The substitution of fish resources as ingredients for aquafeeds by those based on vegetable sources is needed to ensure aquaculture sustainability in the future. It is known that Senegalese sole ...(Solea senegalensis) accepts high dietary content of plant ingredients without altering growth or flesh quality parameters. However, scarce information is available regarding the long-term impact of vegetable diets (combining the inclusion of both vegetable protein and oils) on the stress response and immunity of this fish species. This study aims to evaluate the concomitant effect of the extended use of vegetable protein-based diets with fish oil (FO) replacement (0, 50 or 100%) by vegetable oils (VO), on the response to acute (10 min) or prolonged (4 days) stress, induced by thermal shock. Plasma levels of cortisol, glucose and lactate as well as hepatic levels of glucose, glycogen and lactate were evaluated as primary and secondary responses to stress, 6 and 18 months after feeding the experimental diets (6 and 18 MAF). The brain monoaminergic activity in telencephalon and hypothalamus, and non-specific immune parameters were also evaluated. As expected, thermal shock induced an increase in values of plasma parameters related to stress, which was more evident in acute than in prolonged stress. Stress also affected lactate levels in the liver and the values of the alternative complement pathway-ACH50 in the plasma. Dietary substitution of FO induced an effect per se on some parameters such as decreased hepatic glucose and glycogen levels and peroxidase activity in plasma as well enhanced serotonergic activity in brain of non-stressed fish. The results obtained in some parameters indicate that there is an interaction between the use of vegetable diets with the physiological response to thermal stress, as is the case of the hepatic lactate, serotonergic neurotransmission in brain, and the activity of ACH50 in plasma. These results suggest that the inclusion of VO in plant protein based diets point to a slightly inhibited stress response, more evident for an acute than a prolonged stress.
Cyclodextrins are able to act as host molecules in supramolecular chemistry with applications ranging from pharmaceutics to detergency. Among guest molecules surfactants play an important role with ...both fundamental and practical applications. The formation of cyclodextrin/surfactant host–guest compounds leads to an increase in the critical micelle concentration and in the solubility of surfactants. The possibility of changing the balance between several intermolecular forces, and thus allowing the study of, e.g., dehydration and steric hindrance effects upon association, makes surfactants ideal guest molecules for fundamental studies. Therefore, these systems allow for obtaining a deep insight into the host–guest association mechanism. In this paper, we review the influence on the thermodynamic properties of CD–surfactant association by highlighting the effect of different surfactant architectures (single tail, double-tailed, gemini and bolaform), with special emphasis on cationic surfactants. This is complemented with an assessment of the most common analytical techniques used to follow the association process. The applied methods for computation of the association stoichiometry and stability constants are also reviewed and discussed; this is an important point since there are significant discrepancies and scattered data for similar systems in the literature.
In general, the surfactant–cyclodextrin association is treated without reference to the kinetics of the process. However, there are several examples where the kinetics of the process can be investigated, in particular those where volumes of the CD cavity and surfactant (either the tail or in special cases the head group) are similar in magnitude. This will also be critically reviewed.
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•Surfactants form host–guest supramolecular structures with cyclodextrins.•Values of stability constants depend on techniques and methods of evaluation.•Cyclodextrin–surfactant interactions are exothermic.•Disordered water inside the α-cyclodextrin cavity leads, in general, to a negative binding entropy change.
Dietary inclusion of IMTA-cultivated
Gracilaria vermiculophylla
was evaluated in rainbow trout. Growth and feed efficiency were determined in fish fed 0 % (CTRL), 5 % (G5), and 10 % (G10) of the red ...seaweed for 91 days. Carotenoid concentration (skin and muscle), immunological parameters, and intestinal morphology were also evaluated. G10 group showed the lowest final body weight, with feed and protein efficiency ratios being significantly lower than the CTRL. Although protein intake was similar among groups, G10 diet induced the lowest protein retention and gain probably due to its smallest intestine diameter and lowest
villi
height. Fish fed G10 diet displayed higher carotenoid content in the skin (16.7 μg g
−1
) when compared with the CTRL group, but a lower concentration was registered in the flesh (0.23 μg g
−1
). Instrumental color showed that fillets were more luminous (
L
*), less yellowish (
b
*), and more reddish (a*) with seaweed inclusion and the lowest chrome intensity (
C
*) in the G10 group confirmed the lowest muscle carotenoid content in these fish. G5 diet enhanced the innate immune response of rainbow trout inducing the highest peroxidase, alternative complement (ACH50), and lysozyme activities. The inclusion of
Gracilaria
meal in diets for rainbow trout is possible up to 5 %, but a higher inclusion level impairs growth.
