Relationship between fumonisin contamination of feed and mystery swine disease

Fumonisin is a recently identified mycotoxin that has been shown to be the cause of pulmonary edema disease in swine and leukoencephalomalacia in horses. Mystery Swine Disease (MSD), is an economically devastating disease complex of unknown etiology that has been reported to have occurred in several swine producing states since 1988. To determine the relationship between MSD and fumonisin, a case-control study was carried out in Illinois in mid-1990. Feed samples collected from 12 case and 9 control farms were analyzed for fumonisin. Sera from swine on all farms was screened for titers against encephalomyocarditis (EMC) virus and concentrations of alpha-1 acid glycoprotein (an acute phase reactive protein). Fumonisin concentrations 20 ppm were found on 1 control farm (1/9) and 8 case farms (8/12). Titers against EMC virus ( 116) were found on 5 control farms (5/9) and on 6 case farms (6/12). Farms with 20 ppm fumonisin in the feed were at significantly increased risk (OR= 11.2, Fisher's exact test p=0.037) for MSD. Furthermore, the ² test for trend was significant (p= 0.017), meaning that as the level of fumonisin in the feed increased, the risk of MSD also increased. The presence of EMC virus titers in the sow herd was not a significant risk for MSD (OR =1.25, Fisher's exact test p=0.75). Alpha-1 acid glycoprotein concentrations obtained from 2-week old nursing pigs differed significantly (p=0.0005) between MSD case and control herds.     

A behavioral response of swine to a 60-Hz electric field

It has been shown that rats, given the choice, will spend more time out of a 60-Hz electric field than in it at field strengths ? 75 kV/m. This paper describes research to examine the relevance of these data to a different species, the pig. Miniature pigs that had been exposed to a 60-Hz electric field at 30 kV/m for 20 h/day, 7 days/week for as long as 6 months, were tested for their preference for the presence or absence of the field during a 23.5-h period. Similar to earlier results with rats, miniature pigs spent more time out of the electric field than in it during the sleeping period.     

Effect of irradiance and plant age on the dimensions of the growing shoot of poplar

Populus euramericana (Dode) Guinier cv. Robusta plants were cultivated at irradiances of 7.5, 15 and 30 W m⁻² (32.5, 65 and 130 μmol m² s⁻¹), 400–700 nm at 22°C and a relative humidity between 40 and 60% on a gravel culture subirrigated with Hoagland's nutrient solution. The basal diameter of the growing shoot, a measure of the number of apical cells participating in growth, increased proportionally to irradiance and was correlated with mature leaf length. The development of the length of the growing shoot (L_gs) depended also on the nutritional status of the (young) shoot. L_gs was strongly correlated with the rate of height growth.     

基因组选择在猪杂交育种中的应用

基因组选择是指在全基因组范围内通过基因组中大量的标记信息估计出个体全基因组范围的育种值,可进一步提升育种效率和准确性,目前在猪纯繁育种中得到广泛应用。但有研究表明,现有的基因组选择方法在猪杂交育种上的应用效果并不理想,在跨群体条件下预测准确性极低。杂交作为养猪业中最为广泛的育种手段之一,通过结合基因组选择理论进一步提升猪的生产性能,具有重要的经济和研究价值。本文综述了基因组选择的发展及其在猪育种中的应用现状,并结合国内外猪杂交育种的方式,分析了目前基因组选择方法在猪杂交育种应用方面的不足,旨在为未来基因组选择在猪杂交育种中的合理应用提供参考。     

Effects of various supplements on voluntary intake and performance by growing cattle consuming forage moderate to high in crude protein∗

