Nutrient intake of horses in Thoroughbred and Standardbred stables

SUMMARY Twenty-five Thoroughbred (TB) and 25 Standardbred (SB) stables were visited to determine their feeding practices. The ingredients of the main feed of the day for a mature gelding of average size in full training were weighed at each stable. Nutrient content of diets was calculated using published data for the individual ingredients. Results are expressed as mean±sd. The estimated body weight of TB horses was 493±34 kg and 437±32 kg for SB horses. There was considerable variation in diet composition and nutrient intake between stables. The TB trainers fed 11.0±2.4 kg and SB trainers 11.8±2.5 kg per day. The concentrate component of the diet weighed 7.8±1.6 and 7.7±2.3 kg for TB and SB stables, respectively, and the roughage component for TB horses 3.3±1.4 and SB horses 4.1±1.4 kg per day. The digestible energy intake of horses at TB stables was 129±29 MJ per day and at SB stables 132±31 MJ per day. Crude protein intake of TB horses was 1452±363 g and SB horses 1442±338 g per day. There were differences in some feeding practices at TB and SB stables. Standardbred trainers fed more roughage than TB trainers. Standardbred trainers fed chaffed lucerne (alfalfa) and cereal hays as the major roughage, whereas TB trainers fed more hay. The major hay type fed by TB trainers was lucerne, whereas many SB trainers preferred clover hay. Both trainers fed oats as the major grain, but TB trainers fed slightly more maize (corn) than SB trainers. The SB trainers fed barley as part of the concentrate component of the diet, whereas TB trainers usually fed boiled barley and linseed oil in winter only. Although many trainers used vitamin and mineral supplements, this appeared unnecessary in many Instances, especially with respect to Iron. Calcium and NaCI supplementation was necessary for some diets. We concluded that while there was a wide range in feed intake and diet composition for both TB and SB horses, average nutrient intakes were similar to National Research Council (1989) recommendations for horses performing intense work.     

棕点石斑鱼(♀)×蓝身大斑石斑鱼(♂)杂交后代与棕点石斑鱼低氧耐受能力初步研究

为了研究棕点石斑鱼(Epinephelus fuscoguttatus,♀)与蓝身大斑石斑鱼(E.tukula,♂)杂交后代(简称金虎石斑鱼)和棕点石斑鱼的低氧耐受能力,采用封闭式呼吸室测定棕点石斑鱼和金虎石斑鱼幼鱼的耗氧率与窒息点,在正常溶氧[(5.71±0.31)mg/L]和溶解氧下降至4.0 mg/L、3.0mg...     

评估调质时间和温度对猪颗粒饲料淀粉糊化度和维生素沉积的影响

本论文研究了饲料加工的两个关键参数(调质温度和时间)对育肥猪颗粒饲料淀粉糊化度和维生素沉积的影响。日粮配方为含30%干酒糟及其可溶物的玉米-豆粕型基础日粮。整个试验中配方保持不变。本试验采用2×3双因子设计,调质温度分别为77℃和88℃,调质时间分别15秒、30秒和60秒。此外,本试验还设置一个对照组,对照组饲料不采用调质制粒工艺,而是采用粉料饲喂。因此,本试验共有7个处理组。采集调质后制粒前(热干粉)、制粒后冷却前(热制粒)、以及制粒冷却后(冷制粒)的样品,并分析这三种样品的总淀粉率、淀粉糊化     

Strategies and hurdles using DNA vaccines to fish

DNA vaccinations against fish viral diseases as IHNV at commercial level in Canada against VHSV at experimental level are both success stories. DNA vaccination strategies against many other viral diseases have, however, not yet yielded sufficient results in terms of protection. There is an obvious need to combat many other viral diseases within aquaculture where inactivated vaccines fail. There are many explanations to why DNA vaccine strategies against other viral diseases fail to induce protective immune responses in fish. These obstacles include: 1) too low immunogenicity of the transgene, 2) too low expression of the transgene that is supposed to induce protection, 3) suboptimal immune responses, and 4) too high degradation rate of the delivered plasmid DNA. There are also uncertainties with regard distribution and degradation of DNA vaccines that may have implications for safety and regulatory requirements that need to be clarified. By combining plasmid DNA with different kind of adjuvants one can increase the immunogenicity of the transgene antigen – and perhaps increase the vaccine efficacy. By using molecular adjuvants with or without in combination with targeting assemblies one may expect different responses compared with naked DNA. This includes targeting of DNA vaccines to antigen presenting cells as a central factor in improving their potencies and efficacies by means of encapsulating the DNA vaccine in certain carriers systems that may increase transgene and MHC expression. This review will focus on DNA vaccine delivery, by the use of biodegradable PLGA particles as vehicles for plasmid DNA mainly in fish.     

