scholarly journals Requirements ofn-3 very long-chain PUFA in Atlantic salmon (Salmo salarL): effects of different dietary levels of EPA and DHA on fish performance and tissue composition and integrity

2017 ◽  
Vol 117 (1) ◽  
pp. 30-47 ◽  
Author(s):  
Marta Bou ◽  
Gerd M. Berge ◽  
Grete Baeverfjord ◽  
Trygve Sigholt ◽  
Tone-Kari Østbye ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Membrane Phospholipids ◽  
Commercial Diet ◽  
Farmed Salmon ◽  
Tissue Integrity ◽  
Chain Pufa ◽  
Epa And Dha ◽  
Dietary Requirements ◽  
Low Levels ◽  
Better Than

AbstractFarmed salmon feeds have changed from purely marine-based diets with high levels of EPA and DHA in the 1990s to the current 70 % plant-based diets with low levels of these fatty acids (FA). The aim of this study was to establish the impacts of low dietary EPA and DHA levels on performance and tissue integrity of Atlantic salmon (Salmo salar). Atlantic salmon (50 g) in seawater were fed fourteen experimental diets, containing five levels (0, 0·5, 1·0, 1·5 and 2·0 %) of EPA, DHA or a 1:1 EPA+DHA plus control close to a commercial diet, to a final weight of 400 g. Lack of EPA and DHA did not influence mortality, but then-3-deficient group exhibited moderately slower growth than those fed levels above 0·5 %. The heart and brain conserved EPA and DHA levels better than skeletal muscle, liver, skin and intestine. Decreased EPA and DHA favoured deposition of pro-inflammatory 20 : 4n-6 and 20 : 3n-6 FA in membrane phospholipids in all tissues. When DHA was excluded from diets, 18 : 3n-3 and EPA were to a large extent converted to DHA. Liver, skeletal and cardiac muscle morphology was normal in all groups, with the exception of cytoplasm packed with large or foamy vacuoles and sometimes swollen enterocytes of intestine in both deficient and EPA groups. DHA supplementation supported normal intestinal structure, and 2·0 % EPA+DHA alleviated deficiency symptoms. Thus, EPA and DHA dietary requirements cannot be based exclusively on growth; tissue integrity and fish health also need to be considered.

scholarly journals Plasticity in growth of farmed and wild Atlantic salmon: is the increased growth rate of farmed salmon caused by evolutionary adaptations to the commercial diet?

2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Alison Catherine Harvey ◽  
Monica Favnebøe Solberg ◽  
Eva Troianou ◽  
Gary Robert Carvalho ◽  
Martin Ian Taylor ◽  
...  
Keyword(s):  
Growth Rate ◽  
Atlantic Salmon ◽  
Commercial Diet ◽  
Farmed Salmon

scholarly journals Nutritional quality of salmon products available from major retailers in the UK: content and composition of n-3 long-chain PUFA

2014 ◽  
Vol 112 (6) ◽  
pp. 964-975 ◽  
Author(s):  
João Henriques ◽  
James R. Dick ◽  
Douglas R. Tocher ◽  
J. Gordon Bell
Keyword(s):  
Nutritional Quality ◽  
Clear Correlation ◽  
Farmed Fish ◽  
Farmed Salmon ◽  
Chain Pufa ◽  
Epa And Dha ◽  
The Uk ◽  
Excellent Source ◽  
Long Chain

In the present study, salmon products available from UK retailers were analysed to determine the levels of n-3 long-chain PUFA (LC-PUFA), a key determinant of nutritional quality. There was a wide variation in the proportions and absolute contents of EPA and DHA in the products. Relatively high contents of 18 : 1n-9, 18 : 2n-6 and 18 : 3n-3, characteristic of vegetable oils (VO), were found in several farmed salmon products, which also had generally lower proportions of EPA and DHA. In contrast, farmed salmon products with higher levels of 16 : 0 and 22 : 1, characteristic of fish oil (FO), had higher proportions of EPA and DHA. Therefore, there was a clear correlation between the levels of VO and FO in feeds and the proportions of n-3 LC-PUFA in products. Although wild salmon products were characterised by higher proportions of n-3 LC-PUFA (20–40 %) compared with farmed fish (9–26 %), they contained lower total lipid contents (1–6 % compared with 7–17 % in farmed salmon products). As a result, farmed salmon products invariably had higher levels of n-3 LC-PUFA in absolute terms (g/100 g fillet) and, therefore, delivered a higher ‘dose’ of EPA and DHA per portion. Overall, despite the finite and limiting supply of FO and increasing use of VO, farmed salmon continue to be an excellent source of and delivery system for n-3 LC-PUFA to consumers.

