Prevalence of Toxoplasma gondii antibodies in wild red deer, roe deer, moose, and reindeer from Norway

Serum samples from 4339 wild cervids collected in Norway were tested for antibodies against Toxoplasma gondii using the direct agglutination test. The association between seroprevalence and species, sex, age, and geographic region was investigated. Positive titers (> or =1:40) were found in 33.9% of 760 roe deer (Capreolus capreolus); 12.6% of 2142 moose (Alces alces); 7.7% of 571 red deer (Cervus elaphus); and 1.0% of 866 reindeer (Rangifer tarandus). The seroprevalences were significantly different between the species. There was a significant increase in prevalence with age in roe deer, moose, and red deer, except from yearling to adult in red deer. A significant age-sex interaction was found in moose, and the effect of age was most distinct for females. No association between seropositive animals and sex was found for roe deer and red deer. There were significant differences in prevalence between geographic regions in roe deer and male moose. A widespread exposure to T. gondii in Norwegian cervids is documented, and meat from Norwegian cervids, particularly roe deer, should be regarded a potential source of infection for humans.     

Predicted changes in streamwater chemistry following reduced/increased sulphur deposition using the “Birkenes model”

A sensitivity analysis of some important parameters in a mathematical model previously found to reproduce major short-term variations in water chemistry in some streams, has been carried out. The results are also relevant in a discussion of possible changes in stream acidity for changes in S deposition. In the simulations sulphate concentrations in streamwater were doubled or halved compared to present day values. Assuming no change in the lime potential of the soil, the peak acidity during snowmelt changed with up to 0.9 pH units; shifts from 0.4 to 0.5 units occurred in many cases. By simultaneously changing the sulphate stream concentration and the lime potential with 0.2 units shifts of about 1 pH unit were obtained in the simulations for some acidity peaks.     

Water distribution in brine salted cod (Gadus morhua) and salmon (Salmo salar): a low-field 1H NMR study

Low-field (LF) (1)H NMR T 2 relaxation measurements were used to study changes in water distribution in lean (Atlantic cod) and fatty (Atlantic salmon) fish during salting in 15% NaCl and 25% NaCl brines. The NMR data were treated by PCA, continuous distribution analysis, and biexponential fitting and compared with physicochemical data. Two main water pools were observed in unsalted fish, T 21, with relaxation times in the range 20-100 ms, and T 22, with relaxation times in the range 100-300 ms. Pronounced changes in T 2 relaxation data were observed during salting, revealing changes in the water properties. Salting in 15% brine lead to a shift toward longer relaxation times, reflecting increased water mobility, whereas, salting in saturated brines had the opposite effect. Water mobility changes were observed earlier in the salting process for cod compared to salmon. Good linear correlations ( F 相似文献   

Quality of Filleted Atlantic Mackerel (Scomber Scombrus) During Chilled and Frozen Storage: Changes in Lipids,Vitamin D,Proteins, and Small Metabolites,including Biogenic Amines

Quality changes of vacuum-packed Atlantic mackerel (Scomber scombrus) fillets during 12 months’ frozen storage at ?27°C and 9 days’ chilled storage at +4°C were evaluated. Freezing at ?27°C preserved the long chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs), both in light and dark muscle, vitamin D, and the low molecular weight metabolites (LMW) (studied by high resolution nuclear magnetic resonance spectroscopy, HR NMR). Protein oxidation took place, especially between 1 and 7 months, decreasing water holding capacity and protein extractability. During chilled storage, no lipid or protein oxidation was observed, but lipolysis increased, and several LMW metabolites relevant for sensory and nutritional quality degraded into non-favorable compounds. The content of biogenic amines was high at day 9 (e.g., 18 mg histamine/100 g), jeopardizing safety. Preservation of mackerel fillets by freezing at ?27°C is thus a better option compared to prolonged chilled storage at +4°C; the quality was well preserved for 12 months’ frozen storage.     

Rapid and non-invasive measurements of fat and pigment concentrations in live and slaughtered Atlantic salmon (Salmo salar L.)

The aim of this study was to non-invasively determine fat and pigment concentrations in salmon muscle based on visible and near infrared (VIS/NIR) spectroscopy measurements of live/whole fish and fillets, and by means of digital photography (DP) of fillets. The fish used were two populations of farmed Atlantic salmon (Salmo salar L.) consisting of 46 salmon averaging 0.7 kg (range 0.17–1.7 kg, Group S) and 30 salmon averaging 2.3 kg (range 1.4–4.1 kg, Group L). Chemical analyses (fat and pigment content) and computerized tomography, CT (fat content) were used as reference methods. Group L was analysed in the live state (VIS/NIR), after gutting (VIS/NIR and CT), and as fillets (VIS/NIR and DP). Group S was analysed in the gutted state (VIS/NIR) and as fillets (VIS/NIR and DP). VIS spectroscopy predictions of pigment in whole salmon from Group S were obtained with a root mean square error of prediction (RMSEP) of 0.9 mg kg^− 1 astaxanthin, and a correlation between VIS spectroscopy predicted and chemically measured pigment of r = 0.85 (p < 0.0001). The fat concentration was determined by the NIR spectroscopy in live fish with RMSEP = 1.0 fat% unit, and a correlation with chemical reference values of r = 0.94 (p < 0.0001). Fat predictions from NIR spectroscopy correlated also well with predictions from CT analyses, r = 0.95 (p < 0.0001). VIS spectroscopy and DP were equally well suited to determine pigment concentrations in salmon fillets, with prediction errors of only 0.4 mg kg^− 1 astaxanthin, and a correlation with chemically determined pigment of r = 0.92 (p < 0.0001). The results obtained in the present study are the first to demonstrate successful non-invasive pigment predictions in whole salmon using VIS/NIR spectroscopy, and the possibility for simultaneous, rapid and non-destructive quantification of fat and pigment concentrations.     

