Endogenous production of n-3 long-chain PUFA from first feeding and the influence of dietary linoleic acid and the α-linolenic:linoleic ratio in Atlantic salmon (Salmo salar)

Atlantic salmon (Salmo salar) possess enzymes required for the endogenous biosynthesis of n-3 long-chain polyunsaturated fatty acids (LC-PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), from a-linolenic acid (ALA). Linoleic acid (LA) competes with ALA for LC-PUFA biosynthesis enzymes leading to the production of n-6 LC-PUFA, including arachidonic acid (ARA). We aimed to quantify the endogenous production of EPA and DHA from ALA in salmon fed from first feeding on diets that contain no EPA and DHA, and to determine the influence of dietary LA and ALA:LA ratio on LC-PUFA production. Salmon were fed from first feeding for 22 weeks with three diets formulated with linseed and sunflower oils to provide ALA:LA ratios of approximately 3:1, 1:1 and 1:3. Endogenous production of n-3 LC-PUFA was 5.9, 4.4 and 2.8 mg per g fish and that of n-6 LC-PUFA was 0.2, 0.5 and 1.4 mg per g of fish in salmon fed diets with ALA:LA ratios of 3:1, 1:1 and 1:3, respectively. The ratio of n-3:n-6 LC-PUFA production decreased from 27.4 to 2.0, and DHA:EPA ratio increased and EPA:ARA and DHA:ARA ratios decreased, as dietary ALA:LA ratio decreased. In conclusion, with a dietary ALA:LA ratio of 1, salmon fry/parr produced around 28 μg n-3 LC-PUFA per g of fish per day, with a DHA:EPA ratio of 3.4. Production of n-3 LC-PUFA exceeded that of n-6 LC-PUFA by almost 9-fold. Reducing the dietary ALA:LA ratio reduced n-3 LC-PUFA production, and EPA:ARA and DHA:ARA ratios, and increased n-6 LC-PUFA production, and DHA:EPA ratio

Nutritional characterisation of European aquaculture processing by-products to facilitate strategic utilisation

Sustainability analyses of aquaculture typically ignore the fate and value of processing by-products. The aim of this study was to characterise the nutritional content of the common processing by-products (heads, frames, trimmings, skin and viscera) of five important finfish species farmed in Europe; Atlantic salmon (Salmo salar), European seabass (Dicentrarchus labrax), gilthead seabream (Sparus aurata), common carp (Cyprinus carpio) and turbot (Psetta maxima) to inform on best utilisation strategies. Our results indicate a substantially higher total flesh yield (64–77 %) can be achieved if fully processed, compared to fillet only (30–56 %). We found that heads, frames, trimmings and skin from Atlantic salmon, European seabass, gilthead seabream and turbot frames showed medium to high edible yields, medium to high lipid, and medium to high eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content, indicating significant potential for direct use in human food. By-products which are unattractive for use in food directly but have low ash content and medium to high crude protein, lipid and EPA and DHA content, such as viscera, could be directed to animal feed. Skin showed interesting nutritional values, but has more potential in non-food applications, such as the fashion, cosmetic and pharmaceutical industries. The results indicate potential to increase the direct food, animal feed and non-food value of European aquaculture, without an increase in production volumes or the use of additional resources. The importance of changing consumer perceptions and addressing infrastructure and legislative barriers to maximize utilisation is emphasised

Methylphenidate Treatment in Children with Borderline IQ and Mental Retardation: Analysis of Three Aggregated Studies

Objective: To determine response of low-IQ children with attention deficit hyperactivity disorder (ADHD) symptoms to methylphenidate (MPH). Methods: An aggregated analysis was conducted in 90 children with low IQ who received the same dose regimen of MPH in three independent, placebo-controlled studies. Active drug and placebo were given from 2 to 4 weeks each. Outcome measures included teacher and parent ratings on standardized behavior scales (mean n = 84), performance on computer-controlled cognitive-motor tests (n = 62), and measures of cardiovascular response (n = 85). Results: Both teachers and parents rated the children consistently as being improved on subscales assessing attention, overactivity, and conduct problems. Some 44% of the subjects showed at least a 30% reduction compared with placebo on teacher ratings. MPH improved accuracy on several cognitive tests, response speed was increased on some, and seat activity declined for one of three tests; heart rate was mildly increased (3.9 beats/minute) with MPH. Analyses of IQ and mental age as moderator variables suggested that lower functional level (especially lower IQ) may be associated with a less favorable response to MPH. Conclusions: Children with low IQ and ADHD clearly respond to MPH, but their rate of beneficial response appears to be well under that of normal-IQ children and more varied. Different attentional mechanisms may moderate response to psychostimulants

