This study aimed to investigate the expression abundance of miR-1 and miR-133 in the highest longissimus dorsi muscle from 180-day-old pigs including Landrace, Lantang and Dahuabai pigs using Real-time quantification of microRNAs by stem-loop RT-PCR method. The results showed that miR-1 abundance was the highest in Lantang, and 4.7 times higher than that in Landrace and 6.4 times higher than that in Dahuabai pigs(P<0.05), respectively, but not significantly different(P>0.05) between Landrace and Dahuabai pigs. miR-133 abundance was also the highest in Lantang, followed by Landrace and Dahuabai pigs, the former two were significantly 7.2 and 5.7 times higher(P<0.05) than that in the latter, respectively, but there was no significant differences(P>0.05) between Landrace and Lantang pigs. The results indicate that miR-1 and miR-133 expression are specific among the pig breeds, suggesting that the abundance of miR-1 and miR-133 are associated with meat quality traits in pigs.

The SNPs of VLDLR gene in Wenshang Luhua chicken, Jining Bairi chicken and Laiwu Black chicken were detected by PCR-RFLP method. And the correlation between the polymorphism loci and the yolk traits were analyzed. As a result, a G/A mutation at nt 8 467 in VLDLR-exon6 and an A/G mutation at nt 13 876 in VLDLR-intron17 were identified. The least square analysis showed that the V8467 was significantly associated with yolk weight (P<0.01) and yolk height (P<0.05); the V13876 was significantly associated with yolk weight (P<0.01), yolk rate (P<0.05) and yolk height (P<0.05); the diplotype was significantly associated with yolk weight (P<0.01), yolk rate (P<0.01) and yolk height (P<0.05). These results indicated that V8467 and V13876 loci of VLDLR gene would be useful candidate markers in selection program on yolk traits.

This study was designed to explore characteristics of genetics, mechanism of occurrence and disappearance of poultry piRNAs, and accumulate basic materials for research about birds small RNA-binding protein and practical application. 19 pilRNAs sized 23-39 nt were discovered by constructing cDNA library of small RNAs, TA cloning and sequencing in chicken testicular tissue. According to size, homology and secondary structure, 3 different sequences were selected for analyzing temporal and spatial expression of pilRNAs by using Q-PCR technology in different tissues at different growth and development stages of Rugao chicken and Recessive White Feather chicken. The result showed that, consistent with other species, distribution of pilRNA-encoding sequences in the chicken genome was found to be asymmetrical on chromosomes, meanwhile, displayed a preference for intergenic regions across genome. Unlike the secondary structure of miRNAs, pilRNAs were predicted an unique stem-loop secondary structure. Chicken pilRNAs were not only abundant in germline tissue, but also abundant in other tissues, and expression at mRNA level was influenced mainly by different pilRNAs, breeds and gender. The expression level of gga-piR-1 was the lowest in all tissues of two breeds and reached the consistent trend at week 12, while gga-piR-4 showed moderate expression levels. gga-piR-5 revealed the highest and moderate levels in all tissues of the male Rugao chicken and Recessive White Feather chicken, respectively and they were up to peak at week 8 for the male Rugao chicken, whereas it expressed moderately in female of both breeds. Therefore, the difference of the secondary structures between pilRNAs and miRNAs indicate that the difference in splicing and processing mechanisms of two small RNAs, pilRNAs may not only be confined to development and maintenance for germline tissue, but also play important roles in somatic tissues and different pilRNAs may be involved in different regulatory function in the complex biological processes.

