Age-dependent changes of proinflammatory cytokine production by porcine peripheral blood phagocytes

The aim of the present study was to determine postnatal ontogeny of proinflammatory cytokines IL-1beta, IL-8 and TNF-alpha production by in vitro stimulated porcine blood leukocytes. Four age categories of pigs were chosen. Cytokine production was determined using intracellular flow cytometry. It was found that IL-8 and TNF-alpha production by blood monocytes significantly increased during the postnatal period while production of IL-1beta remained unchanged. In blood neutrophils, the IL-8 production increased only during the postnatal period, while the levels of TNF-alpha and IL-1beta were undetectable during the whole postnatal period. Generally, the most intensive changes in cytokine production occurred before weaning. The production of low levels of cytokines by monocytes and neutrophils from young pigs was not caused by a delayed cytokine response because the cytokine production after 8-h stimulation was lower than that after 4-h stimulation in all age categories. The ontogenetical changes showed the same trends when two different stimulators (LPS, heat-inactivated E. coli) were used, suggesting that the ontogenetical changes are not caused by a simple defect in one signalling pathway, but it is probably a more complex process. No differences in cytokine production between the whole blood and the isolated cells supplemented with newborn or adult serum were found. Thus the ability of newborn monocytes and neutrophils to produce proinflammatory cytokines was not decreased due to the influence of composition of the microenvironment, where the cells were present. In conclusion, the ability of porcine blood leukocytes to produce cytokines develops during postnatal life.     

A cross-sectional study of the prevalence and associated risk factors for bursitis in weaner, grower and finisher pigs from 93 commercial farms in England

A cross-sectional study of 93 farms in England was carried out to estimate the prevalence and associated risk factors for bursitis. A total of 6250 pigs aged 6–22 weeks were examined for presence and severity of bursitis. Details of pen construction, pen quality and farm management were recorded including floor type, presence of bedding, condition of the floor and floor materials. The prevalence of bursitis was 41.2% and increased with each week of age (OR 1.1). Two-level logistic regression models were developed with the outcome as the proportion of pigs affected with bursitis in a pen. Pigs kept on soil floors with straw bedding were used as the reference level. In comparison with these soil floors, bursitis increased on concrete floors where the bedding was deep throughout (OR 4.6), deep in part (OR 3.7), and sparse throughout (OR 9.0), part slatted floors (OR 8.0), and fully slatted floors (OR 18.8). Slip or skid marks in the dunging area (OR 1.5), pigs observed slipping during the examination of the pen (OR 1.3) and wet floors (OR 3.6) were also associated with an increased risk of bursitis. The results indicate that bursitis is a common condition of growing pigs and that the associated risk factors for bursitis were a lack of bedding in the lying area, presence of voids and pen conditions which increased the likelihood of injury.     

A survey on biosecurity and management practices in Belgian pig herds

We surveyed Belgian pig herds to describe their biosecurity status and management practices. Our written questionnaire was sent to a stratified random sample of 609 pig farms. We achieved a 71.6% response, and 421/609 farmers (69.1%) returned questionnaires suitable for analysis. We used multiple-correspondence analysis followed by a two-step clustering procedure. Herd size, herd type and occupation (commercial or hobby herd) were used to describe different groups. We differentiated four biosecurity groups, which we interpreted as indicating low- to high-biosecurity status. Although we felt that most farms had acceptable biosecurity, few used measures such as showering (2.1%) and quarantine periods for people entering the premises (7.1%). We also found three management-practices clusters, although their interpretation was not straightforward. Despite the industrialised character of pig production in Belgium, 9.4% of pig herds were small, hobby herds that reported different biosecurity and management characteristics (such as the equipping pigs on pasture and feeding kitchen waste).     

序批式好氧堆肥处理法对家畜粪便的减量化研究

以新鲜牛粪为处理对象,选择木屑及混合物（木屑与玉米秸秆屑）两种材料为调理剂,采用日本研制生产的S-15型生态厕所为试验装置,进行了序批式好氧堆肥的减量化研究。试验过程中分析了堆制过程中温度、含水量率、有机质、pH值等指标的变化。结果表明,两个处理的堆肥产物均达到明显的减量效果,养分含量也成倍增长。因此,这种堆肥工艺具有良好的应用前景。     

Effects of humus content,farmyard manuring,and mineral‐N fertilization on yields and soil properties in a long‐term trial

Investigations carried out at Field F3 of the Halle long‐term fertilization trials using data from 1974 to 1983 showed that with adequate supply of mineral N‐fertilizer soil organic matter (SOM) had no significant effects of yield. Similarly enhanced SOM did not justify a reduction of mineral N (Stumpe et al., 2000). The studies presented here examine the effects of the SOM differences existing after the termination of those trials in 1986 up until 1997 (then mainly differences of hardly decomposable SOM) in comparison to farmyard manuring with enhanced mineral N application (3‐factor‐experiment). As with total SOM, hardly decomposable SOM did not directly affect yields. The effects of FYM treatment observed at lower mineral‐N levels were compensated for by enhanced mineral‐N supply. The direct effect of FYM (40 t ha^—1) corresponded to a mineral‐N supply of about 60 kg ha^—1 and the residual effect to about 20 kg ha^—1. The differences of the C‐content in the soil at the beginning of the present studies continued throughout the experimental period of 12 years. In addition, significant differentiation has been caused by FYM and N fertilization in comparison to unfertilized treatments. The major finding is that differences in SOM content do not lead to yield differences on physically good soils (chernozem‐like soils) if appropriate compensation by mineral‐N fertilization takes place.     

