The role of phospholipids in nutrition and metabolism of teleost fish

Abstract

27It has been known for almost 25 years now that inclusion of intact phospholipids in the diet could 28 improve culture performance of various freshwater and marine fish species. The primary 29 beneficial effect was improved growth in both larvae and early juveniles, but also increased 30 survival rates and decreased incidence of malformation in larvae, and perhaps increased stress 31 resistance. Determination of absolute dietary requirements has been hampered by the use, in 32 different dietary trials, of a wide range of phospholipid preparations that can vary greatly both in 33 phospholipid content and class composition. Larval studies have been compromised further by the 34 need on many occasions to supply phospholipid through enrichment of live feeds with subsequent 35 re-modelling of the phospholipid and fatty acid compositions. Generally, the levels of 36 phospholipid requirement are around 2 -4% of diet for juvenile fish and probably higher in larval 37 fish. The effects were restricted to young fish, as a requirement for dietary phospholipids has not 38 been established for adult fish, although this has been virtually unstudied. As the majority of 39 studies have used crude mixed phospholipid preparations, particularly soybean lecithin, but also 40 other plant phospholipids and egg yolk lecithin, that are enriched in several phospholipids, it has 41 been difficult to elucidate which specific phospholipid classes impart beneficial effects. Based on 42 the few studies where single pure phospholipid species have been used, the rank order for efficacy 43 appears to be phosphatidylcholine > phosphatidylinositol > phosphatidylethanolamine > 44 phosphatidylserine. The efficacy of other phospholipid classes or sphingolipids is not known. The 45 mechanism underpinning the role of the phospholipids in larval and early juvenile fish must also 46 explain their lack of effect in adult fish. The role of phospholipids appears to be independent of 47 fatty acid requirements although the presence of an unsaturated fatty acid at the sn-2 position may 48 be important. Similarly, the phospholipid requirement is not related to the delivery of other 49 essential dietary components such as the bases choline and inositol. Studies also suggested that the 50 phospholipid effect was not due to generally enhanced emulsification and digestion of lipids. 51Rather the evidence led to the hypothesis that early developing stages of fish had impaired ability 52 to transport dietary lipids away from the intestine possibly through limitations in lipoprotein 53 synthesis. The current hypothesis is that the enzymic location of the limitation is actually in 54 phospholipid biosynthesis, perhaps the production of the glycerophosphobase backbone and that 55 dietary supplementation with intact phospholipids in larvae and juvenile fish compensated for this. 56

Lipid and fatty acid compositions of cod (Gadus morhua), haddock (Melanogrammus aeglefinus) and halibut (Hippoglossus hippoglossus)

“…These results agreed well with those previously reported on dogfish, Scyliorhinus canicula, cod, Gadus morhua (Bell et al, 1983;Bell and Tocher, 1990) and rainbow trout, Salmo gairdneri (Tocher, 1993). The relatively constant phospholipid composition in fish tissue indicates that phospholipids play a key role in the maintenance of metabolic and structural function in fish (Sargent et al, 1989, Tocher et al, 2008.…”

Macronutrient Requirements of Silvery-Black Porgy (Sparidentex hasta): A Comparison with Other Farmed Sparid Species

“…15%) diets that were formulated with graded ratios of DHA/EPA (0.2, 0.4, 0.9, 2.0, and 3.3). No statistically significant differences were observed in growth (SGR and WG) and feed utilization parameters among different treatments, whereas, in other sparid species, the best growth performance in juvenile P. major [126] and juvenile S. aurata [127] was reported to occur at a DHA/EPA ratio of 0.5. However, in the study from Mozanzadeh et al [125], SGR and FCR values in S. hasta juveniles were not affected by different dietary DHA/EPA ratios, possibly reflecting species-specific differences with regard to P. major [113] and S. aurata [126].…”

“…As important part of cell membranes, PLs play a major role in maintaining the structure and function of membranes, as well as in the formation of cell organelles [127,128]. PLs also improve intestinal absorption of lipids by acting as emulsifiers in the chyme, as well as stimulating lipoprotein synthesis in enterocytes and lipid transport, reducing lipid accumulation in the intestine.…”

“…PLs also improve intestinal absorption of lipids by acting as emulsifiers in the chyme, as well as stimulating lipoprotein synthesis in enterocytes and lipid transport, reducing lipid accumulation in the intestine. In addition, it has been suggested that PLs may improve diet quality by reducing the leaching of water-soluble micronutrients, acting as antioxidants, as well as feed attractants and providing choline, inositol, phosphorus and EFA that are essential for fish growth [127,128]. The optimal level of dietary PL supplementation depends on the species, developmental stage, culture conditions, and PL source [127].…”

Crustacean amphipods from marsh ponds: a nutritious feed resource with potential application in Integrated Multi-Trophic Aquaculture.

“…In addition, Valine is involved in synthesis of myelin covering od the nerves 348 (Cowey and Walton, 1988; Brosnan and Brosnan, 2006). , 1997; Fontagne 357 et al, 1998;Salhi et al, 1999;Tocher et al, 2008). Studied amphipods have a similar range of 358 phospholipids (PL) but higher TAG dispersion, with M. acherisicum and M. palmata showing 359 the higher levels of PL and TAG than other preys (Table 8).…”