This article documents the addition of 228 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Anser cygnoides, Apodemus flavicollis, Athene noctua, Cercis canadensis, Glis glis, Gubernatrix cristata, Haliotis tuberculata, Helianthus maximiliani, Laricobius nigrinus, Laricobius rubidus, Neoheligmonella granjoni, Nephrops norvegicuica, claenan, Oen and Samanea saman. These loci were cross-tested on the following species: Apodemus sylvaticus, Laricobius laticollis and Laricobius osakensis (a proposed new species currently being described).
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Using multiple biological markers to establish the fingerprint of a harvest location, individual cod Gadus morhua L. can be classified to their population of origin without error. A combined approach to classification using otolith microchemistry, otolith shape analysis, body morphometry, microbacterial assemblages, internal and external parasites, and microsatellite DNA was found to be more powerful than by any single technique. Binomial and multinomial logistic regression analyzes were used to distinguish wild from farmed fish and subsequently to determine the precise harvest origin of each individual. Two new approaches were used: one focusing on optimal or key variables from each discipline and the other using probability values derived on a technique-by-technique basis. Cod from widely separated origins were classified with high (up to 100% correct) placement success. Focusing on the placement of individual fish, this study represents a decisive advance toward identifying fish harvested from protected populations.
Throughout their range, Sebastes spp. are adapted to a diversity of ecological niches, with overlapping spatial distributions of different species that have little or no morphological differences. Divergence of behavioral groups into depth-defined adult habitats has led to reproductive isolation, adaptive radiation, and speciation in the genus Sebastes. Recent genetic research, supported by life-history information, indicates four biological stocks of Sebastes mentella in the Irminger Sea and adjacent waters: a western stock, a deep-pelagic stock, a shallow-pelagic stock, and an Iceland slope stock. Congruent differences in fatty acids and parasites suggest that these genetically distinct populations are adapted to disparate trophic habitats in pelagic waters (shallower and deeper than the deep-scattering layer) and in demersal habitats on the continental slope. Morphology of pelagic forms is also more streamlined than demersal forms. Although genetic differences and evidence for reproductive isolation are clear, these populations appear to share common nursery habitats on the Greenland shelf. We propose a redefinition of practical management units near the Irminger Sea based on geographic proxies for biological stocks and minimizing mixed-stock catches according to the spatial patterns of the recent fishery.
Juvenile Atlantic halibut (40.5 ± 9.1 g mean initial body mass ± SD) were reared at five different levels of oxygen availability (57%, 84%, 100%, 120%, and 150% of air saturation) for 94 days. The availability of oxygen significantly affected the growth rate of the fish while feed conversion was not significantly different. The final size of fish reared at 57% of air saturation was significantly lower than in groups reared at 100% to 150% of air saturation and the specific growth rate (SGR) in the 57% group over the 94 day period was significantly lower than in all other groups . The increase in biomass was 45% higher in the group exposed to 100% of oxygen saturation than in the group reared at 57% saturation. The group reared at 84% of air saturation was intermediate and the final size of this group was significantly different from fish reared at either 57% or 100% – 150% of air saturation. There was no significant difference in the growth trajectories of fish reared at 100% – 150% of air saturation but they were significantly different from those of fish reared at either 57% or 84% saturation. This suggests that the growth of halibut is progressively increased when the oxygen saturation is increased from 57% to 100% while further increase in oxygen saturation does not improve the growth rate. When oxygen saturation was increased, the blood pH increased as did the partial pressure of CO2, total concentration of CO2 and bicarbonate in blood. This change is likely a result of reduced ventilation rate with increased oxygen saturation. The results challenge the common recommendation that 60% – 80% oxygen saturation is adequate to support maximum growth of fish. The results of the present study suggest that there may be an advantage for halibut farmers to increase the oxygen availability from the recommended 60% – 80% oxygen saturation up to 100%.
An intervention study was conducted at the early juvenile stage of Atlantic cod (Gadus morhua L.) rearing to confirm the properties of two prospective probionts, Arthrobacter sp. and Enterococcus sp. isolated from a cod hatchery. Juveniles (10 g) were fed expanded dry feed for 28 or 55 days, either untreated or treated with the probiotic bacteria in mixture or singly (107–9 CFU g−1 feed). Viability of probionts supplemented to the feed was evaluated during a two-month storage at −20, 4 and 15 ° C and sensory evaluation of the probiotic feed performed at the end of storage. Juvenile growth, survival, feed conversion ratio, and microbial load of rearing water, juvenile gills and gut were examined. Microbiological stability of the probionts added to the feed was demonstrated at all temperatures, while sensory evaluation detected faint oxidative off-odors in feed stored frozen. Juveniles fed the Enterococcus-probiotic feed grew significantly faster and had significantly lower gut Vibrio counts than control juveniles (p <0.05). Overall, the results suggest that both probionts, especially the Enterococcus strain, modified the gut microbiota and contributed to enhanced juvenile growth and survival.
