Die wirtschaftliche Bedeutung der Parasiten im Kampf gegen schädliche Insekten

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Comparative toxicology of monensin sodium in laboratory animals

The toxicology of monensin has been studied in several laboratory animal species. There was considerable species variation in acute oral LD50 values. The consistent signs of acute toxicity were: anorexia, hypoactivity, skeletal muscle weakness, ataxia, diarrhea, decreased weight gain and delayed deaths. The 3-mo study in rats fed diets containing 0, 50, 150 or 500 ppm monensin resulted in no effects at the lowest dose level, slight reduction of body weight gain in the middle-dose group and severe depression in body weight gain, skeletal and cardiac lesions, and deaths in the highest dose group. The 3-mo study in dogs given daily oral doses of 0, 5, 15 or 50 mg/kg monensin resulted in no effects at the lowest dose level. Dogs in the 15 and 50 mg/kg groups developed, during test wk 1 to 4, anorexia, weakness, ataxia, labored respiration, body weight loss, increased serum muscle enzyme values, severe skeletal muscle degeneration and necrosis with less severe heart lesions and deaths. Mice fed diets containing 0, 37.5, 75, 150 or 300 ppm monensin for 3 mo had reduced body weight gain in all test groups but no other physical signs. Serum creatine phosphokinase (CPK) values were increased in mice in the two highest dose groups and minimal heart lesions were found in the highest dose group. Dogs given daily oral doses of 0, 1.25, 2.5, 5 or 7.5 mg/kg monensin for 1 yr survived with no evidence of toxicity in the two lowest dose groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Growth of Mycoplasma bovis in organ cultures of bovine foetal trachea and comparison with Mycoplasma dispar

Inoculation of tracheal organ cultures from bovine foetuses with Mycoplasma bovis resulted in a loss of cellular structure of the lamina propria, followed 20-22 days later by lifting and detachment of overlying epithelium. The effect was associated with large numbers of M. bovis, identified by immunoperoxidase labelling and electromicroscopy, infiltrating between the epithelial cells and amassing in the lamina propria, especially in the region of the basement membrane of the epithelium. Ciliary activity was undiminished for up to 18 days following inoculation and little or no cytopathic effect on the ciliated epithelium was seen in spite of the close proximity of large numbers of organisms. In contrast, M. dispar was restricted to the margin of the ciliated epithelium where, as previously reported, it caused pyknosis, sloughing and flattening of the epithelium with consequent loss of ciliary activity. The cytopathology observed for each mycoplasma bore a close similarity to the behaviour of the two mycoplasmas in vivo and it is suggested that the organ culture system may be a useful and relevant system to elucidate the pathogenic mechanisms for each mycoplasma.     

Pharmacokinetic comparison of six anthelmintics in sheep,goats, and cattle

This study was initiated to determine whether a comparative pharmacokinetic (PK) approach could be used to expand the pool of approved anthelmintics for minor ruminant species. Accordingly, the PK profiles of six anthelmintics (levamisole, albendazole, fenbendazole, moxidectin, doramectin, and ivermectin) in sheep, goats, and cattle were determined. The PK values determined for each anthelmintic included T_max, T_last, C_max, AUC, AUC/dose, and C_max/dose. The results of this study demonstrate that a comparative PK approach does not show commonality in the way these six anthelmintics are individually processed by these three ruminants. While some drugs demonstrated identical PK profiles between sheep and goats, none of these drugs demonstrated PK profiles in sheep and goats comparable to the PK profiles found in cattle. The results from this study suggest drug approval across these three ruminants is not a viable concept. However, the resulting PK profiles for each combination of drug and ruminant species represents a new dataset that can be used to support the US FDA Center for Veterinary Medicine's Minor Use/Minor Species indexing process for drug approvals in minor species such as sheep and goats.     

Changes in thyroid hormone levels in eggs and larvae and in iodide uptake by eggs of coho and chinook salmon,Oncorhynchus kisutsch andO. tschawytscha

Developmental profiles of thyroxin (T₄), triiodothyronine (T₃) and radioactive iodide uptake were established for eggs and T₄ and T₃ profiles were established for larvae (whole-body, yolk-only and body-only) of coho and chinook salmon. T₄ and T₃ were consistently present in all samples. In eggs, hormone levels remained fairly constant in all cohorst for at least the first three weeks of incubation, but then fluctuated in both directions in some sample groups. Large increases in T₄ (from 9 ng/g to 245 ng/g) were seen in 1985 chinook eggs 28 days after fertilization. Radioactive iodide uptake (which was used as a possible indicator of thyroxinogenesis) increased at least 10-fold in both 1986 coho and chinook eggs from 23–30 days after fertilization. T₄ (62 ng/g) and T₃ (393 ng/g) were found in the bodies of 28-day-old 1986 chinook embryos. In whole larvae, hormone levels varied depending upon the cohort studied. In general, initial body-only concentrations of both T₄ and T₃ decreased as body weight increased, but before yolksac resorption was completed, both thyroid hormone content and concentration increased (except for chinook T₃). T₄ and T₃ content in larval yolk stayed constant as yolksac size decreased, resulting in increased thyroid hormone concentration in the yolksac. All of these data suggest that the initial source of thyroid hormones in coho and chinook salmon eggs is maternal, but that by approximately 3–4 weeks after fertilization, the developing embryos begin to produce their own thyroid hormones. After hatching, increases in tissue T₄ and T₃ concentration coupled with constant T₄ and T₃ content in diminishing yolksacs suggest that larvae also produce their own thyroid hormones; yolksac content then may reflect both the original maternal hormones and the larva-producted hormones.     

