Effects of long-term starvation on hepatocyte ultrastructure of olive flounder Paralichthys olivaceus

Abstract

The effects of nutritional conditions on alterations in condition factor, liver-somatic index, and hepatocyte ultrastructure in the olive flounder Paralichthys olivaceus were examined. Twelve weeks of starvation significantly decreased the condition factor and the liver-somatic index in the olive flounder. Hepatocytes underwent marked ultrastructural changes in response to 12 weeks of starvation. Compared to those of the initial control and fed group, the prominent features characterizing the hepatocytes of the starved group were: reduction in cell and nucleus size; apparent loss of nucleoli; condensation of chromatin; loss of stored glycogen; reduction of endoplasmic reticulum profile; increase in the number of electron-dense bodies containing large amounts of iron; and increased mitochondrial size. Results suggest that the histological changes caused by ultrastructural alterations in the hepatocytes can be used as alternative indicators to identify starvation in cultured P. olivaceus.

The effect of starvation on the liver of Aphanius dispar (Pisces; Cyprinodontidae): A microscopic study

“…The effects of starvation on the liver of juvenile flounders showed a decrease in stored products, reduction of endoplasmic reticulum, increased numbers of lysosomes and macrophages, proliferation of collagenous fibers and dissolution of cell junctions [14,6]. The results obtained in our study were similar to findings on the olive flounder in that the size of mitochondria increased due to starvation.…”

“…Widened intercellular spaces are indicative of the decreasing size of some cells, where the diameter of the cell nucleus is reduced. There was also depletion of glycogen and lipid in the cell, condensation of chromatin material and depletion of ribosome-studded ER [15,6]. As seen in flounders, the starved A. dispar rapidly lost vitality after 96 hours of starvation.…”

“…Many empty spaces were observed in light micrographs and this could be correlated to the decrease in the size of hepatocytes or the breakdown of tissue by apoptosis caused by starvation. Many fish go through natural periods of starvation and consequently have to overcome starvation using biochemical, physiological, and behavioral strategies [6]. The effects of nutrient depletion during starvation are quite different in each fish organ [8].…”

“…In the starved groups, cell junctions often were dissolved, except in those complexes surrounding bile canaliculi. This finding indicates metabolic dysfunction and disturbed communication at the tissue level [6].…”

“…During starvation, there is a rapid depletion of energy forcing the animal to use its stored reserves in tissues and cells in order to stay alive [6].…”