Proteome analysis was used to study the effects of feeding early Atlantic cod (Gadus morhua) larvae with a saithe (Pollachius virens) protein hydrolyzate (SPH). Protein hydrolysates have previously been shown to beneficially affect fish larval development. Feeding was initiated on day 2 post hatch (ph) or as soon as the larvae opened their mouth and the protein expression was monitored 4 days later or in 6-dph cod larvae. The results demonstrated changes in the abundance of 13 protein spots in the cod larvae fed SPH. Of these, seven protein spots were up-regulated and six protein spots showed down-regulation. Five of the up-regulated proteins in cod larvae are known to be involved in energy metabolism. A few early larval specific proteins were down-regulated in the SPH-fed cod larvae possibly because of an enhanced development in this group relative to the control group. Two trypsin isoforms were detected within the cod larval proteome. The detection of the trypsin spots was made possible by co-electrophoresis of known cod trypsins with the cod larval protein extract. Surprisingly, no difference in trypsin content was observed between the SPH-fed and the control larval groups.
Microbial communities in food and food production establishments have highly versatile structures based on various extrinsic factors. The information gained by large-scale microbial community analysis not only can deepen the understanding of food microbiology in general but also can lead to improvement of food production systems for increased quality and safety and extension of shelf life. This chapter reviews the most recent methods applied to microbial communities, and presents examples of some cutting-edge technologies. Molecular methods have been developing rapidly in recent years both for specific detection of single species and for screening assays that allow the species composition of a given food sample to be unraveled. Examples of those methods are 16S rRNA clone analysis, fingerprinting methods such as terminal restriction fragment length polymorphism (t-RFLP) and denaturing gradient gel electrophoresis (DGGE), tag-encoded pyrosequencing, single-nucleotide primer extension (SNuPE), and microarrays. Furthermore, flow cytometry is also addressed in the chapter, but this technique is based on single-cell analysis whereby a cell suspension is concentrated by nanofluidics and analyzed by laser technology. High-throughput analysis of microbial populations in food products and food processing environments has revealed the existence of a higher complexity in the microbial world than previously expected. The new approaches provide opportunities for further understanding of the microbial developments that are initiated during food production and storage.
Once considered exceptional rarities, extremophiles have become attractive objects for basic and applied research ranging from nanotechnology to biodiversity to the origins of life and even to the search for extraterrestrial life. Several novel aspects of extremophiles are covered in this book; the focus is firstly on unusual and less explored ecosystems such as marine hypersaline deeps, extreme cold, desert sands, and man-made clean rooms for spacecraft assembly. Secondly, the increasingly complex field of applications from extremophile research is treated and examples such as novel psychrophilic enzymes, compounds from halophiles, and detection strategies for potential extraterrestrial life forms are presented.
An analysis of the temporal trends for mercury in Arctic biota is
important for scientists and managers concerned with making
sound science-based policy with respect to changes in Hg in
the Arctic environment. Long-term datasets (ie, comparing
modern with historical or pre-industrial Hg concentrations)
can be used to estimate the relative importance of natural and
anthropogenic Hg inputs in modern biota and the environment,
while short-term datasets (ie, covering the past one to three
decades) illustrate how Hg concentrations have changed in
recent times and suggest likely trends in the near-term future.
In the previous AMAP assessment of Hg in the Arctic
environment (AMAP, 2005), evidence of increasing Hg
concentrations from pre-industrial or historical to more
recent times was presented for Arctic marine biota. Those
trends were shown to continue in recent (short-term) datasets,
primarily in higher-order marine biota from Canada and West
Greenland. In contrast, time series for lower-order marine biota
for Iceland and the European Arctic showed a general pattern
of recently stable or declining Hg concentrations. The reasons
for this spatial difference in trend patterns were not clear.
Data for higher-order marine biota from Europe and Iceland
were lacking as were temporal trend datasets for biota from
Russia and Finland. One of the recommendations resulting
from the previous AMAP assessment was that temporal trend
monitoring of Hg concentrations should be continued in order
to obtain longer and more statistically reliable trend analyzes.
This chapter presents an update of the information available
for both long-term and short-term trends, including a statistical
meta-analysis of recent temporal trends in Hg concentrations
in Arctic biota. The final section presents a discussion, using
case studies, of the possible mechanisms driving the temporal
trends observed.
The use of injection and brining as the first step in heavy salting of cod increases weight yields of the products through both salting and rehydration, compared to other pre-salting methods, like brining only and pickling. This is interesting since salt content of the muscle exceeds 20% NaCl, in all procedures. Therefore, the dissimilarities in yield were presumed to depend on the degree of protein denaturation and aggregation as influenced by the different salting procedures. This hypothesis was studied and confirmed with the aid of SDS – PAGE and DSC-analysis. Higher water retention of injected products was explained by stronger salting-in effects on proteins during pre-salting, reducing aggregation of muscle proteins during the dry salting step. The degree of protein aggregation during salting increased in the following order with regard to the different pre-salting methods: injection and brining <brining <pickling. These effects were still observed after rehydration. Furthermore, differences in denaturation / aggregation were assigned to both myosin and collagen.