Min Pig Research Articles

Screening out important substances for distinguishing Chinese indigenous pork and hybrid pork and identifying different pork muscles by analyzing the fatty acid and nucleotide contents

Fatty acids and nucleotides are major contributors of pork flavor, which are key quality traits influencing consumers' preference. In this study, we investigated the contents of nucleotides (inosinic acid, inosine, and hypoxanthine) and 26 fatty acids by high-performance liquid chromatography and gas chromatography in longissimus dorsi and semimembranous muscle of four breeds (Dongbei Min pig, Beijing Black pig, Wuzhishan pig, and DLY pigs). Combining with multivariate statistics, we found significant differences in the nucleotides and fatty acids compositions among the breeds and muscles. Furthermore, the content of total unsaturated fatty acids and DHA were higher in native pigs than crossbred pigs. This study provides a theoretical basis for understanding the composition of flavor precursor substances, as well as for the identification of different muscles.

Postural changes, nursing behavior, and production performance of two breeds of sows in enriched environment

This study was performed to compare changes in posture, nursing behavior, and production performance of two breeds of sows. The posture, postural changes, nursing behavior, and production performance of hybrid Damin (Large White × Min pig, n = 32) and Landrace × Large White (n = 32) sows were observed by video recording for 72 h after farrowing and from 07:00 to 09:00 h and 13:00 to 15:00 h within any successive two-day period of each week from the [...]

Screening of cellulose degradation bacteria from Min pigs and optimization of its cellulase production

Abstract Background Cellulose as a potential feed resource hinders its utilization because of its complex structure, and cellulase is the key to its biological effective utilization. Animal endogenous probiotics are more susceptible to colonization in the intestinal tract, and their digestive enzymes are more conducive to the digestion and absorption of feed in young animals. Min pigs are potential sources of cellulase probiotics because of the high proportion of dietary fiber in their feed. In this study, the cellulolytic bacteria in the feces of Min pigs were isolated and screened. The characteristics of enzymes and cellulase production were studied, which provided a theoretical basis for the rational utilization of cellulase and high-fiber food in animal production. Results In our study, 10 strains of cellulase producing strains were isolated from Min pig manure, among which the M2 strain had the best enzyme producing ability and was identified as Bacillus velezensis. The optimum production conditions of cellulase from strain M2 were: 2% inoculum, the temperature of 35°C, the pH of 5.0, and the liquid loading volume of 50 mL. The optimum temperature, pH and time for the reaction of cellulase produced by strain M2 were 55°C, 4.5 and 5 min, respectively. Conclusions Min pigs can be used as a source of cellulase producing strains. The M2 strain isolated from feces was identified as Bacillus velezensis. The cellulase from M2 strain had a good activity and the potential to be used as feed additive for piglets. How to cite: Li F, Xie Y, Gao X, et al. Screening of cellulose degradation bacteria from Min Pigs and optimization of its cellulase production. Electron J Biotechnol 2020;48. https://doi.org/10.1016/j.ejbt.2020.09.001

Complete mitochondrial genome of Min pig in nucleus herd

In this study, the complete mitochondrial genome of Min pig (Sus scrofa) in nucleus herd was sequenced in order to develop the mitogenome data for genus Sus. The complete mitogenome sequence is 16,719 bp in length, containing a D-loop region, 13 protein-coding genes, 2 ribosomal RNA, and 22 transfer RNA genes. The new sequenced complete mitogenome of Min pig in nucleus herd will provide useful information for application in conservation genetics and evolution for this Near Threatened pig genomes.