Over the last few years, several aspects of Senegalese sole (Solea senegalensis) culture have been developed and optimised but the dietary lipid level for optimal growth has never been determined. ...Hence, five isonitrogenous diets (56 % dietary protein) with increasing dietary lipid levels (4, 8, 12, 16 and 20 % DM) were fed to satiation to triplicate groups of twenty fish (mean initial weight 10 g). Fifteen tanks were randomly assigned one of the five diets. Feed was distributed using automatic feeders, and fish were fed over a 16-week period. At the end of the experiment the fish fed on diets containing the two lowest dietary lipid levels (4 and 8 %) showed a 3-fold body-weight increase with a significantly higher daily growth index than fish fed higher lipid levels (1·2 v. 0·8). Moreover, these fish displayed a significantly lower dry feed intake (12 g/kg per d) and feed conversion ratio (1·0) compared with fish fed higher lipids levels (16–19 g/kg per d; feed conversion ratio 2·0). Low dietary lipid levels ( < 12 %) significantly improved nutrient retention and gain and hence growth, without major effects on whole-body composition. Despite the slight alteration in n-3 PUFA muscle content in the fish fed low-fat-diets, this fish fed low dietary lipid still remains a rich n-3 PUFA product and generally maintained its nutritional value. These results evidenced a low lipid tolerance of Senegalese sole juveniles and suggest a maximal dietary inclusion level of 8 % lipids for both optimal growth and nutrient utilisation without compromising flesh quality.
Scheduling jobs in a no-wait flow shop with the objective of minimising total earliness and tardiness is the problem addressed in this paper. Idle time may be needed on the first machine due to the ...no-wait restriction. A model is developed that shows additional idle can be inserted on the first machine to help reduce earliness. Several dispatching heuristics previously used in other environments were modified and tested. A two-phased procedure was also developed, estimating additional idle in the first phase, and applying dispatching heuristics in the second phase. Several versions of an insertion improvement procedure were also developed. The procedures are tested on instances of various sizes and due date tightness and range. The results show the two-phase heuristics are more effective than the simple rules, and the insertion search improvement procedure can provide considerable improvements.
We have assessed the current state of knowledge relative to methods used in assessing sub-tidal benthic habitat quality and the classification of benthic habitats. While our main focus is on marine ...habitat, we extensively draw on knowledge gained in freshwater systems where benthic assessment procedures are at an advanced stage of maturity. We found a broad range of sophistication/complication in terms of the methods applied in assessing and mapping benthic habitats. The simplest index or metric involved some assessment of species richness, while the most complicated required utilizing multi-variate analysis. The simplest mapping attempts equated physical substrate with benthic habitat while the most sophisticated relied on extensive environmental preference and groundtruth data for species of concern. The leading edge of methods for benthic habitat mapping involves combining the advances in optical and acoustic methods that allow for routine classifying and mapping of the seafloor with biological and habitat data for species of concern. The objective of this melding of dispirit methods is to produce benthic habitat maps with broad system wide coverage and sound biological underpinning. It is clear that the disparity in information density between the physical and biological sides of the equation currently hinder applicability and acceptability of benthic habitat mapping efforts. In addition to the lack of basic information on the biological and environmental tolerances of targeted species, the proliferation of metrics for characterizing and assessing biological conditions further clouds the usefulness of any broad scale mapping attempt. The problem of data density mismatch between physical and biological methods will likely not be solved until acoustic methods can routinely resolve the elusive biological components that make a physical substrate a habitat.
