927 resultados para nutrition of fish


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As is known, copepods play an important role in the nutrition of fish. Therefore with a view to facilitating research on the study of the quantitative side of feeding, there have recently appeared a considerable number of papers devoted to the development of methods for determining the wet. weight of these crustaceans. For the further facilitating of research in the nutrition of fish it would be of great interest to clarify the problem, is there not some kind of rule in the growth of the crustaceans during metamorphosis, and if there is such a rule is it not possible, to determine the length of the larvae at each stage, not by measuring them, but by using the formulae derived on the basis of these rules. This article examines the growth curves of different species of freshwater Copepoda, obtained on the basis of experimental observations in cultures or by way of measurement of mass material at all stages of development in samples from water-bodies. The authors study in particular the ratio of the mean diameter of the eggs to the mean length of the egg-bearing females.

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Much of fish consumed by the poor are caught by household members and traded in local markets. These fish are rarely or poorly included in national statistics, and it is therefore difficult to estimate precisely the real contribution of fish to the rural poor households. This report is the first global overview of the role played by fish in improving nutrition. Fish consumption patterns of the poor, the nutritional value of fish, and small-scale fisheries and aquaculture activities are considered. It also highlights the gap in knowledge where more research is needed.

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Background: Haemodialysis patients show signs of chronic inflammation and reduced appetite, which is associated with a worse clinical status and an increased mortality risk. Fish oil has anti-inflammatory properties and may be useful as a therapeutic treatment. There is limited evidence to indicate the feasibility and efficacy of this intervention in dialysis patients. The present study aimed to compare the effect of 12 weeks of supplementation with fish oil on markers of appetite and inflammation in male and female haemodialysis patients. Methods: The study was conducted in 28 haemodialysis patients. All patients were prescribed 3 g of fish oil per day for 12 weeks. Changes in appetite, plasma fatty acid profiles and inflammatory markers were measured at baseline and at 12 weeks. Results: The mean (SD) increase in percent plasma eicosapentaenoic acid was statistically significant [1.1 (0.8) to 4.1 (2.2), P < 0.001], which was a strong indicator of good adherence. There were trends towards reductions in peptide YY (−9%; P = 0.078) and an increase in subjective sensations of hunger (+12%; P = 0.406), which reflects an increase in motivation to eat. Males (n = 13) experienced a more marked increase in hunger compared to females (+23% versus −6%), which was associated with maintenance in C-reactive protein and interleukin-6, and a reduction in soluble intercellular adhesion molecule-1. Conclusions: The results obtained demonstrate meaningful trends towards improvements in subjective appetite and certain inflammatory markers (although no change in dietary intake) and this effect was more pronounced in males. However, the levels of some inflammatory markers increased in females and this requires further study. The high level of adherence achieved indicates that an intervention requiring patients to consume four fish oil capsules per day is achievable. This was a short-term study and the effects need to be confirmed in a randomised controlled trial.

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Four groups of brackishwater catfish were fed four diets: N.F. (NIOMR formula 1 feed), A. B. and C. for seven weeks. Feeds N.F., A., B and C. contained 1.21% fish oil + 5.59% vegetable oil; 1.21% fish oil + 7.39% vegetable oil; 1.21% fish oil + 9.09% vegetable oil; 1.21% fish oil + 10.89% vegetable oil respectively. Results of feeding trial showed that growth was best in the group fed diets containing 10.89% vegetable oil and least in those containing 9.09% vegetable oil

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Based on the potential benefits to human health, there is interest in developing sustainable nutritional strategies to enhance the concentration of long-chain n-3 fatty acids in ruminant-derived foods. Four Aberdeen Angus steers fitted with rumen and duodenal cannulae were used in a 4 × 4 Latin square experiment with 21 d experimental periods to examine the potential of fish oil (FO) in the diet to enhance the supply of 20 : 5n-3 and 22 : 6n-3 available for absorption in growing cattle. Treatments consisted of total mixed rations based on maize silage fed at a rate of 85 g DM/kg live weight0·75/d containing 0, 8, 16 and 24 g FO/kg diet DM. Supplements of FO reduced linearly (P < 0·01) DM intake and shifted (P < 0·01) rumen fermentation towards propionate at the expense of acetate and butyrate. FO in the diet enhanced linearly (P < 0·05) the flow of trans-16 : 1, trans-18 : 1, trans-18 : 2, 20 : 5n-3 and 22 : 6n-3, and decreased linearly (P < 0·05) 18 : 0 and 18 : 3n-3 at the duodenum. Increases in the flow of trans-18 : 1 were isomer dependent and were determined primarily by higher amounts of trans-11 reaching the duodenum. In conclusion, FO alters ruminal lipid metabolism of growing cattle in a dose-dependent manner consistent with an inhibition of ruminal biohydrogenation, and enhances the amount of long-chain n-3 fatty acids at the duodenum, but the increases are marginal due to extensive biohydrogenation in the rumen.

