In F₁ individuals of Large White × Meishan, weight of 180 days, ratio of feedstuff to meat, average daily gain and days for 90 kg living weight were tested, and relative growth ratio and Kleiber ratio were calculated. The relationship between DNA methyaltion and these growth traits were analyzed with methylation-sensitive amplified polymorphism (MSAP) technique. In all, 1 274 sites were amplified with 81 methylated sites significant effected on growth traits in 252 polymorphic sites (P＜0.05). The number of overall cytosine sites between parental lines and hybrid F₁ were not singnificantly different, but the number of methylation sites amplified by each pair primers was significantly different(P＜0.05). Results show that general and neutral individual methylation percentage differences didn’t significantly effect on performance of any growth traits, but special individual methylation percentage difference significantly effected on performance of Kleiber ratio, ratio of feedstuff to meat, average daily gain and days for 90 kg. Performances of the 5 growth traits all decreased as special individual methylation percentage difference (SIMPD) increased in view of improving pig productivity. The linear regression between SIMPD and values of 5 growth traits were significant. It can be concluded that DNA methylation can effects hybrid performance or heterosis and be used as DNA markes in predicting heterosis and related studies of pigs; methylated sites that significantly effect on a trait are superior to other methylated sites in predicting hybrid performance.

In order to understand the molecular basis of chicken heterosis, mRNA differential display method was used to analyze the differential gene expression of ovary tissue between hybrids and their parental lines in a 3×3 diallel cross involving 3 chicken breeds, which were White Plymouth Rock（EE）, CAU Brown（DD）and White Leghorn(AA). Only bands that can be repeated in duplicate DDRT-PCR amplification were used for statistic analysis. Our results showed that differences of gene expression between hybrids and their parent lines were very obvious both in quantitative and qualitative. By using 24 pairs of primer combination, a total of 1 572 bands were displayed, and 71.63% (1 126 out of 1 572) can be repeated. The average differential expression band of 6 hybrids is 169.67(15.07%), which were grouped into seven types of differential expression patterns: Over-expression of parental fragements in hybrids (P1=22.29%)，hybridspecific expressed fragements (P2=9.84%)，Under-expression of parental fragements in hybrids (P3=9.85%)，hybridabsence expressed fragements (P4=3.42%)，parent-specific expressed fragements (P5=22.91%)，Dominant expression fragements of single parent in hybrids (P6=25.74%)， Co-dominance expressed fragements (P7=5.95%). Correlation analysis indicated that there are significant negative correlation or significant correlation between the pattern of P2 or the pattern of P3 and heterosis percentage of 32 week-old egg number, which indicates that hybrid-specific expressed fragements or Under-expression of parental fragements in hybrids are likely to restain or strengthen the heterosis forming of 32 week-old egg number.

5 pairs of bovine male-specific PCR primers were designed based on the sequences of bovine Y-specific repeat sequence, testis-specific protein gene on Y chromosome and sex determining region Y gene (SRY) , meanwhile, based on skeletal alpha action precursor gene and bovine 1.715 satellite DNA, 4 pairs of bovine-specific PCR primers were designed as internal control primers. After PCR amplification of bovine genomic DNA with different primers, 4 pairs of bovine male-specific primers and 1 pair of bovine-specific primers could work very well. Two primer combinations of bovine male-specific PCR primers and internal control primers, B34/A12 and B78/A12, were obtained for sexing bovine preimplantation embryo after multiplex PCR amplifications of bovine genomic DNA, fibroblasts, and clone embryos.

In this research paper, purified goat mammary epithelial cell line was obtained by culturing dispersed cells routinely and purifying them with time-controlled trypsinization. Results indicated that: large numbers of dispersed mammary cells could be obtained by digesting goat mammary tissue with 150 U/mL collegenaseⅠand 150 U/mL hyaluronidase for 4 h at 37 ℃, which is the feasible method for collection goat mammary cells. Adding hydrocortisone, insulinlike growth factor-I (IGF-I), epithelial growth factor (EGF) and insulin-transferrin-seuim (ITS) to RPMI1640 or DEME/F12 medium, which supplied with 10% fetal bovine serum and antibiotics, was benefical to the goat mammary cell growth significantly. The light microscope structure and perspective electron microscope ultrastructure of goat mammary cell indicated that: goat mammary cells formed island monolayer aggregates and dome-like structure. The seventh generation mammary cell cytoplasms had plenty of secretive vesicles and Golgi apparatus, which showed that the seventh generation mammary had vigorous secretive activity and there wasn’t any sign of apoptosis.