Growing cattle were supplemented with substances to lessen or increase ruminai ammonia level to determine if consumption of moderate‐ to high‐crude protein (CP) forage is limited by high ruminai ammonia absorption. In Experiment 1 (5 × 5 Latin square), five Holstein steers (198 kg) had ad libitum access to alfalfa cubes (17% CP) without supplementation or with com at 0.25 or 0.75% body weight (BW) alone (LC or HC) or with 0.06% BW of zeolite (chabazite; LC‐Z and HC‐Z). Total daily organic water (OM) intake was not affected by treatment (6.08, 6.14, 6.11, 6.19 and 6.09 kg for control, LC, LC‐Z, HC and HC‐Z, respectively; SE 0.25). In Experiment 2, Simmental crossbred beef calves grazed fescue‐clover paddocks in the srping (clipped forage: 21 to 27% CP) for 84 days and were supplemented with 0.25 or 0.75% BW com alone or with added zeolite (0.06% BW) or lasalocid (0.5 mg/kg BW). Daily gain did not differ among treatments (1.24 to 1.31 kg/day). In Experiment 3 (6×6 Latin square), six Holstein steer calves (168 kg) had ad libitum access to medium‐quality, orchardgrass‐clover hay (15% CP). Steers received one of the following six treatments: no supplement (Control), 0.35% BW ground com (C), com plus 0.049% BW urea (C‐U), 0.35% BW soybean meal (S), 0.205% BW feather meal (F) or 0.103% BW feather meal, 0.052% BW blood meal and 0.067% BW com gluten meal (F‐BG). Total daily OM intake was 5.00, 5.14, 5.00, 5.11, 4.84 and 4.70 kg for control, C, C‐U, S, F and F‐BG, respectively (SE 0.13). In Experiment 4 (6 × 6 Latin square), six Holstein steer calves (226 kg) were fed 0.75% BW of alfalfa cubes (19% CP) plus ad libitum access to medium‐ to high‐quality orchardgrass hay (16% CP). Steers received one of the following six treatments: no supplement (Control), corn at 0.25% BW alone (c) or mixed with 0.12% BW peanut skins (C‐PSK), a mix of high‐CP feedstuffs high in ruminai escape protein (0.029% BW blood meal, 0.038% BW com gluten meal and 0.028% BW feather meal; C‐REP), 0.139% soybean meal (C‐S) or soybean meal plus peanut skins (C‐PSK‐S). Total daily OM intake was 6.16, 6.25, 6.13, 6.52, 6.50 and 6.60 kg for control, C, C‐PSK, C‐REP, C‐S and C‐PSK‐S, respectively (SE 0.10). In conclusion, with forages moderate to high in CP, high ruminai ammonia absorption did not appear to affect feed intake.     

猪MHC-DQB、DRB近端调控区序列及其多态性

根据人MHC—DRB和MHC—DQB基因组序列和猪MHC-DRB和MHC-DQB基因外显子1设计引物,应用PCR扩增及克隆测序技术,首次得到了猪MHC-DRB和MHC-DQB基因的5上游近端调控区(URR)序列。分析发现所得序列中存在与MHCⅡ类基因表达调控有关的高度保守的W、X、Y、CCAAT及类TATA调控元件,调控元件的空间组织顺序也与其他物种相应序列的相同。利用SSCP技术在313头猪中共发现12个DRB-URR复等位基因和14个DQB-URR复等位基因,序列比对结果表明在这些复等位基因中存在丰富的多态位点,为进一步深入研究猪MHCⅡ类基因近端调控区的多态性及抗病育种研究奠定了基础。     

