猪乳中一组高分子量蛋白的多态性及其与繁殖性能关系的研究

采用十二烷基硫酸钠 聚丙烯酰胺凝胶不连续垂直板电泳 (SDS PAGE)对 16 2头二花脸母猪乳中一组高分子量蛋白质 (HMWP)进行了检测 ,计算了该位点的基因型频率、等位基因频率和遗传多样性指数等 ,并运用线性模型统计方法分析了该位点的不同基因型与母猪繁殖性能的关系。结果表明 ,在二花脸猪种群 ,乳中HMWP存在B(M :11480 0± 40 0 )和D(M :10 140 0± 6 0 0 )两种带 ,分别受二个等位基因HB 和HD 控制。BB、BD和DD三种基因型频率分别为 0 6 6 6 7、0 2 716和 0 0 6 17,两个等位基因HB 和HD 频率分别为 0 80 2 5和 0 1975 ,遗传多样性指数为0 3170。在三种HMWP基因型中 ,不同基因型母猪的繁殖性能在活仔数和窝重上存在着显著差异 (P <0 0 5 ) ,但在初生仔猪个体重和 2 0日龄窝重上未达到显著水平 (P >0 0 5 )。

猪乳中乳成分变化的曲线拟合

以 10 0头二花脸母猪作为试验动物 ,对猪乳中蛋白质、乳糖、IGF- 、EGF和胰岛素含量在泌乳 1～ 2 1d阶段的变化进行了曲线拟合 ,并分析了这些乳成分的变化规律。结果表明 ,倒数曲线为乳蛋白、IGF- 、EGF和胰岛素随泌乳时间变化的最优拟合曲线。乳蛋白、IGF- 、EGF和胰岛素含量随时间的延续而下降 ,其拟合方程分别为 :y=33.74 4+85 .80 3÷ x(g· L- 1 ) ,y=4 2 .5 94 +2 90 .0 2 3÷ x(μg· L- 1 ) ,y=132 .84 1+6 38.5 98÷ x(ng· L- 1 ) ,y=18.0 73+316 .92 3÷ x(U·m L- 1 ) ,其中 x为泌乳天数。乳糖的最优拟合曲线为对数曲线 ,乳糖含量随时间的延续而上升 ,其拟合方程为 :y=32 .2 2 3+9.6 2 6 lnx(g· L- 1 ) ,x为泌乳天数。猪乳成分变化最为剧烈的是在初乳期 。

体外法研究日粮不同来源氮和碳水化合物比例对干物质体外降解率的影响

本试验的氮源是纯化大豆蛋白(IsolatedSoybeanProtein,ISP)和尿素(NPN),按80:20、50:50和20:80分3组;碳水化合物源分别是从干草中提取的中性洗涤纤维(NDF)、玉米淀粉和蔗糖,按10:85:5、10:80:10、10:75:15、30:65:5、30:60:10、30:55:15、50:45:5、50:40:10和50:35:15分9组的3×9因子实验设计。应用体外尼龙袋发酵技术,研究了奶牛日粮不同来源氮和碳水化合物及其比例对干物质(DM)体外降解率的影响。结果表明,过量补充尿素及随着日粮中淀粉和蔗糖比例的增加,日粮干物质的体外降解率均下降。根据试验结果,建议在泌乳期奶牛的全混合日粮中尿素的补充量应低于干物质的2.8%,非结构性碳水化合物的含量不应超过干物质的45%。

日粮不同来源氮和碳水化合物比例对中性洗涤纤维体外降解率的影响

本试验的目的是研究日粮纯化大豆蛋白与尿素蛋白比例和NDF、淀粉与蔗糖比例及其组合对NDF和DM体外降解率的影响,为优化高产泌乳期荷尔斯坦奶牛的日粮结构提供营养参数。试验将纯化大豆蛋白和尿素分别组合成80∶20、50∶50和20∶80三个比例,将干草中提取的NDF、玉米淀粉和蔗糖分别组合成10∶85∶5、10∶80∶10、10∶75∶15、30∶65∶5、30∶60∶10、30∶55∶15、50∶45∶5、50∶40∶10和50∶35∶15九个比例,然后按3×9因子实验设计。应用体外尼龙袋发酵技术,研究了奶牛日粮不同来源氮和碳水化合物及其比例对中性洗涤纤维体外降解率的影响。结果表明,过量补充尿素及随着日粮中淀粉和蔗糖比例的增加,日粮纤维的体外降解率下降。建议在泌乳期奶牛的全混合日粮中尿素的补充量应低于干物质的2.8%,非结构性碳水化合物的含量不能超过干物质的45%。

