Studies on hybridization effects of different geographic populations of Chlamys farreri Ⅱ.The medium-term growth and development of Chlamys farreri populations from China and Russia and their reciprocal crosses

Based on the research of juvenile (2, 3, 4 months) growth and survival of three populations of two different geographic areas in Chlamys farreri from Russian and China and their F1 hybrids derived from Chinese cultural population (CC) (?) × Russian population (RW) (?) , Chinese wild population (CW) (?) × Russian population (RW) (?), Russian population (RW) (?) × Chinese wild population (CW) (?) , the study of the medium-term (6, 8, 10, 12 months) growth and development of Chlamys farreri was carried out. The four determined results indicated that there existed different extent heterosis (3% -52%) for the growth in three types of F1 hybrids, and the offspring derived from CC(?) ×R(?) had a stronger heterosis among the crosses at the medium-term; the uptrend among traits are wet weight >shell width>shell length> shell height, Chinese cultural population could be recognized as excellent parent, and seasonal variations influence very much on the daily increment and growth rate of each trait of Chlamys farreri and it is only able to survive and could barely grow in winter (6-8 months), but grows fast in temperate season (10-12 months).

Quantitative traits correlative analysis and growth comparison among different populations of bay scallop,Argopecten irradians

The shell traits and weight traits are measured in cultured populations of bay scallop, Argopecten irradians. The results of regression analysis show that the regression relationships for all the traits are significant (P<0.01). The correlative coefficients between body weight, as well as tissue weight with shell length, shell height and shell width are significant (P<0.05). But the correlative coefficients between the anterior and posterior auricle length with body weight as well as tissue weight are not significant (P>0.05). The multiple regression equation is obtained to estimate live body weight and tissue weight. The above traits except anterior and posterior auricle length are used for the growth and production comparison among three cultured populations, Duncan's new multiple range procedure analysis shows that all the traits in the Lingshuiqiao (LSQ) population are much more significant than those of the other two populations (P<0.01), and there is no significant difference between the Qipanmo (QPM) and Dalijia (DLJ) populations in all traits (P>0.05). The results indicate that the LSQ population has a higher growth rate and is expected to be more productive than the other two populations.

Comparative Study on Nitrogen Metabolism and the Nitrogen Maintenance Requirement in Lohmann Brown Roosters and Layers

The objective of this study was to in- vestigate the effect of dietary protein level on nitrogen retention and compare nitrogen metabolism in Lohm- ann Brown adult roosters and layers. The nitrogen ma- intenance requirement （Nm ） was determined based on the nitrogen balance. Thirty Lohmann Brown adult roosters and 30 laying hens at 27 weeks of age were randomly divided into five groups of six birds per group. The birds were fed with one of five diets con- taining 10.46%, 11.77%, 13.79%, 16.77% or 18.29% of crude protein. Nitrogen intake, nitrogen retention and nitrogen retention efficiency were higher in roost- ers than in laying hens, and the average nitrogen re- tention rate for groups fed with CP level of 11.77%, 13.79%, 16.77% and 18. 29% was improved by9.14%. The nitrogen maintenance requirement for Lohmann Brown roosters and laying hens at 27 weeks of age were 0.4245 g/d and 0.5059 g/d, respective- ly, and Nm based on average body weight （BW） and metabolic body weight （ BW^Ts ） was 0.2364 g/kg BW and 0. 2739 g/kg BW~＇75 for laying hens and 0. 2754 g/kg BW and 0. 3208 g/kg BW^72 for roost- ers, respectively. The regression equations for daily N gain （NB, protein accretion） vs. daily N intake （NI ） for Lohrnann Brown layers and roosters were NB = 0.3743NI -0.1589（R2 =0.79） and NB =0.6228NI - 0.3151 （ R2 = 0.85 ）, respectively. The results of this study indicate that nitrogen intake and nitrogen reten- tion at the same dietary CP level were higher in roost- ers than in laying hens.