Relationship between soil organic matter and micropores in a long-term experiment at Ultuna,Sweden

Our study showed that long‒term addition of organic matter to a fine textured soil (36.5% clay, 41% silt, 22.5% sand) resulted in an increase of both macro‒ and microporosity in the top soil layer. In terms of changes of the absolute pore volume, macropores were of main importance. However, in relative terms, the increase of microporosity was comparable to that of macroporosity (75% and 90%). Changes in porosity upon different organic matter levels had a marginal effect on the water storage capacity. Micropores with diameters in the range of 1—30 μm were highly significantly correlated to soil organic matter characteristics showing that there is a non‒uniform distribution in relation to pores. Mechanisms leading to disproportionally high concentrations of soil organic matter in relation to micropores are discussed.     

五指山、二花脸和皮特兰猪的SLA-DQB基因外显子2的PCR-RFLP多态性分析

采用PCR-RFLP法对五指山猪、二花脸猪及皮特兰猪的SLA-DQB基因外显子2的PCR产物进行了分析,结果显示,SLA-DQB基因外显子2经限制酶HaeⅢ和RsaⅠ酶切共分出9种RFLP组合带型,五指山猪、二花脸猪和皮特兰猪分别有3种、3种和5种组合带型.Hardy-Weinberg平衡分析表明,五指山猪和二花脸猪的SLA-DQB基因外显子2的两个酶切位点的PCR-RFLP带型达平衡状态,而皮特兰猪中只有RsaⅠ酶切位点达到平衡状态.     

有机无机肥配施对土壤物理性状的影响

经过12 a的不同施肥试验分析,秸秆还田和秸秆还田+NPK处理土壤密度比试验前下降0.34～0.37g/cm3,施栏肥和施栏肥+NPK处理土壤密度比试验前下降0.30～0.36 g/cm3。秸秆还田和秸秆还田+NPK处理田间持水率比试验前增加4.09%～5.01%,施栏肥和栏肥+NPK处理田间持水率比试验前增加3.26%～5.99%,单施NPK和对照处理田间持水率比试验前增加1.82%～2.15%。     

木耳菌糠和鸡粪混合堆肥改良盐碱土壤效果评价

为了评价食用菌菌糠和鸡粪混合堆肥改良盐碱土壤的潜力。笔者研究了木耳菌糠和鸡粪混合堆肥的物理指标,并用混合肥施用盐碱土壤栽培大蒜,测定大蒜苗的生长指标。结果表明：添加一定比例木耳菌糠的盐碱土壤栽培大蒜（对照组）,大蒜苗生长指标好于不添加木耳菌糠的盐碱土壤（空白组）,差异显著(P<0.05);添加木耳菌糠和鸡粪的盐碱土壤栽培大蒜（发酵组）,大蒜苗生长指标好于仅添加木耳菌糠的盐碱土壤（对照组）,差异显著(P<0.05),也明显好于不添加木耳菌糠的盐碱土壤（空白组）,差异极显著(P<0.01)。通过交互试验数据分析,混合堆肥的最佳条件：菌糠添加量15%,鸡粪添加量8%,堆肥含水量45%。由此说明,盐碱土壤添加木耳菌糠和鸡粪混合堆肥物,不仅能够有效提高农作物产量,而且对于农业废弃物资源高效利用和保护生态环境具有重要的现实意义。     

通风方式对牛粪堆肥氨气排放与氮素转化的影响

为揭示通风方式对好氧堆肥过程中氮素转化及损失的影响,设置连续通风T1（通风速率0.2L/（min·kg））和间歇通风T2（平均通风速率0.2L/（min·kg）,通风10min,间歇10min）2个处理,以牛粪和玉米秸秆为原料在反应器中进行好氧堆肥试验。结果表明,堆肥结束后T1和T2处理总氮（TN）损失分别占初始 TN 23.25%和21.12%, TN的损失以NH3挥发为主,分别占 TN损失的74.76%和61.84%,而以N2O排放损失的氮仅占 TN损失的1.12%和1.37%。NH3挥发主要集中在堆肥初期,主要是因为较高的温度和pH值所致,至堆肥结束时T2处理NH3累积排放量比T1处理少24.37%。不同通风方式对堆肥过程中NH+4N和NO-3N的含量变化也产生显著影响,到堆肥结束时,T2处理相比T1处理,其NH+4N含量低11%,而NO-3N含量高6.7%,T2处理酸解总有机氮含量比T1处理高12.4%,说明间歇通风有利于硝化作用和氨同化作用的进行。结构方程模型（SEM）显示,T2处理不同有机氮对NH+4N含量的总影响从大到小顺序为：酰胺态氮(1.006)、氨基糖态氮(0.485)、酸解未知态氮(0.034)、氨基酸态氮(-0.852),说明NH+4N来源于酰胺态氮、氨基糖态氮和酸解未知态氮,同时NH+4N可以通过氨同化作用生成氨基酸态氮,间歇通风能促进NH+4N向氨基酸态氮的转化。间歇通风方式通过抑制有机氮向NH+4N的转化,降低堆肥过程中由NH3排放造成的氮素损失。