Effects of electrofusion parameters and donor cell types on the nuclear transfer of buffalo somatic cells were investigated in this study. Buffalo oocytes obtained from ovaries at slaughter were matured in vitro for 22～24 h, and then enucleated in manipulation medium containing 5 μg/mL cytochalasin B. Fibroblasts or granulosa cells cultured in DMEM supplemented with 0.1 μg/L Aphidicolin (APD) for 24 h and following in 0.5%FBS for 2~9 days were transferred into enucleated oocytes by electronic fusion. The reconstructed embryos were activated by exposuring them to 5 μmol/L ionomycin for 5min and then culturing in 2 mmol/L 6-DMAP for 3h. After activation, embryos were cultured in 30 μL drop of granulosa cell monolayers for 7~9 days. When granulosa cells were used as donor cells and the direct current field intensity was fixed at 1 500 V·μs/mm applied, 3 pulses resulted in a significantly higher fusion rate (74.18%) compared with 2 pulses (52.03%) (P＜0.05), and a significantly higher cleavage rate (71.82%) in comparison with 4 pulses (53.95%) (P＜0.05). When the number of pulses was fixed at 3, increasing the direct current field intensity from 1 500 V·μs/mm to 2 000 or 2 500 V·μs/mm resulted in a significant decrease in either fusion rate or cleavage rate. The fusion rate (59.75%) and cleavage rate (57.45%) of fibroblast cells were significantly lower than that of granulosa cells. Karyotyping analysis showed that 66.7% of reconstructed embryos have normal diploid karyotype (48 XY), which was identical to that of donor cells. One recipient received 2 frozen/thawed embryos derived from the ear fibroblasts of a Mura bull aged at 22 years became pregnant and aborted at 215 days of gestation. These observations suggest that embryos derived from old buffalo somatic cells can develop to the late stage of gestation; the suitable electrofusion parameters on buffalo somatic cells nuclear transfer are 100 V/mm, 15 μs and 3 pulses; and granulosa cells are better than fibroblast cells used as donor karyoplasts for electrofusion in buffalo cloning.

In vitro experiments were carried out to investigate the effects of incubation solution pH, incubation temperature, incubation time and the addition amount of BBMV (presumably dipeptidase) on hydrolysis of dipeptides. The results indicated that incubation solution pH (3.5，4.0，4.5，5.0，5.5，6.0，6.5，7.0，7.5 and 8.0) , incubation temperature (25 ℃ and 37 ℃) , incubation time (0.5, 1, 2, 5, 10, 20, 30 and 40 min) and the addition amount of BBMV were not effective on hydrolysis of the dipeptides. The results suggested that these two dipeptides (Gly-Leu and His-Leu) were not hydrolyzed in small intestinal BBMV of weaned piglets.

The regression analysis technique (REG) and difference technique were used to estimate endogenous P outputs and true P digestibility value with soybean meal (SBM) or wheat middling(WM) as only P source in diets for animals. Eight barrows, average initial body weight 20 kg, were allotted two groups randomly, fed four diets each group according to a 4×4 Latin Square design. Four cornstarch-based diets containing four levels of TP (0.15%, 0.20%, 0.30% and 0.35%) based on fed status each group were formulated from SBM or WM,respectively. Each experimental period comprised 8d with 4 d adaptation and 4 d collection feces. Results showed that: There were significant linear relationship (P＜0.05) between fecal P outputs and dietary inputs of P when both expressed as g/kg DM intake diet with TP level of diet from 0.15% to 0.35%, which suggests a stable amount of endogenous P lose in feces for pig. No significant differences (P＞0.05) of endogenous P existed determined by REG and difference technique with SBM and WM, implicated that the two assays are valid for estimating endogenous P outputs in pigs. The endogenous P output was 0.65~0.68 g/kg DM intake diets under tested TP levels and true P digestibility value of SBM and WM in growing pigs were 52.1% and 63.7%, respectively.

Three yeast culture (YC) products, YC-1, YC-2 and YC-3 were fed respectively to the beef cattle with permanent rumen fistula.We studied the effects of these YC products on rumen fermentation, activities of fiber hydrolytic enzymes and quantities of predominant fibrolytic bacteria. With YC-2 supplement, the concentrations of total VFA, acetate, propionate and butyrate were all increased significantly (P＜0.05). The acetate to propionate ratios were significantly decreased (P＜0.01) with YC-1 and YC-3 supplement. The activities of CMCase, Salicinase and Xylanase in the rumen were all increased significantly (P＜0.01) with three kinds of YC supplements, and the relative population of R. flaveciens was also increased significantly. By hybridization analysis, sum of the relative populations of cellulolytic species was about 3.80%±0.2%.