Effects of environment and breed on growth performance and meat quality of fattening pigs

AbstractMeat quality is not only influenced by breed but also rearing environment. The aim of this study was to evaluate the influence of different housing environments on growth performance, carcase traits, meat quality, physiological response pre-slaughter and fatty acid composition in two pig breeds. A total of 120 growing pigs at 60-70 days of age were arranged in a 2 × 2 factorial design with the breeds (Duroc × Landrace × Large White [D × L × LW] and Duroc × Landrace × Min pig [D × L × M]) and environmental enrichment (barren concrete floor or enriched with straw bedding) as factors. Each treatment was performed in triplicate with ten pigs per replicate. The pigs housed in the enriched environment exhibited a higher average daily gain, average daily feed intake, saturated fatty acid percentage and backfat depth than the pigs reared in the barren environment. Plasma cortisol levels were lower and growth hormone higher in enriched compared to barren pens. The D × L × M pigs showed lower cooking loss compared with the D × L × LW pigs. Moreover, the D × L × M pigs exhibited poor growth performance but had a better water-holding capacity. Only carcase traits and meat quality interaction effects were observed. We concluded that an enriched environment can reduce preslaughter stress and improve the growth performance of pigs and modulate the fatty acid composition of pork products.

Equipping Farrowing Pens with Straw Improves Maternal Behavior and Physiology of Min-Pig Hybrid Sows.

Simple SummaryThis study used different sow breeds combined with an enriched environment to relieve stress and to improve the welfare level of sows. Both groups of sows were in loose-housed pens. Sows living in a barren environment (BE) without straw were compared with sows in farrowing crates that received 3.5 kg of straw daily (enriched environment (EE)). Compared with BE sows, EE sows showed more nest-building behavior prior to farrowing, more nursing behavior, and less ventral recumbency behavior during the first three days postpartum. Furthermore, compared with BE sows, EE sows tended to have higher concentrations of serum oxytocin and prolactin, while the concentration of cortisol was lower, suggesting an increase in maternal behavior and a reduction of stress in this group. In addition, the concentration of oxytocin and both the frequency and duration of prepartum nest-building behavior were higher in Duroc × Min and Landrace × Min sows compared with Landrace × Yorkshire sows. However, the concentration of prolactin was significantly lower in both Duroc × Min and Landrace × Min sows than in Landrace × Yorkshire sows, indicating that hybrid sows of Min-pig inherited good maternal characteristics. Based on these results, straw enrichment improved Min-pig hybrid sow welfare during farrowing and lactation.This study investigated the effects of two factors, enriched environment (EE) and different crossbreeds, on the maternal behavior and physiology of Min-pig hybrid sows. The analysis was performed on a total of 72 multiparous sows, including Duroc × Min pig (DM), Landrace × Min pig (LM), and Landrace × Yorkshire (LY) sows, using a total of 24 sows per cross. The sows were housed in two different farrowing pens, one with straw (EE) and one without straw (barren environment (BE)). The results showed that nest-building behavior, including the frequency, total duration, and bout duration, was significantly higher in EE sows than in BE sows (p < 0.01). The frequency and duration of prepartum nest-building behavior were higher in DM and LM sows than in LY sows (p < 0.0001). During the first three days postpartum, EE sows spent a shorter time in ventral recumbency compared with BE sows (p < 0.05). The oxytocin (p < 0.05) and prolactin (p < 0.01) concentrations of EE sows were significantly higher than in BE sows; however, the concentration of cortisol followed the opposite (p < 0.01). The concentration of oxytocin was significantly higher in DM and LM sows than in LY sows (p < 0.01). In conclusion, both EE increased the expression of hormones related to parental behaviors and prenatal nesting and nursing behavior of sows. Furthermore, an EE can also reduce stress in sows. Min-pig hybrids may inherit highly advantageous characteristics of maternal behavior of Min-pig sows.