N2O emissions from different cropping systems and from aerated,nitrifying and denitrifying tanks of a municipal waste water treatment plant

Nitrous oxide emissions, nitrate, water-soluble carbon and biological O₂ demand (BOD₅) were quantified in different cropping systems fertilized with varying amounts of nitrogen (clayey loam, October 1991 to May 1992), in an aerated tank (March 1993 to March 1994), and in the nitrification-denitrification unit (March to July 1994) of a municipal waste water treatment plant. In addition, the N₂O present in the soil body at different depths was determined (February to July 1994). N₂O was emitted by all cropping systems (mean releases 0.13–0.35 mg N₂O m^-2 h^-1), and all the units of the domestic waste water treatment plant (aerated tank 0–6.2 mg N₂O m^-2 h^-1, nitrification tank 0–204,3 mg N₂O m^-2, h^-1, denitrifying unit 0–2.2 mg N₂O m^-2 h^-1). During the N₂O-sampling periods estimated amounts of 0.9, 1.5, 2.4 and 1.4 kg N₂O–N ha^-1, respectively, were released by the cropping systems. The aerated, nitrifying and denitrifying tanks of the municipal waste water treatment plant released mean amounts of 9.1, 71.6 and 1.8 g N₂O–N m^-2, respectively, during the sampling periods.The N₂O emission were significantly positively correlated with nitrate concentrations in the field plots which received no N fertilizer and with the nitrogen content of the aerated sludge tank that received almost exclusively N in the form of NH ₄ ⁺ . Available carbon, in contrast, was significantly negatively correlated with the N₂O emitted in the soil fertilized with 80 kg N ha^-1 year. The significant negative correlation between the emitted N₂O and the carbon to nitrate ratio indicates that the lower the carbon to nitrate ratio the higher the amount of N₂O released. Increasing N₂O emissions seem to occur at electron donorto-acceptor ratios (C_H2_O or BOD₅-to-nitrate ratios) below 50 in the cropping systems and below 1200–1400 in the waste water treatment plant. The trapped N₂O in the soil body down to a depth of 90 cm demonstrates that agricultural production systems seem to contain a considerable pool of N₂O which may be reduced to N₂ on its way to the atmosphere, which may be transported to other environments or which may be released at sometime in the future.Dedicated to Professor J.C.G. Ottow on the occasion of his 60th birthday     

Impacts of tree canopy structure on wind flows and fire propagation simulated with FIRETEC

Introduction   

Forest fuel management in the context of fire prevention generally induces heterogeneous spatial patterns of vegetation. However, the impact of the canopy structure on both wind flows and fire behavior is not well understood.     

Toxic DNA damage by hydrogen peroxide through the Fenton reaction in vivo and in vitro

Exposure of Escherichia coli to low concentrations of hydrogen peroxide results in DNA damage that causes mutagenesis and kills the bacteria, whereas higher concentrations of peroxide reduce the amount of such damage. Earlier studies indicated that the direct DNA oxidant is a derivative of hydrogen peroxide whose formation is dependent on cell metabolism. The generation of this oxidant depends on the availability of both reducing equivalents and an iron species, which together mediate a Fenton reaction in which ferrous iron reduces hydrogen peroxide to a reactive radical. An in vitro Fenton system was established that generates DNA strand breaks and inactivates bacteriophage and that also reproduces the suppression of DNA damage by high concentrations of peroxide. The direct DNA oxidant both in vivo and in this in vitro system exhibits reactivity unlike that of a free hydroxyl radical and may instead be a ferryl radical.     

Sex pheromone of the winter moth, a geometrid with unusually low temperature precopulatory responses

The sex pheromone for the winter moth, Operophtera brumata (L.), has been identified as the novel compound (Z,Z,Z)-1,3,6,9-nonadecatetraene. The male moths respond to the pheromone at low temperatures (4 degrees to 15 degrees C) and exhibit an upper response limit that coincides with the lower response limit for other reported moth sex pheromone systems. The pheromone attracted two other geometrid species, O. bruceata (Bruce spanworm) and O. occidentalis.