Oral Insulin Stimulates Intestinal Department and Enzyme Maturation in Newborn Pigs

The effects of oral insulin on intestinal tissue growth and brush border enzyme activitiesin newborn pigs were examined in this study. Newborn unsuckled pigs were bottle-fed for3 days with artificial milk(M), milk supplemented with 60mIUmL-1 of insulin(IM) orhydrolyzed milk(HM). Compared with newborn unsuckled pigs, piglets bottle-fed for 3 daysall gained in intestinal weight and length significantly despite a mild loss in bodyweight during the experimental period. The activities of lactase and alkaline phosphatase(AKP) in the small intestinal mucosa declined markedly in pigs fed with M, but theactivity of maltase increased significantly during the experimental period. Dietaryprotein pre-hydrolysis had no significant effect on intestinal tissue mass or length,but it moderated the decline of intestinal lactase and AKP activities. Dietarysupplementation of insulin significantly increased mucosal protein content and brushborder activities of lactase, maltase, AKP and aminopeptidase(AP)in the small intestine.The effect of insulin treatment was particularly obvious at the distal region of the smallintestine. These results demonstrate that oral insulin can stimulate intestinal digestiveenzyme activities in newborn pigs. The finding supports the hypothesis that milk-borneinsulin plays a role in regulating postnatal gut development in the suckling young.

The Present Situation and Prospect of the Study on Locoweed in China

Locoweed is one of main poisonous plants in the world, and also is the most important toxic plant in grassland of China. The distribution range of the locoweed is extending continuously and it has formed or is coming into dominant species gradually in some areas in recent years, which cause the retrogressive succession and grazer poisoning and died in rangeland. Locoweed seriously threatened the grassland agriculture and made typical 'ecology-economic sick' in above district. Based on the investigation, research, prevention and cure practice to the locoweed for more than ten years, this paper reviewed the present situation and prospect of the studies on the locoweed in China, which include the researches of it's biological characteristics, distribution, ecological environment, harmfulness, prevention, weeding, utilization and ecological control etc.

Study on Development of Northeast China Fine-fleece Sheep Fetal Follicles

Different gestational age fetal follicles of Northeast China Fine-fleece Sheep were histologically studied. The results showed that boundaries between medulla and cortex was ambiguous at the eighth week and became obvious at the twelfth week. Primordial follicles could be found in 8-week fetal ovaries and some follicle cells became irregular cuboid in 12-week, but primary follicles could be found until 16-week. There was significant difference between 8-week and 12-week follicles in size (P < 0.01), most mitochondria were round, some diamond, irregular and juvenile ones could be found with the development of oocytes. Some of oocytes degenerated in each stage of development. The diameter of primary oocytes, primordial follicles and primordial follicular oocytes were larger in 12-16 weeks fetal ovaries than other times.

Effects of fucosylated milk of goat and mouse on Helicobacter pylori binding to Lewis b antigen

AIM:To evaluate the effects of animal milk containing fucosylated antigens on Helicobacter pylori (H pylon) binding to Lewis b antigen.METHODS:A mammary gland expression vector containing human α1-3/4-fucosyltransferase cDNA sequences was constructed. Transient expression of human(α1-3/4-fucosyltransferase cDNA in goat mammary cell and establishment of transgenic mice were performed. The adhesion inhibitory properties of milk samples were analyzed by using Hpylori.RESULTS: Goat milk samples were found to inhibit bacterial binding to Lewis b antigen. The highest inhibition was observed 42 h after injection of the plasmid. The binding activity of Hpylori to Lewis b antigen reduced mostly, by 83%, however milk samples from transgenic mice did not inhibit Hpylori binding to Lewis b antigen.CONCLUSION: The use of 'humanized' animal milk produced by the transgenic introduction of fucosylated antigen can perhaps provide an alternative therapy and preventive measure for Hpylori infection.

