA were randomly selected, and their expression was validated using Real-time Quantitative PCR. In summary, this study identifies a number of lncRNA that correlate with muscle growth. The regulation and function of these lncRNA in muscle growth and development need to be further explored.

Enhanced adipogenesis in Mashen pigs compared with Large White pigs

Intramuscular fat (IMF) is critical pork meat quality; however, its content is relatively low in commercial pig breeds. The objective of this experiment was to investigate the difference in intramuscular adipogenesis between Mashen and Large White pigs. 12 male Mashen and Large White piglets (six in each breed) were used, and longissimus dorsi muscle was sampled for analysis. The results showed that back fat thickness (p < .01) and leaf fat weight (p < .05) were increased in Mashen pigs. Moreover, the IMF contents were greater in Mashen pigs (p < .01). With exception of sterol regulatory element-binding protein 1, mRNA expression of other adipogenic markers, including Zinc finger protein 423 (p < .05), platelet-derived growth factor receptor α (p < .05), CCAAT enhancer binding protein β (C/EBPβ, p < .05), C/EBPα (p < .05) and peroxisome proliferator-activated receptor γ (PPARγ, p < .01) were greater in Mashen pigs; consistently, protein abundance of both C/EBPα (p < .01) and PPARγ (p < .05) were also greater. Both mRNA expression of fatty acid synthase (FAS) (p < .01) and its activity (p < .05) were elevated in Mashen pigs, whereas no difference of acetyl-CoA carboxylase activity was observed. In addition, protein content of fatty-acid binding protein 4 (FABP4) was elevated in Mashen pigs. The malate dehydrogenase activity was greater (p < .05) and hormone-sensitive lipase activity was lower in Mashen pigs. In summary, IMF content was enhanced in Mashen pigs, which at least partly through enhancing intramuscular adipogenesis.

LncRNA profiling of skeletal muscles in Large White pigs and Mashen pigs during development

LncRNA profiling of skeletal muscles in Large White pigs and Mashen pigs during development

Study on the Developmental Expression of Lbx1 Gene in Longissimus Dorsi of Mashen and Large White Pigs

In the present study we investigated the developmental expression patterns of Lbx1 gene in skeletal muscle of different genetic profile pigs after birth. A total of 28 Mashen pigs and 28 Large White pigs from seven development stages of 1, 30, 60, 90, 120, 150, 180 d were used and the expression patterns in longissimus dorsi were studied by quantitative real time-polymerase chain reaction and western blot in this study. The results showed that the breed, age, and the interaction of breed and age significantly affected the Lbx1 mRNA and protein expressions in longissimus dorsi (P<0.05). In Large White, the amount of Lbx1 protein was increased from new birth to 30 d, and decreased after 30 d to the lowest level at 180 d. In Mashen pig, Lbx1 protein level showed an increase trend with the age increase before 90 d, then decreased to the lowest level at 120 d, and then gradually increased upwards to the expression peak at 180 d. Before 120 d, the Lbx1 protein content in Large White was higher than that in Mashen pig, except for at 60 d. Afterwards, the protein level in Mashen was higher than that in Large White. The Lbx1 expression pattern was related to the age and genetic profiles of Mashen and Large White pigs, which indicates that Lbx1 could participate in the muscle development through activating the satellite cells of skeletal muscle after birth.

Effects of the MyoG Gene on the Partial Growth Traits in Pigs

Single-nucleotide polymorphisms of the MyoG gene were tested using PCR-SSCP in different pig breeds including Landrace, Large White, Duroc, Shanxi Black, and Mashen pigs, and the effects of the MyoG gene on the birth weight, the weaning weight, the 6-month body weight, and the backfat thickness were also analyzed. On the basis of the published sequence of the porcine MyoG gene, ten pairs of primers were designed, and one polymorphism was found in the PCR product amplified with In2-3 primers. The results showed that: (1) the Landrace, the Large White, and the Duroc breeds differ significantly ( P < 0.05) in genotype distribution from the Shanxi Black and the Mashen breeds; (2) On the basis of the fixed effect model, significant differences were found in the birth weight and the backfat thickness among the different MyoG genotypes, whereas no significant differences existed in the weaning weight and the 6-month body weight; (3) Using least square analysis, it was seen that individuals of the BB genotype had significantly less ( P < 0.01) birth weight than those of the AA and AB genotypes, with the order being AA> AB> BB; the pigs of the AA genotype had significantly lower ( P < 0.01) backfat thickness than those of the AB and BB genotypes, with the order being AA< AB< BB. These results suggest that the genotype has significant effects on the individual birth weight and the backfat thickness, and that the selection of the A allele is favored with regard to the birth weight and the backfat thickness.