Genetic diversity and selection signatures of four indigenous pig breeds from eastern China.

Chinese indigenous pig breeds have been undergoing selection for thousands of years, and have become invaluable genetic sources over the world. To investigate the population structure and genetic diversity of Jinhua (JH), Longyou Black (LYW), Shengxian Spotted (SXH), and Lanxi Spotted (LXH) breeds, a total of 200 pigs belonging to 10 diverse population were genotyped using SNP chips. The results showed that LYW pigs exhibited higher level of heterozygosity than the other indigenous pigs. In addition, gene introgression from intensively reared commercial pig breeds to LYW pigs was detected. Moreover, selection signature analysis revealed the possibility of differences between Chinese indigenous and intensively reared commercial pig breeds were mainly present for meat and carcass traits. Furthermore, we found that ANXA13, DISP1, and SRSF6 were the nearest genes located around the common selection signatures detected between each indigenous pig breed and Chinese wild boars. Our findings provide new insights into the selection signatures of Chinese indigenous pigs, and may contribute to future pig breeding.

Investigation of the CEBPA gene expression pattern and association analysis of its polymorphisms with meat quality traits in chickens.

Meat quality is closely related to the fat deposition which is regulated by a cascade of transcription factors. As a transcription factor, the CCAAT/enhancer binding protein alpha (CEBPA) is considered as one of the key molecules regulating adipogenesis. Therefore, the objective of this study was to detect the expression pattern of the CEBPA gene and evaluate whether its single nucleotide polymorphisms (SNPs) were associated with the meat quality traits in Wuliang Mountain Black-bone (WLMB) chickens. The results showed that the chicken CEBPA mRNA was widely expressed in the 11 tissues, and the expression pattern of it might be tissue- and time-specific different. The locus of g.74C > G was not significantly associated with chicken meat quality. For the locus of g.552G > A, chickens with the GG genotype showed higher pH (p < 0.01), lower drip loss (p < 0.01) and higher intramuscular fat (p < 0.05) than those with other genotypes. It suggested that polymorphisms of the CEBPA gene were significantly associated with the meat quality traits of WLMB chickens. The results of this study contribute to the functional research of the CEBPA gene and lay the foundation for improving meat quality based on the marker-assisted selection in chickens.

Integrated mRNA and miRNA profile expression in livers of Jinhua and Landrace pigs.

Objective: To explore the molecular mechanisms of fat metabolism and deposition in pigs, an experiment was conducted to identify hepatic mRNAs and miRNAs expression and determine the potential interaction of them in two phenotypically extreme pig breeds. Methods: mRNA and miRNA profiling of liver from 70-day Jinhua (JH) and Landrace (LD) pigs were performed using RNA sequencing. Blood samples were taken to detect results of serum biochemistry. Bioinformatics analysis were applied to construct differentially expressed miRNA-mRNA network. Results: Serum total triiodothyronine (TT3) and total thyroxine (TT4) were significantly lower in Jinhua pigs, but the content of serum total cholesterol (TCH) and low-density lipoprotein cholesterol (LDLC) were strikingly higher. A total of 467 differentially expressed genes (DEGs) and 35 differentially expressed miRNAs (DE miRNAs) were identified between JH and LD groups. Gene ontology analysis suggested that DEGs were involved in oxidation-reduction, lipid biosynthetic and lipid metabolism process. Interaction network of DEGs and DE miRNAs were constructed, according to target prediction results. Conclusion: We generated transcriptome and miRNAome profiles of liver from Jinhua and Landrace pig breeds which represent distinguishing phenotypes of growth and metabolism. The potential miRNA-mRNA interaction networks may provide a comprehensive understanding in the mechanism of lipid metabolism. These results serve as a basis for further investigation on biological functions of miRNAs in the porcine liver.

Distribution of runs of homozygosity in Chinese and Western pig breeds evaluated by reduced-representation sequencing data.

