Massive Hepatic Necrosis and Nodular Regeneration in Largemouth Bass Fed Diets High in Available Carbohydrate     

Andrew E.  Goodwin  Rebecca T.  Lochmann Darlene M.  Tieman Andrew J.  Mitchell 《Journal of the World Aquaculture Society》2002,33(4):466-477

Largemouth bass Micropterus salmoides are piscivorous fish raised on farms then sold live in Asian fish markets on the east and west coasts of the United States. In the winter of 1998, a major producer of feed‐trained bass suffered a significant increase in fish mortality both during shipping and while the fish were still in ponds. No bacterial, viral, or significant parasitic pathogens were found at necropsy. Livers of affected fish were pale and translucent with 3–10 mm pink nodules on their surface and deeper in the parenchyma. Histological examination of these livers showed that the translucent regions of the liver contained few hepatocytes and were composed of tissue consistent with a chronic inflammatory response. Also present were eosinophils, islands of pancreatic and biliary cells, and granulomas that did not stain positively for mycobacteria. The pink nodules were areas of multifocal regeneration of normal hepatocytes. Sequential studies of bass in ponds revealed that the bass were progressively accumulating glycogen in their hepatocytes to an extent sufficient to explain the massive necrosis of that organ. In order to determine the effect of diets varying in available carbohydrate on fish growth, survival, and liver glycogen content, a 12‐wk feeding trial was conducted in aquaria with juvenile largemouth bass. Nitrogen‐free extract values indicated that an extruded trout diet, a steelhead trout diet, and a diet designed to contain 45% protein and 25% fat, contained 35, 27, and 21% carbohydrate, respectively. Weight gain was lowest in fish fed the extruded trout diet, while liver glycogen was significantly higher in fish fed diets with >27% carbohydrate than in fish fed the diet with 21% carbohydrate. The farmer switched to a diet similar to the 45–25 diet used in our trial. Subsequently, 16‐mo‐old fish examined in October 2000 had no hepatic nodules or necrosis, were significantly larger and less variable in size than previous crops, and the farmer experienced no significant losses in ponds or during shipping.  相似文献   

Duration of tick activity     

K Webster  G B Mitchell  C L Wright 《The Veterinary record》1985,116(14):378-379

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Evaluation of four point-of-care meters for rapid determination of blood lactate concentrations in dogs     

Acierno MJ  Mitchell MA 《Journal of the American Veterinary Medical Association》2007,230(9):1315-1318

OBJECTIVE: To determine whether blood lactate values determined in dogs with 4 commercially available point-of-care meters were in agreement with values determined with a critical care laboratory blood analyzer. DESIGN: Prospective study. ANIMALS: 50 dogs evaluated for emergency treatment. PROCEDURES: Blood samples were collected at initial evaluation and processed on 4 point-of-care meters and on a critical care laboratory blood analyzer. RESULTS: All 4 point-of-care lactate meters generated measurements that were in agreement with the hospital's critical care analyzer. Values for agreement (bias) between the 4 point-of-care meters and the critical care analyzer were -0.652 (limits of agreement [LA], -1.958 to 0.654]), -0.670 (LA, -2.110 to 0.769), -0.096 (LA, -2.071 to 1.879), and -0.498 (LA, -2.616 to 1.620), respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Despite its prognostic and therapeutic relevance, blood lactate measurement in dogs has been hampered by the inability to perform the test in a timely fashion. Results of the present study indicated that several handheld point-of-care lactate meters provided results that were in agreement with a laboratory critical care blood analyzer.  相似文献   

Anthelmintic use in goats     

Edwards GT  Mitchell ES  Harwood DG 《The Veterinary record》2007,161(22):763-764

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Alterations in the bovine bronchoalveolar lavage proteome induced by dexamethasone     

Mitchell GB  Clark ME  Caswell JL 《Veterinary immunology and immunopathology》2007,118(3-4):283-293