Genomic variants associated with the number and diameter of muscle fibers in pigs as revealed by a genome-wide association study

Muscle fiber characteristics comprise a set of complex traits that influence the mea quality and lean meat production of livestock. However, the genetic and biological mechanisms regulating muscle fiber characteristics are largely unknown in pigs. Based on a genome-wide association study (GWAS) performed on 421 Large White × Min pig F2 individuals presenting well-characterized phenotypes, this work aimed to detect genome variations and candidate genes for five muscle fiber characteristics: percentage of type I fibers (FIB1P), percentage of type IIA fibers (FIB2AP), percentage of type IIB fibers (FIB2BP), diameter of muscle fibers (DIAMF) and number of muscle fibers per unit area (NUMMF). The GWAS used the Illumina Porcine SNP60K genotypic data, which were analyzed by a mixed model. Seven and 10 single nucleotide polymorphisms (SNPs) were significantly associated with DIAMF and NUMMF, respectively (P < 1.10E-06); no SNP was significantly associated with FIB1P, FIB2AP or FIB2B. For DIAMF, the significant SNPs on chromosome 4 were located in the previously reported quantitative trait loci (QTL) interval. Because the significant SNPs on chromosome 6 were not mapped in the previously reported QTL interval, a putative novel QTL was suggested for this locus. None of the previously reported QTL intervals on chromosomes 6 and 14 harbored significant SNPs for NUMMF; thus, new potential QTLs on these two chromosomes are suggested in the present work. The most significant SNPs associated with DIAMF (ALGA0025682) and NUMMF (MARC0046984) explained 12.02% and 11.59% of the phenotypic variation of these traits, respectively. In addition, both SNPs were validated as associated with DIAMF and NUMMF in Beijing Black pigs (P < 0.01). Some candidate genes or non-coding RNAs, such as solute carrier family 44 member 5 and miR-124a-1 for DIAMF, and coiled-coil serine rich protein 2 for NUMMF, were identified based on their close location to the significant SNPs. This study revealed some genome-wide association variants for muscle fiber characteristics, and it provides valuable information to discover the genetic mechanisms controlling these traits in pigs.

Expression pattern and association analysis of porcine matrix metallopeptidase 9 (MMP9) with diarrhea and performance traits in piglets

Matrix metalloproteinase 9 (MMP9) plays critical roles in multiple biological processes, such as reproduction, cell proliferation and differentiation, and host defenses. The aim of this study was to evaluate whether MMP9 is a candidate gene for resistance to diarrhea in piglets. In this study, quantitative real-time PCR was used to analyze the expression of MMP9 mRNA in different tissues of specific pathogen-free piglets. MMP9 was expressed in all the tissues (heart, liver, spleen, lung, kidney, stomach, duodenum, jejunum, ileum, and colon) analyzed. An association analysis between MMP9 polymorphisms and piglet diarrhea score and performance traits were performed in Min (Chinese indigenous breed) and Landrace populations. In the statistical analysis, at the g.48178429 G>A locus, AA piglets had a lower diarrhea score than that of GA in the Min population (P < .05), whereas GG had higher day-35 body weight and average daily gain (ADG) than AA in the Landrace breed (P < .05). At the rs336583561 locus, Min piglets with the GG genotype have a lower diarrhea score than AG piglets (P < .05). At g.48184777C>T, CC animals have higher body weight than TC Landrace piglets (P < .05 or P < .01). A 5′ flanking deletion assay indicated that g.48178429 G>A was not located in the MMP9 promoter region. Our results suggest that the A allele at the g.48178429 G>A locus and the G allele at rs336583561 are resistance alleles in Min pigs. Before these markers are used in pig breeding programs, more studies in larger populations are needed.

The complete mitochondrial genome of Min pig (Hebao) and a phylogenetic analysis

The complete mitochondrial genomes of Min pig (Hebao) are published in this paper. The full length of mtDNA is 16,719 bp and contained 13 PCGs, 2 rRNA and 22 tRNA, and 1D-loop(MN258706). A phylogenetic tree with the 13 protein-coding genes sequences of Min pig (Hebao) together with 45 other Chinese pig breeds and 7 foreign pig breeds was constructed. The results can be subsequently used to provide information for pig phylogenetic and insights into the evolution of genomes. The result of phylogenetic analysis showed that the genetic relationship of Min pig (Hebao) is closer to that of Dapulian pigs.

