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

Abstract

ABSTRACT. The postvalvular intestine of sea bass, which is involved in the absorption of protein macromolecules by pinocytosis, was studied by light microscopy, scanning electron microscopy and transn~ission electron microscopy. We describe the morphofunctional characteristics of this enteric region for control specimens from a natural environment. In comparison, we distinguished a disease affecting the intestine of farm-reared sea bass nourished with artificial feed. The disease is characterized by vacuolization and hypertrophy of enterocytes, combined with modifications of organelles (scarce mitochondrial cristae, enlarged elements of endoplasmic reticulum, pycnotic nucleus) and microvilli. It results in hypertrophy of intestinal folds and abrasion of degenerating epithelium. Observations of the intestine of farm-reared sea bass at different periods of the year showed that enterocyte vacuolization varies with season.

Effects of fasting and re-alimentation on gill and intestinal morphology and indicators of osmoregulatory capacity in genetically selected sea bass ( Dicentrarchus labrax ) populations with contrasting tolerance to fasting

“…Most individuals of the F+ population have enlarged ovoid supra-nuclear vacuoles, some filled with dense material. Similar enlarged vacuoles have already been observed in farm-reared sea bass overfed with artificial feed (Deplano et al, 1991). It is thus hypothesized that the F+ group is not as efficient in feed assimilation as the F-group.…”

Light and Scanning Electron Microscopic Studies on the Intestine of Grass Carp (Ctenopharyngodon idella): II-Posterior Intestine

“…Moreover, Deplano et al [13] and Sklan et al [14] stated that the abilities to absorb protein in the intestine of carnivorous fish are welldeveloped, but carbohydrate absorption is low compared to omnivorous and herbivorous fishes, while the absorption of protein is less developed in herbivorous fish. However the activity of pancreatic enzymes was maximal in anterior intestine and decreased distally.…”

“…Although, Iida and Yamamoto [16] and Deplano et al [13] reported the presence of pinocytotic vesicles and numerous vacuoles in the posterior intestine of both herbivorous and carnivorous fishes, which considered evidence of the uptake of undigested protein-like substances. This process begins by the proteins, which are incorporated into pinocytotic vesicles and transported to supranuclear vacuoles where they accumulate.…”

“…Although large lymphoid centers are lacking, many lymphoid cells, either scattered or in small groups were reported to be present in the epithelium and lamina propria, so that intraepithelial lymphocytes are necessary for a local or mucosal immune response [22]. Moreover, Deplano et al [13] demonstrated presence of IgM in gut mucus of some fish species and they concluded that the posterior intestine contained lymphoid cells, macrophages and plasma cells between the enterocytes or in lamina propria, which indicate the existence of local immune system in the intestine. Gastrointestinal endocrine cells are distributed in the mucosa of the gastrointestinal tract and they synthesize various kinds of gastrointestinal hormones.…”

Effect of dietary water content on European sea bass (Dicentrarchus labrax) growth and disease resistance

“…This observation was already reported in farm-reared Dicentrarchus labrax fed with commercial pellets and compared to fish from fishing fed with natural prey with 70-80% water content. Pronounced hypertrophy of the intestinal folds and abrasion-induced degeneration of the epithelium has been demonstrated in aquaculture fish (Deplano et al 1991).…”