Lipid degradation of cod liver during frozen storage was studied, where the effects of storage temperatures (−18 / −24 ° C), packaging methods (vacuum packing / regular plastic bag and waxed cardboard box), and seasonal variations (March / June / September) were evaluated. For this, the formations of free fatty acids (FFA) and peroxide value (PV) were analyzed. Lipid degradation within different parts of the liver (middle / surface) was also investigated. Increase in FFA and PV was observed for most of the samples throughout the frozen storage period. Vacuum packaging and lower storage temperature had a significantly stronger preservative effect on lipid degradation in all seasons. Higher FFA content was observed in cod liver captured in June than in its counterparts from September and March. More intense increase in PV was observed for liver collected in June compared to September. Furthermore, significant difference in PV was observed in different layers of the liver while FFA showed minimum variation between the surface and the middle part of the cod liver. Based on the present results, packaging method and storage temperature have a significant effect on lipid hydrolysis and oxidation in frozen cod liver.
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A dietary study was conducted to investigate the effect of partly substituted levels of fish meal in feed for juvenile (140-500 g) turbot (Scophthalmus maximus Rafinesque) on growth performance. The experimental diets were formulated to contain 53, 73 and 93 % fish meal protein and different levels of plant protein substitutes (wheat meal, corn gluten meal, soybean meal and canola meal) with three replicates for each diet. Fish fed 53% fish meal diets had lower final mean weights compared to fish fed the 93% fish meal diet, whereas the 73% fish meal group displayed intermediate values. However, only minor differences were found in specific growth rate, feed conversion ratio, daily feed intake and total feed consumption between dietary treatment groups. Overall the findings demonstrate that substitution of fish meal by plant protein raw materials down to 53 % fish meal protein (44% replacement) does not affect overall specific growth rate, feed conversion ratio or feed intake in juvenile turbot (<500 g). © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey.
A screening of a broad range of pharmaceuticals and additives in personal care products (PPCPs) in sub-arctic locations of the Faroe Islands (FO), Iceland (IS) and Greenland (GL) was conducted. In total 36 pharmaceuticals including some metabolites, and seven additives in personal care products were investigated in influent and effluent waters as well as sludge of waste water treatment plants (WWTPs) and in water and sediment of recipients. Concentrations and distribution patterns for PPCPs discharged via sewage lines (SLs) to the marine environment were assessed. Of the 36 pharmaceuticals or metabolites analyzed 33 were found close to or above the limit of detection (LOD) in all or a part of the samples. All of the seven investigated additives in personal care products were detected above the LOD. Some of the analyzed PPCPs occurred in every or almost every sample. Among these were diclofenac, ibuprofen, lidocaine, naproxen, metformin, citalopram, venlafaxine, amiloride, furosemide, metoprolol, sodium dodecyl sulphate (SDS) and cetrimonium salt (ATAC-C16). Additionally, the study encompasses ecotoxicological risk assessment of 2/3 of the analyzed PPCPs in recipient and diluted effluent waters. For candesartan only a small margin to levels with unacceptable risks was observed in diluted effluent waters at two locations (FO). Chronic risks for aquatic organisms staying and / or living around WWTP effluent pipe-outlets were indicated for 17β-estradiol and estriol in the three countries. Additives in PCPs were found to pose the greatest risk to the aquatic environment. The surfactants CAPB and ATAC-C16 were found in concentrations resulting in risk factors up to 375 for CAPB and 165 for ATAC-C16 in recipients for diluted effluents from Iggia, Nuuk (GL) and Torshavn (FO) respectively. These results demonstrate a potentially high ecological risk stemming from discharge of surfactants as used in household and industrial detergents as well as additives in personal care products.
Prochlorococcus and Synechococcus are the two most abundant and widespread phytoplankton in the global ocean. To better understand the factors controlling their biogeography, a reference database of the high-resolution taxonomic marker petB, encoding cytochrome b6, was used to recruit reads out of 109 metagenomes from the Tara Oceans expedition. An unsuspected novel genetic diversity was unveiled within both genera, even for the most abundant and well-characterized clades, and 136 divergent petB sequences were successfully assembled from metagenomic reads, significantly enriching the reference database. We then defined Ecologically Significant Taxonomic Units (ESTUs) —that is, organisms belonging to the same clade and occupying a common oceanic niche. Three major ESTU assemblages were identified along the cruise transect for Prochlorococcus and eight for Synechococcus. Although Prochlorococcus HLIIIA and HLIVA ESTUs codominated in iron-depleted areas of the Pacific Ocean, CRD1 and the yet-to-be cultured EnvB were the prevalent Synechococcus clades in this area, with three different CRD1 and EnvB ESTUs occupying distinct ecological niches with regard to iron availability and temperature. Sharp community shifts were also observed over short geographic distances — for example, around the Marquesas Islands or between southern Indian and Atlantic Oceans — pointing to a tight correlation between ESTU assemblages and specific physico-chemical parameters. Together, this study demonstrates that there is a previously overlooked, ecologically meaningful, fine-scale diversity within some currently defined picocyanobacterial ecotypes, bringing novel insights into the ecology, diversity, and biology of the two most abundant phototrophs on Earth.
