A review of carotenoid utilisation and function in crustacean aquaculture

Crustaceans are cultured extensively around the world in intensive farming systems. High-performance formulated feeds have been developed for crustacean aquaculture, which are often supplemented with a number of natural and synthetic carotenoid sources. Studies over a number of years have consistently shown that dietary carotenoid supplementation is beneficial for crustacean aquaculture across a range of commercially relevant parameters. Most obvious is the effect on pigmentation, where carotenoid inclusion levels in feeds and duration of feeding diets with carotenoids have been optimised across many species to improve product colour, and subsequently quality and price. However, beneficial effects of carotenoid inclusion have increasingly been demonstrated on other parameters. This review updates the recent progress in our understanding of dietary carotenoid utilisation and storage, and the combined effects of diet, genetics and environment on crustacean pigmentation. In addition, the range of other physiological benefits this class of molecules brings to these animals is summarised. These include improvements in survival, growth, reproductive capacity, disease resistance and stress resistance. © 2015 Wiley Publishing Asia Pty Ltd

Évolution de la méthode thermodynamique de détermination du rendement des machines hydrauliques

The principle of efficiency evaluation of a hydraulic machine by this method was described in La Houille Blanche (No. 4-5) by Wilm and Gampmas in 1954, in a form in which basic reasoning lines were taken from thermodynamics, especially so as to explain internal energy in terms of such measurable values as water pressure, temperature and physical properties. Enthalpy and entropy were both considered too unfamiliar to hydraulicians to be used at the time. The method has come into much more widespread use during the last twelve years, however, and heat engineers are becoming interested in it as a potential means of determing feed pump and boiler efficiency. This has made it necessary to produce a rather more general form of description of the method, and especially to feature the considered effects in the enthalpy/ entropy diagram. The expression for elementary enthalpy variation (1) integrated between the extreme points representing the machine inlet and outlet represents energy per unit mass given up (turbine) or received (pump). This integration brings forth the measurable quantities, i.e. pressure and temperature. Observing that the representative inlet and outlet points e and 8 can be replaced by points 1 and 2 on the same constant-enthalpy line, expression (5) is obtained. In practice, constant-enthalpy expansions at the inlet or outlet (performed on a small flow considered as a representative sample) are adjusted to simplify the measurements or to make them more accurate, depending on circumstances or the equipment available. Several alternatives are thus available ; in one, the water drawn off undergoes slight expansion, and both pressure and temperature diferences are measured ; in another, temperature equilibrium is achieved between inlet and outlet by making the water drawn off undergo carefully controlled partial expansion, and instead of measuring temperature difference, the point at which the temperatures are equal is determined ; in yet another alternative, the water drawn off can be expanded to outlet pressure, so that only the temperature difference measurement remains. In a theoretically perfect machine without losses, the difference in enthalpy between inlet and outlet is the reference value to which the previously calculated specific energy must be related in order to obtain the efficiency. This is calculated by integrating expression (5) from the truc inlet to a fictitious outlet on the same isentropic line, which yields expression (7). In practice, this integration can be calculated along the e isothermal without appreciable error. The practical expression for turbine efficiency is (11), in which energy is made to appear in terms of unit weight (head), and into which the velocity and gravity terms neglected in the initial reasoning are introduced. Use is also made of precalculated non-dimensional coefficients (1 - α1) and (1 - βc), which represent the enthalpy difference between the extreme pressures, respectively along the isothermal and isentropic lines passing through the entry point (e or 1) and with respect to a reference enthalpy difference (P8 - pc) u0, in which u0 is a reference density. The physical characteristics of water, i.e. compressibility, thermal expansion and specific heat come into the enthalpy difference calculations. The values willm and Campmas originally considered from old sources appear to be unchallenged to this day. They have received indirect confirmation by comparisons between the thermodynamic and more conventional methods, especially by the results of temperature measurement bridge calibrations by isenthalpic expansion. The calibration coefficient for these bridges remains constant from 2 °C to 20 °C, which can be considered to be a very favourable indication as to the reliability of the characteristics of the water used. Emphasis is laid on the homogeneity required for the data regarding the various physical characteristics of water. This homogeneity stems from the laws of thermodynamics ; it must in practice be complied with between coefficient α and specific heat values, in order that the physical characteristics of the water all have the same weight in the various alternative versions of the method. Until the last few years, the "partial expansion" variant was the one most frequently applied. The reason for this preference was that with this method, the temperature difference term can be dropped from the expression for efficiency, and there had also been some doubt as to the possibility of measuring temperature differences sufficiently accurately. People have now become accustomed to reasoning along thermodynamics lines, however, and platinum temperature measurement bridges can be considered sufficiently reliable for differential measurement not just to eletect equal temperatures. This reliability has been confirmed by the results of numerous calibrations. This enables the most general form of the method-without expansion-to be applied, which does not need any heat input to the equipment (such as certain recently proeluced "incorporated" pressure reducers) and thus makes for more rapid, reliable measurement. Because of its general character, this variant is not affected by any of the limitations applicable to the "partial expansion" method, for instance when used on pumps. When compared, results of both above variants are not found to differ to any significant degree. Some general features of data obtained by the thermodynamic method are discussed. Eighteen comparisons between this and more conventional methods generally show differences mostly not exceeding ± 1 %. Four of these results are particularly instructive ; they refer to comparisons with laboratory methods, and the differences are found to be 0.2 %. The closeness of the results is shown up by a set of 74 "point" efficiency measurements on the same turbine over a period of three years. Standard deviation for the scatter in the points with respect to the mean efficiency curve is equivalent to a practical temperature difference of 1/1,000 °C. Electricité de France have been systematically using the thermodynamic method since its development in 1954 in acceptance-testing hydraulic machines, and in investigating operating problems, for example the effect of wear on machine efficiency. The number of complete acceptance tests done by the thermodynamic method has been 700 out of a total 1,100. Progress in differential temperature instrument design should enable the variant without expansion to be used as current practice and slightly more accurate efficiency data obtained than has been possible so far