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Fish oil supplementation has been shown to improve the cachectic state of tumor-bearing animals and humans. Our previous study showed that fish oil supplementation (1 g per kg body weight per day) for 2 generations had anticancer and anticachetic effects in Walker 256 tumor-bearing rats as demonstrated by reduced tumor growth and body weight loss and increased food intake and survival. In this study, the effect of fish oil supplementation for 2 generations on membrane integrity, proliferation capacity, and CD4/CD8 ratio of lymphocytes isolated from mesenteric lymph nodes, spleen, and thymus of Walker 256 tumor-bearing animals was investigated. We also determined fish oil effect on plasma concentration and ex vivo production of cytokines [tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukin-4 (IL-4), IL-6, and IL-10]. Lymphocytes from thymus of tumor-bearing rats presented lower viability, but this change was abolished by fish oil supplementation. Tumor growth increased proliferation of lymphocytes from all lymphoid organs, and fish oil supplementation abolished this effect. Ex vivo production of TNF-alpha and IL-6 was reduced in supplemented animals, but IL-4 and IL-10 secretion was stimulated in both nontumor and tumor-bearing rats. IL-10 and IFN-gamma plasma levels was also decreased in supplemented animals. These results suggest that the anticachetic effects of fish oil supplementation for a long period of time (2 generations) in Walker 256 tumor-bearing rats may be associated to a decrease in lymphocyte function as demonstrated by reduced viability, proliferation capacity, and cytokine production.

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Nutrition of 6 deep-sea ophiuroid species of the genus Amphiophiura in the Pacific and Indian Oceans has been studied. One species is a detritus-feeder while the others are carnivorous. All 6 are widespread in deep-sea eutrophic regions of both oceans. Carnivorous species are also necrophagous, feeding on dead fish, surface pteropods, and crustaceans. Fishes are consumed mainly in the Indian Ocean, pteropods in the Pacific. Thus, as shown by carnivorous Amphtophiura, the rain of dead surface pelagic organisms is one of the most important sources of food for a number of deep-sea bottom-dwelling invertebrates.