商品肉鸡和肉种鸡在过去30年中体重指标改变及影响

随着市场需求逐渐转向深加工家禽产品以及对新的高产品系的偏爱,家禽育种业得以不断改变.高效率,胸肌大的品系已经占有了北美大部分市场,并且在全球范围正逐步扩大市场份额.现代肉鸡生长效率不断提高,生长速度比1957年随机交配的品系快4.6倍.与使用1957年的饲料配方的同时代的品系相比,使用2001年的饲料配方的当代品系胴体产量的6倍的增长中80%～90%可归因于遗传学,只有10%～15%是由营养改变所造成的.     

Proteolytic activity in byproducts from cod species caught at three different fishing grounds

Proteolytic activity in byproducts from cod species caught at three different fishing grounds has been characterized and compared. The overall highest activity in the byproduct fractions was found in viscera at pH 3 (35 degrees C). Cut off and liver fractions also show maximum activity at pH 3, 35 and 50 degrees C, respectively. Proteolytic activity in viscera and cut off fractions are more affected by fishing ground than by species. Proteolytic activity at pH 3 in viscera is higher in samples from the south coast of Ireland, while viscera samples from the Icelandic Sea have the highest activity at pH 7. For cut off, the activity is higher in samples from the south coast of Ireland than the other two fishing grounds.     

Soil response to s and n treatments in a Northern New England low elevation coniferous forest

A field experiment was designed to evaluate the effects of differing forms of acidifying S and N compounds on the chemistry of soils and soil solutions in a low elevation coniferous forest in northern New England. Treatments consisted of O, 1500, 3000, and 6000 eq of SO₄ ^2? or NO₃ ^? ha^?1 for the 1987 growing season applied biweekly as H₂SO₄ or HNO₃, or in a single application as dry] (NH₄)₂SO₄. Acidifying treatments resulted in a significant increase in soil solution SO₄ ^2? (1.2 to 2.6) or NO₃ ^? (12 to 80) in the upper B horizon. Excess strong acid anion leaching was associated with an accelerated loss of base cations, particularly MG²⁺ As solutions passed through the upper 25 cm of the soil profile, mean SO₄ ^2? concentrations decreased by 5 to 50% of the initial values, indicating that much of the applied SO₄ ^2? was immobilized in the upper portion of the pedon. Elevated concentrations of adsorbed and water-soluble SO₄ ^2? indicate that abiotic adsorption of SO₄ ^2? by soils is the dominant mechanism for the initial attenuation of SO₄ ^2? concentrations in these solutions. Other soil properties showed only small or no change due to treatments over the single growing season of this study. These results indicate that H₂SO₄, HNO₃, and (NH₄)₂SO₄ can all effectively increase strong acid anion concentrations in the soil-soil solution system.     

Feed intake, growth and nutrient utilization in Atlantic halibut (Hippoglossus hippoglossus) fed diets containing a bacterial protein meal

Triplicate groups of Atlantic halibut were fed diets containing 0%, 9% or 18% of a bacterial protein meal (BPM) produced from natural gas in a 9‐week trial. Growth rates, relative feed intake, feed efficiency ratio and retention of all indispensable amino acids were significantly lower in fish fed the 18% BPM diets than in those fed the 0% and 9% BPM diets. There were no significant treatment effects on urea levels in plasma, liver or muscle, or in uric acid levels in plasma. The hepatosomatic index was lowest in fish fed the 18% BPM diet. Although the concentration of copper, an element abundant in BPM, increased in the liver as dietary BPM level increased, the total copper content in liver decreased. Fish fed the 0% and 9% BPM diets had a higher degree of supranuclear vacuolization of pyloric caeca and mid‐intestine epithelia compared with fish fed the 18% BPM diet. In conclusion, the halibut fed the 9% BPM diet performed equally well as the control group regarding growth, feed intake and feed efficiency ratio, whereas performance was reduced in the fish fed the 18% BPM diet.     

Contribution of Bleeding to Total Handling Stress During Slaughter of Atlantic Salmon

White muscle high-energy phosphate levels showed that the bleeding procedure applied during slaughter of Atlantic salmon (Salmo salar) did not overshadow the total pre-slaughter handling stress. The energy status of the muscle seemed to increase as a result of bleeding and the bleeding per se did not have adverse effects on flesh freshness resulting from excessive handling stress. The time for onset of rigor mortis and rigor strength were clearly related to the initial stress level and the rate of ATP depletion. The onset of rigor in stressed fish occurred about one day earlier compared with rested fish and the stressed fish also became stiffer.