Inbreeding, which has several causes including genetic drift, population bottlenecks, mating of close relatives and selection, can leave tracts of runs of homozygosity (ROH) along genomes. Recently, decreasing performance on reproductive traits, which might have resulted from inbreeding, has been observed in Chinese pigs. In this study, 830 individuals from Western and Chinese pig breeds were genotyped using the reduced-representation sequencing method. After imputation and quality control, 60 850 high-confidence SNPs were retained for ROH detection. A simulation was performed to explore the reliability of ROH detection with imputed data. Different ROH-related variables were compared between imputed and non-missing genotypes used in ROH detection. Furthermore, ROH islands were evaluated and annotated to find genes influenced by inbreeding in these pigs. The simulation results showed that imputed data with 0.7 as the average missing genotype rate and three heterozygotes allowed in a sliding window have comparable ROH detected compared with data with no missing genotypes. Compared with Western pig breeds, Chinese pigs had more autosomes covered by ROH longer than 5 Mb, indicating higher inbreeding in Chinese pigs in recent times. Genes related to reproduction, immunity, meat quality and adaptability in Chinese pigs and several genes related to growth speed and immunity in Western pigs were observed in short ROH islands. The reproduction-related gene PRM1 was found to be located in the most frequent long ROH island in Chinese pigs, which might explain the decreasing fertility in Chinese pig breeds.

Circular RNA expression profiles in the porcine liver of two distinct phenotype pig breeds.

OBJECTIVE: An experiment was conducted to identify and characterize the circular RNA expression and metabolic characteristics in the liver of Jinhua pigs and Landrace pigs. METHODS: Three Jinhua pigs and three Landrace pigs respectively at 70-day were slaughtered to collect the liver tissue samples. Immediately after slaughter, blood samples were taken to detect serum biochemical indicators. Total RNA extracted from liver tissue samples were used to prepare the library and then sequence on HiSeq 2500. Bioinformatic methods were employed to analyze sequence data to identify the circRNAs and predict the potential roles of differentially expressed circRNAs between the two breeds. RESULTS: Significant differences in physiological and biochemical traits were observed between growing Jinhua and Landrace pigs. We identified 84,864 circRNA candidates in two breeds and 366 circRNAs were detected as significantly differentially expressed. Their host genes are involved in lipid biosynthetic and metabolic processes according to the gene ontology analysis and associated with metabolic pathways. CONCLUSION: Our research represents the first description of circRNA profiles in the porcine liver from two divergent phenotype pigs. The predicted miRNA-circRNA interaction provides important basis for miRNA-circRNA relationships in the porcine liver. These data expand the repertories of porcine circRNA and are conducive to understanding the possible molecular mechanisms involved in miRNA and circRNA. Our study provides basic data for further research of the biological functions of circRNAs in the porcine liver.

Detection of selection signatures of population-specific genomic regions selected during domestication process in Jinhua pigs.

Chinese pigs have been undergoing both natural and artificial selection for thousands of years. Jinhua pigs are of great importance, as they can be a valuable model for exploring the genetic mechanisms linked to meat quality and other traits such as disease resistance, reproduction and production. The purpose of this study was to identify distinctive footprints of selection between Jinhua pigs and other breeds utilizing genome-wide SNP data. Genotyping by genome reducing and sequencing was implemented in order to perform cross-population extended haplotype homozygosity to reveal strong signatures of selection for those economically important traits. This work was performed at a 2% genome level, which comprised 152 006 SNPs genotyped in a total of 517 individuals. Population-specific footprints of selective sweeps were searched for in the genome of Jinhua pigs using six native breeds and three European breeds as reference groups. Several candidate genes associated with meat quality, health and reproduction, such as GH1, CRHR2, TRAF4 and CCK, were found to be overlapping with the significantly positive outliers. Additionally, the results revealed that some genomic regions associated with meat quality, immune response and reproduction in Jinhua pigs have evolved directionally under domestication and subsequent selections. The identified genes and biological pathways in Jinhua pigs showed different selection patterns in comparison with the Chinese and European breeds.

MicroRNA expression profiling of lactating mammary gland in divergent phenotype swine breeds.

MicroRNA (miRNA) plays a key role in development and specific biological processes, such as cell proliferation, differentiation, and apoptosis. Extensive studies of mammary miRNAs have been performed in different species and tissues. However, little is known about porcine mammary gland miRNAs. In this study, we report the identification and characterization of miRNAs in the lactating mammary gland in two distinct pig breeds, Jinhua and Yorkshire. Many miRNAs were detected as significantly differentially expressed between the two libraries. Among the differentially expressed miRNAs, many are known to be related to mammary gland development and lactation by interacting with putative target genes in previous studies. These findings suggest that miRNA expression patterns may contribute significantly to target mRNA regulation and influence mammary gland development and peak lactation performance. The data we obtained provide useful information about the roles of miRNAs in the biological processes of lactation and the mechanisms of target gene expression and regulation.

MicroRNA expression profiling of the porcine developing hypothalamus and pituitary tissue.