scholarly journals Low levels of very-long-chain n-3 PUFA in Atlantic salmon (Salmo salar) diet reduce fish robustness under challenging conditions in sea cages

2017 ◽  
Vol 6 ◽  
Author(s):  
Marta Bou ◽  
Gerd M. Berge ◽  
Grete Baeverfjord ◽  
Trygve Sigholt ◽  
Tone-Kari Østbye ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
High Water ◽  
Membrane Phospholipids ◽  
Lower Growth ◽  
Experimental Fish ◽  
Significant Difference ◽  
Minimum Requirements ◽  
Low Levels

AbstractThe present study aimed to determine the minimum requirements of the essential n-3 fatty acids EPA and DHA in Atlantic salmon (Salmo salar) that can secure their health under challenging conditions in sea cages. Individually tagged Atlantic salmon were fed 2, 10 and 17 g/kg of EPA + DHA from 400 g until slaughter size (about 3·5 kg). The experimental fish reared in sea cages were subjected to the challenging conditions typically experienced under commercial production. Salmon receiving the lowest EPA + DHA levels showed lower growth rates in the earlier life stages, but no significant difference in final weights at slaughter. The fatty acid composition of various tissues and organs had remarkably changed. The decreased EPA + DHA in the different tissue membrane phospholipids were typically replaced by pro-inflammatory n-6 fatty acids, most markedly in the skin. The EPA + DHA levels were maintained at a higher level in the liver and erythrocytes than in the muscle, intestine and skin. After delousing at high water temperatures, the mortality rates were 63, 52 and 16 % in the salmon fed 2, 10 and 17 g/kg EPA + DHA. Low EPA + DHA levels also increased the liver, intestinal and visceral fat amount, reduced intervertebral space and caused mid-intestinal hyper-vacuolisation. Thus, 10 g/kg EPA + DHA in the Atlantic salmon diet, a level previously regarded as sufficient, was found to be too low to maintain fish health under demanding environmental conditions in sea cages.

scholarly journals 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)

2019 ◽  
Vol 122 (10) ◽  
pp. 1091-1102 ◽  
Author(s):  
Matthew Sprague ◽  
Gong Xu ◽  
Monica B. Betancor ◽  
Rolf E. Olsen ◽  
Ole Torrissen ◽  
...  
Keyword(s):  
Linoleic Acid ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Chain Pufa ◽  
First Feeding ◽  
Endogenous Production ◽  
Epa And Dha ◽  
Salmon Fry ◽  
Sunflower Oils ◽  
Long Chain

AbstractAtlantic salmon (Salmo salar) possess enzymes required for the endogenous biosynthesis of n-3 long-chain PUFA (LC-PUFA), EPA and DHA, from α-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 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 about 28 μg n-3 LC-PUFA per g fish per d, 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 but increased n-6 LC-PUFA production and DHA:EPA ratio.

EFFECTS OF LANGUAGE AND PRIOR KNOWLEDGE LEVELS ON HYPERTEXT READING COMPREHENSION

2020 ◽  
Author(s):  
Kshema Jose
Keyword(s):  
Reading Comprehension ◽  
Prior Knowledge ◽  
Language Proficiency ◽  
Language Competence ◽  
Additional Information ◽  
Reading Order ◽  
Low Levels ◽  
Online Texts ◽  
Characteristic Features ◽  
Better Than

