Adipocytes and lipid distribution in the muscle tissue of Atlantic salmon (<i>Salmo salar</i>)

Zhou, Shengying; Ackman, R. G.; Morrison, Carol M.

doi:10.1139/f95-197

Cited by 72 publications

(43 citation statements)

References 17 publications

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“…3b) resembled mammalian white adipose tissue cells. These oil sacs also show similarity to the adipocytes of fish tissues (Zhou et al 1996). During reproduction or periods of low food, oil sac wax esters or triacylglycerols are used for energy and materials.…”

Section: Oil Sacmentioning

confidence: 89%

Lipid storage in marine zooplankton

Lee

Hagen²,

Kattner³

2006

Mar. Ecol. Prog. Ser.

643

548

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Zooplankton storage lipids play an important role during reproduction, food scarcity, ontogeny and diapause, as shown by studies in various oceanic regions. While triacylglycerols, the primary storage lipid of terrestrial animals, are found in almost all zooplankton species, wax esters are the dominant storage lipid in many deep-living and polar zooplankton taxa. Phospholipids and diacylglycerol ethers are the unique storage lipids used by polar euphausiids and pteropods, respectively. In zooplankton with large stores of wax esters, triacylglycerols are more rapidly turned over and used for short-term energy needs, while wax esters serve as long-term energy deposits. Zooplankton groups found in polar, westerlies, upwelling and coastal biomes are characterized by accumulation of large lipid stores. In contrast, zooplankton from the trades/tropical biomes is mainly composed of omnivorous species with only small lipid reserves. Diapausing copepods, which enter deep water after feeding on phytoplankton during spring/summer blooms or at the end of upwelling periods, are characterized by large oil sacs filled with wax esters. The thermal expansion and compressibility of wax esters may allow diapausing copepods and other deep-water zooplankton to be neutrally buoyant in cold deep waters, and they can thus avoid spending energy to remain at these depths. Lipid droplets are often noted in zooplankton ovaries, and a portion of these droplets can be transferred to developing oocytes. In addition to lipid droplets, zooplankton eggs have yolks with lipovitellin, a lipoprotein with approximately equal amounts of protein and lipid. The lipovitellin lipid is predominantly phosphatidylcholine, so during reproduction females must convert a portion of their storage lipid into this phospholipid. Developing embryos use their lipovitellin and lipid droplets for energy and materials until feeding begins. The various functions storage lipids serve during the different life history stages of zooplankton are very complex and still not fully understood and hence offer a multitude of fascinating research perspectives.

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Section: Oil Sacmentioning

confidence: 89%

Lipid storage in marine zooplankton

Lee

Hagen²,

Kattner³

2006

Mar. Ecol. Prog. Ser.

643

548

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“…Adipose tissue is distributed in the abdominal cavity located periviscerally in many fish species, including gilthead seabream. Few studies have analyzed the morphology and distribution of adipose cells in visceral fat and muscle of salmonids (9,42). Although there is abundant literature on the endocrine control of adipocyte function in either isolated or cultured mammalian adipose cells (16,40), this in vitro model has not been fully studied in fish (23,38,41).…”

Section: Discussionmentioning

confidence: 99%

Nutritional and hormonal control of lipolysis in isolated gilthead seabream (Sparus aurata) adipocytes

