中华富铁康900对断奶仔猪的饲喂效果试验

试验选用体重约8kg的三元杂交(杜长大)猪60头,随机分成3组,每组2个重复,分别饲喂含不同剂量中华富铁康900的饲粮,研究中华富铁康900对仔猪生产性能、肤色的影响。结果表明,以中华富铁康900取代饲粮中部分硫酸亚铁,显著提高仔猪平均日增重(P<0.05),显著降低料重比(P<0.05),明显改善仔猪肤色。根据试验效果,仔猪饲粮中中华富铁康900的添加量为2×10-4～4×10-4。     

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为促进四川省油菜产业的发展,培育适宜稻-油两熟制地区种植的早熟油菜品种,解决稻-油轮作地区作物接茬季节矛盾,避开不良天气对油菜生产的危害,南充市农业科学院油菜研究所以甘蓝型油菜细胞质雄性不育系南A5为母本,以油菜游离小孢子培养并染色体加倍选育获得的胞质不育恢复系23R为父本,配组育成甘蓝型早熟杂交油菜新品种德恒油900,2015年通过四川省农作物品种审定委员会审定.该品种2014年、2015年参加四川省油菜早熟组区域试验,平均产量2 718.00 kg/hm2,较对照德油早1号增产10.05％;全生育期214 d,与对照德油早1号熟期相当;芥酸含量未检出,硫苷含量22.93 μmol/g饼,含油量平均42.95％,具有早熟、优质、高产、稳产、抗(耐)病及适应性广等特点.适宜四川省平坝、丘陵区及类似生态区种植.     

Detection of Mycobacterium avium subsp paratuberculosis in formalin-fixed paraffin-embedded intestinal tissue by IS900 polymerase chain reaction

OBJECTIVES: To evaluate and compare methods for DNA extraction from formalin-fixed, paraffin-embedded tissues and methods for detection of Mycobacterium avium subsp paratuberculosis by IS900 PCR for confirmation of Johne's disease in ruminants. DESIGN: A laboratory study. PROCEDURE: Three methods of DNA extraction of differing complexity and two PCR protocols using different pairs of IS900 primers were compared. Sensitivity and specificity were assessed using samples from ruminants with and without histological evidence of Johne's disease. RESULTS: The simplest method of DNA extraction, which involved two cycles of boiling and freezing followed by centrifugation, gave more consistent results than two methods that required solvent extraction of paraffin, proteinase digestion and DNA purification. The sensitivity of detection of M avium subsp paratuberculosis in paraffin blocks stored for 1 to 6 years from 34 cases of Johne's disease in sheep, cattle and goats was 88% for a 229 bp IS900 PCR assay and 71% for a 413 bp assay, using the detection of acid-fast bacilli by Ziehl Neelsen staining of histological sections from the same blocks as the gold standard test. PCR results correlated with the abundance of acid-fast organisms in the tissues. No false positive reactions were detected. CONCLUSION: PCR for identification of M avium subsp paratuberculosis in formalin-fixed, paraffin-embedded intestinal tissues from ruminants is a rapid and useful method. A simple method of sample preparation is effective. Amplification of short fragments of IS900 is more effective than amplification of longer fragments.     

Pathogenic 'Bison-type' Mycobacterium avium subspecies paratuberculosis genotype characterized from riverine buffalo (Bubalus bubalis) in North India

Despite low per-animal productivity of ruminants in developing countries, Johne's disease has not been investigated in buffaloes, which are primarily found in these countries. This is due to lack of expertise, diagnostic kits and priority to production diseases like Johne's disease. Presence of pathogenic Mycobacterium avium subspecies paratuberculosis (Map) was investigated by screening of target tissues (mesenteric lymph nodes and large intestine) by culture and IS 900 PCR, in 50 sacrificed buffaloes. Indigenous ELISA kit originally developed for goats and sheep was standardized in buffaloes and used to estimate sero-presence of Map in 167 serum samples representing population of buffaloes in Agra region of North India. In culture, 48.0% buffaloes were positive from 50 tissues each from mesenteric lymph nodes (34.0%) and large intestine (36.0%). IS 900 PCR was standardized using specific primers (150 C and 921) and 229 bp-amplified product was characteristic for Map. Of the 25 mesenteric lymph nodes, 40.0% were positive in IS 900 PCR. Genomic DNA from Map cultures was successfully amplified from all the 24 isolates (100.0%). Map was further genotyped as 'Bison type' using IS 1311 PCR-REA. Culture of tissues showed high presence of Map in target tissues, despite high culling rate in buffalos in view of high demand of buffalo meat. Specific tissue-PCR provided rapid confirmation of Map infection in sacrificed buffaloes. In tissue-PCR, all the cultures were positive as compared to 40.0% detected directly from tissues. ELISA kit using indigenous protoplasmic antigen was highly sensitive as compared to commercial antigen in detecting Map infection therefore, could be used as 'Herd Screening Test' in buffaloes against Johne's disease. This pilot study first time reports a highly pathogenic 'Bison-type' genotype of M. avium subspecies paratuberculosis from the riverine buffaloes (Bubalus bubalis) of Agra region in North India.     