Expression and subcellular localization of HSPC117 in min pig tissues and the PK15 cell line.

BACKGROUND: The human hematopoietic stem/progenitor cell 117 (HSPC117) protein is involved in many important biological processes.OBJECTIVE:This study was designed to identify the level of HSPC117 mRNA expression in 10 min pig tissue samples and HSPC117 subcellular localization in the PK15 cell line.METHODS: In this study, 10 tissue samples of min pigs were collected, and EGFP-HSPC117 vectors were constructed to express EGFP-HSPC117 fusion proteins in PK15 cells.RESULTS: HSPC117 mRNA was expressed in all of the tissue samples, although the levels of expression in fat and lung tissues were significantly lower than in other tissues ( 0.01). After generating and detecting the EGFP-HSPC117 fusion protein, fluorescence was found to be distributed throughout the cytoplasm and nucleus during interphase; however, the fluorescence was concentrated in the nuclear area in mitotic cells.CONCLUSIONS: These results indicate that the HSPC117 gene is expressed in many min pig tissues. The HSPC117 protein was distributed throughout the cells during interphase, but was concentrated in the nuclear area in mitotic cells.

Duration of cardiac arrest requires different ventilation volumes during cardiopulmonary resuscitation in a pig model.

There are few studies examining the ventilation strategies recommended by current CPR guidelines. We investigated the influence of different minute volume applying to untreated cardiac arrest with different duration, on resuscitation effects in a pig model. 32 Landrace pigs with 4 or 8min (16 pigs each) ventricular fibrillation (VF) randomly received two ventilation strategies during CPR. "Guideline" groups received mechanical ventilation with a tidal volume of 7ml/kg and a frequency of 10/min, while "Baseline" groups received a tidal volume (10ml/kg) and a frequency used at baseline to maintain an end-tidal PCO2 (PETCO2) between 35 and 40mmHg before VF. Mean airway pressures and intrathoracic pressures (PIT) in the Baseline-4min group were significantly higher than those in the Guideline-4min group (all P < 0.05). Similar results were observed in the 8min pigs, except for no significant difference in minimal PIT and PETCO2 during 10min of CPR. Venous pH and venous oxygen saturation were significantly higher in the Baseline-8min group compared to the Guideline-8min group (all P < 0.05). Aortic pressure in the Baseline-8min group was higher than in the Guideline-8min group. Seven pigs in each subgroup of 4min VF models achieved the return of spontaneous circulation (ROSC). Higher ROSC was observed in the Baseline-8min group than in the Guideline-8min group (87.5% vs. 37.5%, P = 0.039). For 4min VF but not 8min VF, a guideline-recommended ventilation strategy had satisfactory results during CPR. A higher minute ventilation resulted in better outcomes for subjects with 8min of untreated VF through thoracic pump.

Data Mining and Validation of AMPK Pathway as a Novel Candidate Role Affecting Intramuscular Fat Content in Pigs.

