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Abstract:Carapace of commercial crustaceans species (mantis shrimps ; Erugosquilla. massavensis, the penaeid shrimps ; Peaneus. semisulcatus ; Metapenaeus monoceros and blue crab; Portunus pelagicus ) and commercial mollusks (cuttlefish ; Sepia and bivalve mollusks; Cardium edule) were chosen for this study to assess carbohydrates, protein, lipids and to estimate their Fe, Cu, Co, Hg, Pb and Cd contents, as an attempt to use the carapace of marine invertebrates organisms as a cheap protein animal feed. Additionally, to investigate the interrelation between the exoskeleton of these marine animals and water pollution. In the terms of nutritive quality, the present results show that the carapace of both sex of E. massavensis was the richest nutritive source compared to that of all studied samples. Furthermore, the recorded data indicate that the exoskeleton of all studied crustaceans organisms and the internal shell of cephalopod mollusks had higher nutritive contents than the exoskeleton of bivalve mollusks. Concerning with heavy metal bioaccumulation, the present study show that the carapace in both sexes of E. massavensis accumulated higher percentages of the determined metals than those of other studied crustaceans species. On the other hand, Sepia spp. exhibited the lowest levels of the studied metals comparable to crustaceans and C. edule species. While, all species of C. edule accumulated the higher concentrations of Fe, Co, Pb and Cd in their shells than those in all studied crustaceans species. In this respect, the values of Metal Pollution Index (MPI) of studied essential elements in all studied species were higher than that of non-essential elements. Moreover, the highest values of essential and non-essential elements were recorded in all E. massavensis and C. edule samples respectively. While, the lowest level was detected in Sepia spp. followed by crab species. This primary work is an attempt to pursue further research in this line and will also be useful in the preparation of value added sea foods; the findings of the current study may help to select the appropriate species for animal feed. Moreover, the present study suggests that the exoskeleton of crustaceans and bivalves mollusks can be used as indicator of water pollution and this suggest their tendency to detoxification mechanism of heavy metals as a mean of protection. This in turn suggests that a close monitoring program is need to ensure the safety of these crustacean and mollusks species as a food source for animals.

Abstract:Penaeus indicus is a valued crustacean species. Currently P. indicus is mainly cultured in many areas of the world to overcome the increase of population consumption. Yet, the biochemical composition of this species is still inadequately understood. So, the purpose of the present work was, therefore, to assess the protein, carbohydrates, lipid , vitamins B 1 , B 2 , amino acids, minerals and protein electrophoresis to evaluate the nutritive quality of this cultured prawn. In the present study, nutritional analysis of muscle of both sexes indicated that the presence of a high amount of protein, 9 essential amino acids and 7 non-essential amino acid. Furthermore, the edible portion of females had the highest levels of vitamin B 1 and B 2 compared with their males. While, mineral contents of muscles of male indicate this decreasing arrangement S > P > Ca > Zn > K > Na >Se and females had this order S > P > Zn> Ca > K > Na >Se. From the electrophoretic analysis of protein, 13 bands were identified around molecular weight 10.42 to121.07 KD, while the electrophoretic analysis of muscle of females showed 14 bands with molecular weight ranged from 10.09 to 198.7 KD. Regarding the results obtained in the present study in light of nutritional point of view commercial culture P. indicus is considered to be very good crustaceans species and can be very well used as food for human consumption .

White spot syndrome virus (WSSV) is the causative agent of a disease which has recently caused high shrimp morbidity, mortality and severe damage to shrimp cultures. In this study a strain of WSSV from tiger shrimp Penaeus monodon was used to detect DNA damage in muscle cells by using Comet Assay. The term "comet" refers to the pattern of DNA migration through the electrophoresis gel, which often resembles a comet. The present results declare that Comet Assay is a rapid, simple, visual and sensitive technique for detecting and analyzing DNA in damaged cells. In WSSV infected shrimps, damaged cells looked like a tiny comet under a microscope. When DNA is broken in infected cells it forms a tail that moves away from the unbroken DNA. The amount of DNA damage in cells was estimated from comet tail length as the extent of migration of the genetic material. Significant increases in intensity percentage of DNA tail portion, tail length and tail moments of infected shrimps were observed in comparison with normal healthy shrimps. Furthermore, the clinical signs of white spot disease were also discussed in this study.