Albalat¹,

Gómez‐Requeni²,

Rojas³

et al. 2005

American Journal of Physiology-Regulatory, Integrative and Comp

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-We examined the effects of diet composition and fasting on lipolysis of freshly isolated adipocytes from gilthead seabream (Sparus aurata). We also analyzed the effects of insulin, glucagon, and growth hormone (GH) in adipocytes isolated from fish fed with different diets. Basal lipolysis, measured as glycerol release, increased proportionally with cell concentration and time of incubation, which validates the suitability of these cell preparations for the study of hormonal regulation of this metabolic process. Gilthead seabream were fed two different diets, FM (100% of fish meal) and PP (100% of plant protein supplied by plant sources) for 6 wk. After this period, each diet group was divided into two groups: fed and fasted (for 11 days). Lipolysis was significantly higher in adipocytes from PP-fed fish than in adipocytes from FM-fed fish. Fasting provoked a significant increase in the lipolytic rate, about threefold in isolated adipocytes regardless of nutritional history. Hormone effects were similar in the different groups: glucagon increased the lipolytic rate, whereas insulin had almost no effect. GH was clearly lipolytic, although the relative increase in glycerol over control was lower in isolated adipocytes from fasted fish compared with fed fish. Together, we demonstrate for the first time that lipolysis, measured in isolated seabream adipocytes, is affected by the nutritional state of the fish. Furthermore, our data suggest that glucagon and especially GH play a major role in the control of adipocyte lipolysis.fish; nutritional and hormonal regulation; insulin; glucagon; growth hormone; fasting ADIPOSE TISSUE PLAYS A CENTRAL role in energy homeostasis in storing lipids in the form of triacylglycerols and in mobilizing them via breakdown into free fatty acids (FFAs) and glycerol (34). Adipose tissue is one of the most important lipid stores in several teleosts, although in some species liver or muscle also constitutes lipid storage organs (33). In salmonids, adipose tissue is distributed primarily in the abdominal cavity, associated with the mesenteric and pyloric ceca (31). In gilthead seabream, adipose tissue is also located periviscerally. It is known that fish adiposity changes seasonally and is affected by trophic status. High-fat feeds can lead to increases in visceral fat (4), resulting in reduced product yield and quality of cultured fish (7). In gilthead seabream, replacing fish meal with plant protein seems to alter lipid metabolism and results in smaller fat depots (10).Endocrine control of adipose tissue mobilization and storage remains almost unexplored in fish, although insulin and glucagon are clearly involved (12,24,28). Key hepatic enzymes in lipid metabolism such as hepatic lipase and acetyl-CoA carboxylase are also regulated by pancreatic hormones in vitro in isolated hepatocytes or in vivo in injected fish (13,21). Several in vivo studies suggest that growth hormone (GH) and somatolactin act together, in a complementary way, to regulate fat stores in gilthead seabream (4, 20). Howev...

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“…Thus, in the red muscle, it is stored as droplets within the fibres, whereas in the white muscle, lipids accumulate within adipocytes mainly located in the myosepta, (i.e. the connective tissue surrounding the fibres; Jafri, 1973;Henderson and Tocher, 1987;Zhou et al, 1996;Nanton et al, 2007).…”

Section: Imf and Marbling: Definition And Role In Palatability Of Meamentioning

confidence: 99%

Intramuscular fat content in meat-producing animals: development, genetic and nutritional control, and identification of putative markers

Hocquette

Gondret

Baéza³

et al. 2010

Animal

632

447

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Intramuscular fat (IMF) content plays a key role in various quality traits of meat. IMF content varies between species, between breeds and between muscle types in the same breed. Other factors are involved in the variation of IMF content in animals, including gender, age and feeding. Variability in IMF content is mainly linked to the number and size of intramuscular adipocytes. The accretion rate of IMF depends on the muscle growth rate. For instance, animals having a high muscularity with a high glycolytic activity display a reduced development of IMF. This suggests that muscle cells and adipocytes interplay during growth. In addition, early events that influence adipogenesis inside the muscle (i.e proliferation and differentiation of adipose cells, the connective structure embedding adipocytes) might be involved in interindividual differences in IMF content. Increasing muscularity will also dilute the final fat content of muscle. At the metabolic level, IMF content results from the balance between uptake, synthesis and degradation of triacylglycerols, which involve many metabolic pathways in both adipocytes and myofibres. Various experiments revealed an association between IMF level and the muscle content in adipocyte-type fatty acid-binding protein, the activities of oxidative enzymes, or the delta-6-desaturase level; however, other studies failed to confirm such relationships. This might be due to the importance of fatty acid fluxes that is likely to be responsible for variability in IMF content during the postnatal period rather than the control of one single pathway. This is evident in the muscle of most fish species in which triacylglycerol synthesis is almost zero. Genetic approaches for increasing IMF have been focused on live animal ultrasound to derive estimated breeding values. More recently, efforts have concentrated on discovering DNA markers that change the distribution of fat in the body (i.e. towards IMF at the expense of the carcass fatness). Thanks to the exhaustive nature of genomics (transcriptomics and proteomics), our knowledge on fat accumulation in muscles is now being underpinned. Metabolic specificities of intramuscular adipocytes have also been demonstrated, as compared to other depots. Nutritional manipulation of IMF independently from body fat depots has proved to be more difficult to achieve than genetic strategies to have lipid deposition dependent of adipose tissue location. In addition, the biological mechanisms that explain the variability of IMF content differ between genetic and nutritional factors. The nutritional regulation of IMF also differs between ruminants, monogastrics and fish due to their digestive and nutritional particularities.

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Adipocytes and lipid distribution in the muscle tissue of Atlantic salmon (Salmo salar)

Cited by 72 publications

References 17 publications

Lipid storage in marine zooplankton

Lipid storage in marine zooplankton

Nutritional and hormonal control of lipolysis in isolated gilthead seabream (Sparus aurata) adipocytes

Intramuscular fat content in meat-producing animals: development, genetic and nutritional control, and identification of putative markers

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