It is necessary to prepare polyclonal antibody of c-Myc in Capra Hircus since c-Myc protoncogene plays an important role in maintaining biological characteristics of embryonic stem cells (ES cells) and inducing pluripotent stem cells (iPS cells). The plasmid pMD18T-Myc was used as templete to amplify c-Myc fragment, which was subcloned into vector pSE380 to construct recombinant plasmid pSE380-Myc.The plasmid was then transformed into E. coli BL21 (DE3), and His-Myc fusion protein was expressed with induction of IPTG, which was subsequently verified by SDS-PAGE and Western blot assay. Purified with Ni-NTA argrose under denaturing conditon, His-Myc fusion protein was applied as antigen to immunize New Zealand White rabbits, whose blood was collected, serum (polyclonal anti-c-Myc antibody) was isolated after 4 times of immunization, and its specificity was detected with Western blot. The results showed that: (1) The recombinant plasmid pSE380-Myc was efficiently expressed in E.coli BL21 (DE3); (2) His-Myc fusion protein with higher purity was obtained; (3) Western blot analysis illustrated that the polyclonal anti-c-Myc antibody could specifically respond to His-Myc fusion protein. In conclusion, the polyclonal anti-c-Myc antibody obtained in the present study will lay a foundation for the research of self-renewing mechanism of ES cells and iPS cells in Capra Hircus.

The previous genomewide association studies (GWAS) with Illumina Bovine50K chip have identified 35 significant SNPs associated with one or multiple milk production traits in a Chinese Holstein population from Beijing region with daughter design. The purpose of this study was to determine potential genes affecting milk yield and milk composition and function annotation based on such GWAS results. Through bioinformatics and comparative genomics analysis, potential genes screening and function prediction were performed. Twelve of 35 significant SNPs were located within genes and 23 were in the flanking region based on Btau 4.2 database. As a result, total 28 genes corresponding to the aforementioned 35 SNPs were determined. The functions of such genes were classified into 6 categories, including regulating body metabolism and nutrient balance, cytoskeleton or extracellular matrix, regulation of proliferation, cell cycle and apoptosis, cell signal transduction and saltion channel composition, kinase activity, mRNA transcription and translation regulation, transportation or transduction, transcription and translation regulation of fat granule protein. The findings could be useful for further investigations on gene identification and function validation for milk production traits in dairy cattle.

SNPs of the whole genome were genotyped through highdensity SNP chip technology in a population with 223 Chinese Simmental. Seven SNPs were found in SCD1 gene. The results of association of the seven loci with meat quality traits showed that the loci were all significantly correlated with marbling score(P<0.05 or P<0.01). The effect of different genotypes at A10050C, A13655G, C14790T and A15565G on sheare force were significant(P<0.05). The locus A13655G was correlated with intramuscular fat(IMF) content, and individuals with AA genotype has higher IMF（P<0.05）. The effect of different genotypes at locus A10050C, C14790T and A15565G on fat color were significantly different(P<0.05). The result of haplotype analysis showed that 6 haplotypes and 14 haplotype combinations were detected. For IMF content, the individuals with haplotype combination H3H6 was significant higher than others at 0.01 level while the individuals with haplotype combination H6H6 had a higher marbling score and the individuals with haplotype combination H4H6 had a higher sheare force. The effect of the haplotype combinations on meat color and fat color was not significant.

This study was carried out to obtain and analyze sequence of duck CYP7α1 gene, and to reveal the expression of CYP7α1 mRNA in different tissues of duck. Based on other species mRNA sequences, the cDNA of CYP7α1 gene in duck was amplified successfully by using RACE-PCR. The structure and the function of the duck CYP7α1 gene were analyzed by bioinformatics methods. The mRNA abundance of duck CYP7α1 gene was tested in 10 tissues. The result showed that the cDNA of duck CYP7α1 gene was 2 351 nucleotides in length with an open reading frame (ORF) 1 539 bp(114-1 652 bp) in length and encoded 512 amino acids. The amino acid homology of duck CYP7α1 were 97.5%, 92.8%, 67.3%, 66.5%, 65.7%, 65.5%, 65.5% and 65.1% comparing to that of the goose, chicken, human, pig, rabbit, rat, mouse and cattle, respectively. The CYP7α1 amino acid sequence of duck contained a P450 domain. The mRNA expression level of duck CYP7α1 gene was high in liver and was not detected in other 9 tissues, the mRNA expression of duck CYP7α1 gene was tissue specific.

