Quality of raw and smoked fillets from clinically healthy Atlantic salmon,Salmo salar L., following an outbreak of pancreas disease (PD)

Pancreas disease (PD) is a viral disease of farmed salmonid fish, which causes huge economic losses. Pathological changes in skeletal muscle, pancreas and heart are hallmarks of PD. Stakeholders in the fish‐smoking industry have claimed that fillets from PD‐affected Atlantic salmon, Salmo salar L., are of poor quality. We therefore examined harvest‐ready, clinically healthy Atlantic salmon from a population of fish previously affected by PD. Histopathological changes in skeletal muscle tissues ranged from minor to severe. Fillet quality measurements showed that fish with severe skeletal muscle changes provided a paler raw fillet and a yellowish and harder cold‐smoked fillet than normal. PD had no significant effect on fillet gaping, bacteriological quality or off‐odour development during storage. An unexpected finding was a significant subendocardial fibrosis in 23% of the PD‐affected fish. The latter may indicate susceptibility to stress‐related heart failure.     

Coral reef growth in the galapagos: limitation by sea urchins

The regular echinoid Eucidaris thouarsii is a conspicuous omnivore on coral bottoms in the Galápagos. Unlike Eucidaris in Panama and mainland Ecuador, Galápagos Eucidaris are large and abundant and graze heavily in the open on live corals day and night. These differences are probably due in large part to more intense predation by fishes on mainland compared with island urchin populations. An assessment of coral growth versus coral attrition from grazing shows that Eucidaris interferes with the establishment of pocilloporid reef frame and therefore reduces reef growth in the Galápagos.     

Effects of Additives and Packaging Method on Quality and Microbiological Characteristics in Mild Thermal Processed Fish Mince

The effect of adding 2% sodium lactate (NaL) premix to mild thermal processed fish mince, and the effect of packaging the product in vacuum, modified atmosphere (MA), or pretreated with soluble gas stabilization (SGS) prior to MA packaging were investigated. Adding 2% NaL premix significantly affected the color, and the bacterial load was significantly decreased compared to the control product, together with significant differences in the sensory score. Breaking force, firmness, stiffness, and gel strength were significantly increased by adding NaL, while no effect was found on head space gas composition, top web deflation, and pH. SGS significantly decreased the microbial load, but had no interaction effect with NaL. SGS significantly increased the amount of CO₂ in the head space gas, together with decreased top web deflation compared to modified packaging. Vacuum packaging significantly increased the breaking point, firmness, and stiffness and increased pH compared to MA and SGS. Addition of a NaL premix to minced fish products can be used successfully to increase shelf life without compromising other quality characteristics. SGS treatment before packaging in MA can successfully be used as an alternative to adding NaL with respect to microbiological product quality and without compromising other quality characteristics.     

Quantifying suitable late summer brood habitats for willow ptarmigan in Norway

Background

Habitat models provide information about which habitat management should target to avoid species extinctions or range contractions. The willow ptarmigan inhabits alpine- and arctic tundra habitats in the northern hemisphere and is listed as near threatened (NT) in the Norwegian red list due to declining population size. Habitat alteration is one of several factors affecting willow ptarmigan populations, but there is a lack of studies quantifying and describing habitat selection in willow ptarmigan. We used data from an extensive line transect survey program from 2014 to 2017 to develop resource selection functions (RSF) for willow ptarmigan in Norway. The selection coefficients for the RSF were estimated using a mixed-effects logistic regression model fitted with random intercepts for each area. We predicted relative probability of selection across Norway and quantile-binned the predictions in 10 RSF bins ranging from low-(1) to high-(10) relative probability of selection.

Results

Random cross-validation suggest that our models were highly predictive, but validation based spatial blocking revealed that the predictability was better in southern parts of Norway compared to the northernmost region. Willow ptarmigan selected for herb-rich meadows and avoided lichen rich heathlands. There was generally stronger selection for vegetation types with dense field layer and for rich bogs and avoidance of vegetation types with sparse field layer cover and for lowland forest. Further, willow ptarmigan selected for areas around the timberline and for intermediate slopes. Mapping of the RSF showed that 60% of Norway is in the lowest ranked RSF bin and only 2% in the highest ranked RSF bin.