MicroRNAs (miRNAs), a class of small non-coding RNA molecules, play important roles in gene expressions at transcriptional and post-transcriptional stages in mammalian brain. So far, a growing number of porcine miRNAs and their function have been identified, but little is known regarding the porcine developing hypothalamus and pituitary. In the present study, Solexa sequencing analysis showed 14,129,397 yielded reads, 6,680,678 of which were related to 674 unique miRNAs. After a microarray assay, we detected 175 unique miRNAs in the hypothalamus, including 136 previously known miRNAs and 39 novel candidates, while a total of 140 miRNAs, including 104 known and 36 new candidate miRNAs, were discovered in pituitary. More importantly, 37 and 30 differentially expressed miRNAs from several developmental stages of hypothalamus and pituitary were revealed, respectively. The 37 differentially expressed miRNAs in hypothalamus represented 6 different expression patterns, while the 30 differentially expressed miRNAs in pituitary represented 7 different expression patterns. To clarify potential target genes and specific functions of these differentially expressed miRNAs in hypothalamus and pituitary, TargetScan and Gorilla prediction tools were then applied. The current functional analysis showed that the differentially expressed miRNAs in hypothalamus and pituitary shared many biological processes, with the main differences being found in tissue-specific processes including: CDP-diacylglycerol biosynthetic/metabolic process; phosphatidic acid biosynthetic/metabolic process; energy reserve metabolic process for hypothalamus; adult behavior; sterol transport/homeostasis; and cholesterol/reverse cholesterol transport for pituitary. Overall, this study identified miRNA profiles and differentially expressed miRNAs among various developmental stages in hypothalamus and pituitary and indicated miRNA profiles change with age and brain location, enhancing our knowledge about spatial and temporal expressions of miRNAs in the porcine developing brain.

Association of pig UCP3 gene mutations and back fat thickness in the sixth and seventh rib.

Accumulated studies have documented extensive links between UCP3 polymorphisms and pig productive traits, and quantitative trait loci linkage results, on the other hand, provided extensive evidences showing that UCP3 was in the core of several QTLs for carcass and meat quality traits. In this research, we screened two substitutions in coding sequence and one 9-base continuous mutated site in 3'UTR of pig UCP3 gene using the reference population of 293 pigs which were F (2) generation of hybrids between Chinese native Jinhua pigs and European Pietrain. The two missense mutations of G1406A in Exon 3 and T3602C in Exon 5 which led to changes in the G150R and M259T, respectively, were digested by SmaI and introduced Tth111I separately for genotype analysis, and the 9-base continuous mutated site in the 3'UTR was analyzed by an AvaI cleavage. As a result, the 9-base continuous mutated site of 3'UTR manifested significantly close association with the backfat thickness at the sixth and seventh rib, but the polymorphisms of G1406A and T3602C were not associated significantly with any of the seven carcass traits. The same results were shown by RT-qPCR and western blotting. These findings inferred that UCP3 probably has tissue-specific effects on pig carcass traits.

Mapping, cDNA cloning and tissue expression of the porcine thyrotropin-releasing hormone receptor gene.

Thyrotropin-releasing hormone receptor (TRHR) is a G-protein-coupled receptor that plays a crucial role in regulating the hypothalamic-pituitary-thyroid axis by conveying the action of the hypothalamic tripeptide TRH, which is the primary central activator of this hormonal cascade. In the present study, the porcine TRHR (pTRHR) gene was localized to chromosome 4 by Radiation hybrid mapping. Quantitative trait loci affecting average backfat thickness, daily gain, and carcass and meat quality traits have been mapped to the region containing this gene. Further, the full-length cDNA of pTRHR was cloned and sequenced. pTRHR contains an open reading frame encoding 398 amino acids and shares 96.2% amino acid identity to human TRHR. Real-time quantitative RT-PCR showed that the mRNA of pTRHR is expressed in a variety of tissues, with high expression in the brain, hypothalamus, pituitary, testis, and fat tissue. The considerable expression level of TRHR mRNA found in fat tissue indicates potential direct action of TRH on lipocyte might exist. Additionally, two alternative spliced transcript variants of pTRHR were also isolated in this study. Our data provided basic molecular information which will be useful for further investigation on pTRHR gene.

Comparative Transcriptome Profiling of mRNA and lncRNA of Ovaries in High and Low Egg Production Performance in Domestic Pigeons (Columba livia).