Elucidating the origin of superior electrochemical cycling performance: New insights on sodiation-desodiation mechanism of SnSb from: Operando spectroscopy

As it has been recently shown in the literature, SnSb exhibits better performance in Na-ion than in Li-ion batteries in spite of its even larger volume expansion. Where is this special behaviour coming from? In this work, the reversible sodiation-desodiation reaction of SnSb was investigated by simultaneous operando Sn and Sb K-edge X-ray absorption spectroscopy along with operando119Sn Mössbauer spectroscopy. Chemometric tools such as principal component analysis and multivariate curve resolution-alternating least squares were used to analyse the whole data sets to gain information on the nature and sequence of formation of different species during electrochemical cycling vs. Na. The obtained results indicate that the sodiation reaction is a two-step process clearly distinct from the reaction of SnSb vs. Li. Firstly Sb is sodiated to form Na3Sb and an intermediate phase of nanosized metallic Sn, which we were able to identify as α-Sn, commonly unstable at ambient conditions. During the second step, this tin phase is fully sodiated to form Na15Sn4, as rarely observed for pure Sn-based electrodes. Finally, EXAFS analysis proves that the amorphous SnSb phase formed after one complete cycle is clearly distinct from the pristine material. These new insights on the mechanism of SnSb vs. Na provide a basis for understanding the exceptional electrochemical performance, which is superior not only to SnSb vs. Li but also to Sn vs. Na. The key to the enhanced cycle life and capacity retention lies in the gradual formation of amorphous, nano-confined intermediate phases and correlated elastic softening of highly sodiated tin and antimony phases which have enhanced ability to absorb and mitigate the strong volume changes occurring upon sodiation and desodiation.RST/Fundamental Aspects of Materials and Energ

Effects of dietary vitamin C and soybean lecithin in the nutrition of brown bullhead (Ameiurus nebulosus L.) fingerlings

<p>The effects of different forms of vitamin C and soybean lecithin on growth performance, feed utilization and body composition of brown bullhead <em>(Ameiurus nebulosus</em>, Lesuer 1819) were evaluated during a 9-week growth trial. A special interest was to investigate a possible combine effect of these nutritional components. The diets used contained three forms of vitamin C (crystallized ascorbic acid, encapsulated L-ascorbic acid and Ca-L-threonate) (100 mg/kg) with and without the combination of soybean lecithin. Besides control diet (K), one more diet was supplemented with soybean lecithin (L) only. One-hundred-ninety-two brown bullhead of about 45 g initial body weight was randomly divided in 24 tanks (115 L each). Testing conditions included 8 fish per tank, with triplicate tanks for treatment. All diets with supplemented components had higher final weight. Specific growth rate, feed conversion rate and condition factor were significantly higher with encapsulated vitamin C diets (CC, CC_L), followed by the results of enriched ascorbic acid diets. Vitamin C and lecithin supplementation showed positive influence on significantly higher number of erythrocytes, haematocrit, triglycerides and total protein. Vitamin C content of muscle and liver tissue was not uniform and was significantly higher in AA_L, CC_L, CC and AA feeding groups. The fatty acids profile of muscle and liver tissue showed that phospholipids from soybean lecithin and vitamin C diets enhanced the quality of usable part of the fish body. Combine supplementation of vitamin C and soy lecithin indicated positive production effects, but did not cause a statistically significant difference.</p

Reflexion, analysis and language practice: from individual critical thinking to collaborative learning using blogs in a literature class

In modern times, blended learners may easily access a high variety of media to express and share their thoughts and opinions with others. These may include typical blog websites such as WordPress.com or blogger.com or indeed Social Networking Sites (SNS) such as SnapChat, Instagram, Facebook or Twitter, all of which continue to encourage self-expression on the part of the users, which is known as User Generated Content (Levina & Arriaga, 2014). Furthermore, the employment of such tools for practising writing and analysis skills in a literature class requires further investigation by the CALL community, most notably for investigating the potential for raising critical thinking from an individual to a collaborative basis. This chapter aims to add to this ongoing debate and will describe the pedagogical impact, effectiveness and viability of using blogs to enhance both student learning and peer collaboration in a literature class with final year learners of French

Development of the digestive tract in larval summer flounder

Histological changes of the digestive system and its associated glands, and structures of the jaw were studied in summer flounder Paralichthys dentatus from hatching (day 0) until day 44. Specimens for this study were hatched from artificially spawned broodstock and maintained in the laboratory (20 ± 1° C). During the first 3 days after hatching, the formation of the oral jaw apparatus, lengthening of the digestive tube, yolk resorption, and mucosae differentiation are the most conspicuous elements of development. The larval digestive system is morphologically ready to process external food at the time of mouth opening (3–4 days after hatching). Epithelial cells of the anteromedian and the posterior intestine show evidence of lipid and protein absorption, respectively, after first feeding. The most noticeable events occurring during the next month of independent life are an increase in mucosal folding, cellular differentiation in the luminal epithelia, gut segmentation and looping, and liver growth. Gastric glands and pyloric caeca appear by day 31 and complete the morphological digestive features characteristic of the juvenile stage. Copyright © 1995, Wiley Blackwell. All rights reserve