The effects of soybean, linseed and marine oils on aerobic gut microbiota of Arctic charr Salvelinus alpinus L. before and after challenge with Aeromonas salmonicida ssp. salmonicida   总被引：2，自引：0，他引：2  

Einar Ringø  Jørgen B Lødemel  Reidar Myklebust  Liss Jensen  Vera Lund  Terry M Mayhew  & Rolf Erik Olsen 《Aquaculture Research》2002,33(8):591-606

Populations of heterotrophic bacteria present in the hindgut region of Arctic charr Salvelinus alpinus L. fed dietary soybean, linseed and marine oils before challenge with Aeromonas salmonicida ssp. salmonicida and marine oil after challenge were estimated using the dilution plate technique. There were differences in bacterial composition between the rearing groups before and after challenge, as well as interindividual variations. For example, carnobacteria were only isolated from the hindgut region of fish fed soybean oil and linseed oil before challenge, whereas Carnobacterium spp. and Carnobacterium funditum‐like species were isolated from fish fed the same oils after challenge. Three non‐motile Aeromonas spp. were isolated from infected fish fed marine oil. One of these isolates was identified as identical to A. salmonicida ssp. salmonicida used in&the challenge test by microbial fingerprinting (amplified fragment length polymorphism). Electron microscopic examinations of hindgut regions demonstrated substantial numbers of bacterial cells associated with enterocytes, but bacterial colonization of the enterocyte surface varied between different rearing groups. The potential of bacteria found associated with the hindgut region to inhibit the fish pathogens A. salmonicida, Vibrio salmonicida and Vibrio anguillarum differed between rearing groups.  相似文献   

Growth of Atlantic salmon (Salmo salar L.) in a variable diel temperature regime     

Ole Kristian Berg  Bengt Finstad  Gjert Grande  Einar Wathne 《Aquaculture (Amsterdam, Netherlands)》1990,90(3-4)

In five experiments, Atlantic salmon (Salmo salar L.) parr were found to grow better under conditions of rhythmically alternating water temperature (P<0.031), than control groups reared under stable temperature conditions. The daily temperature sums for the experimental and the control groups were carefully equalized and monitored in all five experiments. The experimental group was reared in a rhythmically alternating temperature regime, of 10.0 h of high temperature (16.0°C) and 10.0 h of low temperature (10.0°C), the temperature adjustments being made during the 2 h between the periods of fixed temperature. The control group were reared in a relatively stable temperature regime (13.00–13.98°C). The growth rate of the fish reared under the varying temperature conditions was higher (mean for all five experiments 1.96% day⁻¹) than that for the salmon reared under stable conditions (1.85% day⁻¹).  相似文献   

State-Space Estimation of the Intrinsic Soil Phosphorus Pools from the Mehlich-3 Test     

Xiufu Shuai  Russell S. Yost  Ole Wendroth 《Communications in Soil Science and Plant Analysis》2016,47(8):1058-1068

Widely popular Mehlich-3 phosphorus (P) was not used in the estimation of the intrinsic status of soil P. The objectives of this study were to develop the state-space model to determine the intrinsic soil P pools, a weakly adsorbed P pool, and a tightly adsorbed P pool, from the Mehlich-3 P. A linear relationship between Mehlich-3 P and the intrinsic soil P pools was derived from theoretical analysis of the extraction process of adsorbed P as competitive exchange by aqueous fluoride. Adsorption experiments of soil P were carried out to determine the dynamics of Mehlich-3 P after fertilizer phosphate was applied to soils. The results showed that state-space models of the two soil P pools could describe the dynamics of soil Mehlich-3 P in P adsorption experiments. Mehlich-3 P was a fraction of the weakly adsorbed P, and this fraction showed a linear relationship with soil P-sorption site density.  相似文献   

A quick and sensitive method for the quantification of peroxidase activity of organic surface soil from forests     

Anders R. Johnsen  Ole S. Jacobsen 《Soil biology & biochemistry》2008,40(3):814-821

The purpose of the present study was to test the non-mutagenic compound 3,3′,5,5′-tetramethylbenzidine (TMB) as a model substrate for peroxidase in forest topsoil, as an alternative to the conventional substrate l-3,4-dihydroxyphenylalanine (l-DOPA). TMB was highly sensitive; linear absorbance changes of 0.6 were achieved within 20 min for 1000-fold diluted soil. Brief heating (denaturation) of the soil suspension gave a 34-fold reduction of TMB oxidation, indicating that the reaction measured by TMB was indeed an enzymatic reaction. TMB oxidation showed a narrow peak at pH 4.4. A proportional decrease in peroxidase activity, when the soil suspension was diluted, demonstrated that TMB estimates of peroxidase activity are directly comparable when corrected for differences in sample size. Oxidation of TMB was slow in the absence of H₂O₂ suggesting that TMB is a poor substrate for phenol oxidases. TMB oxidation was tested in nine different forest topsoils. The peroxidase activity, when normalised to the amount of soil organic matter, ranged from 1.4±0.1 Δabs₄₅₀ h^?1 mg^?1 to 34.9±4.3 Δabs₄₅₀ h^?1 mg^?1. In comparison, l-DOPA oxidation by soil peroxidases and commercial peroxidases gave inconsistent results, suggesting that one should be cautious when using l-DOPA as a soil peroxidase substrate. The high sensitivity of TMB, compared to l-DOPA, and the low interference from phenol oxidase and humic substances suggest that TMB is a better substrate than l-DOPA for estimation of peroxidase activity of forest topsoil.  相似文献   