Egg production performance is one of the most important economic traits in pigeon industry. However, little is known regarding how egg production performance is regulated by long non-coding RNAs (lncRNAs) in pigeons. To evaluate the lncRNAs and mRNAs in ovaries associated with egg production performance in domestic pigeons, high-throughput RNA sequencing of ovaries between high and low egg production performance groups were performed and analyzed in this study. A total of 34,346 mRNAs and 24,601 lncRNAs were identified, including 14,525 known lncRNAs and 10,076 novel lncRNAs, of which 811 mRNAs and 148 lncRNAs (P < 0.05) were significantly differentially expressed (DE) between the groups of high and low egg production performance. GO and KEGG annotation analysis indicated that the target genes of DE lncRNAs and DE mRNAs were related to cell differentiation, ATP binding and methylation. Moreover, we found that FOXK2, a target gene of lncRNA MSTRG.7894.4, was involved in regulating estrogen receptors. Our study provided a catalog of lncRNAs and mRNAs associated with egg production performance, and they deserve further study to deepen the understanding of biological processes in the ovaries of pigeons.

Mechanisms of Oogenesis-Related Long Non-coding RNAs in Porcine Ovaries Treated With Recombinant Pig Follicle-Stimulating Hormone.

Reproductive efficiency is of significant importance in pork production for it has a great impact on economic success. Ovulation rate is an early component of reproduction efficiency of pigs, and it contributes to the upper limit of litter size. In this study, we used the newly developed recombinant pig follicle stimulating hormone (rpFSH) instead of traditional PMSG to increase ovulation rate of pigs in order to achieve higher litter size, for it was better at stimulating ovulation, and showed more cheaper and greener. However, relatively little is known about the underlying genetic bases and molecular mechanisms. Consequently, an experiment was carried out in ovaries of replacement gilts to screen the key genes and lncRNAs that affect the fecundity of pigs by RNA-seq technology. Twenty gilts were divided into two groups, including 10 rpFSH treatment pigs and 10 control animals. After slaughtering and collecting the phenotypic data, ovaries of five pigs in each group were selected for RNA-seq. Total RNA was extracted to construct the library and then sequence on an Illumina Hiseq 4000 system. A comprehensive analysis of mRNAs and long non-coding RNAs (lncRNAs) from 10 samples was performed with bioinformatics. The phenotypic data showed that rpFSH treatment groups had the higher (P < 0.01) ovarian weight and more mature follicles. The RNA-seq results showed that a total of 43,499 mRNAs and 21,703 lncRNAs were identified, including 21,300 novel lncRNAs and 403 known lncRNAs, of which 585 mRNAs and 398 lncRNAs (P < 0.05) were significantly differentially expressed (DE) between the two groups of rpFSH treatment group and controlled group. GO and KEGG annotation analysis indicated that the target genes of DE lncRNAs and DE mRNAs were related to prolactin receptor activity, mitophagy by induced vacuole formation, and meiotic spindle. Moreover, we found that NR5A2 (nuclear receptor subfamily 5, group A, member 2), a target gene of lncRNA MSTRG.3902.1, was involved in regulating follicular development, ovulation, and estrogen production. Our study provided a catalog of lncRNAs and mRNAs associated with ovulation of rpFSH treatment, and they deserve further study to deepen the understanding of biological processes in the regulation of ovaries of rpFSH treatment pigs.

Chronological Expression of PITX2 and SIX1 Genes and the Association between Their Polymorphisms and Chicken Meat Quality Traits.

Meat quality is closely related to the development of skeletal muscle, in which PITX2 and SIX1 genes play important regulatory roles. The present study firstly provided the data of chronological expression files of PITX2 and SIX1 genes in the post-hatching pectoral muscle and analyzed the association of their polymorphisms with the meat quality traits of Wuliang Mountain Black-bone (WLMB) chickens. The results showed that both PITX2 and SIX1 genes were weakly expressed in the second and third weeks, and then increased significantly from the third week to the fourth week. Furthermore, there was a significant positive correlation between the expression levels of the two genes. Twelve and one SNPs were detected in the chicken PITX2 and SIX1 genes, respectively, of which four SNPs (g.9830C > T, g.10073C > T, g.13335G > A, g.13726A > G) of the PITX2 gene and one SNP (g.564G > A) of the SIX1 gene were significantly associated with chicken meat quality traits. For the PITX2 gene, chickens with the CT genotype of g.9830C > T showed the highest meat color L*, shear force (SF), pH, and the lowest electrical conductivity (EC), and drip loss (DL) (p < 0.05 or p < 0.01); chickens with the CC genotype of g.10073C > T had the lowest L*, pH, and the highest DL (p < 0.01). For the SIX1 gene, chickens with the GG genotype of g.564G > A had the highest (p < 0.05) SF and pH. Furthermore, pH had a significant correlation with all the other meat quality traits. The current study could contribute to the research of regulatory mechanisms of meat quality and lay the foundation for improving meat quality based on marker-assisted selection in chickens.