Conclusions

Willow ptarmigan selected for vegetation types with dense field layer and bogs at intermediate slopes around the timberline. Selection coincides with previous habitat selection studies on willow ptarmigan. This is the first attempt to assess and quantify habitat selection for willow ptarmigan at a large scale using data from line transect distance sampling surveys. Spatial variation in predictability suggests that habitat selection in late summer might vary from north to south. The resource selection map can be a useful tool when planning harvest quotas and habitat interventions in alpine areas.

     

Virulence of environmental Stenotrophomonas maltophilia serologically cross-reacting with Shigella-specific antisera

This research involved an environmental strain of Stenotrophomonas maltophilia which has been reported to produce serological cross-reactivity with Shigella dysenteriae type 8 specific antisera. Since clinical diagnosis of shigellosis is largely based on culture and serology, the investigation was aimed at in vivo and in vitro virulence comparison between the culturally similar environmental S. maltophilia isolate and the reference S. dysenteriae strains. The findings of this study revealed the absence of virulent genes of Shigella sp. like ipaH, virA and stx1 and characteristic invasive large plasmid in the test isolate. The Western blot analysis revealed that serological cross-reactivity of Stenotrophomonas maltophilia was due to certain protein component(s) in its outer membrane. The isolate was capable of producing extracellular protease, exhibited alpha hemolysis and was negative for hemagglutinating assay. The isolate gave negative reaction with rabbit ileal loop and Sereny tests. The S. maltophilia isolate did not possess any enterotoxic or invasive property as that of virulent S. dysenteriae strains. Further characterizations and adequate genetic manipulations of this environmental isolate may contribute to the development of a potential vaccine candidate for shigellosis.     

The Effect of K-Lactate Salt and Liquid Smoke on Bacterial Growth in a Model System

The effects of a commercial lactate salt formulation—containing potassium lactate (KL) and potassium acetate (KA)—and liquid smoke (LS) on the growth of selected lactic acid bacteria (LAB; Carnobacterium maltaromaticum, Carnobacterium inhibens, Lactococcus lactis, Lactobacillus curvatus, and Enterococcus faecalis), fish spoilage bacteria (Photobacterium phosphoreum, Pseudomonas putida, and Vibrio vulnificus), and Listeria innocua, were examined in a tryptic soy broth model system at 20ºC based on BioScreen data. The most pronounced inhibition effect on growth of bacteria was seen in the presence of 6% KL + 0.4% KA, used either combined with LS or alone. Only a minor inhibition effect on growth was found in the presence of LS alone. The only exception was Lactobacillus curvatus, which grew quite well in the presence of LS compared to control medium. The growth of Vibrio vulnificus was prevented in 6% KL + 0.4% KA, and significantly inhibited in the presence of 3% KL + 0.2% KA. When V. vulnificus was grown in NaCl, KA, and KL + KA, it was observed that KL + KA had a better inhibition effect than sodium salt within the same concentration range.     

Holocene soil chronofunctions,Southern Alps,New Zealand

Field and laboratory data for two soil chronosequences from the high country of the South Island of New Zealand suggest rapid soil formation rates. The areas studied are the Ben Ohau Range and the Mt. Cook area, where mean annual precipitation is about 1 and 4 m, respectively. Most soil ages are estimated from the thicknesses of rock weathering rinds. Soil chronofunctions are derived for indices that depict field profile and color development, and a modified index of profile anisotropy for laboratory data. Out of a possible 21 chronofunctions, 16 are statistically significant (at the 0.05 level) and 8 are from each area. Most (13) of the chronofunctions best fit a power model, and the remaining ones are split between linear (2) and exponential (1) models. Although problems exist in the purity of the chronosequences because other soil-forming factors are not constant, duration of pedogenesis seems to be the most significant factor in explaining the trends. Despite the large differences in mean annual precipitation between the two areas, many of the derived curves for property vs. time are quite similar.     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.