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European Journal of Forest Research -  相似文献   
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Specific antibodies directed against enterotoxic E. coli strains from the yolk of immunized hens were exposed in vitro to the influence of varying digestive phenomena like reduction of pH and proteolytic digestion. The remaining antibody activity was tested in a specific ELISA system. It could be shown that already within the stomach a considerable loss in antibody activity caused by a lowering of pH and peptic cleavage can be expected. A further loss in antibody activity is due to the proteolytic effect of the pancreas proteases trypsin and chymotrypsin. It was found that antibodies in protein rich solutions like egg or yolk suspensions were more resistant than mere globulin fractions or antibodies isolated by affinity chromatography. Prospects for further in vivo tests are discussed.  相似文献   
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The fine particles serving as cloud condensation nuclei in pristine Amazonian rainforest air consist mostly of secondary organic aerosol. Their origin is enigmatic, however, because new particle formation in the atmosphere is not observed. Here, we show that the growth of organic aerosol particles can be initiated by potassium-salt-rich particles emitted by biota in the rainforest. These particles act as seeds for the condensation of low- or semi-volatile organic compounds from the atmospheric gas phase or multiphase oxidation of isoprene and terpenes. Our findings suggest that the primary emission of biogenic salt particles directly influences the number concentration of cloud condensation nuclei and affects the microphysics of cloud formation and precipitation over the rainforest.  相似文献   
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Intensive lamb fattening systems are evolving in developing Middle Eastern countries due to high demand for lambs at favorable prices; however, little is known about their characteristics and constraints. A survey was conducted in Syria involving 241 farmers to characterize the fattening production systems and main constraints, with emphasis on feeding, management, labor, and marketing. Most farmers (90%) considered the income from fattening to be from medium to high, and 57% expressed that lamb fattening along with alternative income sources compose the family's livelihood strategies. Fattening systems offer employment to family members. Market price was the main decision factor to buy and sell lambs, but this was only part of various marketing aspects. Male lambs usually bought at markets at the mean age of 4 months (mean weight of 31 kg) are sold after fattening at a 50–60 kg weight range. The average yearly fattening cycle was 2.7 batches, and the average number of lambs per batch was 232. For 65% (n = 241) of the farmers the major constraint to fattening was feeding cost, and for about a half of farmers (51%, n = 241), disease outbreaks and prices for veterinarian services constituted the second important constraint. Research on least-cost fattening diets and curbing disease problems to increase farmer's income margins is needed. It is expected that due to existing commonalities, the information emerging from this study regarding major constraints to Awassi lamb fattening systems could be useful for an across-synthesis on Awassi fattening production in the region.  相似文献   
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A field study and a controlled infection trial showed the protective effect of egg yolk lyophilisate and whole egg lyophilisate against enterotoxic E. coli germs. The lyophilisates were gained from eggs of hens immunized against pilus antigen of porcine-enterotoxic E. coli. In a first field study using egg yolk antibodies, 92% of 299 diarrhea affected piglets were cured. In a further field study diarrhea affected piglets were cured after 3 days by application of egg yolk lyophilisate from immunized hens. Piglets treated only with egg yolk of not immunized hens showed no signs of recovery. The infection trial showed, that whole egg lyophilisate of immunized hens was as successful as a common antibiotic therapy in curing piglets, orally infected with 5 x 10(10) E. coli/feeding and animal. The present data show that chicken egg antibodies can be used for treatment of infectious diarrheal diseases in young animals. So far they represent a good alternative to the common used antibiotic therapy.  相似文献   
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