Nutrition and health of fish (original) (raw)
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Nutrition and health of fish 1
Research on nutrition and immune function of fish is slowly expanding to define the role of specific nutrients in disease resistance in fish. The potential impact of certain vitamins (A, E and C), trace elements (iron and selenium), protein, carbohydrate and lipid on the immune response and the pathogenesis of deficiency diseases is briefly reviewed. Recent developments on the functional role of n-3 and n-6 polyunsaturated fatty acids (PUFA) on nonspecific and specific humoral and cellular immunity are summarized. In addition to cell membrane function (e.g. fluidity and permeability), the immunological effects of PUFAs are associated with the formation of eicosanoids such as leucotrienes (LT) and prostaglandins (PG). Dietary n-3 and n-6 PUFAs intake have a significant effect on LT and PG production by macrophage and leukocytes, which directly influence the piscine immune function. Although potential for disease prevention in fish by dietary changes exists, additional information is ...
Dietary Lipids, Immune Function and Pathogenesis of Disease in Fish
Lipids supply essential fatty acids (EFA) and energy in fish diets. Most fish cannot synthesize (de novo) polyunsaturated fatty acids (PUFA) and therefore they must be supplied in the diet for normal growth, reproduction and health. EFA include PUFA of the n-3 and n-6 series, e.g. α-linolenic acid, 18:3n-3 and linoleic acid, 18:2n-6. Generally, EFA requirements of freshwater fish can be met by the supply of 18:3n-3 and 18:2n-6 fatty acids in their diets. By contrast, the EFA requirement of marine fish can only be met by supplying the correct concentrations and ratios of the long-chain PUFAs, eicosapentaenoic acid (20:5 n-3; EPA) and docosahexaenoic acid (22:6n-3; DHA) with perhaps some arachidonic acid (20:4n-6; AA), a highly unsaturated member of the n-6 series. (NRC, 1993; Higgs and Dong, 2000). Freshwater fish are able to elongate and desaturate 18:3n-3 to 22:6n-3, whereas marine fish, which lack or have a very low activity of 5-desaturase, require the long-chain PUFAs, mainly from the n-3 series. This presentation will briefly review the status of knowledge on the relationship between EFA and immune functions with emphasis on eicosanoid production. Fish tissues contain relatively higher concentrations of PUFA than are found in those from mammals. PUFAs are important components of all cell membranes,
Dietary Fish, Fish Nutrients, and Immune Function: A Review
Frontiers in Nutrition
Dietary habits have a major impact on the development and function of the immune system. This impact is mediated both by the intrinsic nutritional and biochemical qualities of the diet, and by its influence on the intestinal microbiota. Fish as a food is rich in compounds with immunoregulatory properties, among them omega-3 fatty acids, melatonin, tryptophan, taurine and polyamines. In addition, regular fish consumption favors the proliferation of beneficial members of the intestinal microbiota, like short-chain fatty acid-producing bacteria. By substituting arachidonic acid in the eicosanoid biosynthesis pathway, long-chain omega-3 fatty acids from fish change the type of prostaglandins, leukotrienes and thromboxanes being produced, resulting in anti-inflammatory properties. Further, they also are substrates for the production of specialized pro-resolving mediators (SPMs) (resolvins, protectins, and maresins), lipid compounds that constitute the physiological feedback signal to sto...
Scientific Reports, 2019
The quality and relative amounts of dietary lipids may affect the health and growth of cultured Atlantic salmon. So far, little is known about their effects on the performance of the fish immune system during early life stages and, in particular their importance in the transition from endogenous nutrition (yolk) in the alevin stage to exogenous nutrition in the later fry stage. We investigated the immunomodulatory effects of fish oil, vegetable oil and phospholipid-rich oil in feeds for farmed Atlantic salmon using a transcriptomic approach. The experiment allowed a fine-scale monitoring of gene expression profiles in two tissues, the pyloric caeca of the intestine and the liver, in a 94 days-long first feeding experiment. The analysis of transcriptional profiles revealed that first feeding induced a strong immunomodulation in the pyloric caeca after 48 days of feeding, lasting up to day 94 and possibly beyond. On the other hand, the differential effect of the three dietary regimes was negligible. We interpret this upregulation, undetectable in liver, as a potentiation of the immune system upon the first contact of the digestive system with exogenous feed. This process involved a complex network of gene products involved in both cellular and humoral immunity. We identified the classical pathway of the complement system, acting at the crossroads between innate and adaptive immunity, as a key process modulated in response to the switch from endogenous to exogenous nutrition. The feeding regime in fish farming is a crucial factor in ensuring the health of animals and improving the quality of product for human nutrition. The aquaculture production of Atlantic salmon (Salmo salar) currently exceeds 2,000,000 tons per year, accounts for over 50% of the global production of salmonids and is rapidly growing worldwide 1. The requirements of this important sector include a continuous and adequate feed supply, to achieve a high quality, safe and sustainable animal product. Indeed, fish nutrition and the connected issues of overfeeding and waste production may have a direct impact both on fish and consumer welfare, and on the ecological quality of the environment 2. Although fish oil has been traditionally used as the main source of long chain polyunsaturated fatty acids (LC-PUFAs) in the aquaculture industry, the use of vegetable oil as a substitute increased significantly in recent years 3. Vegetable oil is devoid of LC-PUFA, but often contains high amounts of linoleic acid (LNA) or alpha-linolenic acid (ALA)-rich, which serve as sources of n-6 and n-3 fatty acids, respectively 4. The amount of LC-PUFAs present in fish tissues is related to the intake of dietary fatty acids 4. The content of phospholipids in the feeds is another aspect which needs to be taken into account, as they are key components of cell membranes and indispensable for normal growth and development, homeostasis 5 and modulation of immune defense against pathogens 6 .