Simple SummaryIntramuscular fat (IMF) is increasingly being recognized as a key meat trait in the modern pork industry. The aims of this research were to identify potential signaling pathways associated with IMF content in the longissimus dorsi (LD) muscle of different pig breeds and investigate the gene expression levels in the screened signaling pathways. Our results indicated that the AMPK signaling pathway may be related to IMF deposition in the LD muscle of pigs. The results of qRT-PCR analysis showed that the expression of ten key hub genes (AMPK, ADIPOR1, ADIPOR2, LKB1, CAMKKβ, CPT1A, CPT1B, PGC-1α, CD36, and ACC1) differed between the LD muscle of Min and Large White pigs. The protein expression levels of AMPK, LKB1, CaMKK2, CPT1A, and ACC1 were similar to the genes expression patterns in the LD muscle of Large White pigs. The results of this study provide novel insights into the regulatory function of the AMPK signaling pathway in relation to the IMF content in the LD muscle of different pigs.Intramuscular fat (IMF) is an important economic trait for pork quality and a complex quantitative trait regulated by multiple genes. The objective of this work was to investigate the novel transcriptional effects of a multigene pathway on IMF deposition in the longissimus dorsi (LD) muscles of pigs. Potential signaling pathways were screened by mining data from three gene expression profiles in the Gene Expression Omnibus (GEO) database. We designed quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) arrays for the candidate signaling pathways to verify the results in the LD muscles of two pig breeds with different IMF contents (Large White and Min). Western blot analysis was used to detect the expression levels of several candidate proteins. Our results showed that the AMPK signaling pathway was screened via bioinformatics analysis. Ten key hub genes of this signaling pathway (AMPK, ADIPOR1, ADIPOR2, LKB1, CAMKKβ, CPT1A, CPT1B, PGC-1α, CD36, and ACC1) were differentially expressed between the Large White and Min pigs. Western blot analysis further confirmed that LKB1/CaMKK2-AMPK-ACC1-CPT1A axis dominates the activity of AMPK signaling pathway. Statistical analyses revealed that AMPK signaling pathway activity clearly varied among the two pig breeds. Based on these results, we concluded that the activation of the AMPK signaling pathway plays a positive role in reducing IMF deposition in pigs.

Identification of porcine CTLA4 gene polymorphism and their association with piglet diarrhea and performance traits.

The objective of this study was to evaluate the association between the cytotoxic T-lymphocyte-associated antigen 4 (CTLA4) gene and piglet diarrhea. In this study, the mRNA expression of the CTLA4 gene increased significantly in IPEC-J2 cells after Escherichia coli K88 infection. Single nucleotide polymorphisms (SNPs) located in the 5' flanking region (SNPs g.107281989C>T) and 3'-untranslated region (3'-UTR; SNPs g.107288753C>A) were identified, and they were in linkage disequilibrium in both Min pigs and the Landrace population. Association analysis showed that Landrace piglets with a TT or AA genotype had a lower diarrhea index, and AA animals had higher average daily gain when compared to CC pigs, respectively (p < 0.05). However, the relationship between SNPs and diarrhea and performance traits in the Min population was not significant. Haplotype analysis indicated that the TC haplotype had the lowest diarrhea index. The 5' flanking deletion assay suggested that SNP g.107281989C>T was a molecular marker instead of the functional marker. This research demonstrated that genetic variances in the CTLA4 gene had significant effects on Landrace piglet diarrhea resistance.

Behavior and physiology of two different sow breeds in a farrowing environment during late 35-day lactation.

To improve the overall welfare levels of sows and to reduce stress levels at late 35-day lactation, we selected targeted behavioral indicators that might be associated with stress. Therefore, we monitored and evaluated the adaptive capability of two different breeds of sows to the farrowing environment. In this study, Damin sows (Large White × Min pig sows, n = 20) and Large White sows (n = 20) were farrowed in individual pens. Saliva was collected and tested for cortisol density at –15 min, and then at +15, 30, 60, 90, 120, 180 and 240 min after an adrenocorticotropic hormone (ACTH) stimulation test conducted at 20, 27 and 34 d post-partum. The postures, including ventral and lateral recumbency to other postures, defecating, urinating, sham-chewing and bar-biting behavior, were observed by video from 07:00 to 09:00 and from 13:00 to 15:00 on the 7th day of each week from the 3rd to the 5th week post-parturition. In addition, the concentrations of salivary interleukin (IL)-6, tumor necrosis factor (TNF)-α and secretory immunoglobulin (SIgA) were assayed after the observed behaviors. The results showed no significant difference between Damin sows and Large White sows in terms of behaviors at the 3rd week. Additionally, there were no significant differences between Damin and Large White sows in terms of the behaviors of ventral recumbency and bar-biting with the exception of lateral recumbency to other postures, sham-chewing, defecation and urination in the fifth week. Meanwhlie, there was significant difference between two breeds in term of ventral recumbency at the 4th week. The result of the ACTH test showed a significant difference between the Damin and Large White sows by the 27th and 34th days postpartum (P<0.01). In addition, the serological concentrations of IL-6 and TNF-α were not significantly different between the two breeds at the 3rd week postpartum. However, these indicators were significantly different at the 5th week postpartum (P = 0.000, and P = 0.003, respectively). The SIgA concentrations in saliva were significantly different between breeds at the 3rd week postpartum (P<0.01). In conclusion, both breeds of sows maybe in a state of stress after the 4th week postpartum. However, the Damin sows may be better than the Large White sows in terms of adapting to this farrowing environment.