Mycobacterium porcinum strains isolated from bovine bulk milk: implications for Mycobacterium avium subsp. paratuberculosis detection by PCR and culture

In this study, the isolation of 52 mycobactin-independent fast growing mycobacteria from 631 bulk milk samples (8.2%), is reported. These strains, isolated during a bulk milk survey for Mycobacterium avium subsp. paratuberculosis (Map), strongly affected Map detection both by PCR and by culture, as they gave a positive IS900 PCR signal and resulted to totally inhibit the growth of Map when spotted on HEYM slants already inoculated with 200 microl of 10-fold dilutions containing from 5 x 10 to 5 x 10(3)Map cells/ml. 16S rRNA gene sequencing, using the MicroSeq 500 16S rDNA Bacterial Sequencing Kit (Applied Biosystems), was performed on a subset of six strains, identifying Mycobacterium porcinum with 100% homology in all six cases. The 52 strains were characterized by PCR-restriction fragment length polymorphism (RFLP) analysis of the hsp65 gene, which confirmed the identification of M. porcinum for all the isolates. Using specific primers designed on the Map-IS900 sequence and on the M. porcinum sequence determined in this study, a 1385bp sequence from the M. porcinum genome was characterized. This IS900-like sequence showed 82% homology with Map IS900. From our findings the following results emerged: (a) any culture showing one or more M. porcinum colonies represents a potential "false negative" result and should therefore be considered as contaminated; (b) IS900-like elements could be more widespread than was previously thought; (c) IS900 PCR positive results should be interpreted cautiously, as confirmed by the evidence that the primer pair used in this study resulted not to be specific.     

Newly developed primers for the detection of Mycobacterium avium subspecies paratuberculosis

Recent publications reported the existence of IS900 like sequences in mycobacteria different from Mycobacterium avium subspecies paratuberculosis (Map). The primers used for IS900 detection of Map have amplified these sequences causing false positive results. In this study, we have developed two new PCR assays for the detection of Map. The first assay is based on the IS900 sequence using primers different from the ones previously reported, the second assay on the f57 sequence. The specificity of the tests was checked by analysis of 190 mycobacterial isolates (74 Map and 116 non-Map isolates). All Map strains were positive and all non-Map strains were negative. Serial dilutions of Map bacteria were used to assess the sensitivity of the assays. We achieved a sensitivity of 1 CFU per PCR for both assays. In addition, a PCR-simulating computer programme was used to evaluate the specificity of the new IS900 primers.

The combination of the two PCR assays has proven to be useful for the identification of Map but validation on a large range of clinical samples still needs to be done.     

基于SIM900的粮仓通风自动控制监测系统

设计了一套基于SIM900的无线传输粮仓风机自动控制监测系统,能随时随地了解风机的各种运行参数及仓房内部温湿度情况。当出现异常情况时,能随时上报并控制风机运行状态,保证风机的安全运行。设计提高了风机运行的可靠性,降低了劳动成本。     

Distribution and hybridization patterns of the insertion element IS900 in clinical isolates of mycobacterium paratuberculosis

Reference strains and 31 clinical isolates of M. paratuberculosis, mainly from goats, were analysed for restriction fragment length polymorphism (RFLP). Restriction digests of bacterial DNA were hybridized with a repetitive insertion sequence, IS900, to obtain banding patterns for comparison of strains. Twenty-five of the 31 field-strains hybridized with IS900, and five hybridization patterns were identified. It was not possible to identify specific patterns for goat strains of M. paratuberculosis. Four hybridization patterns were similar, whereas the fifth pattern of a sheep strain diverged considerably in position and number of band. Six goat strains failed to hybridize with IS900, and the absence of IS900 was verified by the polymerase chain reaction and hybridization with an oligonucleotide probe. The six IS900-negative goat strains had diverging phenotypic properties, and the identification of these strains is discussed. The present study shows that M. paratuberculosis strains infecting goats are genetically similar to cattle strains and that IS900 is a specific genetic element for identification of M. paratuberculosis.     

超高产水稻新组合Y两优900百亩方15.40t/hm^2高产栽培技术研究

Y两优900是以广适性光温敏不育系Y58S为母本,籼粳杂交选育的偏籼型恢复系R900为父本配组育成的超高产杂交稻新组合,具有根系发达、穗大粒多、结实率高、株叶形态理想、熟期适中、适应性广、高产稳产、优质多抗等特点。2014年在湖南溆浦对该组合进行了较大面积攻关试验,创造了6.84 hm^2面积单产15.40 t/hm^2的世界纪录。介绍了Y两优900的特征特性,并详细阐述了Y两优900百亩攻关片单产达15.40 t/hm^2的高产栽培技术。     

高氮密植栽培对湘两优900产量形成及氮利用效率的影响

为探明湘两优900在热带稻区的高产性和适应性,在海南三亚进行4个施氮水平(0、150、225、300 kg·hm^-2)和2个移栽密度(25.0×10⁴、16.7×10⁴ hills·hm^-2)大田栽培试验,研究施氮水平和移栽密度对湘两优900产量形成和氮肥利用率的影响。结果表明,施氮水平和移栽密度对湘两优900产量影响显著,产量随着施氮水平和移栽密度的提高而显著增加,以施氮量300 kg·hm^-2与移栽密度16.7×10⁴ hills·hm^-2组合的产量最高(15.32 t·hm^-2),其增产优势主要表现为有效穗数多,地上部干物重和叶面积指数(LAI)大,叶绿素含量和净光合速率(Pn)高。施氮水平与移栽密度对氮肥吸收利用效率有影响,且施氮水平起显著作用。施氮量为300 kg·hm^-2时,氮肥吸收利用率最大(44.5%),增加施氮量能显著提高氮肥利用率,同时也会显著降低氮素吸收效率、氮生理效率、氮肥效率。从产量和氮肥利用效率综合考虑,施氮量300 kg·hm^-2与移栽密度25.0×10⁴ hills·hm^-2是本试验条件下的最优密肥组合。本研究结果为超级杂交稻在热带稻区(海南)推广应用提供了科学依据。