In order to explore the effects of chitosan on intestinal barrier of weanling pigs, thirty piglets with an average body weight of (6.62±0.59) kg were challenged with enterotoxigenic Escherichia coli (10⁹ cell per head) during preliminary trial period and randomly assigned to three treatment groups, a basal diet was added in control group, 50 mg·kg^-1 chlortetracycline, 300 mg·kg^-1 chitosan were added in the experimental groups, respectively, for 21 d. The results showed that, compared with the control group, chitosan could decrease the level of D-Lactate(P＜0.05) and the activity of DAO(P＜0.05) in plasma and the level of ET-1(P＜0.05) in serum, but it had no significant effect on the contents of NO(P＞0.05) in serum. The result of immunohistochemistry showed that the protein expression levels of Occludin (P＜0.01) and ZO-1 (P＜0.05) in piglets jejunum mucous added with chitosan were increased. The result of fluorescence quantitative PCR showed that the expression abundances of Occludin (P＜0.01) and ZO-1 (P＜0.05) mRNA in piglets jejunum mucous added with chitosan were improved. These result indicate that diet supplemented with 300 mg·kg^-1 chitosan can protect greatly the intestinal barrier of early weanling piglets from injuring.

This experiment was conducted to investigate the effects of bacillus preparation on growth performance， gastrointestinal pH, intestine morphology development, VFA concentrations in the cecum and colon of weaned piglets. Ninety six 35-day-old weaned piglets were randomly divided into 4 groups, with 3 replications per group and 8 piglets each replication. Piglets in control group were fed basal diet. The trailⅠ,Ⅱ, Ⅲ groups were fed basal diet supplemented with 0.75%, 1.50%, 3.00% bacillus preparation, respectively. The experiment lasted for 35 d. On day 36, a piglet were slaughtered from each replication, boundaries of each gastrointestinal segment were ligated quickly to determine pH, tissues from duodenum, jejunum and ileum were obtained and used for tissue slice, cecum and colon contents were collected to determine volatile fatty acids. The results showed that: (1) There were no significant influence of bacillus preparation on growth performance of piglets (P>0.05)；(2) Jejunum and cecum fermentation pH were significantly lower in 0.75% group than that in control group (P<0.05)； (3) Compared with the control group, the villus height were significantly improved in duodenum and middle section of jejunum in 0.75% group(P<0.05), the crypt depth were significantly lower in primal section of jejunum and distal section of jejunum in 0.75% group (P<0.05). In addition, the villus height/crypt depth in middle section of jejunum and distal section of jejunum was higher in 0.75% group than that in control group; (4) Compared with the control group, propionate and total volatile fatty acid content of 0.75% group in cecum section was significantly higher (P<0.05). It was concluded that supplementation of bacillus preparation in weaned piglets may be benefit for the development of intestinal tract and improve the morphology and function by reducing the gastrointestinal pH, promoting the development of intestinal morphology and increasing volatile fatty acids.

This experiment was conducted to study the molecular diversity of rumen methanogens from goat and its comparison with other ruminant. The methanogenspecific primers Met86F/Met1340R was used to analyze the 16S rRNA gene diversity of methanogens. One hundred clones were randomly picked up for sequence analysis. The result showed that sixteen OTUs were obtained after RFLP analysis, and the majority belonged to the Methanobrevibacter strains, AK-87 (58%), and others to ZA-10 (19%), OCP (7%), SM9 (2%), and 30Y(2%), and Methanosphaera stadtmanae-like (1%), Methanobacterium aarhusense-like (2%), Aciduliprofundum boonei-like (3%), Methanobrevibacter sp. AK-87-like (4%) and Methanobrevibacter sp. 1Y-like (2%) sequences, respectively. With comparison to rumen methanogens from other ruminants reported in previous studies, it can be concluded that the structure of methanogenic communities in the rumen can be affected by the different primers, feed types and animal species.