The impact of perennial cormorant colonies on soil phosphorus status     

Henrik Breuning-Madsen  Ole K. Borggaard 《Geoderma》2008,148(1):51-54

During the last decades, the population of cormorants in Northern Europe has grown rapidly due to protection. Their impact on vegetation has been recognized, as many trees containing cormorant colonies have collapsed, but their influence on the soil phosphorus (P) status and related ecological impacts have not been studied in details.In this study, total and plant available P (P_Total, P_Olsen) together with phosphate adsorption capacity and saturation (PAC, P_Sat) were measured in the soil at a reference area (control) and below two cormorant sub-colonies that differed in age and bird dropping density (indicated by number of used nests). One colony with totally 831 nests was 24 years old (Cormorant₂₄), while the age of the other colony with totally 181 nests was 12 years (Cormorant₁₂). Analyses of soil samples collected in four layers down to 80 cm showed strong decreases in P_Total and P_Olsen in the order: Cormorant₂₄ >> Cormorant₁₂ >> control and severe leaching of P into the subsoil below 80 cm at Cormorant₂₄ but not at Cormorant₁₂. Accordingly, in all four Cormorant₂₄ soil layers and in the upper three Cormorant₁₂ layers, P_Sat exceeded 0.25, which is considered the limit between retaining and leaking soils; P_Sat = P_Ox/PAC and PAC = 0.5 × (Al_Ox + Fe_Ox), i.e. half the sum of oxalate-extractable aluminium and iron. The importance of P_Olsen and P_Sat as indicators for P leaching was demonstrated as well as the strong impact that cormorants can have on the soil P status. This, in turn, will not only affect the ecosystem balance below the colonies but probably also threaten the water quality in nearby open waters as cormorant colonies are normally located on small lake islands or close to shallow bays.  相似文献   

Ruminal metabolism of DNOC and DNBP   总被引：1，自引：0，他引：1  

Arne Frslie  Ole Karlog 《Acta veterinaria Scandinavica》1970,11(1):114-132

The metabolism of DNOG and DNBP in rumen fluid was examined in vitro after elaboration of analytical methods for quantitative determination of dinitrophenols, their 6-amino derivative and diamino-phenols. It was shown that, under anaerobic conditions, the dinitrophenols were rapidly converted into 6-amino derivatives, which successively were reduced to diamino compounds. Reduction did not take place in heat-sterilized rumen specimens, and the metabolism was inhibited by high initial concentrations of the dinitro compounds in the rumen fluid (1—4 × 10⁻³M).In vivo experiments were performed for determination of the concentrations of the dinitrophenols and their metabolites in rumen fluid and blood plasma in a cow. Ruminai metabolism was rapid like in vitro, and the parent compounds were reduced in 10—30 min. The 6-amino derivatives persisted in the rumen fluid for 1 nr., and thereafter only diaminophenols could be detected for another 8—10 hrs. At least 95 % of the absorbed DNOG or DNBP were bound to plasma proteins. 6-amino-4-nitro-o-cresol w^τas found in plasma exclusively in conjugated form, while 6-amino-4-nitro-sec.-butylphenol was free. The diamino compounds were not demonstrated in blood plasma.Severe methaemoglobinaemia and haemolysis were seen after administration of DNBP. The difference in toxicity for ruminants between the two dinitrophenols is discussed on the basis of the observations reported pointing at the unconjugated 6-amino-4-nitro-sec-butylphenol as a potent inducer of methaemoglobinaemia.  相似文献   

Comparison of nociceptive withdrawal reflexes and recruitment curves between the forelimbs and hind limbs in conscious horses     

Spadavecchia C  Arendt-Nielsen L  Andersen OK  Spadavecchia L  Doherr M  Schatzmann U 《American journal of veterinary research》2003,64(6):700-707