Identification of differentially expressed genes in adipose tissue of min pig and large white pig using RNA-seq

ABSTRACTMin pigs and Large White pigs are two breeds that vary significantly in thickness of adipose tissue. In this study, transcriptome profiling was used to examine the fat tissues of both breeds. Min pig compared to Large White pig, 523 DEGs were down-regulated, and 112 DEGs were up-regulated. The DEGs were significantly enriched in biological process of oxidoreductase activity; helicase activity and others. In cellular component, DEGs were enriched in intracellular. In molecular function, DEGs were enriched in cytoskeletal protein binding and ion binding. Although there were many DEGs between Min pigs and Large White pigs, no significant pathway was enriched surprisingly. ATP6V0A4, TAP2, FGFBP1, PHEROA and GLYATL2 were expressed significantly higher in Large White pigs. These results suggest that the gene expression pattern in the back fat tissue was different between Large White pigs and Min pigs.

Differential Transcriptome Analysis of Early Postnatal Developing Longissimus Dorsi Muscle from Two Pig Breeds Characterized in Divergent Myofiber Traits and Fatness

ABSTRACTMeat quality traits (MQTs) are very important in the porcine industry, which are mainly determined by skeletal muscle fiber composition, extra-muscular and/or intramuscular fat content. To identify the differentially expressed candidate genes affecting the meat quality traits, first we compared the MQTs and skeletal muscle fiber characteristics in the longissimus dorsi muscle (LDM) of the Northeast Min pig (NM) and the Changbaishan wild boar (CW) with their body weight approaching 90 kg. The significant divergences in the skeletal muscle fiber phenotypes and fatness traits between the two porcine breeds established an ideal model system for further identifying potential key functional genes that dominated MQTs. Further, a transcriptome profile analysis was performed using the Illumina sequencing method in early postnatal developing LDM from the two breeds at the ages of 42 days. Comparative analysis between these two cDNA libraries showed that there were 17,653 and 22,049 unambiguous tag-mapped sense transcripts detected from NM and CW, respectively. 4522 differentially expressed genes (DEGs) were revealed between the two tissue samples, of them, 4176 genes were found as having been upregulated and 346 genes were identified as having been downregulated in the NM library. By pathway enrichment analysis, a set of significantly enriched pathways were identified for the DEGs, which are potentially involved in myofiber development, differentiation and growth, lipogenesis and lipolysis in porcine skeletal muscle. The expression levels of 30 out of the DEGs were validated by real-time quantitative reverse transcriptase PCR (qRT-PCR) and the observed result was consistent noticeably with the Illumina transcriptome profiles. The findings from this study can contribute to future investigations of skeletal muscle growth and development mechanism and to establishing molecular approaches to improve meat quality traits in pig breeding.