High levels of dietary lipids are incorporated in feeds for most teleost fish to promote growth and reduce nitrogen waste. However, in Senegalese sole (Solea senegalensis) previous studies revealed ...that increasing the level of dietary lipids above 8% negatively affect growth and nutrient utilization regardless of dietary protein content. It has been shown that glucose regulation and metabolism can be impaired by high dietary fat intake in mammals, but information in teleost fish is scarce. The aim of this study was to assess the possible effect of dietary lipids on glucose metabolism in Senegalese sole with special emphasis on the regulation of proteins involved in the muscle insulin-signalling pathway. Senegalese sole juveniles (29 g) were fed two isonitrogenous diets (53% dry matter) for 88 days. These two diets were one with a high lipid level (∼17%, HL) and a moderate starch content (∼14%, LC), and the other being devoid of fish oil (4% lipid, LL) and with high starch content (∼23%, HC). Surprisingly, feeding Senegalese sole the HL/LC diet resulted in prolonged hyperglycaemia, while fish fed on LL/HC diet restored basal glycaemia 2 h after feeding. The hyperglycaemic phenotype was associated with greater glucose-6-phosphatase activity (a key enzyme of hepatic glucose production) and lower citrate synthase activity in the liver, with significantly higher liver glycogen content. Sole fed on HL/LC diet also had significantly lower hexokinase activity in muscle, although hexokinase activity was low with both dietary treatments. The HL/LC diet was associated with significant reductions in muscle AKT, p70 ribosomal S6-K1 Kinase (S6K-1) and ribosomal protein S6 (S6) 2 h after feeding, suggesting down regulation of the AKT-mTOR nutrient signalling pathway in these fish. The results of this study show for the first time that high level of dietary lipids strongly affects glucose metabolism in Senegalese sole.
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•Novel high-performance p-CuO@CuS/n-Si photodetectors have been facilely fabricated.•Structural and vibrational studied confirm the synthesis of fabrication of CuO@CuS nanocomposite ...system.•Core-shell structure like morphology was approved by FESEM & HRTEM analyses.•High Ps of ∼ 7.76 104 % & R ∼ 798.61mA/W was observed for the fabricated photodetector.•High detectivity (D*) of 8.19 ×1011 J & of ∼ 309.66%, was observed for the fabricated photodetector.
Development of photo detectors based on different semiconducting materials with high performance has been in progress in recent past, however, there is a lot of difficulties in developing the more effective photo detectors-based devices with high responsivity, detectivity and quantum efficiency. Hence, we have synthesized pure CuS and CuO@CuS core-shell heterostructure based photo detectors with high performance by simple and cost-effective two-step chemical co-precipitation method. The phase purity of CuS and CuO@CuS composite was observed by XRD analysis and the result were verified with Raman spectroscopy studies. Sphere like morphology of pure CuS and core-shell structure formation of CuO@CuS are observed with scanning and transmission electron microscopes. The presence of expected elements has been confirmed with EDX elemental mapping. Light harvesting photodiodes were fabricated by using n-type silicon substrate through drop cost method. Photo sensitive parameters of fabricated diodes were analyzed by I–V characteristics. The p-CuO@CuS (1:1)/n-Si diode owned a maximum photosensitivity (Ps) ∼ 7.76 × 104 %, photoresponsivity (R) ∼ 798.61 mA/W, external quantum efficiency (EQE)∼309.66 % and specific detectivity (D*) ∼ 8.19 × 1011 Jones when compared to p-CuS/n-Si diode. The obtained results revealed that the core/shell heterostructure of CuO@CuS is the most appropriate for photo detection.
Sea urchin population harvest in the North Atlantic coast of Portugal was characterized in terms of gonad yield, nutritional composition and important market-related traits, over one reproductive ...cycle (March 2016 to March 2017). Most of the quality attributes showed a seasonal variation strongly dependent on sea urchin sex. Maximum gonad yield (18%) was observed in March 2017. A single spawning event occurred between May and July. Gonads are rich sources of protein (12-18% WW) with low fat content (≤6% WW), that increase during the gametogenic stages of recovery and growing (November-December). Polyunsaturated fatty acids were the dominant class in both sexes (4.2-14.7 mg.g
WW), being preferentially accumulated in females. Total gonads carotenoid varied seasonally, with the highest level being observed in males during spawning season. Echinenone was the main pigment present in gonads, showing highest concentrations in males during spawning and gonad recovering. During the growing and early maturation period gonads were more reddish, yellowish and brighter, as well as more firm, irrespectively of the sex. Based on all seasonal changes affecting gonad yield and quality, the period between November and February seems the most suitable to harvest high quality gonads in the Atlantic coast of Portugal.
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