[Effect on factors of energy metabolism in rats skeletal muscle by cold traditional Chinese medicine].

OBJECTIVE: To investigate the effect of six cold traditional Chinese medicine on the energy metabolism factors in rats skeletal muscle. METHOD: The activity of Na(+)-K(+) -ATPase, Ca(2+) -ATPase and succinate dehydrogenase (SDH), the content of muscle glycogen, and the mRNA expression of skeletal muscle uncoupling protein 3 (UCP3) were measured after rats having been administrated with water extracts of Radix Sophorae Flavescentis, Fructus Gardeniae, Cortex Phellodendri, Radix Scutellariae, Rhizoma Coptidis, and Radix Gentianae respectively at the dose of 6.0, 7.0, 8.4, 6.0, 7.0, 4.0 g x kg(-1) for 30 days. RESULT: The activity of Na(+) -K(+) -ATPase has been depressed significantly and the content of skeletal muscle glycogen has been increased remarkably by six cold traditional Chinese medicine. The decreased tendency has been found on activity of Ca(2+) -ATPase and SDH, only the Radix scutellariaeg group decreased the Ca(2+) -ATPase activity significantly (P < 0.05), the SDH activity was decreased high significantly by Radix scutellariae, Cortex Phellodendri, Radix Gentianae and significantly by Rhizoma Coptidis. The mRNA expression of UCP3 has been decreased high significantly by all five cold traditional Chinese medicine except Cortex Phellodendri group with the decreased tendency of UCP3 mRNA expression. CONCLUSION: The cold traditional Chinese medicine has the significant effects on the skeletal muscle energy metabolism by decreasing the utlization of the glucose and the activity of mitochondria SDH to reduce the production of ATP, and depressing the activity of Na(+)-K(+) -ATPase and Ca(2+) -ATPase to cut down the consumption of ATP, by decreasing the mRNA expression of UCP3 to decrease the heat production.

Expression Analysis of the PITX2 Gene and Associations between Its Polymorphisms and Body Size and Carcass Traits in Chickens.

PITX2 is expressed in and plays an important role in myocytes of mice, and it has effects on late myogenic differentiation in chickens. However, the expression profile and polymorphisms of PITX2 remain unclear in chickens. Therefore, the aim of the present study was to detect its expression and investigate single nucleotide polymorphisms (SNPs) within its exons and then to evaluate whether these polymorphisms affect body size as well as carcass traits in chickens. The expression analysis showed that the expression level of chicken PITX2 mRNA in the leg muscle and hypophysis was significantly higher (p < 0.01) than those in other tissues. The results of polymorphisms analysis identified two SNPs (i.e., g.9830C > T and g.10073C > T) in exon 1 and 10 SNPs (i.e., g.12713C > T, g.12755C > T, g.12938G > A, g. 3164C > T, g.13019G > A, g.13079G > A, g.13285G > A, g.13335G > A, g.13726A > G and g.13856C > T) in exon 3, including four novel SNPs (i.e., g.9830C > T, g.12713C > T, g.12938G > A and g.13856C > T). In the loci of g.10073C > T and g.12713C > T, chickens with the CT genotype had the highest (p < 0.05 or p < 0.01) breast depth and breast angle, respectively. For the locus of g.13335G > A, chickens with the GG genotype had the highest (p < 0.05 or p < 0.01) breast angle and shank circumference. For the locus of g.13726A > G, chickens with the GG genotype had the highest breast width, fossil keel bone length and shank circumference. The locus of g.12713A > G had significant effects on the PITX2 mRNA expression level in leg muscle. The H1H7 diplotype showed the highest shank circumference, and the H2H8 diplotype showed the highest breast muscle rate. The present research suggested that polymorphisms of the exons of the PITX2 gene were significantly associated with the body size and carcass traits of Wuliang Mountain Black-bone chickens and the PITX2 gene could be a potential candidate gene for molecular marker-aided selection in Wuliang Mountain Black-bone chickens and other chicken breeds.

Evaluation of the four breeds in synthetic line of Jiaxing Black Pigs and Berkshire for meat quality traits, carcass characteristics, and flavor substances.