乙酸菌糖磷酸化作用的研究

对７ 种乙酸菌（ Ａｃｅｔｉｔｏｍａｃｕｌｕｍ ｒｕ ｍｉｎｉｓ， Ａｃｅｔｏｂａｃｔｅｒｉｕｍ ｗｏｏｄｉｉ， Ｅｕｂａｃｔｅｒｉｕ ｍ ｌｉｍｏｓｕ ｍ 和分离株Ａ２ 、Ａ４ 、Ａ１０ 、Ｈ３ＨＨ） 的葡萄糖和２脱氧葡萄糖磷酸化作用进行了研究。尽管所有机体都存在磷酸化反应，但它们在依赖ＰＥＰ 和ＡＴＰ 的比例上有实质性区别。分离菌株Ａ１０ 具有最高的依赖ＰＥＰ 的葡萄糖磷酸化活力（１１６２ｎｍｏｌ·Ｌ－１·ｍｇ － １·ｍｉｎ － １） ，Ａ１０ 、Ｈ３ＨＨ和Ｅ．ｌｉｍｏｓｕｍ 都具有葡萄糖磷酸转移酶系统（ｐｈｏｓｐｈｏｔｒａｎｓｆｅｒａｓｅ ｓｙｓｔｅｍ ，ＰＴＳ） 。相反，Ａ．ｒｕｍｉｎｉｓ、Ａ．ｗｏｏｄｉｉ、Ａ２ 和Ａ４ 则不具有ＰＴＳ活力。这七株菌的葡萄糖依赖ＡＴＰ 的磷酸化活力都高于依赖ＰＥＰ的磷酸化活力，但其程度有所不同。Ａ１０ 和Ｈ３ＨＨ 的葡萄糖ＰＴＳ可通过胞外葡萄糖诱导，并且其比活在对数期随培养时间延长而增加。此外，还检测到Ａ１０

Growth Response and Fatty Acid Composition of Juvenile Procambarus clarkii Fed Different Sources of Dietary Lipid

An experiment was conducted to evaluate the effects of feeding various sources of dietary lipid on weight gain, feed conversion, survival and fatty acid composition of juvenile red swamp crawfish, Procam-barus clarkii. Six semi-purified diets containing vitamin-free casein, defatted soybean meal, 0. 5% choline chloride, 0. 5% glycine and 0. 5% cholesterol were supplemented with 6. 0% of either anchovy oil, linseed oil, soybean oil, rapeseed oil, safflower oil or pork lard. Each diet was fed to crawfish (3. 07±0. 21 g average weight) in three replicate aquaria for 60 days. Survival rate, weight gain and feed conversion were best for crawfish fed the diet containing anchovy oil. Crawfish fed the linseed oil diet had the second highest weight gain, followed by crawfish on soybean oil, repaseed oil, safflower oil and pork lard diets, respectively. Feed conversion values were a reflection of weight gain. Results showed that both n-6 and n-3 fatty acids are dietary essential for juvenile Procambarus clarkii, although n-3 fatty acids promoted faster growth than n-6. However, highly unsaturated fatty acids (HUFA) (20 : 5n-3 and 22 :6n-3) had better growth-promoting effect than 18 : 3n-3, due probably to the limited ability of crawfish to bioconvert fatty acids to polyenoic forms of longer chain length. The fatty acid composition of the crawfish generally reflected that of the dietary lipids, especially for the diets containing unsaturated fatty acids.

Study on pig growth hormone gene polymorphisms in western meat-type breeds and Chinese local breeds

Chinese Meishan and Jiangquhai pigs are two of the most prolific pigs in the world, but their growth rate is lower than that of Duroc, Landrace and Pietrain pigs. It is suggested that growth rate is regulated by growth hormone. The objective of the current study was to analyze the porcine growth hormone (p GH) gene polymorphisms based on the polymerase chain reaction restriction fragment-length polymorphism method (PCR-RFLP) for three western meat-type breeds (Duroc, Landrace and Pietrain) and two local Chinese pigs (Meishan and Jiangquhai) . Five polymorphic restriction sites were detected with the ApaI, MspI, BspI and HhaI restriction enzymes in two amplified fragments (605 bp, - 119 to + 486; 506 bp, + 206 to + 711).Breed difference was found only in the 506 bp fragment. There was no difference in allelic frequencies of BspIand HhaI restriction sites among the five breeds ( P > 0.05) . Landrace and Meishan pigs lacked allele G3 of Msp I site. The allele G3 frequency of restriction Msp I site of the 506 bp fragment in Pietrain pigs was higher than that in Duroc and Jianquhai pigs (P < 0.001 ). For ApaI site, the Meishan pigs lacked allele G1 i no difference was found in allelic frequencies among Pietrain, Duroc, Landrace and Jiangquhai pigs (P >0.05) . This new and rapid PCR-RFLP typing method is an attractive tool for analysis of porcine growth hormone gene restriction sites. The differences in MspI and ApaI restriction sites may explain the growth difference between the foreign meat-type breeds above mentioned and local Chinese pigs.