Digesta pH and activities of amylase,trypsin,chymytropsin,lipase and lactase in different part of small intestine(duodenum,jejunum and ileum)in lamb of Small Tail Han Sheep were measured. The results indicated that there were different digesta pH in different part of small intestine. Digesta pH in ileum were significantly higher than those in jejunum. Digesta pH in jejunum and ileum were significantly higher than those in duodenum. There were no significant change in digesta pH in different part of small intestine after the age of one month in lamb. There were different activities of amylase,trypsin,chymytropsin and lipase in different part of small intestine. Activities of amylase,trypsin,chymytropsin and lipase in jejunum were higher than those in duodenum and ileum, increased with the growth of lamb and there were no significant change after 3 months. There were different lactase activities in different part of small intestine. Lactase activities in jejunum were significantly higher than those in duodenum and ileum, decreased with the growth of lamb.

The aim of this study was to explore the develompental pattern of liver during neonatal period.Fifteen neonatal pigs were killed and sampled on newborn(day 0),day 3 and day 7 after birth,respectively.A portion of liver tissue was taken for transmission electron microscopic examination.Such biochemical indices as DNA,RNA and liver glycogen were analyzed according to appropriate methods.The hepatocyte cords were arranged in a radial mode and there were abundant mature cellular organelles such as mitochondria and rough endoplasmic reticula in the liver of neonatal pigs.Liver weight increased at a higher rate than body weight in the first 7 days,especially in the first 3 days after birth.Similarly,liver protein content increased significantly in the first postnatal week(P＜0.01).In contrast,liver glycogen content was highest at birth and decreased markedly after birth(P＜0.01).DNA concentration was lowest(P＜0.05) and RNA concentration highest (P＜0.05) in the liver of 3-day old piglets.In conclusion,the hepatocytes of piglets had already developed both in structure and in function at birth.Both the size and the number of hepatocytes increased greatly,and therefore liver grows quickly during the short period after birth.

Lungs of prenatal goat(3~22 weeks) were observed with eyes,LM and TEM,the results are as following: 1. The 7~22 weeks goat fetal lungs have the same outer appearance which have no relationship with its age. The left lung have two lobes and most of the right lung have four lobes .Most fissures are incomplete which are connected with lobes by lung tissure and/or serosa tissure.2. The lungs of prenatal goat have five stages during their development: (1) Embryologic stage(3~5 weeks) : The lung bud branching and forming into the two principal bronchi, the principal bronchi increase in length and budding lobar bronchi lined with pseudostratified columnar epithelium.(2) Pseudoglandular stage(6~12 weeks): The bronchial divisions were differentiated and their air conducting system became established, lined with pseudostratified and/or single-walled columnar epithelium. The terminal bud assumes a glandular aspect. The terminal bud epithelium were differentiated from pseudostratified columnar epithelium into singlewalled columnar epithelium. The nuclei transfer to the top of the epithelial cells gradually. Short and small microvilli appeared on the luminal surface of the epithelial cells. Mitochondria, rough endoplasmic reticulum and ribosomes are all in the top of the cells and increased in number with the development of the lungs.(3) Canalicular stage(13~14weeks):The respiratory bronchioles developed quickly,the primitive alveoli had developed, the respiratory bronchioles were lined by cuboid cells. The terminal buds’ glandular structures disappeared gradually, the respiratory bronchioles and primitive alveoli epithelium were differentiated from single-walled columnar epithelium into cuboid epithelium. More short and small microvilli appeared on the luminal surface of the epithelial cells. Mitochondria, rough endoplasmic reticulum and ribosomes developed dramatically in the cells. (4) Saccular stage (15 week): The respiratory divisions developed dramatically, the lung assumes a more “aerated” appearance, i.e. the prospective air space volume increases relate to the tissue components. Parts of the primitive alveoli epithelium differentiated into flattened type I alveolar cells and cuboid type II alveolar cells. The osmiophilic bodies were first observed in type II alveolar cells.(5) Alveolar stage (16~22 weeks): The alveoli developed dramatically, more alveoli epithelium differentiated into flattened(type I cell)and cuboid (type II cell)epithelial cells.During this stage, the capillary endothelium were pressed close to some of the alveolar epithelium. The alveolar epithelial cells can be divided into three types as follow: Type I alveolar cells,assumed short columnar or ellipse aspect.Ribosomes，expanded rough endoplasmic reticulum and denatured mitochondria are prominent in the cytoplasm. The blood-air barrier was composed of type I cell,basement membrane and endothelium. Type II alveolar cells: The osmiophilic lamellar bodies and ribosomes are seen abundantly,rough endoplasmic reticulum pools expand and multivesicular bodies are observed. Mitochondria denatured, microvilli of the epithelial cells appear on the luminal surface. The third type of cells are undifferentiated cuboid epithelium, they are small while the nuclei are large relatively. The cells have round or ellipse nuclei, less cytoplasm and little organelles.