Currently, H5N1 viruses in Clade 2.3.2 are predominant viruses which prevail in China and other countries, and occurrence of a certain evolutionary trends of amino acid changes. In this report, a reassortant virus containing the HA and NA genes from an new isolate A/chicken /Yangzhou/1117/2011（YZC3） and the backbone A/Puerto Rico/8/34 (H1N1) (PR8) strain were constructed. The virus was rescued from the COS-1 cell line and prepared as inactivated wholevirus vaccine. Vaccine virus was avirulent to SPF chickens and embryonated chicken eggs, replicating well in eggs and MDCK cells. The results indicate that the reassortant viruses is suitable for vaccine manufacturing and being used as reference vaccine virus against the H5N1 Clade 2.3.2 viruses.

The extracellular gD gene was amplified by PCR from DEV genomic DNA according to our laboratory discovered gene sequence (GenBank accession number EU714267). The recombinant expression plasmid pET-30a-gDw could effectively express gDw fusion protein that was used to immunize rabbits. The titer of antibody tested by agar diffusion reaction was 1:16. Plaque reduction neutralization test showed that its neutralization antibody titer was up to 1:64. By indirected immunofluorescence, the results showed that gD appeared in the cell cytoplasm near the nuclear as early as 4 hours post infection. After 12 hours post infection, the fluorescence in cytoplasm was increased. Above all, the results afforded significant data for the study on the function of DEV gD.

The objective of this study was to investigate the difference of biological characteristics between infections bursal disease virus (IBDV) field strain HQ-b and its cell-adapted virus strain HQ, and the relationship between the virulence change and mutation of VP2 and VP5 genes. Cell culture characteristics, pathogenicity to SPF chicken, sequences of VP2 and VP5 genes of the two strains were analyzed and compared. The results showed that the field strain HQ-b can not be adapted to grow in CEF, CEK, CELi, DF-1 and Vero cell lines. Cell-adapted virus strain HQ can be adapted to above cells except for Vero cell line. TCID₅₀ titers in cultured cells were stable in different lot. It was indicated that the Field Strain HQ-b was a very virulent IBDV strain (vvIBDV). Mortality of 4 -week-old SPF chicken infected with HQ-b and HQ was 80% and 0% respectively. The results of VP2 sequence (the hv regions) analyses showed that the Field Strain HQ had vvIBDV conserved amino acids (aa): 222 A, 242 I, 256 I, 294 I and 299 S. The 222th (A→P), 256th (I→V), 294th (I→L), 299th (S→N), 253th (Q→H), 279th (D→N) and 284th ( A→T) aa of HQ were all changed, which caused it having attenuated strain conserved aa: 222 P, 256 V, 279 N, 284 T, 294 L and 299 N. The analyses results of VP5 sequence showed that the HQ-b had molecular characteristics of vvIBDV. HQ virus had 12 mutation sites and 9 of them made the corresponding aa change, especially, the mutation from T to C at the second bp of VP5 gene open-reading-frame of HQ virus caused lose first “ATG” and 4 aa at the N-terminal of VP5 protein．The mutations were very similar to vaccine strains. The research provides the molecular mechanism of alteration of culture properties and pathogenicity for vvIBDV HQ-b after adaption and enriches the molecular epidemiological theory for IBDV.

This experiment was conducted to study the genetic variation and phylogenetic analysis of Porcine teschovirus (PTV) HB strain isolated from a pig farm in Hebei Province. ST cells and animal infection experiments were conducted after the virus was originated from clinical tissue samples successfully, and the genome sequence of PTV HB strain had been determined, comparative genome analysis was performed with other 42 PTV strains in GenBank. The virus titer was 10^－6.4 TCID₅₀·mL^－1, and the infected pigs showed the same clinical signs and homological changes as natural infected ones after 28 days，and the complete genome sequence was composed of 7 090 nucleotides. Phylogenetic tree analysis demonstrated that PTV HB strain (JQ664746) belonged to serotype 8 and had a very closely genetic relationship with PTV-jilin/2003 strain (GQ293092) isolated from Jilin Province, China. Our results provided an essential reference for investigating the genetic variation of PTV HB strain.