To investigate breed characteristics and the effect of hybridization of Jiaxing Black Pig (JBP) with Western breeds, the carcass and meat quality traits and flavor substances such as inosinic acids (IMP), intramuscular fat (IMF) in longissimus muscle (LM) from five breeds including JBP, Berkshire, Berkshire × JBP (BJBP), Duroc × Berkshire × JBP (DBJBP), Duroc × Landrace × JBP (DLJBP) were compared in this study. It was found that water holding capacity (WHC) of LM in JBP was significantly higher than that in the other strains (p < 0.01). Dressing out percentage and lean percentage of JBP were both significantly lower than those in the others (p < 0.01) in connection with their lighter carcass weight and higher subcutaneous fat percentage (p < 0.01). Heterosis was realized in DJBP, DBJBP, and DLJBP since their carcass weight, lean percentage, and loin eye muscle area (LEMA) were markedly higher when compared to JBP, whereas lower than those in Berkshire. Among the breeds, the content of IMF and IMP in the LM of JBP were the highest. These traits were also palpably improved in the crossbreds, especially for DBJBP, of which pork was considered outstanding for containing the most abundant essential amino acids (EAA) and total amino acids (TAA).

Cloning, sequencing and identification of single nucleotide polymorphisms of partial sequence on the porcine CACNA1S gene.

CACNA1S gene encodes the alpha1 subunit of the calcium channel. The mutation of CACNA1S gene can cause hypokalemic periodic paralysis (HypoKPP) and maliglant hyperthermia synarome (MHS) in human beings. Current research on CACNA1S was mainly in human being and model animal, but rarely in livestock and poultry. In this study, Yorkshire pigs (23), Pietrain pigs (30), Jinhua pigs (115) and the second generation (126) of crossbred of Jinhua and Pietrain were used. Primers were designed according to the sequence of human CACNA1S gene and PCR was carried out using pig genome DNA. PCR products were sequenced and compared with that of human, and then single nucleotide polymorphisms (SNPs) were investigated by PCR-SSCP, while PCR-RFLP tests were performed to validate the mutations. Results indicated: (1) the 5211 bp DNA fragments of porcine CACNA1S gene were acquired (GenBank accession number: DQ767693 ) and the identity of the exon region was 82.6% between human and pig; (2) fifty-seven mutations were found within the cloned sequences, among which 24 were in exon region; (3) the results of PCR-RFLP were in accordance with that of PCR-SSCP. According to the EST of porcine CACNA1S gene published in GenBank (Bx914582, Bx666997), 8 of the 11 SNPs identified in the present study were consistent with the base difference between two EST fragments.

[Effect of SNP in the exon 8 of SIM1 gene on backfat thickness in pigs].

SNP in exon 8 of the Single-minded 1 (SIM1) gene was detected using PCR-SSCP in 169 pigs of 6 pig breeds including Yorkshire, Duroc, Pietrain, Landrace, Jiaxinghei and Jinhua. The results showed three genotypes (CC, CT, TT) were found and their frequencies between domestic and foreign breeds were different. Only one genotype TT was found in Jiaxinghei and Jinhua pigs, but three genotypes were detected in each foreign breed. The effects of this SNP on backfat thickness in Landrace, Yorkshire and Duroc were estimated using least square method. The homozygote pigs had thicker backfat than the heterozygote ones. The significant effect of various genotypes was found in foreign breeds (P < 0.05). SIM1 had different effects on backfat thickness of different points.

[Expression characteristics of prolactin gene in Eastern Zhejiang white geese].

This study was conducted to clone the prolactin gene (PRL) in Eastern Zhejiang White Geese and to investigate the PRL gene expression characteristics during egg-laying, out-of-lay and incubating periods by real time PCR. Comparisons were made respectively of concentration of prolactin mRNA in the hypothalamus, pituitary gland and ovary of the adult female geese at different reproductive periods. The result indicated that there were significant differences (P<0.05) in PRL mRNA expression between different reproductive periods of the geese. The lowest level of PRL expression was found in out-of-lay geese, higher in the egg-laying geese, and the highest in incubating geese. Furthermore, the analysis of PRL expression in different tissues indicated that the highest levels of PRL was expressed in the pituitary gland, followed in hypothalamus, and the least in ovary of the geese. There were significant difference (P<0.01) expression of PRL between the pituitary gland/hypothalamus and ovary of the geese, whereas no any difference was observed between the pituitary gland and hypothalamus (P>0.05). In summary, the PRL mRNA expression had variance in different reproductive periods of the geese.