Intestinal steatosis in the farm-reared sea bass Dicentrarchus labrax

Abstract

Light microscopy, scanning and transmission electron microscopy were used to study the anterior intestine of the sea bass Dicentrarchus labrax L., involved in lipid absorption. In the first part of the study, intestinal morphology of control feral fishes was described and lipid absorption through the intestinal mucosa was defined by comparing starved and fed individuals. In the second part, similar investigations were made on specimens reared on artificial food. These show injuries of the mucosa, ranging from simple impairment of enterocytic striated border to cellular necrosis and abrasion. The severity of injuries was related to the extent of lipid overloading within the mucosa. This overloadng was mainly represented by abundant lipid droplets in epithelial cells, and by the accumulation of numerous and large lipid granules in interenterocytic spaces and in the lamina propria. Possible influences of artificial feed on this digestive pathology are discussed from quantitative and qualitative points of view.

Comparative study on the intestine of Schilbe mystus and Labeo niloticus in correlation with their feeding habits

“…This observation agrees with that of Deplano et al (1989), in Dicentrarchus labrax, Olsen et al (1999), in Salvelinus alpinus, Kozarić et al (2004), in Merluccius merluccius, andOlsen et al (2005), in Oncorhynchus mykiss, who stated that the presence of the endocytotic vesicles in the rectal enterocytes may be a complement to the luminal protein digestion by absorbing protein macromolecules. Moreover, Gargiulo et al (1998), in Tilapia spp, suggested that the endocytosis is followed by the intracellular digestion by the lysosomes.…”

“…These observations suggest that the enterocytes of the anterior portion of the intestine are involved in lipid absorption. This suggestion is in accordance with that of Stroband and Debets (1978), in Ctenopharyngodon idella, Anderson (1986), in Girella tricuspidata, Deplano et al (1989), in Dicentrarchus labrax, Olsen et al (1999), in Salvelinus alpinus, Gallagher et al (2001), in Lagodon rhomboids, Caballero et al (2003), in Sparus aurata, Kozarić et al (2004), in Merluccius merluccius, and Carrassón et al (2006), in Dentex dentex. Moreover, Fontagné et al (1998), in Cyprinus carpio, stated that the intestinal fat droplets can be interpreted as a temporary storage form of the re-esterified fatty acids.…”

Criteria for Safe Use of Plant Ingredients in Diets for Aquacultured Fish

“…REQUIREMENT Fish probably have an absolute requirement for phospholipids (PL), mainly phosphatidylcholine (PC) and possibly phosphatidylinositol (PI) (Coutteau et al 1997). The most striking example of this is seen in some marine larvae where lipid droplets tend to accumulate, sometimes in livers (Salhi et al 1999), but most commonly in enterocytes upon feeding with artificial or supplemented live feeds (Deplano et al 1989;Geurden et al 1997;Salhi et al 1999;Morais et al 2006;. The cause appears to be linked to impaired enterocyte lipoprotein synthesis where PC (and apolipoproteins) is needed to form a coat around the absorbed TAG enabling it to be transported out of the cell.…”

Postvalvular enterocytes in feral and farm-reared sea bass Dicentrarchus labrax; hypervacuolization related to artificial feed

“…We have previously described (Deplano et al 1989) the absorption of lipids in the proximal intestine of the immature sea bass Dicentrarchus labrax. Con~parison of feral and farm-reared individuals revealed detenoration of the mucosa resulting in lipid overloading in enterocytes and intercellular spaces, mainly caused by artificial feed.…”