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Protein-energy wasting (PEW) is commonly seen in patients with chronic kidney disease (CKD). The condition is characterised by chronic, systemic low-grade inflammation which affects nutritional status by a variety of mechanisms including reducing appetite and food intake and increasing muscle catabolism. PEW is linked with co-morbidities such as cardiovascular disease, and is associated with lower quality of life, increased hospitalisations and a 6-fold increase in risk of death1. Significant gender differences have been found in the severity and effects of several markers of PEW. There have been limited studies testing the ability of anti-inflammatory agents or nutritional interventions to reduce the effects of PEW in dialysis patients. This thesis makes a significant contribution to the understanding of PEW in dialysis patients. It advances understanding of measurement techniques for two of the key components, appetite and inflammation, and explores the effect of fish oil, an anti-inflammatory agent, on markers of PEW in dialysis patients. The first part of the thesis consists of two methodological studies conducted using baseline data. The first study aims to validate retrospective ratings of hunger, desire to eat and fullness on visual analog scales (VAS) (paper and pen and electronic) as a new method of measuring appetite in dialysis patients. The second methodological study aims to assess the ability of a variety of methods available in routine practice to detect the presence of inflammation. The second part of the thesis aims to explore the effect of 12 weeks supplementation with 2g per day of Eicosapentaenoic Acid (EPA), a longchain fatty acid found in fish oil, on markers of PEW. A combination of biomarkers and psychomarkers of appetite and inflammation are the main outcomes being explored, with nutritional status, dietary intake and quality of life included as secondary outcomes. A lead in phase of 3 months prior to baseline was used so that each person acts as their own historical control. The study also examines whether there are gender differences in response to the treatment. Being an exploratory study, an important part of the work is to test the feasibility of the intervention, thus the level of adherence and factors associated with adherence are also presented. The studies were conducted at the hemodialysis unit of the Wesley Hospital. Participants met the following criteria: adult, stage 5 CKD on hemodialysis for at least 3 months, not expected to receive a transplant or switch to another dialysis modality during the study, absence of intellectual impairment or mental illness impairing ability to follow instructions or complete the intervention. A range of intermediate, clinical and patient-centred outcome measures were collected at baseline and 12 weeks. Inflammation was measured using five biomarkers: c-reactive protein (CRP), interleukin-6 (IL6), intercellular adhesion molecule (sICAM-1), vascular cell adhesion molecule (sVCAM-1) and white cell count (WCC). Subjective appetite was measured using the first question from the Appetite and Dietary Assessment (ADAT) tool and VAS for measurements of hunger, desire to eat and fullness. A novel feature of the study was the assessment of the appetite peptides leptin, ghrelin and peptide YY as biomarkers of appetite. Nutritional status/inflammation was assessed using the Malnutrition-Inflammation Score (MIS) and the Patient-Generated Subjective Global Assessment (PG-SGA). Dietary intake was measured using 3-day records. Quality of life was measured using the Kidney Disease Quality of Life Short Form version 1.3 (KDQOL-SF™ v1.3 © RAND University), which combines the Short-Form 36 (SF36) with a kidney-disease specific module2. A smaller range of these variables was available for analysis during the control phase (CRP, ADAT, dietary intake and nutritional status). Statistical analysis was carried out using SPSS version 14 (SPSS Inc, Chicago IL, USA). Analysis of the first part of the thesis involved descriptive and bivariate statistics, as well as Bland-Altman plots to assess agreement between methods, and sensitivity analysis/ROC curves to test the ability of methods to predict the presence of inflammation. The unadjusted (paired ttests) and adjusted (linear mixed model) change over time is presented for the main outcome variables of inflammation and appetite. Results are shown for the whole group followed by analyses according to gender and adherence to treatment. Due to the exploratory nature of the study, trends and clinical significance were considered as important as statistical significance. Twenty-eight patients (mean age 61±17y, 50% male, dialysis vintage 19.5 (4- 101) months) underwent baseline assessment. Seven out of 28 patients (25%) reported sub-optimal appetite (self-reported as fair, poor or very poor) despite all being well nourished (100% SGA A). Using the VAS, ratings of hunger, but not desire to eat or fullness, were significantly (p<0.05) associated with a range of relevant clinical variables including age (r=-0.376), comorbidities (r=-0.380) nutritional status (PG-SGA score, r=-0.451), inflammatory markers (CRP r=-0.383; sICAM-1 r=-0.387) and seven domains of quality of life. Patients expressed a preference for the paper and pen method of administering VAS. None of the tools (appetite, MIS, PG-SGA, albumin or iron) showed an acceptable ability to detect patients who are inflamed. It is recommended that CRP should be tested more frequently as a matter of course rather than seeking alternative methods of measuring inflammation. 27 patients completed the 12 week intervention. 20 patients were considered adherent based on changes in % plasma EPA, which rose from 1.3 (0.94)% to 5.2 (1.1)%, p<0.001, in this group. The major barriers to adherence were forgetting to take the tablets as well as their size. At 12 weeks, inflammatory markers remained steady apart from the white cell count which decreased (7.6(2.5) vs 7.0(2.2) x109/L, p=0.058) and sVCAM-1 which increased (1685(654) vs 2249(925) ng/mL, p=0.001). Subjective appetite using VAS increased (51mm to 57mm, +12%) and there was a trend towards reduction in peptide YY (660(31) vs 600(30) pg/mL, p=0.078). There were some gender differences apparent, with the following adjusted change between baseline and week 12: CRP (males -3% vs females +17%, p=0.19), IL6 (males +17% vs females +48%, p=0.77), sICAM-1 (males -5% vs females +11%, p=0.07), sVCAM-1 (males +54% vs females +19%, p=0.08) and hunger ratings (males 20% vs females -5%, p=0.18). On balance, males experienced a maintainence or reduction in three inflammatory markers and an improvement in hunger ratings, and therefore appeared to have responded better to the intervention. Compared to those who didn’t adhere, adherent patients maintained weight (mean(SE) change: +0.5(1.6) vs - 0.8(1.2) kg, p=0.052) and fat-free mass (-0.1 (1.6) vs -1.8 (1.8) kg, p=0.045). There was no difference in change between the intervention and control phase for CRP, appetite, nutritional status or dietary intake. The thesis makes a significant contribution to the evidence base for understanding of PEW in dialysis patients. It has advanced knowledge of methods of assessing inflammation and appetite. Retrospective ratings of hunger on a VAS appear to be a valid method of assessing appetite although samples which include patients with very poor appetite are required to confirm this. Supplementation with fish oil appeared to improve subjective appetite and dampen the inflammatory response. The effectiveness of the intervention is influenced by gender and adherence. Males appear to be more responsive to the primary outcome variables than females, and the quality of response is improved with better adherence. These results provide evidence to support future interventions aimed at reducing the effects of PEW in dialysis patients.