British Journal of Nutrition, 2007
Within a decade or so insufficient fish oil (FO) will be available to meet the requirements for aquaculture growth. Consequently, alternative sources are being investigated to reduce reliance on wild fish as a source of FO. Vegetable oils (VO) are a feasible alternative to FO. However, it is important to establish that alternative dietary lipids are not only supplied in the correct quantities and balance for optimal growth, but can maintain immune function and prevent infection, since it is known that the nutritional state of the fish can influence their immune function and disease resistance. A way of maintaining immune function, while replacing dietary FO, is by using a blend of VO rather than a single oil. In this study, juvenile European sea bass (Dicentrarchus labrax) were fed diets with a 60 % substitution of FO with a blend of rapeseed, linseed and palm oils. Two oil blends were used to achieve a fatty acid composition similar to FO, in terms of energy content, and provide a similar balance of SFA, MUFA and PUFA. Fish were fed the diets for 64 weeks, after which time growth and fatty acid compositions of liver and blood leucocytes were monitored. The impact of the dietary blends on selected innate immune responses and histopathology were also assessed, together with levels of plasma prostaglandin E 2. The results suggest that potential exists for replacing FO with a VO blend in farmed sea bass feeds without compromising growth, non-specific immune function or histology.
Fish & Shellfish Immunology, 2017
The main objective of this study was to assess the effects of graded levels of dietary arachidonic acid (ARA), supplemented from alternative sources, on fatty acid composition of plasma and head kidney leucocytes of European sea bass (Dicentrarchus labrax). For that purpose, sea bass juveniles were fed four diets containing graded levels of ARA as follows: 0.5% (ARA0.5), 1% (ARA1), 2% (ARA2) and 4% (ARA4) during 60 days. At the end of the feeding trial fatty acid profiles of plasma and head kidney leucocytes were analyzed. Besides, plasma prostaglandins levels, head kidney leucocytes respiratory burst activity; peroxidase activity and phagocytic index were assayed. Reducing dietary ARA levels below 1% markedly reduced European sea bass growth performance. However, fish fed diet ARA0.5 tried to compensate this dietary ARA deficiency by a selective deposition of ARA on plasma and head kidney leucocytes, reaching similar levels to those fish fed diet ARA1 after 60 days of feeding. Nevertheless, head kidney phagocytic capacity was reduced as dietary ARA content in relation not only to variations on membrane composition but also to changes on fish basal prostaglandins levels. Results obtained demonstrated the importance to supply the necessary quantity n-6 LC-PUFA, and not only n-3 LC-PUFA levels, in European sea bass diets, in relation to not only growth performance but also immune system function.
Journal of the World Aquaculture Society, 2008
The effect of varying dietary lipid and n-3 polyunsaturated fatty acids (PUFAs) on growth, feed efficiency, protein and energy utilization, carcass quality, and nonspecific immune functions was investigated in rainbow trout reared at two different water temperatures (7.5 and 15 C). Six diets were formulated to contain 47% digestible protein and 21 MJ/kg digestible energy. Three of the diets were formulated to contain increasing lipid levels (10, 16, and 18%) and three additional diets formulated to 18% lipid with different lipid sources. Varying dietary lipid and n-3 PUFA levels had little effect on growth and on protein and energy utilization. Diet composition only had limited effect on susceptibility of the flesh to rancidity and on the nonspecific immunity of the fish. Increasing lipid levels did not affect fish carcass or fillet proximate composition. Replacing half of fish oil with beef tallow resulted in lower n-3 PUFAs in fish fillet but did not affect nutrient digestibility or growth performance of fish even at 7.5 C. Increasing dietary n-3 levels using a fish oil concentrate resulted in significant enrichment of n-3 PUFAs and elevated n-3 : n-6 ratio of the whole body and carcass. Water temperature significantly affected apparent digestibility coefficient (ADC) of protein and energy but did not affect the ADC of lipid, nor did it affect nitrogen and energy retention efficiencies. The study suggests that highly saturated fats, such as beef tallow, can be used to partially replace fish oil without negative effect on digestibility and growth even at low water temperature. High dietary n-3 PUFAs levels can be used to enrich n-3 PUFAs of the flesh without negative effect on the immune response.
n-3 Polyunsaturated fatty acids and immune function
Proceedings of the Nutrition Society, 1998
Considerable interest in fish oil was initially generated by epidemiological studies in Eskimos showing the beneficial effect of consuming fish and fish oil in preventing IHD (Dyerberg et al. 1978; Dyerberg & Bang, 1979). In the following two decades, investigations of fish oil have been motivated by, and extended to, many different aspects of health and disease. A wide spectrum of studies has revealed the ability of fish oil to affect the course of cardiovascular disease, autoimmune and inflammatory diseases, immune function, infection, allograft rejection, and certain cancers (Fernandes & Venkatraman, 1993; Calder, 1996). The biological effects of fish oil are attributed to their n-3 polyunsaturated fatty acids (PUFA), mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA can be incorporated into cell membranes where they influence membrane fluidity, receptor function, enzyme activity and production of lipid mediators. ~~ ~ ~~ Abbreviations: AA, arachidonic acid; ALA, a-linolenic acid; Con A, concanavalin A, DHA, docosahexaenoic acid; EPA, eicosapentaenoic acid IL, interleukin; LT, leukotriene; PBMC, peripheral-blood mononuclear cells; PG, prostaglandin; PHA, phytohaemagglutinin; PUFA, polyunsaturated fatty acids; TNF, tumour necrosis factor.