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Matthew W. Miller DVM Dipl ACVIM Sonya G. Gordon DVM Dipl ACVIM Ashley B. Saunders DVM Dipl ACVIM Wendy G. Arsenault DVM Dipl ACVIM Kathryn M. Meurs DVM Dipl ACVIM Linda B. Lehmkuhl DVM Dipl ACVIM John D. Bonagura DVM Dipl ACVIM Philip R. Fox DVM Dipl ACVIM Dipl ECVIM 《Journal of Veterinary Cardiology》2006,8(2):109-114
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Tolerance of snakehead Channa striatus to ammonia was tested at three pH levels (8.0, 9.0. and 10.0) in experimental tanks. At pH 8.0, ammonia LC50 estimates for snakehead at 24, 48, 72, and 96 h were >205.7, >203.5, 152.6, and 107.3 mg total ammonianitrogen (TAN)/L (or >10.3, >10.2, 7.6, and 5.4 mg NH3 -N/L), respectively. At pH 9.0, ammonia LC50 estimates at 24, 48, 72, and 96 h were >52.4, 62.8, 56.1, 43.4 mg TAN/L (or >18.0, 21.6, 19.3, and 14.9 mg NH3 -N/L), respectively. At pH 10.0, ammonia LC50 estimates at 24, 48, 72, and 96 h were 25.7, 21.6, 20.3, and 18.7 mg TAN/L (or 21.6, 18.1, 17.1, and 15.7 mg NH3 -N/L). respectively. Our data indicate that the tolerance of snakehead to ammonia was associated with pH. Thus, we recommend that snakehead should not be subjected to prolonged exposures of NH3 -N concentration more than 0.54 ma at pH 8.0, more than 1.49 mg/L at pH 9.0, or more than 1.57 mg/L at pH 10.0. 相似文献
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Polycyclic aromatic hydrocarbons (PAHs) are one class of chemical compounds that (1) are present at low to trace levels in unburned cigarette filler, and (2) are predominantly generated during combustion. According to a recent report of the International Agency for Research on Cancer, 10 carcinogenic PAHs together with 53 other known carcinogens are present in cigarette smoke. Accurate quantification of these chemicals helps assess public health risk to both smokers and nonsmokers exposed to second-hand smoke. We have developed and validated a specific and sensitive method for measuring these 10 carcinogenic PAHs in the particulate phase of mainstream tobacco smoke. Cigarette smoke particulate, produced using standard machine smoking protocols, was collected on glass fiber Cambridge filter pads. The particulate matter was solvent extracted, purified by solid-phase extraction, and analyzed by liquid chromatography/atmospheric pressure photoionization tandem mass spectrometry using isotopically labeled analogues as internal standards. Our method's limits of detection ranged from 11 to 166 pg and achieved sufficient reproducibility and accuracy to provide useful information on a range of cigarettes having dramatically different machine-smoked tar and nicotine deliveries. The identity of each PAH analyte was established from chromatographic retention time, analyte-specific fragmentation patterns, and relative peak area ratios of the product/precursor ion pairs. This new method provides higher sensitivity, specificity, and throughput than did earlier methods. We found relatively consistent PAH levels among a selection of domestic full-flavor cigarettes. The PAH levels in smoke from highly ventilated light and ultralight cigarettes were low when smoked using ISO (International Organization for Standardization) conditions. However, if highly ventilated cigarettes were smoked under more intense conditions (e.g., larger or more frequent puffs, vents blocked), their PAH levels equaled or exceeded their full-flavor counterparts under ISO conditions. 相似文献
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Wade T. Walker Robert J. Callan Ashley E. Hill Kelly B. Tisher 《The Canadian veterinary journal. La revue veterinaire canadienne》2014,55(8):765-771
This study evaluated the effects of administering oral powder electrolytes on packed cell volume (PCV), plasma chemistry parameters, and incidence of colic in horses participating on a 6-day 162-km trail ride in which water was not offered ad libitum. Twenty-three horses received grain with powder electrolytes daily while 19 control horses received grain only. Horses were ridden approximately 32 km a day at a walk or trot. Packed cell volume and plasma chemistry parameters were analyzed daily. Episodes of colic were diagnosed and treated by a veterinarian unaware of treatment group allocation. Blood parameters and incidence of colic were compared between treatment groups. Electrolyte administration did not alter PCV or plasma chemistry parameters compared to controls. The incidence of colic was significantly higher in treated horses (P = 0.05). Oral powder electrolytes did not enhance hydration status or electrolyte homeostasis and may be associated with colic in horses participating on long distance trail rides similar to this model. 相似文献