OBJECTIVE: To compare nociceptive withdrawal reflexes (NWRs) evoked from the distal aspect of the left forelimb and hind limb in conscious standing horses and to investigate NWR recruitment for graded electrical stimulation intensities. ANIMALS: 20 adult horses. PROCEDURE: Surface electromyographic (EMG) activity evoked by transcutaneous electrical stimulation of the digital palmar (or plantar) nerve was recorded from the common digital extensor and cranial tibial muscles. Stimuli consisted of 25-millisecond train-of-5 constant current pulses. Current intensity was gradually increased until NWR threshold intensity was reached. The EMG signal was analyzed for quantification of the NWR. Behavioral responses accompanying the reflex were scored (scale, 0 to 5). The NWR recruitment curves were determined at 0.9, 1.1, 1.2, and 1.3 times the NWR threshold intensity. RESULTS: The NWR threshold was significantly higher for the hind limb (median value, 6.6 mA; range, 3 to 10 mA) than the forelimb (median, 3 mA; range, 1.7 to 5.5 mA). The NWR of the hind limb had a significantly longer latency (median, 122.8 milliseconds; range, 106 to 172 milliseconds), compared with the forelimb (median, 98 milliseconds; range, 86 to 137 milliseconds), and it was associated with significantly stronger behavioral reactions. Gradual increase of NWR amplitude was evident at increasing stimulation intensities and supported by the behavioral observations. CONCLUSIONS AND CLINICAL RELEVANCE: We documented NWRs evoked from the forelimb and hind limb and their recruitment with stimuli of increasing intensity in horses. These results provide a basis for use of NWRs in studies on nociceptive modulation in horses.  相似文献   

The agreement in isolation of Salmonella enterica IIIb 61:k:1,5,(7) from rectal swabs,faecal samples and ileo-caecal lymph nodes from sheep     

Sandberg M  Alvseike O  Nesbakken T  Skjerve E 《Preventive veterinary medicine》2003,60(2):167-174

The agreements between various culturing-method combinations and specimens to detect sheep naturally infected by Salmonella enterica IIIb 61:k:1,5,(7) were tested. Rectal swabs, faecal samples and ileo-caecal lymph nodes were collected from each individual. Rectal swabs called "group I" (n = 54) were cultured directly on selective media (selenite cysteine, SC). Rectal swabs called "group II" (n = 47) were pre-incubated in buffered peptone water. The four other combinations of culturing-method and specimen (one lymph node and three faecal) in each of the two groups were cultured directly on SC. The results from all the combinations of method and specimens were compared to the result from the rectal-swab test by kappa and McNemar's chi-square. Kappas for the agreement between rectal swabs and faecal sample tests were only 0.4. The lymph-node test agreed even-more poorly, with mean kappa value -0.02. The McNemar's test revealed that the discordancies between the rectal-swab test and all of the other tests went in both directions but sometimes did show bias (directionality) in the discordancies.  相似文献   

A Method for Collection of Bile in the Conscious Sheep     

Nils E. Sli  Reidar Birkeland 《Acta veterinaria Scandinavica》1977,18(2):221

A method to collect bile directly from the hepatic duct is described for use in the sheep. The technique is a combination of the intestinal re-entrant cannulae and a catheter from the duodenal lumen to the hepatic duct. The cystic duct is ligated near its junction with the common bile duct. The catheter is fixed in the proximal visible end of the hepatic duct. One plastic cannula is fixed to the duodenum opposite to the opening of the common bile duct and the other is fixed in the same way about 15 cm posterior to the first one. The two plastic cannulae fixed together with a plastic tube serve as an extra-abdominal anastomosis. During the collection periods the bile duct catheter is passed through an opening in the wall of the connection tube into a collection bag that is fixed to the plastic cannulae. Between the collection periods the catheter ends in the lumen of the anastomosis.  相似文献   

Quantitative assessment of nociception in horses by use of the nociceptive withdrawal reflex evoked by transcutaneous electrical stimulation     

Spadavecchia C  Spadavecchia L  Andersen OK  Arendt-Nielsen L  Leandri M  Schatzmann U 《American journal of veterinary research》2002,63(11):1551-1556

OBJECTIVES: To evoke and measure the nociceptive withdrawal reflex (NWR) by use of electromyographic recordings and to score the behavioral nociceptive responses to electrical pulses in standing nonsedated horses. ANIMALS: 10 adult horses. PROCEDURE: The lateral palmar digital nerve of the forelimb was transcutaneously stimulated, and surface electromyographic responses were recorded from the ulnaris lateralis, extensor carpi radialis, and common digital extensor muscles. Stimuli consisted of a 25-millisecond train of 5 constant-current pulses delivered by a computer-controlled stimulator. The 80- to 250-milliseconds poststimulation interval was analyzed to detect the NWR. The current intensity was increased in steps of 0.5 mA until the NWR threshold intensity (lt) was reached. The stimulus at It was repeated twice. Latency and amplitude of the NWR, together with the behavioral reaction of horses, were analyzed. The latter was scored according to a scale from 0 (no reaction) to 5 (vigorous reaction). Finally, 3 suprathreshold stimuli at 1.2 X It were analyzed. RESULTS: The median It to elicit NWR was 2.5 mA. Median onset latency of the NWR was 96.0 milliseconds at It and 89.6 milliseconds for suprathreshold stimuli. The amplitude of the reflexes was higher for suprathreshold stimulations, and behavioral reactions were slightly stronger when stimulus intensity increased. CONCLUSIONS AND CLINICAL RELEVANCE: Results of our study indicate that it is possible to record NWR in conscious standing horses, to define a reflex threshold, and to measure reflexes in response to increasing stimulus intensity.  相似文献