Using RT-PCR, Nested PCR and Half-nested PCR, 3 substitutes of cDNA fragments were amplified from total RNA extracted from spleens of experimentally infected rabbits. After cloned in pMD18-T vector,　they were analyzed by sequencing. F1, F3 and F51 fragments in 5′ half cDNA or 3′ half cDNA were substituted by genetic engineering　recombination. The reconstructed 5′ half cDNA and 3′ half cDNA were then ligated to a new full length cDNA. The mutation sites were confirmed to be corrected by the method of sequencing. The reconstructed cDNA show infectivity by primary identifications. The study established a foundation for reverse genetic system of CSFV.

The hemagglutinin（HA） gene of a strain of swine influenza virus （H1N1）, A/Swine/ GuangDong /711/2001, was amplified by RT-PCR. The PCR products were sequenced after cloning into pMD18-T plasmid and the sequence was compared with the HA gene sequences from others reference strains of influenza virus in GenBank. The result indicated that 1 771 bp fragment covered the complete HA open reading frame, and encoded 579 amino acid residues. There were 8 glycosylation sites in the amino acid sequences of A/Swine/GuangDong/711/2001. The 5 glycosylation sites were positioned at 27, 28, 40, 104 and 287 of HA1 gene, others at 21,153 and 213 of HA2 gene. Compared with typical strains of swine influenza viruses(H1N1), the glycosylation sites were not conservative. Among A/Swine/GuangDong/711/2001 and A/South Carolina/1/18, A/MD/12/91 and A/Swine/Wisconsin/238/97, the homology of the nucleotides were 93.9%,94.7% and 93.9% respectively. Phylogenetic analysis showed that A/Swine/GuangDong/711/2001 had a close relationship with A/South Carolina/1/18 and A/Swine/ Wisconsin/238/97.

The exotoxin ApxⅠ, ApxⅡ and ApxⅢ of Actinobacillus pleuropneumoniae was expressed in E.coli, the recombinant protein was purified and mixed with A.pleuropneumoniae serotype 7, which is prevalent in China, then emulsified with Freund’s incomplete adjuvant in equal volumes to get a sort of mixed subunit bacterin. Groups of BALB/c mice were immunized twice at week 0 and 2,then challenged intraperitoneally with serotype 1 and serotype 7 at week 4. Antibodies were detected with ELISA and IHA. After second immunization, antibody level increased obviously and the immune protection rate against serotype 1 and serotype 7 reached 83.3％ and 91.7％ respectively, challenge strains were reisolated from dead mice. These preliminary results showed that this mixed subunit bacterin had good protection against homologous and heterologous A.pleuropneumoniae，which built a good foundation for the further research of high efficacy vaccine against porcine pleuropneumonia.

Fifty-eight Chinese isolates of Riemerella anatipestifer which agglutinated only in antiserum to serotype 10 representative strain (H2199) were further serotyped by agar gel precipitin methods. Based on precipitation patterns, these strains can be divided into four groups: the first group contained 30 isolates represented by C2, the second contained 3 isolates represented by C449, the third contained 6 isolates represented by C459, and the fourth contained 19 isolates represented by C598. Isolates in the first group showed identical to H2199, and isolates in other groups showed identical to representative strain of their own respectively, but had antigenic differences with H2199 or one another.Antigenic relationships between H2199 and four groups were further studied using slide and tube agglutination tests with adsorbed antiserum. Isolates represented by C2 were real serotype 10. Isolates identical to C459 showed distinct from H2199, such strains possessed their own specific antigenic materials,in addition they had antigens in common with H2199. The relationship between H2199 and C459 could be described as ab-bc. Similar antigenic relationships were observed between C598 and H2199, C598 and C449 respectively. However, compared with C449, C459 and C459 strains, H2199, C598 and C449 had no type-specific antigenic materials of their own in tube agglutination test respectively. So the relationship between H2199 and C449, C598 and C459, C449 and C459 can be described as b-bc respectively. It might be better to divide the isolates agglutinated in anti H2199 serum into subtypes 1～4 represented by strains H2199 (or C2), C449, C459, C598 respectively.