Sequence Comparison of MHCClassⅡβ(Exon 2)and Phylogenetic Relation-ship Between Poultry and Mammalian

A fragment spanning over exon 2 and intron 2 of major histocompatibility complex B-LB Ⅱ genes was amplified using PCR, cloned and sequenced in 13 individuals from eight Chinese indigenous chicken breeds and one introduced breed. Another 41 sequences of MHC class Ⅱ β from ten vertebrate species were cited from the NCBI GenBank. Thirteen new B-LB Ⅱ alleles were found in the chicken breeds sampled. Alignment of the exon 2 sequences revealed 91.1-97.8% similarity to each other within the chickens sampled, and the chickens shared 84.1-87.0% homology to Phasianus colchicus, 78.5-81.5% similarity to Coturnix japonica. The sequences in poultry showed 62.6-68.1% identity to HLA-DRB1, 50-61.5% similarity to DQB (HLA-, SLA- and H2-BB), 53.7-60% to HLA-DPB and 53.3-57.8% similarity to HLA-DOB. The frequency of nonsynonymous substitutions of nucleotide was higher than that of synonymous substitutions, and the frequencies of nonsynonymous and synonymous substitutions in poultry B-LB Ⅱ genes were lower than those observed in mammalian DRB1 and DQB1 genes. The deduced amino acid sequences of MHC class Ⅱ β1 domain exhibited extreme difference in conversed region and variable region patterns among the various species, but the two conserved cysteines forming disulfide-bond were shown consistent in poultry with that in mammalian species; and the carbohydrate attachment site was found more conserved in chicken, Homo sapiens, Bos taurus, Ovis aries and Capra hircus than in Sus scrofa and rodent animals. Compared with exon 2 of DQB1 genes of Homo sapiens, ruminant species and Sus scrofa, the differentia that the deletion of six nucleotides at position195 to 200 of exon 2 of DQB1 genes, and insertion of three nucleotides at position 247 to 249 of the exon 2 existed in rodent species were found, which led to the absence of three AA residues at position 65, 66, and 67 within β1 domain of DQB1 chain, and the insertion of one AA residue at position 85. The difference of the deletion of six nucleotides at position 72 to 77 of exon 2 of DPB1 genes was observed with Homo sapiens DQB1, which caused absence of three AA residues at position 24, 25, and 26 of β1 domain of DPB1 chain. The phylogenetic tree revealed that the B-LB Ⅱ sequences from poultry are not orthologous to the class Ⅱ MHC β-chain genes of mammalian species. The tree indicated that genetic evolutionary relationship of chickens with Phasianus colchicus was much closer than with Coturnix japonica, and the DQB and DPB clusters are more tightly related to each other than to the remaining clusters.

Effects of Ooplasmic Transfer on Rabbit Oocyte Fertilization and Early Embryonic Development

In order to evaluate the effects of ooplasm on oocyte fertilization and early embryonic development and to study themitochondrial DNA (mtDNA) heterogeneity of early embryos, microinjection was first performed to transfer a smallamount (5 to 7%) of donor ooplasm into recipient oocytes, then the eggs were fertilized with rabbit sperm throughintracytoplasmic sperm injection (ICSI). In group 1 (homogeneous ooplasmic transfer), both the donor and recipient rabbitoocytes were at metaphase II (MII). In group 2 (heterogeneous ooplasmic transfer), the donor was mouse MII oocyte andthe recipient was rabbit MII oocyte. In the control group, only ICSI was done on rabbit oocyte without ooplasmic transfer.No significant difference (P>0.05) was observed in blastocyst development rates between group 1 (13.0%, 3/23) and thecontrol group (16.7%, 4/24), but significant difference (P<0.05) was examined in blastocyst development rate betweengroup 2 (0, 0/27) and the control group. Blastomeres cleaved unequally and embryonic fragments increased after ooplasmictransfer and ICSI. In early embryos, in group 2, donor mouse mtDNA was detected in 2-cell embryos (3/3), 4-cell embryos(3/4), 8-cell embryos (4/4), and morulae (2/2). The mtDNA fingerprinting analysis showed that mouse mtDNA detected inheterogeneous embryos of different developmental stages had exactly the same sequence as that of the donor mousemtDNA, thus indicating that homogenous ooplasmic transfer had no significant influence on rabbit oocyte fertilizationand early embryonic development, and that heterogeneous ooplasmic transfer did cause notable reduction in blastocystdevelopment rate. Heterogeneous mtDNA sequence in early embryos did not mutate. Compared with the control group,the embryonic quality declined after ooplasmic transfer operation in the present experiment.