Variations in the Abundances of Potassium and Thorium on the Surface of Mercury: Results from the MESSENGER Gamma-Ray Spectrometer

A technique for converting gamma-ray count rates measured by the Gamma-Ray Spectrometer on the MESSENGER spacecraft to spatially resolved maps of the gamma-ray emission from the surface of Mercury is utilized to map the surface distributions of the elements Si, O, and K over the planet's northern hemisphere. Conversion of the K gamma-ray count rates to elemental abundances on the surface reveals variations from 300 to 2400 ppm. A comparison of these abundances with models for the maximum surface temperature suggests the possibility that a temperature-related process is controlling the K abundances on the surface as well as providing K to the exosphere. The abundances of K and Th have been determined for several geologically distinct regions, including Mercury's northern smooth plains and the plains interior to the Caloris basin. The lack of a significant variation in the measured Th abundances suggests that there may be considerable variability in the K/Th abundance ratio over the mapped regions

Sources of Intravascular ATP During Exercise in Humans: Critical Role for Skeletal Muscle Perfusion

Exercise hyperemia is regulated by several factors and one factor known to increase with exercise that evokes powerful vasomotor action is extracellular ATP. The origination of ATP detectable in plasma from exercising muscle of humans is, however, a matter of debate and ATP has been suggested to arise from sympathetic nerves, blood sources (e.g. erythrocytes), endothelial cells, and skeletal myocytes, among others. Therefore, we tested the hypothesis that acute augmentation of sympathetic nervous system activity (SNA) results in elevated plasma ATP draining skeletal muscle, and that SNA superimposition during exercise further increases ATP vs exercise alone. We show that increased SNA via −40mmHg lower body negative pressure (LBNP) at rest does not increase plasma ATP (51±8 vs 58±7 nmol/L with LBNP), nor does it increase [ATP] above levels observed during rhythmic handgrip exercise (79±11 exercise alone vs 71±8 nmol/L with LBNP). Secondly, we tested the hypothesis that active perfusion of skeletal muscle is essential to observe increased plasma ATP during exercise. We identify that complete obstruction of blood flow to contracting muscle abolishes exercise-mediated increases in plasma ATP (90±19 to 49±12 nmol/L), and further, that cessation of blood flow prior to exercise completely inhibits the typical rise in ATP (3 vs 61%; obstructed vs intact perfusion). The lack of ATP change during occlusion occurred in the face of continued muscle work and elevated SNA, indicating the rise of intravascular ATP is not resultant from these extravascular sources. Our collective observations indicate that the elevation in extracellular ATP observed in blood during exercise is unlikely to originate from sympathetic nerves or the contacting muscle itself, but rather is dependent on intact skeletal muscle perfusion. We conclude that an intravascular source for ATP is essential and points toward an important role for blood sources (e.g. red blood cells) in augmenting and maintaining elevated plasma ATP during exercise

Feasibility of Harbor-wide Barrier Systems: Preliminary Analysis for Boston Harbor

The aim of this study is to provide the City of Boston with a preliminary assessment of the feasibilities and potential benefits, costs, and environmental impacts of three harborwide barrier configurations. While this study is not comprehensive, and there are many ways that further research could refine and extend its findings, those findings were clear enough to justify making recommendations for next steps. The authors recommend that the City continue to focus its climate resilience strategy for the next several decades on the shore-based multi-layered approach described in Climate Ready Boston. Shore-based solutions would provide flood management more quickly at a lower cost, offer several key advantages over a harbor-wide barrier, and provide more flexibility in adapting and responding to changing conditions, technological innovations, and new information about global sea level rise. These shore-based solutions would be needed in any case over the next few decades to manage coastal flooding during the design and construction period of a harbor-wide barrier if a decision was made to build one in the future