Stressors such as transportation, weaning and co-mingling increase susceptibility to bacterial pneumonia in cattle and are associated with elevated levels of endogenous glucocorticoids. To determine the effect of glucocorticoids on the proteins expressed in the fluid lining the respiratory tract, bronchoalveolar lavage (BAL) was performed on cattle treated with dexamethasone or saline and proteins were resolved by two-dimensional electrophoresis (2-DE). Significant changes in expression were observed for 9 of the 363 detected spots, and the identities of these proteins were determined by mass spectrometry. Consistent with the initiation of an acute phase response, the expression of alpha-1-acid glycoprotein (orosomucoid) and alpha-1-antitrypsin was increased and alpha-2-HS-glycoprotein (fetuin) was decreased in the BAL fluid of dexamethasone-treated cattle. In addition, dexamethasone induced the expression of two hydrophobic ligand-binding proteins, adipocyte-fatty acid binding protein and odorant binding protein (OBP), as well as the proteins alpha-enolase, cofilin-1 and immunoglobulin J chain. OBP mRNA expression in bronchial biopsies was quantified by real-time RT-PCR and the 6-fold higher levels of expression observed in dexamethasone- versus saline-treated animals correlated with the changes observed in OBP protein level. These findings demonstrate glucocorticoid-dependent changes in the protein composition of the epithelial lining fluid of the respiratory tract, identifying proteins potentially integral to respiratory disease susceptibility.  相似文献   

Effects on nutrients and on grain quality in spring wheat crops grown under elevated CO₂ concentrations and stress conditions in the European, multiple-site experiment ‘ESPACE-wheat’     

A. Fangmeier  L. De Temmerman  L. Mortensen  K. Kemp  J. Burke  R. Mitchell  M. van Oijen  H. -J. Weigel 《European Journal of Agronomy》1999,10(3-4):215-229

Nutrient element concentrations and grain quality were assessed in spring wheat grown under elevated CO₂ concentrations and contrasting levels of tropospheric ozone at different nitrogen supply rates at several European sites. Carbon dioxide enrichment proved to affect nutrient concentrations in a complex manner. In green leaves, all elements (with exception of phosphorus and iron) decreased. In contrast, effects on the element composition of grains were restricted to reductions in nitrogen, calcium, sulphur and iron. Ozone exposure resulted in no significant effects on nutrient element concentrations in different tissues in the overall analysis. The nitrogen demand of green tissues was reduced due to CO₂ enrichment as shown by reductions in the critical leaf nitrogen concentration and also enhanced nitrogen use efficiency. Reductions in the content of ribulose-bisphosphate carboxylase/oxygenase and repression of the photorespiratory pathway and reduced nitrogen allocation to enzymes driving the photosynthetic carbon oxidation cycle were chiefly responsible for this effect. Thus, nitrogen acquisition by the crop did not match carbon acquisition under CO₂ enrichment. Since crop nitrogen uptake from the soil was already completed at anthesis, nitrogen allocated to the grain after anthesis originated from vegetative pools—causing grain nitrogen concentrations to decrease under CO₂ enrichment (on average by 15% when CO₂ concentrations increased from 360 to 680 μmol mol⁻¹). Correspondingly, grain quality was reduced by CO₂ enrichment. The Zeleny value, Hagberg value and dry/wet gluten content decreased significantly with increasing [CO₂]. Despite the beneficial impact of CO₂ enrichment on growth and yield of C₃ cereal crops, declines in flour quality due to reduced nitrogen content are likely in a future, [CO₂]-rich world.  相似文献   

Urban Influences on Stream Chemistry and Biology in the Big Brushy Creek Watershed, South Carolina     

Gregory P. Lewis  Jennifer D. Mitchell  C. Brannon Andersen  Dennis C. Haney  Min-Ken Liao  Kenneth A. Sargent 《Water, air, and soil pollution》2007,182(1-4):303-323