Study on Isolation, Passage, Cryopreservation and Histology of Mouse Fibroblasts

The embryonic ages were determined for the best preparation of mouse fibroblasts. Four methods were adapted to verify cryopreservation of mouse fibroblasts. The results showed that embryonic cryopreserving method was best one with 0.86 of thawing viability. The embryos from 13-14 d pregnant mouse were superior to 11-12 d and 15-16 d in isolating, growing, laying and living. The first 6 generations were better than following ones in the same aspects above. Cell laying time became longer and vailable time became shorter after the sixth generation. With culture time increasing, fibroblast nuclear size became larger, fibrous filament appeared among fibroblasts, and macrocyst vesicle with floccule appeared in the cells. Cyst vesicle structure with pyknotic granule appeared in 24 h cultured fibroblasts and macrocyst vesicle also appeared in passaging fibroblasts.

Effects of Cultivar and Maturity Stage on Chemical Composition and Ruminal Digestibility of Oat and Barley Hay Using Rumen Fluid or Faecal Liquor as the Inoculum

Two experiments were conducted to study the effects of variety and maturity stage on chemical composition and in vitro dry matter degradability of oat and barley forages. In exp1, four oat varieties and one barley variety were harvested at three maturity stages: stage 1, Two weeks before stage 2; stage 2, Mid-dough for oat and early-dough for barley; stage 3, One week after stage 2. All samples were analyzed for DM, CP, ether extract, ash, ADF(acid detergent fiber), NDF(neutral detergent fiber), ADL(acid detergent lignin), NDICP(neutral detergent insoluble crude protein) and IVDMD(In vitro dry matter digestibility). There was no difference in chemical components and IVDMD among oat variety. But maturity stage had a profound influence on some nutrient contents and IVDMD. With maturity advancing, CP decreased from15.5% to 11.03% and from 14.7% to 10.9% at stage 1 and stage 2 for oat and for barley, respectively, and IVDMD decreased slowly from 72.0% to 64.9% and from 73.5% to 68.8% for oat and for barley, respectively. For fiber fractions, NDF declined before stage 2 and then level off after stage 2, while ADF changed little throughout maturation. The ADL trended to increase with increased maturity. The results from the present experiment revealed that Bailor has relatively greater IVDMD value and kept lower ADL content than any other cultivars. The observed variation in chemical composition and ruminal digestibility among various oat cultivars would allow breeders choose suitable oat forages for cattle diet. In experiment. 2, the DaisyⅡ incubator was used to compare IVDMD values of forages of seven oat cultivars using rumen fluid or faecal liquor as the inoculum source. There was a strong linear relationship between the two estimates (R 2 = 0.809; P < 0.001), which indicated that fecal liquor method has the potential to be used instead of rumen fluid for estimation of in vitro digestibility of forage. It is suggested the method for determination of IVDMD using faecal liquor was appropriate for batch operation with precision and efficiency.