Characterization of porcine cytokine inducible SH2-containing protein gene and its association with piglet diarrhea traits

ObjectiveThe cytokine inducible SH2-containing protein (CISH), which might play a role in porcine intestine immune responses, was one of the promising candidate genes for piglet anti-disease traits. An experiment was conducted to characterize the porcine CISH (pCISH) gene and to evaluate its genetic effects on pig anti-disease breeding.MethodsBoth reverse transcription polymerase chain reaction (RT-PCR) and PCR were performed to obtain the sequence of pCISH gene. A pEGFP-C1-CISH vector was constructed and transfected into PK-15 cells to analysis the distribution of pCISH. The sequences of individuals were compared with each other to find the polymorphisms in pCISH gene. The association analysis was performed in Min pigs and Landrace pigs to evaluate the genetic effects on piglet diarrhea traits.ResultsIn the present research, the coding sequence and genomic sequence of pCISH gene was obtained. Porcine CISH was mainly localized in cytoplasm. TaqI and HaeIII PCR restriction fragment length polymorphism (RFLP) assays were established to detect single nucleotide polymorphisms (SNPs); A-1575G in promoter region and A2497C in Intron1, respectively. Association studies indicated that SNP A-1575G was significantly associated with diarrhea index of Min piglets (p<0.05) and SNP A2497C was significantly associated with the diarrhea trait of both Min pig and Landrace piglets (p<0.05).ConclusionThis study suggested that the pCISH gene might be a novel candidate gene for pig anti-disease traits, and further studies are needed to confirm the results of this preliminary research.

A comparative study of the effects of long-term cold exposure, and cold resistance in Min Pigs and Large White Pigs

ABSTRACTMin Pig (Sus scrofa) is a northern Chinese domestic pig breed, whose cold resistance is remarkable. However, the cold-resistant phenotype of Min Pig is unclear. Our studies showed that in long-term cold exposure, the death rate of Min Pigs is significantly lower than that of the control Large White (LW) Pigs. The ear tissue freezing rate for Min Pigs is 0%, but that for LW Pigs is 100%. The shivering time and shivering frequency of Min Pigs are both significantly lower than that of LW Pigs at 5 months (P < .005) and in 80–90 kg pigs (P < .001). Our results indicated that Min Pig is more cold resistant than LW Pig in long-term cold exposure. These findings provided important reference data for the field of cold resistance research in Min Pigs, and for the breeding of cold-resistant pigs.

Haplotype diversity in MC1R locus between the Min and white-haired pig breeds

ABSTRACTIn this article, we investigated the genetic variations in the coding region of porcine melanocortin receptor 1 (MC1R) gene in three pig breeds (Min, Yorkshire and Landrace) with black and white coat colors. Six polymorphic sites were found to be significantly associated with coat color. Two blocks were identified in the linkage disequilibrium map, the haplotypes in the first block are nt67/68indelCC and nt67/68indel--, and the haplotypes in the second block are ACCGA and GTTAG. The median-joining network diagram of MC1R haplotypes showed most Min pigs and other Asia domestic breeds own similar haplotypes to ACCGA, while the haplotypes of Europe pig breeds are similar to GTTAG. The phylogenetic analysis of the MC1R CDS further showed Min pigs are close to Laiwu pigs (Shandong, China), which indicated that the black coat color trait of Min pig might be originated and evolved from the black pig breed in Shandong Peninsula of China.

Molecular cloning and functional characterization of myogenin promoter in Min pig

ABSTRACTMyogenin (MyoG) plays an important role in muscle differentiation, which can initiate the formation of the fusion of muscle cells and myofibroblasts. To investigate the transcriptional regulatory mechanism of MyoG gene in Min pig, the promoter fragment spanning from −2085 bp to +118 bp was amplified with PCR, and the potential transcriptional elements were predicted via bioinformatics analysis. Subsequently, nine promoter segments with different base pair sizes were obtained and ligated into PGL3-Basic vectors, respectively. Lastly, the functional activity of each of the aforementioned promoters was tested separately in transiently transfected C2C12 cells via a dual-luciferase assay system. The results indicated that the sequence −199 bp to −31 bp may have the basic activity of the promoter. Further analysis demonstrated that the sequence −137 bp to −101 bp was important for the basic transcriptional activity. Bioinformatics analysis showed that CdxA and MZF1 transcription factors may play an important role in the regulation of MyoG expression.