A RT-PCR-RFLP assay was developed for the detection and differentiation between wild-type and rabbit attenuated vaccine viruses of classical swine fever virus (CSFV). A pair of specific primers was designed based on the Shimen strain, and used to verify the assay. Eight epidemic wild-type strains isolated from 20 clinical pathological samples of suspected swine fever and 2 vaccine strains were amplified by RT-PCR, cloned and sequenced. The results showed that a fragment of 825 bp was amplified from genomic RNA of CSFV wild-type which could be digested with ApaⅠ into two fragments of 322 bp and 503 bp when analyzed with RFLP, while the vaccine strain could not be digested with ApaⅠ. The lowest concentration of RNA could be detected in the present assay is 0.028 6 μg·mL^－1. Eight epidemic wild-type strains contained the ApaⅠ recognition sequence GGGCCC while the two vaccine strains contained the sequence GAGCCC. Eight epidemic wildtype strains belonged to Genomic Group 2. On the contrary, two vaccine strains with close genetic relationship to HCLV belonged to Genomic Group 1. The developed RT-PCR-RFLP could be used to detect and differentiate wild-type CSFV from pig vaccinated with the vaccine viruses.

To prepare monoclonal antibodies (Mabs) against capsid protein of swine hepatitis E virus Ⅳ (HEV), the gene of swine HEV encoding Cterminal 267 (408-675) amino acids of capsid protein was cloned into pET-28a (+) vector to construct recombinant plasmid pET-28a-ORF2-C. The protein was expressed in E. coli Rosetta (BL21), and identified by SDS-PAGE and Western blot. Spleens of BALB/c mice immunized with the purified protein were used to produce monoclonal antibodies (Mabs). The Mabs were selected and characterized with the indirect ELISA and competitive ELISA. Protein was expressed correctly. Three Mabs, designated Mab-2C7, 2G9 and 1E4, were selected and recognized three independent epitopes. Mab-2G9 is IgG2b and Mab-2C7 and Mab-1E4 are IgG1. The positive HEV swine sera could be blocked by Mab-1E4 and Mab-2G9 indicating the epitopes recognized by Mab-1E4 and Mab-2G9 are predominant epitopes in capsid protein of swine HEV genotype Ⅳwhile Mab-2C7 can not. The results suggest that the Mab-1E4 and Mab-2G9 are potential diagnostic reagents for detection of swine HEV infection genotype Ⅳ.

To develop vaccine for raccoon dog enteritis caused by raccoon dog parvovirus, parvovirus strains with high immunogenicity and high efficacy were selected as vaccine candidates. Live parvovirus was isolated from feces of clinical raccoon dog by CrandallReese feline kidney (CRFK) cells. The virus strains were isolated then identified with morphological methods, serological methods, molecular biological methods, animal regression experiment and immunogenic evaluation. One RDPV strain named LN10-1 was isolated successfully. Its complete VP2 sequence of LN10-1 strain had the highest identity with FPLV monkey/BJ-22/2008/CHN (99.7 percent). The two AA residues characterized as determination of host range were changed. The phylogenetic analysis of VP2 gene sequences revealed that the LN10-1 isolation was presented between the two genetic clusters, one was composed with CPV, and the other cluster was consist of carnivores parvovirus (FPLV, MEV and BFPV). The Immunological assay result shows the neutralizing antibody titre of parvovirus is higher than 64 folds on 28 day postimmunization. It is supposed that LN10-1 is evolving between FPLV and CPV, or there may be a new virus that becomes adapted to its new host (raccoon dog). And this strain could be used as a candidate inactivated vaccine for preventing haemorrhagic enteritis in Raccoon dogs.