A total diet study (TDS) is a public health tool for determining population dietary exposure to chemicals across the entire diet. TDSs have been performed in several countries but the comparability of data produced is limited. Harmonization of the TDS methodology is therefore desirable and the development of comparable TDS food lists is considered essential to achieve the consistency between countries. The aim of this study is to develop and test the feasibility of a method for establishing harmonized TDS food and sample lists in five European countries with different consumption patterns (Czech Republic, Finland, Germany, Iceland and Portugal). The food lists were intended to be applicable for exposure assessment of wide range of chemical substances in adults (18–64 years) and the elderly (65–74 years). Food consumption data from recent dietary surveys measured on individuals served as the basis for this work. Since the national data from these five countries were not comparable, all foods were linked to the EFSA FoodEx2 classification and description system. The selection of foods for TDS was based on the weight of food consumed and was carried out separately for each FoodEx2 level 1 food group. Individual food approach was respected as much as possible when the TDS samples were defined. TDS food lists developed with this approach represented 94.7–98.7% of the national total diet weights. The overall number of TDS samples varied from 128 in Finland to 246 in Germany. The suggested method was successfully implemented in all five countries. Mapping of data to the EFSA FoodEx2 coding system was recognized as a crucial step in harmonization of the developed TDS food lists.
Recently, we have shown that glycoside hydrolases enzymes of family GH17 from proteobacteria (genera Pseudomonas, Azotobacter) catalyze elongation transfer reactions with laminari-oligosaccharides generating (β1 → 3) linkages preferably and to a lesser extent (β1 → 6) or (β1 → 4) linkages. In the present study, the cloning and characterization of the gene encoding the structurally very similar GH17 domain of the NdvB enzyme from Bradyrhizobium diazoefficiens, designated Glt20, as well as its catalytic properties are described. The Glt20 enzyme was strikingly different from the previously investigated bacterial GH17 enzymes, both regarding substrate specificity and product formation. The Azotobacter and Pseudomonas enzymes cleaved the donor laminari oligosaccharide substrates three or four moieties from the non-reducing end, generating linear oligosaccharides. In contrast, the Glt20 enzyme cleaved donor laminari-oligosaccharide substrates two glucose moieties from the reducing end, releasing laminaribiose and transferring the remainder to laminari-oligosaccharide acceptor substrates creating only (β1 → 3) (β1 → 6) branching points. This enables Glt20 to transfer larger oligosaccharide chains than the other type of bacterial enzymes previously described, and helps explain the biologically significant formation of cyclic β-glucans in B. diazoefficiency.
In land-based fish farms, water quality can be controlled to support maximum growth and good feed conversion. Oxygen is an important water quality parameter in aquaculture and the objective of this study was to detect the range of oxygen saturations that maximizes juvenile growth Atlantic cod. The fish (initial body mass 21.9 g) were reared at five different levels of oxygen saturation: 65%, 81%, 103%, 121% and 150% of air saturation, for 98 days. At oxygen saturation under 100%, the growth of the fish decreased linearly with progressively lower oxygen saturation with the final body mass of fish reared at 65% saturation being 24% lower than that of fish reared at 103% saturation. The final body mass of fish reared at 150% saturation was significantly higher (7%) than that of fish reared at 103% saturation. Feed intake was also affected by oxygen saturation and was proportional to growth while the feed conversion ratio was not significantly affected by oxygen levels. The results suggest that oxygen saturation of at least 100% is required to obtain maximum growth of juvenile Atlantic cod.
In this study, a changepoint model, which can detect either a mean shift or a trend change when accounting for autocorrelation in short time-series, was investigated with simulations and a new method is proposed. The changepoint hypotheses were tested using a likelihood ratio test. The test statistic does not follow a known distribution and depends on the length of the time-series and the autocorrelation. The results imply that it is not possible to detect autocorrelation and that the estimate of the autocorrelation parameter is biased. It is therefore recommended to use critical values from the empirical distribution for a fixed autocorrelation.
Atlantic sea cucumber (Cucumaria frondosa) is a marine invertebrate that occurs naturally in the North Atlantic. Its collagen rich body walls make the sea cucumber an appreciated food source in many countries. The heteroglycans derived from the cartilage of Atlantic sea cucumbers have shown potential as a source of bioactive compounds, but further investigation is needed to confirm this hypothesis. The objectives of this work were to test the immunomodulating properties of heteroglycan fractions (FCFs) derived from Atlantic sea cucumbers toward phorbol 12-myristate 13-acetate (PMA) differentiated THP-1 macrophages. Oxygen Radical Absorbance Capacity (ORAC) was determined and cell culture media was collected and analyzed for the presence of pro-inflammatory and anti-inflammatory cytokines (TNF-α, IL-6, and IL-10). FCFs toxicity toward macrophages was evaluated by light microscopy and confirmed by XTT proliferation assay. Heteroglycans derived from cartilage of Atlantic sea cucumber showed immunomodulatory activity in THP-1 macrophages. FCF-1, −2, and - 3) at concentrations 0.1–100 µg / mL induced levels of TNF-α, IL-6, and IL-10 proofing their bioactivity towards THP-1 macrophages. However, fractions of FCF-1 and FCF-2 may have induced oxidative stress in the macrophages, which possibly could lead to decreased cellular viability.
This study utilized Life Cycle Assessment (LCA) to quantify the environmental impacts of 1 kg of live-weight Arctic char, cultivated in an Icelandic land-based aquaculture farm. The functional unit included assessments of three different feed types; standard feed with high inclusion levels of marine ingredients (Conv.), experimental feed with high inclusion levels of agricultural ingredients (ECO) and a hypothetical Black soldier fly larvae based feed (BSF). Results of the study indicated that the feed production causes the greatest environmental impacts from all feed types considered. The Black soldier fly based feed demonstrated the best environmental performance of the three feed types. Furthermore, it can be concluded that by increasing agriculture based ingredients at the cost of marine based ingredients, a better environmental performance can be reached. This study demonstrated the importance of feed production for aquaculture in terms of environmental impacts and showed that byoptimizing feed consumption, reducing the amount of fishmeal and fish oil and even creating new types of feed from novel ingredients, the overall impacts of aquaculture can be greatly reduced .