Comparison of effects of high-pressure processing and heat treatment on immunoactivity of bovine milk immunoglobulin G in enriched soymilk under equivalent microbial inactivation levels

Immunoglobulin-rich foods may provide health benefits to consumers. To extend the refrigerated shelf life of functional foods enriched with bovine immunoglobulin G (IgG), nonthermal alternatives such as high-pressure processing (HPP) may offer advantages to thermal processing for microbial reduction. To evaluate the effects of HPP on the immunoactivity of bovine IgG, a soymilk product enriched with milk protein concentrates, derived from dairy cows that were hyperimmunized with 26 human pathogens, was subjected to HPP or heat treatment. To achieve a 5 log reduction in inoculated Escherichia coli 8739, the HPP or heat treatment requirements were 345 MPa for 4 min at 30 degrees C or for 20 s at 70 degrees C, respectively. To achieve a 5 log reduction in natural flora in the enriched soymilk, the HPP or heat treatments needed were 552 MPa for 4 min at 30 degrees C or for 120 s at 78.2 degrees C, respectively. At equivalent levels for a 5 log reduction in E. coli, HPP and heat treatment caused 25% and no detectable loss in bovine IgG activity, respectively. However, at equivalent levels for a 5 log reduction in natural flora, HPP and heat resulted in 65 and 85% loss of bovine IgG activity, respectively. Results of combined pressure-thermal kinetic studies of bovine milk IgG activity were provided to determine the optimal process conditions to preserve product function.     

不同提取方法山苍子油的化学成分与抗氧化活性分析

【目的】比较不同提取方法对山苍子油提取效率与抗氧化活性的影响,通过 GC-MS分析,研究山苍子油成分构成与抗氧化活性的内在关联,分析山苍子油抗氧化活性的主要物质基础。【方法】采用液液萃取(分别加以超声波与磁化辅助处理)、二氧化碳超临界萃取以及水蒸气蒸馏法提取山苍子油,DPPH 法比较不同提取方式对山苍子油抗氧化活力的影响,GC-MS分析山苍子油的主要成分,并以1,4－二溴苯为内标,采用面积归化法解析主要成分的相对含量。【结果】山苍子油具有显著的抗氧化活性。液液萃取法的提取效率与山苍子油抗氧化活性最高,超声波辅助处理油得率最高,为26.3%,磁化辅助处理抗氧化活性最优,达到31.22 mg·mL －1( IC50),二氧化碳超临界萃取法次之,抗氧化活性为56.95 mg·mL －1( IC50),水蒸气蒸馏法抗氧化活性最弱,为64.95 mg·mL －1( IC50); GC-MS分析检测出122种以上的化合物,包括12种脂肪酸,16种萜烯,18种含氧萜烯以及其他微量化合物包括烯烃、醇、酮类与烷烃等。GC-MS分析结果表明：山苍子干果主要成分为饱和脂肪酸(月桂酸等)、不饱和脂肪酸(9,12－十八碳二烯酸、9－十八碳烯酸等)以及α蒎烯、β蒎烯、柠檬烯等萜烯、氧化萜烯类物质。液液萃取法得到的山苍子油脂肪酸含量(53.51%～66.61%)明显高于二氧化碳超临界萃取(17.64%)与水蒸气蒸馏法(8.1%),而二氧化碳超临界萃取与水蒸气蒸馏法得到的萜烯、氧化萜烯类含量分别达到29.37%和17.69%,明显高于液液萃取法(6.49%～9.75%)。【结论】磁化辅助处理有利于抗氧化活性物质的提取,且不饱和脂肪酸的含量最高;超声波辅助处理可以提升油的得率;水蒸气蒸馏法和超临界流体萃取法更有利于萜烯类化合物的获取;联系到水蒸气蒸馏法得到的山苍子油富含萜烯化合物却显示较低的抗氧化活性(64.95 mg·mL －1 ),色谱级的柠檬醛抗氧化活性最低(74.33 mg·mL －1),因此推测脂肪酸成分(特别是不饱和脂肪酸)是山苍子油抗氧化活性的主要物质基础。