The specific primers were designed and produced according to E.tenella sporozoite surface antigen 5401 gene sequence. EcoRⅠ and SalⅠ restriction enzyme cut sites and protective bases were added at the two ends of the primer respectively. A fragement of 881bp was cloned by RT-PCR from the E.tenella sporulated oocysts. The recombinant plasmid pGEM-T-5401 was identified with EcoRⅠ and SalⅠ restriction enzyme, the fragements were collected by agarose gel fraction method. After purificaion the fragement was ligated to the pET-30a express vector, the recombinant pET-30a-5401 express plasmid was constructed. After transformation, the engineered strain E.coli BL21/ 6×His-5401 was expressed by the induction of IPTG in a form of dimer protein. The specific approximate 66.2 ku band was obtained by analysis of SDS-PAGE and Western-blotting. The result indicated that E.tenella 5401 protein had been expressed successfully in E.coli expressing system.

The effect of Zafirlukast on pulmonary hypertension (PH) induced by low ambient temperature in broiler chickens was investigated. Sixty male 17-day-old broiler chickens were randomly divided into three groups: normal ambient temperature group (NT,22~23 ℃), low ambient temperature group (LT, 9~11 ℃) and Zafirlukast group in low ambient temperature (ZLT, 9~11 ℃). At 31, 38 days of age, 7 birds were randomly taken from each group for measuring the pulmonary artery pressure by right cardiac catheter and femoral artery pressure (FAP) by directly measured methods. The ascites heart index (right ventricular weight/total heart weight，AHI) and the packed cell volume (PCV) was measured too. The results showed: (1) At 31 days of age, the pulmonary artery systolic pressure of ZLT was significantly higher than that of LT and NT(P＜0.05), and at 38 days the pulmonary artery diastolic pressure of ZLT was significantly higher than that of NT (P＜0.05). (2) The PCV of ZLT was significantly greater than that of LT (P＜0.05) at 31，38 days. (3) The AHI of ZLT was significantly greater than that of LT (P＜0.05) at 31 days. (4) The FAP of all groups were not significantly different (P＞0.05). These data indicate that Zafirlukast promote the development of PHS induced by low ambient temperature in broiler chickens.

90 cases with thoracolumbar intervertebral disc protrusion/extrusion were choosed to study the effects of acupuncture on the discase by retrospective study. Medical records were reviewed to obtain information at the Veterinary Hospital of China Agricultural University (CAU), including signalment; initial complaint; results of physical examination, radiography, myelography; acupunctural treatment; outcome and investigate recurrence of the disease by telephone.The outcome was excellent or good in 81(90%) of 90 dogs. For the Grade Ⅳ, the effect was poor, only 5(45.5%) in 11 dogs. The relapse was relatively high and the mean recurrence ratio could reach to 15%, especially for the grade Ⅳ dogs, reach to 40%. In addition, the acupuncture could lesson pain, improve the appetite and inspirit, and prevent muscle atrophy for some cases. Acupuncture therapy is a marked effect, economical and simple therapeutics with little side effect and sequelae. At the same time, it is easy to be accepted by the patient owner and it is a good and affirmative selected therapeutics for the veterinary.

In order to find out the regularity of antigenic variation, 10⁷ cloned population of Trypanosoma evansi stock YN was inoculated sequentially into 5 New Zealand rabbits during 165 days. Blood was collected from the rabbits at 3-day intervals after infection. Ten clone-derived populations were isolated from each; twenty VATs were determined from the 50 populations with the indirect fluorescent antibody staining technique (IFT) and ABC-enzyme-linked assay (ABC-ELA) and designated as BeTat 1.1, BeTat 1.2,…BeTat 1.20.

Random Amplified Polymorphic DNA (RAPD) analysis was used with 10 primers to assess genetic variability in Shanxi native goats (Yangcheng White，Licheng Daqing，Lüliang Black). The results showed as follows: 1.The DNA of 3 breeds provided a great number of molecular markers with high polymorphism. 2. According to their RAPD fingerprinting map, the genetic distance and average band similarity among 3 breeds were calculated, 0.182 7 between Yangcheng White Goat and Licheng Daqing Goat is the smallest. Cluster analysis also showed that Licheng Daqing Goat and Yangcheng White Goat from alike region had a smaller distance. 3. The genetic diversity and its partition within and between populations of the 3 populations were calculated by using Shannon index. The genetic diversity index of Licheng Daqing，Yangcheng White，Lüliang Black were 0.328 8，0.349 9 and 0.154 5 respectively, Genetic differentiation (Gst) was estimated to be about 68.49% among 3 populations. The results indicated that the genetic variation was mainly among breeds; the genetic character of Lüliang Black Goat was peculiar in native breeds indicating that protection and further selection should be strengthened.