Effects of Source of Inorganic Phosphorus and Phytase Supplementation on Performance,Physiological Parameters and Bone Mineralization in Broilers

The objective of this study was to eval- uate the effects of inorganic phosphorus source and phytase addition on performance, nutrient digestibility and bone mineralization in broiler chickens. In Exp. 1,150 two-day old, male broiler chicks were fed a corn-soybean meal basal diet supplemented with phos- phorus provided by dicalcium phosphate, tricalcium phosphate or defluorinated rock phosphate. Five cages containing 10 birds were allotted to each of the three treatments. In Exp. 2,120 three-day old, male broiler chicks were fed the basal diet from Exp. 1 supplemen- ted with 0,250,500 ,or 1,000 P-＇rU phytase per kg of diet. Six cages containing five chicks were allotted to each of the four treatments. In Exp. 1, there was no difference in weight gain, feed intake or feed conver- sion as a result of feeding the different sources of in- organic phosphorus. The digestibility of phosphorus was significantly lower （P =0.01 ） for chicks fed di- ets supplemented with tricalcium phosphate than for chicks fed the other two diets. However, despite the lower digestibility, serum phosphorus levels did not differ among the three treatments. For Exp. 2, feedconversion showed a linear improvement （P = 0.03 ） with increasing levels of phytase inclusion （ days 0 to 33 ）. Phytase supplementation resulted in linear increa- ses in the digestibility of dry matter （P = 0.02 ）, crude protein （ P --- 0.04 ） and energy （ P 〈 0.01 ）. Chicks fed 1,000 FTU/kg phytase had significantly higher bone calcium （ P = 0.05 ） and bone breaking strength （P = 0.04 ） than chicks fed the basal diet on day 33. In conclusion, the results of the current study indicated that the performance of birds fed diets sup- plemented with dicalcium phosphate, tricalcium phos- phate or defluorinated phosphate was similar and therefore production costs could be lowered by choo- sing the cheapest inorganic phosphorus source when formulating diets for poultry. When diets were formu- lated to meet dietary phosphorus requirements, the growth of broilers was not enhanced with phytase sup- plementation. However, increases in feed conversion and bone breaking strength and its potential to impact culling and mortality in broiler operations may be suf- ficient justification for the routine inclusion of phytase in diets fed to broilers.

First isolation and characterization of a new species of Vibrio from diseased flounder(Paralichthys olivaceus Temminck et Schlegel)

Appropriate pathogenic bacteria were isolated from diseased (or dead) flounder (Paralichthys olivaceus L) occurring in a mariculture farms of Qinhuangdao, which all diseased fishes expressed bacterial septicaemia. The phenotypic information of the 12 pure cultures was studied extensively, including morphological characteristics, colony characteristics in different media, physiological and biochemi- cal characteristics, and the mole fraction G+C ratio of the DNA for representative strain. The results show that the isolates belong to a new species of Vibrio, and are designated as Vibrio qinhuangdaora sp.nov. by the area from which the diseased flounders are collected (Qinhuangdao) based on its biological properties following Rules of International Code of Nomenclature of Bacteria. At the same time, studies on the serum homology of isolates, and pathogenicity of isolates were conducted by experimental infection. The results show that all the isolates are of serologic similarity, and the isolates have strong pathogenicity to flounder. The studies can extensively reflect the main biological properties of this new species of Vibrio.