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Atlantic sturgeon (Acipenser oxyrhynchus), which are bottom dwelling and migratory fish, experience environmental hypoxia in their natural environment. Atlantic sturgeon,
acclimated to either 5 or 15°C, were subjected to a 1 h severe (<10 mm Hg) hypoxia challenge in order to document their physiological
responses. We measured hematological parameters, including O2 transport (hemoglobin, hematocrit), ionic (chloride, osmolality), and metabolic (glucose, lactate) variables under normoxic
conditions (~160 mm Hg), immediately following a 1 h exposure to hypoxic water, and following a further 2 h of recovery from
this challenge in normoxic water. In a second experiment, we assessed the opercular beat frequency before, during, and after
hypoxic exposure. Hemoglobin concentrations and hematocrit were significantly different between fish held at 5°C vs. 15°C
and also significantly different between normoxia prior to hypoxia and following recovery. Plasma lactate concentrations increased
following hypoxia at both temperatures, indicative of an increase in anaerobic metabolism. In contrast, a significant increase
in plasma glucose concentrations in response to hypoxia only occurred at 5°C, suggesting different fuel demands under different
temperatures. Changes in opercular beat frequency (OBF) were dependent on temperature. At 5°C, OBF increased upon exposure
to hypoxia, but returned to pre-exposure levels within 35 min for the remainder of the experiment. During hypoxia at 15°C,
OBF increased very briefly, but then rapidly (within 20 min) decreased to levels below control values. Following a return
to normoxia, OBF quickly increased to control levels. Overall, these findings suggest that Atlantic sturgeons are relatively
tolerant to short-term and severe hypoxic stress, and the strategies for hypoxia tolerance may be temperature dependent. 相似文献
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Juvenal Kanani ;Dirk Philipp ;Kenneth P Coffey ;Elizabeth B Kegley ;Charles P West ;Shane Gadberry ;John Jennings ;Ashley N Young ;Robert T Rhein 《畜牧与生物技术杂志(英文版)》2014,(3):310-317
Background: The potential for acid-detergent insoluble ash (ADIA), alkaline-peroxide lignin (APL), and acid-detergent lignin (ADL) to predict fecal output (FO) and dry matter digestibility (DMD) by cattle offered bermudagrass [Cynodon doctylon (L) Pers.] hays of different qualities was evaluated. Eight ruminally cannulated cows (594 ± 35.5 kg) were allocated randomly to 4 hay diets: low (L), medium low (ML), medium high (MH), and high (H) crude protein (CP) concentration (79, 111,131, and 164 g CP/kg on a DM basis, respectively). Diets were offered in 3 periods with 2 diet replicates per period and were rotated across cows between periods. Cows were individually fed 20 g DM/kg of body weight in equal feedings at 08:00 and 16:00 h for a 10-d adaptation followed by a 5-d total fecal collection. Actual DM intake (DMI), DMD, and FO were determined based on hay offered, ort, and feces excreted. These components were then analyzed for ADL, APL, and ADIA concentration to determine marker recovery and marker-based estimates of FO and DMD. Results: Forage DMI was affected by diet (P = 0.02), and DMI from MH and H was greater (P 〈 0.05) than from L. Apparent DMD tended (P = 0.08) to differ among diets while FO (P = 0.20) was not affected by diet treatments. Average ADL recovery (1.16) was greater (P 〈 0.05) than that of ADIA (1.03) and APL (1.06), but ADIA and APL did not differ (P = 0.42). Estimates of FO and DMD derived using APL and ADIA were not different (P≥0.05) from total fecal collection while those using ADL differed (P 〈 0.05). There was no diet by marker interaction (P≥ 0.22) for either FO or DMD. Conclusion: Acid-detergent insoluble ash and APL accurately predicted FO and DMD of cattle fed bermudagrass hay of varying nutrient composition. These internal markers may facilitate studies involving large numbers of animals and forages. Results from such studies may be used to develop improve 相似文献
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The effects of kin and familiarity on interactions between fish 总被引:8,自引:0,他引:8
Fish have been shown to discriminate between individuals on very general bases such as species, body length and colour. More recently, evidence has been accumulating from a number of species that relatedness and familiarity may be extremely important in mediating a range of interactions between individual fish. Studies have shown that fish are able to recognize kin and/or familiars, and that this ability potentially conveys significant benefits, including increased inclusive fitness, reduced inbreeding costs, reduced competition and enhanced antipredator behaviour. Here, we review the literature and consider future directions and applications for this research. 相似文献