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In the latter half of the nineteenth century the railway became an emblem of technological advancement, stood for the improvement and progression of European life, and became a recognizable symbol for the achievements of governments and citizens. The implementation and use of the railway became closely linked with notions of national identity and character. The railway became an identifiable artefact in official history but at the same time it became a part of everyday life. Richard Flanagan’s Gould’s Book of Fish retells the life-story of a fictionalized convict sent to Sarah Island and who paints fish, eventually he metamorphoses into one. It could be thought that a novel set in convict times would have little to do with notions of national identity, technological advancement, and railway travel. However, Richard Flanagan, in this very complex, almost surreal, novel, has used the construction of a fictional national railway as one of the ways to explore Australia's complex relationship with history and space. The novel tells of the plans of a history-loving Commandant and his desire to build a national railway on Sarah Island. This paper explores how Sarah Island becomes a metonym for Australia as a whole and Flanagan's novel takes on a metaphysical dimension as he reveals the struggles that emerge when official history collides with non-official versions. The fabulations of the novel contribute to an historical reconstruction of the spatial/architectural history of the Tasmanian colonial project.

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Chlamydial infections of fish are emerging as an important cause of disease in new and established aquaculture industries. To date, epitheliocystis, a skin and gill disease associated with infection by these obligate intracellular pathogens, has been described in over 90 fish species, including hosts from marine and fresh water environments. Aided by advances in molecular detection and typing, recent years have seen an explosion in the description of these epitheliocystis-related chlamydial pathogens of fish, significantly broadening our knowledge of the genetic diversity of the order Chlamydiales. Remarkably, in most cases, it seems that each new piscine host studied has revealed the presence of a phylogenetically unique and novel chlamydial pathogen, providing researchers with a fascinating opportunity to understand the origin, evolution and adaptation of their traditional terrestrial chlamydial relatives. Despite the advances in this area, much still needs to be learnt about the epidemiology of chlamydial infections in fish if these pathogens are to be controlled in farmed environments. The lack of in vitro methods for culturing of chlamydial pathogens of fish is a major hindrance to this field. This review provides an update on our current knowledge of the taxonomy and diversity of chlamydial pathogens of fish, discusses the impact of these infections on the health, and highlights further areas of research required to understand the biology and epidemiology of this important emerging group of fish pathogens of aquaculture species.

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Reducing unwanted trawl bycatch is actively encouraged in Australia, particularly in prawn trawl fisheries. We tested the performance of a Bycatch Reduction Device, the Yarrow Fisheye, during two periods of commercial fishing operations in Australia's Northern Prawn Fishery, by comparing the catches of paired treatment and control nets. We compared the catch weights of the small fish and invertebrate bycatch, and the commercially important tiger prawns, from 42 trawls in 2002. The Yarrow Fisheye reduced the weight of small bycatch by a mean of 22.7%, with no loss of tiger prawn. We also compared the numbers of seasnakes caught in 41 and 72 trawls during the spring trawling seasons of 2004 and 2005, respectively. The Yarrow Fisheye reduced the catches by a mean of 43.3%. Flume-tank tests of the Yarrow Fisheye showed that this device created a slow water-flow region extending over 2 m downstream from its position in the net, and close to where the catch accumulates. Finfish and seasnakes may be exploiting this slow water-flow region to escape via the eye, Although the reductions in fish and seasnake bycatch were excellent, we think they could be further improved by relating differences in fisheye position and localised water displacements, to design and rigging changes.

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The effects of fish density distribution and effort distribution on the overall catchability coefficient are examined. Emphasis is also on how aggregation and effort distribution interact to affect overall catch rate [catch per unit effort (cpue)]. In particular, it is proposed to evaluate three indices, the catchability index, the knowledge parameter, and the aggregation index, to describe the effectiveness of targeting and the effects on overall catchability in the stock area. Analytical expressions are provided so that these indices can easily be calculated. The average of the cpue calculated from small units where fishing is random is a better index for measuring the stock abundance. The overall cpue, the ratio of lumped catch and effort, together with the average cpue, can be used to assess the effectiveness of targeting. The proposed methods are applied to the commercial catch and effort data from the Australian northern prawn fishery. The indices are obtained assuming a power law for the effort distribution as an approximation of targeting during the fishing operation. Targeting increased catchability in some areas by 10%, which may have important implications on management advice.