<p>This study observed how two hypertext features – absence of a linear or author-specified order and availability of multiple reading aids – influence reading comprehension processes of ESL readers. Studies with native or highly proficient users of English, have suggested that readers reading hypertexts comprehend better than readers reading print texts. This was attributed to (i) presence of hyperlinks that provide access to additional information that can potentially help overcome comprehension obstacles and (ii) the absence of an author-imposed reading order that helps readers exercise cognitive flexibility. An aspect that remains largely un-researched is how well readers with low language competence comprehend hypertexts. This research sought to initiate research in the area by exploring the question: Do all ESL readers comprehend a hypertext better than a print text?</p> <p>Keeping in mind the fact that a majority of readers reading online texts in English can be hindered by three types of comprehension deficits – low levels of language proficiency, non-availability of prior knowledge, or both – this study investigated how two characteristic features of hypertext, viz., linking to additional information and non-linearity in presentation of information, affect reading comprehension of ESL readers. </p> <p>Two types of texts that occur in the electronic medium – linear or pre-structured texts and non-linear or self-navigating texts, were used in this study. Based on a comparison of subjects’ comprehension outcomes and free recalls, text factors and reader factors that can influence hypertext reading comprehension of ESL readers are identified. </p> Contradictory to what many researchers believe, results indicate that self-navigating hypertexts might not promote deep comprehension in all ESL readers.

Evaluation of Gas-Liquid Chromatography in Assays for Blood Volatiles

1965 ◽  
Vol 11 (11) ◽  
pp. 1023-1035 ◽  
Author(s):  
Alan Mather ◽  
Angel Assimos
Keyword(s):  
Liquid Chromatography ◽  
Alcohol Concentration ◽  
Quantitative Assay ◽  
Gas Liquid Chromatography ◽  
Internal Reference ◽  
Detection And Identification ◽  
Large Populations ◽  
The Common ◽  
Low Levels ◽  
Better Than

Abstract A simple screening by gas-liquid chromatography (GLC) can provide definitive answers in the detection and identification of a number of volatile substances, including acetone and the common alcohols. After identification, quantitative assay by an internal-reference technic yields highly specific values for ethyl alcohol concentration with a precision at least equal to (and for low levels, better than) that of conventional assays. The unique advantage of GLC is in its simultaneous quantitative assay of mixtures, some of which cannot be satisfactorily assayed or even recognized in any other way. The combination of speed and negligible sample volumes render the technic valuable for sequential studies on capillary blood samples and, potentially, for mass screening of large populations.

The use of hollow sphere pigments as strength additives in paper and paperboard coatings—Part 1: The predictive nature of packing models on coating properties

TAPPI Journal ◽  
2020 ◽  
Vol 19 (11) ◽  
pp. 585-593
Author(s):  
ETHAN GLOR ◽  
BRIAN EINSLA ◽  
JOHN ROPER ◽  
JIAN YANG ◽  
VALERIY GINZBURG
Keyword(s):  
Particle Size ◽  
Hollow Sphere ◽  
Particle Packing ◽  
Particle Sizes ◽  
Coating Properties ◽  
Ideal System ◽  
Thermal Paper ◽  
Effect Of Particle Size ◽  
Low Levels ◽  
Better Than

Hollow sphere pigments (HSPs) are widely used at low levels in coated paper to increase coating bulk and to provide gloss to the final sheet. However, HSPs also provide an ideal system through which one can examine the effect of pigment size and particle packing within a coating due to their unimodal and tunable particle sizes. The work presented in Part 1 and Part 2 of this study will discuss the use of blends of traditional inorganic pigments and HSPs in coating formulations across a variety of applications for improved coating strength. Part 1 of this study focuses on the theory of bimodal spherical packing and demonstrates the predictive nature of packing models on the properties of coating systems containing HSPs of two different sizes. This study also examines conditions where the model fails by examining the effect of particle size on coating strength in sytems like thermal paper basecoats where the non-HSP component has a broad particle size distribution, and how these surprising trends can be used to generate better-than-expected thermal printing performance in systems with low HSP/clay ratios. Part 2 of this study focuses on the incorporation of HSPs of different particle sizes into paperboard formulations to affect coating strength and opacity.