A comparative proteomic analysis of blood serum for developmental stages in pigs

This study aimed to differentiate genes at developmental stages of pigs from 0 to 150 days of age, to build up a protein database and to find candidate genetic markers for growth traits. The analysis of two‐dimensional electrophoresis and matrix‐assisted laser‐desorption/ionization mass spectrometry separated 252 protein segments. After successfully blasting the peptide sequences, the analysis confirmed 37 differentially expressed proteins that increased from birth to 150 days of age (type A), whereas the type B proteins presented the inverse pattern. The type C proteins included proteins that were expressed continuously throughout the developmental periods. A total of 319 primer sets for 33 genes were designed to find genetic variants using pooled DNA samples of Yorkshire pigs. Amplification products for all primer sets produced approximately 20 000 clones that were sequenced, and 48 candidate SNP sites were finalized for genotyping. A total of 475 animals were used for high throughput genotyping analysis. Among these, phenotype data of all 475 animals were collected for average daily gain, backfat thickness and days to 90 kg, whereas feed conversion data were collected for 300 animals and body measurement traits (starting weight, ending weight, body length, wither height and chest depth) were collected for 209 animals. Association analysis found significant statistical differences between the animals having genotypes of 13 SNPs (g.78935883C>T, g.147629986C>T, g.98266037T>C, g.214707340G>A, g.88350299C>T, g.17180956C>T, g.17181024C>T, g.2350283A>G, g.138361311C>T, g.44996379C>T, g.44996247A>C, g.107715245C>T, g.4149631C>T) for the various measured traits. The identified genetic polymorphisms, of which one was novel (g.214707340G>A), may serve as candidate molecular markers to change population means for the targeted growth traits.     

稳定表达非洲猪瘟病毒P54蛋白的Vero细胞系的建立

旨为建立稳定表达非洲猪瘟病毒(ASFV)P54蛋白的Vero细胞系,将ASFV-P54基因与绿色荧光基因Azami Green的融合基因片段,将其克隆至慢病毒载体pLV-puro中构建重组慢病毒质粒pLV-ASFV-P54-AG,将该质粒与慢病毒包装质粒pH1和pH2共转染HEK-293V细胞,包装表达ASFV-P54蛋白的慢病毒。将重组慢病毒在聚凝胺(Polybrene)的介导下感染Vero细胞,筛选出一株稳定表达ASFV-P54蛋白的Vero细胞系,命名为Vero-AG-ASFV-P54。间接免疫荧光试验表明,该细胞系能够与P54多克隆抗体反应;经波兰国家兽医研究所进一步验证,结果显示,该细胞系与ASFV抗体阳性血清也能发生反应,并且与阴性血清无反应。结果表明,Vero-AG-ASFV-P54细胞系能够稳定高效的表达具有生物活性的ASFV-P54蛋白。     

笼养条件下朱鹮雏鸟的饲养管理和生长发育

2002~2004年,通过对人工繁殖的103只朱(Nipponia nippon)雏鸟的饲喂和护理,系统测量了1~35日龄雏鸟的体重、体长、翅长、嘴峰、跗、中爪、尾长生长发育情况,并与野外朱雏鸟的生长发育作了对比分析。结果表明,人工条件下的朱雏鸟生长发育良好,在不同日龄期,基本达到甚至超过野外朱雏鸟生长发育指标的水平。35日龄雏鸟出飞,比野外雏鸟出飞提前了一周。     

Effect of infrared temperature on thermoregulatory behaviour in suckling piglets

The objective of this study was to investigate the effect of infrared (IR) temperature on thermoregulatory behaviour in suckling piglets in the first 3 weeks after farrowing. A total of 10 piglets from each of the 16 litters were exposed to recommended IR temperature conditions at 1, 2 and 3 weeks of age, with a mild offset (4°C) in IR temperature during the first experiment and a more challenging offset (8°C) during the second experiment. Digital photos were taken when all piglets had settled in the creep area, and the lying posture and huddling behaviour were analysed. A lying posture score and a huddling score was calculated by multiplying the number of piglets in each category with a given value for each category, based on different lying postures and different degrees of huddling behaviour. With a 4°C change in IR temperature, the piglets tended to alter their lying posture, while an 8°C change had a significant effect on lying posture (P < 0.01). A change in IR temperature of 4°C had no effect on the degree of huddling. The huddling score decreased significantly with 8°C change in IR temperature (P < 0.05). Postural changes, rather than changes in degree of huddling were the preferred thermoregulatory strategy for suckling piglets.