The gB, gC and gD genes of Inner Mongolia IBRV strain were cloned and sequenced. The results showed that the gB, gC and gD genes were 2 850, 1 723 and 1 559 bp, respectively. And the 3 genes contained their corresponding open reading frames (ORF) which encoding 933, 508 and 417 amino acids, respectively. The gB, gC and gD genes of Inner Mongolia strain shared 94.9% to 99.9% homology in nucleotide with others strain from GenBank, and shared 90.3% to 99.7% homology in deduced amino acid sequence by the sequences and phylogenetic analysis. The gB, gC and gD genes were highly conserved among IBRV strains. Phylogenetic tree of IBRV revealed that the Inner Mongolia strain was consistently located in the same lineages with Sweden strain.

The aim of the current study was to investigate the genetic polymorphisms of Echinococcus granulosus obtained from sheep in Qinghai Province, and provide the foundational data for prevention and control of echinococcus disease. The complete mitochondrial DNA 12S genes of 42 isolates（33 were from liver and 9 were from lung）were sequenced, and phylogenetic analyses were conducted using neighbor-joining tree-building methods. There were five haplotypes (H₁ to H₅) detected among the samples, and H₅ was the main type. Phylogenetic analysis supported these observations. The haplotype diversity (H) and nucleotide diversity (Pi) were 0.418 and 0.000 66, respectively. It was demonstrated that the genetic homology of these isolates with the 12S gene of E. granulosus G1 genotype（AF297617）was over 99.86%. All 42 samples were identified as E. granulosus sensu stricto (G1-G3 clusters). In this study，genotypes H1 to H₄ has not been identified elsewhere.

In order to detect the expression of enJSRV and IFN-τ in endometrial tissue of Mongolian sheep as well as relationship of the expression of enJSRV and the variety of progesterone content in peripheral blood during early pregnancy. TaqMan Real-time Quantify PCR was performed on the relative expression of enJSRV and IFN-τ in uterine endometrium, as well as progesterone content in peripheral blood was detected by electrochemiluminescence analyses. The results demonstrated that enJSRV and IFN-τ mRNA were expressed specifically in uterine endometrium of Mongolian sheep. The mRNA expression level of enJSRV was high on Day 12-14, while lower than the former on Day 2-10 and 16-30 during pregnancy. IFN-τ mRNA was expressed on Day 12-25 of gestation with the maximum value on Day 14, and IFN-τ cannot be detected on Day 30. Electrochemiluminescence results showed the progesterone level was 0.4 ng·mL^-1 on Day 2 and rose afterwards on Day 8 of gestation, then kept at about 8.3 ng·mL^-1 on Day 8-16 and decreased during Day 19-30 with the value 2.5 ng·mL^-1 on Day 30. These results indicated that the expression of enJSRV mRNA in endometrium was highly correlated with changes in peripheral blood progesterone content and IFN-τ. Furthermore, enJSRV plays a significant role during placental morphogenesis and reproductive biology.

In order to determine the distribution of the oxytocin receptor (OTR) on celiac superior mesenteric ganglion in female goats, we established an immunohistochemical assay in female goats using SP method as the detecting measure of OTR localization in celiac superior mesenteric ganglion in female goats. Our results indicated that OTR immunoreactive substances were distributed in nerve cells, supporting cells and crossing fiber. OTR mainly expressed in the nerve cells, the relative expression of immunoreactive product OTR was extremely significantly compared with other non-nerve cells (P＜0.01). In nerve cells, OTR immunoreactive substances were distributed mainly in the membrane and cytoplasm, but not in the nuclear. The results suggested that neurons in superior mesenteric ganglion had reaction with OT in female goats and OT might regulate the functional activities of the gastrointestinal system by sympathetic nerve from celiac superior mesenteric ganglion.

