Now showing items 1-3 of 3

    • Article

      Accumulation and excretion of metal granules in the prawn, Penaeus monodon, exposed to water-borne copper, lead, iron and calcium 

      G Vogt & ET Quinitio - Aquatic Toxicology, 1994 - Elsevier
      Juveniles of the giant tiger prawn, Penaeus monodon, were exposed for 10 days to 1 mg/l copper, lead, iron or calcium in order to investigate the formation and accumulation of metal granules in major soft tissues as well as their excretion from the body. Metal deposition was investigated by histochemistry and electron microscopy in the hepatopancreas and surrounding organs and tissues like the stomach, midgut, anterior midgut caecum, thoracal antennal gland extensions, haematopoietic tissue, and interspersed musculature, connective tissue and pigment tissue. The abundance of metal granules varied greatly between the metals and the tissues. Iron and calcium deposits were found in none of the tissues investigated. Copper granules were accumulated in high quantity in the hepatopancreas tubules, were scarce in the antechamber of the hepatopancreas, the anterior midgut and the anterior midgut caecum, and were lacking in the other tissues. The amount and size of copper granules increased along the hepatopancreas tubules in accordance with the cells' age. The granules were released by discharge of senescent hepatopancreas cells in the antechamber region and were added to the faeces. Lead granules were primarily found in the thoracal extensions of the antennal gland. In the hepatopancreas they occurred only in very small quantities, and in the other organs and tissues they were absent. In the antennal gland, the lead granules were individually discharged into the gland lumen by apocrine secretion and excreted with the urine. The observed ability of Penaeus monodon to detoxify and remove metals like copper and lead by granule formation and excretion and to prevent other metals like iron from entrance into major soft tissues corroborate that decapods are no suitable organisms for a long-term biomonitoring of heavy metal pollution.
    • Book chapter

      Fate and effects of water-borne heavy metals in Penaeus monodon 

      G Vogt & ET Quinitio - In N De Pauw & J Joyce (Eds.), Aquaculture and the environment: short communications and abstracts of contributions presented at the International Conference Aquaculture Europe '91, Dublin, Ireland, June 10-12, 1991, 1991 - European Aquaculture Society
      Heavy metals impair the aquaculture of shrimps and the quality of shrimp products. Some heavy metals occur in high amounts particularly in the hepatopancreas and the antennal gland (Gibson and Barker, 1979). This study was performed in order to determine whether copper, iron, and lead are accumulated in the hepatopancreas and the antennal gland extensions running along the hepatopancreas. Furthermore, damages of these metals and cadmium to the hepatopancreas cells were investigated. According to its commercial significance the giant tiger prawn, Penaeus monodon, was chosen as test species.
    • Conference poster

      Hepatopancreas cells as monitor cells for the nutritional value of prawn diets in aquaculture 

      G Vogt, FP Pascual & ET Quinitio - In Y Taki, J Primavera & JA Llobrera (Eds.), Proceedings of the First International Conference on the Culture of Penaeid Prawns/Shrimps, 4-7 December 1984, Iloilo City, Philippines, 1985 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The hepatopancreas is considered to be the central organ of metabolism in decapod Crustacea. It is a system of blind tubules consisting of four cell types. The E-cells at the summits of the tubules develop into R-cells (for resorption of nutrients), F-cells (for production of digestive enzymes) and B-cells (function unknown).

      The ultrastructure of Penaeus monodon R-cells changes largely after starvation and feeding different diets. B-cells show slight reactions, while F- and E-cells are rather constant. Thirteen day-starvation results in a large decrease of the cell size and in a significant reduction of all cell organelles. After seven days starvation and four days refeeding with various extreme diets, the R-cells develop completely different food-specific ultrastructures. A distinct proliferation of the endoplasmic reticulum is characteristic of protein diets. Large fat drops are the main feature after refeeding with cod liver oil. Sucrose feeding results in "empty" cells with only few organelles. The most diversified ultrastructure with fat droplets and a high amount of all cell organelles is obtained by feeding a mixed diet.

      The study indicates that R-cells are very sensitive to the application of different diets. They could be used as monitor cells for the nutritional value and the availability of a diet for prawns. Particularly poor or badly formulated feed could be detected early by electron microscopy. This method may be very helpful for the development of artificial prawn diets in aquaculture, especially if natural sources will be used as food components.