LIGHTNER: POSTMORTEM CHANGES IN BROWN SHRIMP 



the cuticle remaining by 4 h. Distant from the 

 hepatopancreas, the epidermis showed pyknotic 

 nuclei and cell rounding by 4 to 8 h (Figures 5a 

 and 5b). A slight hemocytic response was 

 present at this time in the subepidermal tissue 

 layers representing the only inflammatory- 

 like response observed in the study. 



The epidermis had frequently become de- 

 tached from the overlying cuticle by 12 to 24 

 h postmortem and many of the epidermal cells 

 had lysed, with those remaining having pyknotic 

 nuclei (Figure 5c). By 24 to 48 h nearly all 

 traces of the epidermis had been lost and in 

 some animals examined only cellular debris or 

 clumps of bacteria marked its former location 

 (Figure 5d). Though usually interrupted, the 



cuticle was the most resistant structure to 

 autolytic change and showed only slight histo- 

 logical change by 72 h. 



Gills 



The shrimp respiratory system consists of 

 paired gills in the branchial chambers of the 

 cephalothorax. The structure of the gills is 

 dendrobranchiate (Barnes. 1963). The gills are 

 covered by a thin cuticle underlain by a thin 

 epithelium and other supportive cells (Figure 

 6a). 



A peritrichous ciliated protozoan (Figure 6b), 

 presumably a commensal on shrimp (especially 

 common on the gills but also found elsewhere on 



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Figure 5. — a. Integument consisting of epidermis and overlying cuticle at 4 h postmortem. Some of the epidermal cells 

 possess pyknotic nuclei. A few hemocytes are present in the subepidermal tissues (arrows). 480x. b. Integument at 8 h 

 postmortem. Inflammatory cells are present in the subepidermal tissue. There is an increase in nuclear pyknosis in the 

 epidermis and in the subepidermal tissue. 300 X. c. Epidermis and cuticle at 24 h postmortem. All of the epidermal cells 

 have intensely pyknotic nuclei, as does all the subepithelial tissue. 600 X . d. Integument at 48 h postmortem. The cuticle is 

 present, but the epidermis is represented by debris (arrows). 750 X . 



231 