In order to study the effect of low oxygen on cell proliferation in vitro by culturing bovine somatic cells under the normoxic (20%) and hypoxic (5%) conditions, three types of bovine donor cells commonly used for nuclear transfer (fetal fibroblasts, fetal oviduct epithelial cells, cumulus granulosa cells) were cultured in 20% and 5% oxygen content of the culture environment for continuous subculture and cell colony formation, at the same time, cell proliferation lifespan (be determined by Population doubling level) and colony formation efficiency. The results indicated that 5% oxygen environment promoted the three kinds of cells proliferation in vitro, and proliferation lifespan of cells in hypoxic group extended significantly (50.61±2.47, 16.35±0.43, 43.38±0.84 vs 27.42±0.23, 12.14±0.83, 32.76±1.53, P<0.01). In the case of culture at 500 cells·dish^-1 (diameter 100 mm), the cell colony formation efficiency of fetal oviduct epithelial cells cultured in low oxygen was much higher than that cultured in normal oxygen ((53.05±4.62)% vs (36.68±5.68)%, P<0.01), however, fetal fibroblasts and cumulus granulosa cells in hypoxic group displayed only a litter more cell colonies than the normoxic group, the difference was not significant (P>0.05). When seeding at one cell·well^-1 in 96-well plates, single-cell colony formation efficiency of hypoxic group was significantly higher than that of the normoxia group ( (21.60±2.37)%, (22.29±5.42)%, (27.92±3.69)% vs (12.01±1.42)%, (7.92±2.86)%, (10.49±3.07)%, P<0.01 or P＜0.05). The result indicate that reducing the oxygen content(20%) of in vitro culture conditions to low oxygen (5%), which better approximate to the physiologic situation, can extend cell proliferation lifespan and improve the efficiency of single-cell colony formation, low oxygen has a good role in promoting cell growth.

The purpose of this study was to analyze MSTN and p21 mRNA expression profiles and differences among chicken, quail and hybrids of chicken-quail during embryonic myogenesis, and evaluate the potential relationships between their relative expression and myogenesis. The cross-bred eggs of quail (♀) were acquired by artificial insemination with chicken(♂)-semen, the eggs of chicken, quail and hybrid were hatched in one batch according to the standard condition of chicken, the breast muscle tissues was collected from day 7 to 17. The expression of MSTN and p21 mRNA in different species every day was revealed by real-time quantitative PCR. The expression of MSTN and p21 mRNA was detected from day 7 to 17. Peak of MSTN and p21 expression was noticed at day 9 in chicken, and day 7 in quail, with the development of muscle, the expression level was rising, which was almost maintained at this level until day 17. And the peak expression was also noticed at day 9 in hybrid which was in accordance with chicken, however, the expression of p21 mRNA in hybrid was significantly higher than that in chicken and quail (P<0.01). The expression profile of MSTN was in accordance with the profile of the withdrawal of myoblasts from the cell cycle, and MSTN could up-regulated the expression of p21 specifically during embryonic myogenesis.

18S rRNA and 28S rRNA sequences of several Eimeria species from chickens and squirrels were aligned to design common primers for Eimeria parasites from various hosts based on the conserved sequences of both 3′ end of 18S rRNA and 5′ end of 28S rRNA. 1 178 bp of the ITS1-5.8S rRNA-ITS2 complete sequence of E. stiedai, including 423 bp of ITS1, 155 bp of 5.8S rRNA, and 600 bp of ITS2, was firstly cloned with the common primers and genomic DNA of oocysts of LY isolate as templates. In contrast to 5.8S rRNA fragment, ITS1 and ITS2 sequences of E. stiedai LY isolate was more variable, and less than 60% of ITS1 and ITS2 sequences of LY isolate was identical to those of Eimeria species in chickens and other rodent hosts. A sensitive and specific PCR diagnostic assay based on the ITS1-5.8S rRNA-ITS2 sequence was developed to identify E. stiedai, one of high pathogenic species from rabbits by designing specific primers for E. stiedai at the mutative sites of ITS1 and ITS2. These findings will provide a powerful tool for clinical differentiation of high pathogenic Eimeria species in rabbits and revealing population genetic characteristics of rabbit coccidia.