Study on the NO Concentration and NOS Activity in the Serum and Tissues of Ducklings with Selenium Poisoning

One-day-old healthy ducklings(n=100)were divided into control group and experimental group randomly, and selenium poisoning of ducklings was artificially caused by feeding ration containing 8 mg kg-1 Se every day. The dynamic changes of No content and NOS activity in the serum and tissues were determined by means of the method of nitric acid reductase. Results showed that the NO content and NOS activity in serum and tissues in experimental group increased significantly(P<0. 05)and they were time-dependent. It was suggested that the high level of selenium in bodies could increase the NOS activity and NO content as it destroyed the metabolism of material and energy as well as structure and function of tissues and cells. These changes of NO content and NOS activity might be involved in the metabolism of selenium poisoning.

Effect of Hydropqinone on Ruminal Urease in the Sheep and its Inhibition Kinetics in Vitro

Effect of hydropuinone (HQ) on rumen urease acivity was studied. Hydroquinone at concentration of 0.01 mg·L -1 ,1 mg·L -1 and 10 mg·L -1 inhibited urease of intact rumen microbes in vitro by 25%, 34%, 55% and 64% respectively. In the present of low concentration of βmercaptoethanol,rumen urease could be solubilized and partially purified. The Km for the enzyme was 2×10 -3 mol·L -1 with Vmax of 319.144 μmoles/mg/min.The kinetics of inhibition with partially purified rumen urease was investigated.The result showed that the inhibuitory effect was not eliminated by increasing urea concentration indicating a noncompetitive in nature with inhibition constant 1.2×10 -5 mol·L -1 .Hydropuinone at a concentration that produced 64% urease inhibition did not affect ruminal total dehydrogenase, proteolytic enzyme( P >0.05)but increased cellulase activity by 28%( P <0.05)in vitro.These results demonstrated that hydropuinone was a specific inhibutor of rumen urease and could delay urea hydrolysis effectively without negative effect.The inhibitor appeared to offer the potential to improve nitrogen utilization by ruminants fed diets containing urea.

Histological Study on in vitro Co-cultivation of the Myocardium Tissue and Cells with Mouse Embryonic Fibroblasts

The histological observation was experimentally conducted on in vitro cultured mouse embryonic myocardium cells and myocardiumoid cell mass. The mouse embryo tissue were cultured and regular pulsatile myocardiumoid tissue could be found. During in vitro culture, the myofilament bundles in the cell were gradually increasing and strongly connectted each other with embryonic age and there were loose muscle fibers initially and intercalated discs were close to each other. The lose myofilament bundles were developed in muscle fibers with age and the distance between intercalated discs was enlarged. There were myofilamentoid structure in inactive cells and filament peripherily.

AFLP and RAPD Analysis of the Boer and Indigenous Breeds of the Goat in Jiangsu

Blood and tissue samples were collected from 105 goats including 60 Boer goats (30 for each sex), 30 Xuhuai goats (15 for each sex) and 15 Haimen goats (7 stud and 8 does). DNA was extracted and DNA pools were constructed on the basis of goat breeds. In 36 selective primer combinations, 29 combinations amplified totally 3 253 markers including 92 polymorphic markers by amplified fragment length polymorphism (AFLP). On average, 3.17 polymorphic markers were amplified per combination, with a polymorphic frequency of 2. 8%. The primer combinations amplifying more polymorphic markers (showed in brackets) were involved in E00+ACG/M00+CAA (13), E00+ACG/M00+CAG (10), E00+AAC/M00+CAC (8) and E00+A AC/M00+ACT (7). A total of 183 markers including 60 polymorphic markers were amplified by RAPD from the pooled DNA of three breeds using 22 primers with strong polymorphism and high reproduc-ibility selected from 93 RAPD primers. On average, 2. 73 polymorphic markers were amplified per primer, with a polymorphic frequency of 32.8%. The results of AFLP and RAPD coincidently suggested that the genetic distance is the closest between Xuhuai and Haimen goat, next between Xuhuai and Boer goat, and the farthest between Haimen and Boer goat. According to the UPGMA method, Haimen and Xuhuai goats can be gathered together as a cluster, then Boer goat. Both methods can be used to implicate the genetic difference of these three breeds, in particular AFLP has more polymorphic markers.