Isolation and characterization of a new species of Vibrio-Vibrio olivaceus sp.nov. from diseased flounder （Paralichthys olivaceus temminck et schlegel）

One kind of pathogenic bacteria was isolated from diseased (or dead) flounder (Paralichthys olivaceus L.) which expressed bacterial septicaemia. The phenotyic information of the 10 pure cultures was studied extensively, including morphological characteristics, colony characteristics in different media, physiological and biochemical characteristics, and the mol%G+C ratio of the DNA for representative strain. The results showed that the isolates belonged to a new species of Vibrio. In addition, the representative strains have been re-checked by China Center for Type Culture Collection (CCTCC), the results were the same as ours, the examined strains were also regarded as a new species of Vibrio, and designated as Vibrio olivaceus sp.nov. by its isolated fish (Paralichthys olivaceus) based on its biological properties following Rules of International Code of Nomenclature of Bacteria. In the same time, we conducted studies on the serum homology of isolates, pathogenicity of isolates by experimental infection. The results showed that all the isolates were of serologic similarity and the isolates have strong pathogenicity to flounder. Inspection to pure cultures and isolates from liver of moribund fish from infection experiment by fluorescent antibody technique showed the feasibility of fluorescent antibody technique as an auxiliary method of examination.

Effect of Divergent Selection for Plasma very Low Denstity Lipoprotein Concentration on Reproductive Performance in Broiler Chickens

The reproductive performance and abdominal fat of the high VLDL (H-VLDL) and low VLDL (L-VLDL) lines were studied after divergent selection for plasma very low density lipoprotein (VLDL) concentration in broiler chickens at 8 weeks of age. It was shown that the main reproductive traits were higher in L-VLDL line than H-VLDL line. The beneficial correlated responses of the reproductive traits were produced by the selection for plasma VLDL. 1) Plasma VLDL concentration was significantly correlated with abdominal fat (r=0.50, P<0.01), ahich was higher than that with plasma triglyceride concentration. There was a significant difference in abdominal fat between both lines but age increase or food restriction may decrease this difference. The H-VLDL line had about twice as much abdominal fat as had L-VLDL at 8 weeks of age, while its mean body weight was similar to that of the L-VLDL line from birtl to the end of laying. 2) Mortality from apparently stress-related causes by food restriction for H-VLDL line females began to increase from 15 weeks of age and was 21% (38/180) higher compared with 13% (23/180) for L-VLDL line females. 3) Age of 5% Lying for L-VLDL line was 3 days less than that of H-VLDL line, age of 50% Lying was 37 days less for L-VLDL line than H-VLDL line, and the age of laying peak was similiar in both lines. Rate of lay at peak in L-VLDL and H-VLDL lines were 70.3%, 66.4%, respectively. 4) Fertility rate in L-VLDL line was significantly higher than that of H-VLDL line at 27 weeks of age (P=0.01) and there was a little difference in fertility rates between H-VLDL and L-VLDL line during late laying period. There were no significant differences between H-VLDL and L-VLDL lines in of day-old healthy the numbers chicks and hatchabilities of fertile and total eggs wheres mean numbers of healthy day-old chicks per hen were more is L-VLDL line than in H-VLDL line. 5) Under food restriction, egg production was higher in L-VLDL line than in H-VLDL line. It should be emphasized that the rate and amount of egg production in L-VLDL line were both significant higher than in H-VLDL line during early laying period (from 23 to 43 weeks of age, P<0.01). The mean egg production of LF line hens was ll eggs more than that of HF line ones throughtout the laying period (from 23 to 62 weeks of age). 6) Eggs in L-VLDL line were slightly heavier than those in H-VLDL line. Feed conversion (FC) ratio for L-VLDL line was lower than that in H-VLDL line betwen 23 and 62 weeks of age (5.01 and 5.46, respectively), especially FC ratio of L-VLDL line was significantly lower than that of HF line during 23 and 43 weeks of age (P<0.01). Also FC efficiency of breeding hens was higher in L-VLDL line than in H-VLDL line.

Studies on the Relationship between the Follicular Blood Micro—Circulation and Ovulation

Twelve purebred Har Bai rabbits with a body weight of 3-4 kg were seleeted and divided in-to four groups at random.they were treated with FSH and hCG atfter the second estrus,The four groups of rabbits were killed at the beginning of estrus ,the beginning of ovulation,15h and 39 h after the beginning of ovulation respectively ,The follicles of 0.5-2 mm in diameter were dissected from the ovaries were fixed ,sectioned ,mounted and stained for examination under light and elec-tron microscopes,The results showed that blood micro-circulation of follicles at the onset of esturs was normal and cells of the theca interna and granular cells were active in metabolism in most of the follicles ,examined at the beginning of ovulation,the blood micro-circulation became disordered,the cells became not active in matbolism and follicular stigmaes appeared at the upper wall of the follicles .At 15 h after the beginning of ovulation ,the unovulated follicles whic were developing into follicular corpus luteam had normal blood micro-circulation,At 39 h after the beginning of ovulation most of the follicles began to degenerate,In was coneluded that there was a close relationship between blood micro-circulation of follicele and the ovulation.