La competencia motriz en estudiantes chilenos de 3° y 4° de educación básica. Aprendizajes esperados versus realidad (Motor competence in Chilean students in 3rd and 4th grade of primary school. Expected learning versus reality)

Retos ◽  
2021 ◽  
Vol 44 ◽  
pp. 515-524
Author(s):  
Daniel Rodríguez-Briceño ◽  
Felipe Castro-Vilugron ◽  
Mauricio Díaz-Alvarado ◽  
Jaime Carcamo Oyarzun
Keyword(s):  
Motor Performance ◽  
Fourth Grade ◽  
Learning Objectives ◽  
Motor Competence ◽  
Object Control ◽  
Third Grade Students ◽  
Fourth Grade Students ◽  
Low Levels ◽  
And Gender ◽  
Better Than

  Este estudio busca determinar los niveles de competencia motriz de estudiantes chilenos y las posibles diferencias en función del grado y del sexo. Participaron 377 estudiantes (37.7% niñas) de tercer y cuarto básico. La competencia motriz fue evaluada a través del test MOBAK 3-4. Se encontraron bajos niveles de competencia motriz. Los estudiantes de cuarto grado presentan un mejor desempeño motriz que los de tercero. Los niños presentan un mayor desempeño que las niñas en control de objetos, mientras que las niñas obtienen puntajes más altos que los niños en control del cuerpo, aunque con un tamaño del efecto irrelevante. Al contrastar estos resultados con los objetivos del currículum, muchos estudiantes no alcanzan los aprendizajes esperados, siendo necesario poner mayor énfasis en el fomento de la competencia motriz.  Abstract. This study aims to determine the levels of motor competence of Chilean students and possible differences according to grade and gender. 377 students (37.7% girls) of the third and fourth grade participated in the study. Motor competence was evaluated through the MOBAK 3-4 test. Low levels of motor competence were found. Fourth grade students showed a better motor performance than third grade students. Boys performed better than girls in object control, while girls scored higher than boys in self-movement, although with an irrelevant effect size. When these results are contrasted with the learning objectives stipulated in the curriculum, many students do not achieve the expected skills, what makes it necessary to place greater emphasis on the promotion of motor competence.

scholarly journals Documentation of multiple species of marine fish trapped in Atlantic salmon sea-cages in Norway

2018 ◽  
Vol 31 ◽  
pp. 31
Author(s):  
Per Gunnar Fjelldal ◽  
Monica F. Solberg ◽  
Kevin A. Glover ◽  
Ole Folkedal ◽  
Jonatan Nilsson ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Trutta ◽  
Gadus Morhua ◽  
Mesh Size ◽  
Anguilla Anguilla ◽  
Wild Fish ◽  
Melanogrammus Aeglefinus ◽  
European Eel ◽  
Farmed Salmon ◽  
Sea Trout

The production of salmonids in sea-cages has been developed for monoculture of the target species. However, we show here for the first time, that wild fish may enter sea-cages used for farming of Atlantic salmon (Salmo salar L.) in Norway, out-grow the mesh size, and thereafter become permanently trapped. Within seven different sea-cages located in western Norway, eight different species of wild fish were identified; European eel (Anguilla anguilla), sea trout (Salmo trutta L.), cod (Gadus morhua), haddock (Melanogrammus aeglefinus), saithe (Pollachius virens), pollack (Pollachius pollachius), hake (Merluccius merluccius) and whiting (Merlangius merlangus). In the two most extreme cases, a 5 × 5 × 7 m cage with 311 farmed salmon (903 g) also contained 542 whiting (79 g), 77 haddock (43 g), and 5 cod (26 g), and a 12 × 12 × 15 m cage with 1695 farmed salmon (559 g) also contained 1196 haddock (35 g), 1115 whiting (31 g), 46 cod (23 g), 23 saithe (48 g), 15 pollock (22 g), 5 sea trout (54 g), and 2 hake (29 g). The present study thus demonstrates that aquaculture cages designed for monoculture may attract and effectively ‘trap’ wild fish. We did not investigate the frequency of this occurrence, and the ecological significance of these observations remains unclear. However, with the ever-increasing number of sea-cages used for global aquaculture, this is clearly a topic for further research.

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