2型猪链球菌的血清学鉴定

本试验首次证实了２型猪链球菌在我国的存在，采用玻片凝集、琼脂扩散及毛细管沉淀等３项试验，对１９９０年以来广东某猪场断奶仔猪暴发流行的败血症、脑膜炎及关节炎病猪中分离的１５株链球菌进行了血清学鉴定。结果表明：１５株链球菌均为２型猪链球菌；用高压法提取抗原进行沉淀反应，其结果比酸热法提取抗原具有简便、敏感、特异性强的特点。     

Determination of bacterial N portions in feces and differently collected ileum chymus from swine]

In faeces and ileal digesta samples of 31 intact (INT) as well as 73 surgically differently prepared pigs bacterial fractionations and 2.6-diaminopimelic acid (DAP) estimations were carried out in order to calculate the bacterial N proportion in faeces N and digesta N after feeding various diets. Because of a high individual variability and the analytical variation width of the DAP/N-ratios no distinct influences of the fed diets could be found. The average DAP/N-values in the faeces (0.224) of INT pigs ranged in the same magnitude as in the digesta (0.0272) of ileorectostomized (IRA) pigs with open colon descendens (IRAo), where a digesta backflow is possible. Distinct lower DAP/N-ratios (0.0125 resp. 0.0043), however, were found in the digesta of pigs with ileo-caecal cannulae (IZB) or IRA pigs with closed colon (IRAg). On the base of various premises (N of the "bacterial fraction" C is only bacterial N; the DAP found in fraction A originates from intestinal bacteria adhering to feed particles) conducted calculations of the bacterial N proportions (in per cent of total N) led to the following data: Faeces of INT pigs: 43.0 ... 68.2 vs. 69.6 ... 89.0; digesta of operated pigs (except protein free diet) IRAo: 22.3 ... 57.0 vs. 46.2 ... 73.8; IZB: 17.0 ... 35.7 vs. 25.2 ... 53.6; IRAg (only 3 pigs): 23.6 vs. 24.2. The proportion of bacterial N in the digesta N of protein free fed IRAo pigs was 22.0 vs. 22.6%.     

Comments on the method to test side effects of pesticides on the predatory mitePhytoseiulus persimilis Ath.-Hen

A paper published byKniehase & Zoebelein (1990) describes a new laboratory method to test the side effects of pesticides on the predatory mitePhytoseiulus persimilis and criticizes the laboratory test developed by the International Working Group pesticides and beneficial organisms of the International Organization for Biological Control (IOBC), West Palaearctic Regional Section (WPRS). The present publication discusses the advantages and disadvantages of both methods, responds to the criticism and mention the overall concept of the IOBC/WPRS Working Group including semifield and field test methods.In einer Arbeit vonKniehase undZoebelein (1990) wird ein neues Laborverfahren zur Prüfung der Nebenwirkung von Pflanzenschutzmitteln auf die RaubmilbePhytoseiulus persimilis beschrieben. Die genannten Autoren äußern sich kritisch über das seither von der Arbeitsgruppe Pflanzenschutzmittel und Nutzorganismen der International Organization for Biological Control (IOBC), West Palaearctic Regional Section (WPRS) praktizierte Verfahren. In der vorliegenden Arbeit werden die Vor- und Nachteile der beiden Prüfmethoden diskutiert. Einer Reaktion auf die Kritik folgt eine kurze Beschreibung der gesamten Konzeption der genannten Arbeitsgruppe, die auf einer Kombination aus Labor-, Halbfreiland- und Feldprüfverfahren beruht.     

Depression of polymorphonuclear leukocyte function associated with experimentally induced Escherichia coli mastitis in sows

In a study of susceptibilities of sows from 2 herds to experimentally induced Escherichia coli mastitis, a marked difference was seen. The "susceptible" sows were from a conventional herd and "resistant" sows were from a specific-pathogen-free herd. The purpose of the study was to determine whether deficient neutrophil function was associated with increased susceptibility to E coli-induced mastitis. Four in vitro procedures were used to evaluate polymorphonuclear leukocyte (PMN) function: (i) random migration under agarose, (ii) ingestion of 125I-iododeoxyuridine-labeled Staphylococcus aureus, (iii) quantitative nitroblue tetrazolium reduction, and (iv) iodination. After parturition and intramammary inoculation with E coli, sows from the susceptible herd were neutropenic and the neutrophils which were present in the peripheral blood had reduced function. Specifically, there were depressed random migration under agarose, S aureus ingestion, and iodination when compared with PMN function in resistant sows. These data indicate that susceptibility to E coli mastitis was associated with deficiencies in PMN numbers and function. Potential causes of the neutrophil dysfunction are discussed and include possible systemic hormonal aberrations or the presence of an inapparent viral or bacterial infection.     

Atrophic rhinitis of swine--a multifactorial disease?

Atrophic rhinitis is caused by toxigenic Pasteurella multocida strains. The infection is supported by Bordetella bronchiseptica and other widespread agents and by non-infectious factors damaging the nasal epithelium. The term "infectious multifactorial disease" means in German, that ubiquitous low-virulent agents cause disease when intensified by non-infectious factors. Atrophic rhinitis does not belong to this group but is an infectious disease, caused by a specific agent and influenced by several factors.     

“火罐”柿减压处理、低乙烯MA贮藏技术研究

利用减压贮藏的原理,提出了减压处理低乙烯ＭＡ贮藏技术,并利用该技术对陕西优良柿子品种－－火罐柿进行了室温条件下的保鲜贮藏研究。结果表明,减压处理低乙烯ＭＡ贮藏技术甬地抑制火罐柿硬度的下降,延长果实贮藏期。保硬期为４３ｄ,比对照长２４ｄ;贮藏期达９７ｄ,比对照长６７ｄ。     

Occurrence and distribution of antibiotic resistant E. coli strains in faeces from young pigs and calves in Denmark]

A comparative study of investigations from 1970 (before the prohibition against therapeutically used antibiotics as food additives for growth promotion) and from 1978 respectively proves that the prevalence of young pigs and calves with resistant E. coli has increased significantly from 61% to 92% and from 69% to 86% (tables I and II). Figures 1 and 2 show the prevalence of young pigs and calves with antibiotic resistant E. coli with resistance determinants towards sulfonamides, tetracycline, streptomycin, ampicillin, chloramphenicol, neomycin and furazolidone. This shows that the prevalence of young pigs with resistance determinants towards sulfonamides, tetracycline, streptomycin, ampicillin, and chloramphenicol has increased significantly from 1970 to 1978. The same facts apply to the calves. However, the increase in tetracycline resistance is not significant. Neomycin resistant E. coli for both young pigs and calves were only found in 1978. Figure 3 shows the distribution of the number of resistance determinants per young pig and calf with resistant E. coli. The figure shows the significant tendency that the pigs and calves investigated contain resistant E. coli with more resistance determinants in 1978 than in 1970. The distribution of R-factors among resistant E. coli seems to be reduced at first sight but a closer examination establishes that this only goes for R-factor mediated sulfonamide resistance (the experimental conditions may account for this). R-factor mediated streptomycin resistance has increased while R-factor mediated tetracycline resistance was at the same level. On the basis of literature the causes and risks of an increased distribution of antibiotic resistant E. coli are discussed.