Naturally high total dissolved solids and upstream agricultural runoff often mask the influence of urban land cover on stream chemistry and biology. We examined the influence of headwater urbanization on the water chemistry, microbiology, and fish communities of the Big Brushy Creek watershed, a 96 km² drainage basin in the piedmont of South Carolina, USA. Concentrations of most major anions and cations (especially nitrate, sulfate, chloride, sodium, potassium, and calcium) were highest in the urban headwaters and decreased downstream. Generally, the highest concentrations of suspended coliform bacteria occurred in the urban headwaters. In contrast, stream habitat quality and the abundance, species richness, and species diversity of fishes did not differ significantly between urban and rural sites. Discharge of wastewater treatment plant effluent at one rural location caused an increase in concentrations of many solutes and possibly the abundance of benthic algae. We hypothesize that atmospheric dry deposition and domestic animal wastes are important sources of stream solutes and of coliform bacteria, respectively, in the urban headwaters. The lack of significant differences in fish abundance and diversity between urban and rural sites may indicate that urban development in the Big Brushy Creek watershed has not yet degraded habitat conditions greatly for stream fishes. Alternatively, agriculture or other land uses may have degraded stream habitat quality throughout the watershed prior to urbanization.  相似文献   

Potassium Dynamics in US Coastal Plain Soils     

Charles C. Mitchell  Gobena Huluka 《Communications in Soil Science and Plant Analysis》2016,47(22):54-63

ABSTRACT

Potassium (K) deficiency in crops in southern US Coastal Plain soils has been documented since the l880s. Long-term soil fertility studies such as Alabama’s “Cullars Rotation” experiment (circa 1911) have been conducted with K since 1911. Other Alabama long-term experiments on several Coastal Plain and related Hapludults, Paleudults, and Kandiudults also contain K variable treatments which have been monitored since 1929. Soil test data from these long-term experiments have allowed us to answer some practical questions regarding K dynamics in Coastal Plain soils. Potassium movement through the soil profile is dependent on the soil’s cation exchange capacity (CEC) but relative accumulation is greater in the plow layer regardless of soil CEC. While subsoil K testing may be useful for identifying situations where subsoil K has been depleted, this extra effort and expense is not necessary for most cropping situations. A crop will remove most of its K from the plow layer if it is present in sufficient quantity based on soil test. Crop depletion of plow-layer K to the point where yield may be reduced is gradual and may take 10–15 years or more depending upon soil CEC and initial soil K concentration. Depletion is most rapid in low CEC soils as would be expected. However, soil test K can vary considerably during the course of a crop season with the lowest soil test K concentrations occurring immediately after harvest.  相似文献   

Validity and repeatability of a simple index derived from the short physical activity questionnaire used in the European Prospective Investigation into Cancer and Nutrition (EPIC) study     

Wareham NJ  Jakes RW  Rennie KL  Schuit J  Mitchell J  Hennings S  Day NE 《Public health nutrition》2003,6(4):407-413

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Comparative Evaluation on Nitrogen Saturation of Forest Catchments in Japan and Northeastern United States     

Nobuhito Ohte  Myron J. Mitchell  Hideaki Shibata  Naoko Tokuchi  Hiroto Toda  Goro Iwatsubo 《Water, air, and soil pollution》2001,130(1-4):649-654

To analyze the differences in the status and processes of nitrogen saturation in Japan and northeastern United States, we examined the hydrobiogeochemistry of nitrogen of forested watersheds in these regions. Two distinct differences were found between watersheds in Japan compared with those in US. 1) In Japanese watersheds, marked decreases of NO₃ ^? concentration in surface waters during the summer growing season were not found and NO₃ ^? concentrations sometimes increased especially in the summer at nitrogen saturated sites. This contrast with watersheds in US where decreases in NO₃ ^? concentration during the summer are commonly observed except those watersheds in advanced stages of nitrogen saturation. These differences in NO₃ ^? concentration relationships can be attributed to climatic differences, with Japan having high precipitation and high discharge during the summer, while in many regions of North America lowest discharges are found in the summer. The climatic regime in Japan leads to high rates of mineralization and the rapid transport of NO₃ ^? to streams in summer. 2) Japanese watersheds, even those with high NO₃ ^? concentrations in surface waters, show little evidence of acidification. This is in contrast to sites in US where increased NO₃ ^? concentrations, especially during episodic events, result in surface water acidification.  相似文献