Evaluation of practical diets in the culture of the rabbitfish, Siganus guttatus (Bloch) (Pisces: Siganidae) using liver ultrastructural methods

Abstract

The starvation-induced ultrastructural modifications in the hepatocytes were reversed when Siganus guttatus resumed feeding on a suitable feed. The liver cells regained their structural integrity soonest when the fish was refed Chaetomorpha, whereas the other diets tested promoted inferior results or even caused deleterious effects. Prolonged feeding on sucrose provided insight on the nutritional orientation of this herbivorous fish.

A 14-day starvation period resulted in the mobilization of fuel reserves indicated by a decrease and total loss of glycogen and lipids, respectively. Organelle morphology was slightly affected by the short-term fast, but was severely disturbed as the fish were deprived of food over prolonged periods . Severe starvation was demonstrated through the deformation of the nuclei and the swelling of the mitochondria. These findings provide support on the practicability of liver ultrastructural methods as supplementary tool in diagnosing the nutritional state of fish.