Model Optimization of Litter Size and Genetic Analyses of Model Parameters in Sows

According to two properties of the life cycle and to fluctuation with parities, four mathemati- cal models, the Poisson cycle model, the cubic polyno- mial model, the modified quadratic polynomial model- I artd the modified quadratic polynomial model-H, were used to fit the records of litter size in Jiangquhai sows. From the viewpoint of statistics and biological significance, the modified quadratic polynomial mod- el-I was found to be the optimum model. A single traitanimal model and DFREML procedures were further used to estimate the heritability values of optimum model parameters. The results show that the heritabili- ty values for the coefficients A and B and the herita- bility value for the acme of the model pure quadric curve are larger than the heritability value for the litter size. This suggests that selection for model parameters may be more effective than direct selection for litter size.

Studies on Pharmacokinetics of Porcine Somatotropin Liposomes

This paper focuses on the pharmacokinetics in fattening pigs as well as the change of serum resulting from the use of porcine somatotropin(PST) and its liposomes. A slow-release model was determined to be relevant to following an examination of all dynamic parameters. The results indicate that the slow-release effect of PST liposomes was significant, with an extended release time of over 7 d.

Detection of TGEV Antibody by Enzyme-Linked Immunosorbent Assay Using Recombinant Nucleocapsid Proteins

An enzyme linked immunosorbent assays (ELISA) based on recombinant nucleocapsid (N) protein generated in Escherichiacoli was evaluated for its sensitivity and specificity for diagnosis of transmissible gastroenteritis virus (TGEV) infection.The N gene encoding the N protein was cloned and expressed as a fusion protein with His tag protein in E. coli. Therecombinant N protein migrated at 42 kDa and reacted with His6 tag specific monoclonal antibody by immunoblotting.Recombinant N protein ELISA (rnELISA) demonstrated 97.5% specificity among 80 TGEV-free individuals, and 97.3%sensitivity ranging among 110 clinical samples with TGEV. Taken together, these results indicated that nucleocapsid maybe a useful antigen for the sera-diagnosis of TGEV and it was also suggested that the ELISA is a highly sensitive andspecific test for detecting antibodies against TGEV.

Effects of Ages of Donors and Conditions of Preserving Ovaries on Porcine Oocytes Maturation in vitro and Efficiency of Parthenogenetic Activation

Effects of different ages of donors and different conditions of preserving ovaries onporcine oocytes maturation in vitro and efficiency of parthenogenetic activation werestudied. The experiments included: 1) effects of different temperatures (22, 30, 37, 38.5and 40℃) of preserving ovaries on porcine oocytes maturation in vitro and developmentalpotential; 2) effects of periods of preserving ovaries on porcine oocytes maturation invitro and development in vitro; 3) effects of different ages of donors on porcine oocytesmaturation in vitro and developmental potential. The results of the experiment showed:1) There were no statistical differences (p>0.05) of the parthenogenetic cleavage rate(79.64% vs 76.18%) and blastocyst rate (18.11% vs 33.82%) between oocytes from ovariespreserved at 38.5℃ and those preserved at 37℃. When the preserving temperature wasincreased to 40℃, the cleavage rate (21.68%) and the blastocyst rate (0) were greatsignificantly lower than those at 37℃(p<0.01). The cleavage rate (80.79% vs 76.18%) andblastocyst rate (29.61% vs 33.82%) were not different between 30 and 37℃(p>0.05). Whenthe preserving temperature was decreased to 22℃, the rate of cleavage was not different,but the rate of blastocyst was significantly lower, compared with that at 37℃; 2) Thecleavage and blastocyst rates of the porcine oocytes collected after slaughter 2 or 6hwere not different (p>0.05); 3) The cleavage rate of oocytes from gilts and sows aftermaturation was not different, but the blastocyst rate of the sow group was significantlyhigher than that of gilt group (p<0.05). The blastocyst cell number of sows and giltshowed no difference (p>0.05).