LIGHTNER: POSTMORTEM CHANGES IN BROWN SHRIMP 



Table 3. — Time ui' appearance of poslmortem spoilage- 

 odor in whole shrimp held at 10", 20", and 30"C in air and 



Table 4. — Rate of poslmortem histologic change 

 shrimp held in air or seawater at three temperatures. 



indicated by a loo.sening of the junction of the 

 cephalothorax and abdomen. By 48 h the junc- 

 tion was very loose and Vjy 72 h the tissues of 

 the junction appeared mostly liquified. At IC 

 and 20 'C the same process was observed but at 

 a proportionately slower rate. 



Histological Observations 



Since the same patterns of autolysis were seen 

 in .shrimp held at all three temperatures, the 

 differences l>eing a function of time (Table 4), 

 only the histological re.sults from the 30 '-C 

 portion will be presented in the text. The only 

 significant histological differences between 

 groups held in air and water noted were the 

 more rapid tissue decomposition due to increased 

 bacterial action in animals held submerged in 

 seawater. 



Digestive Tract 



According to Roberts (1966j, the digestive 

 tract in shrimp is composed of three divisions: 

 flj the foregut, which includes the mouth, 

 esophagus, stomach, and associated glands; 

 (2) the midgut and hepatopancreas; and (3) 

 the hindgut. Of these organs the hepatopancreas, 

 the foregut, and midgut were studied in detail. 

 The hindgut was not .studied. 



Hepatopancreas 



The glandular hepatopancreas is the first 

 organ to undergo autolytic change (Figure la). 

 This organ is a compound tubularacinar exocrine 

 gland composed of tubules which end in blind 

 sacs or acini. The tubules and acini are lined 

 with a simple low to high columnar epithelium 

 (Figure Ibj. Autolysis of the epithelium of this 



b. Midgut epithelium. 



Temperoture (^•'C) 



H postmortem 







2 



4 



8 



12 



24 



48 



72 



lO'C 



20 ''C 



30 -C 



Air Water Air Water Air Water 



0* 



r 



2 

 4 



5 

 5 

 5 







1 



1-2 



4-5 



2 



5 

 5 





 1 

 1-2 



4 

 5 

 5 

 5 





 1-2 



3 

 5 

 5 



c. Abdominal muscle. 



- No observation made. 



Average assigned values from a scale of to 5 denoting the 

 general histological appearance of the tissue or organ. 



= 



3 = 



4 = 



5 = 



appearance, like the control, no post- 

 pyknotic nuclei, slight stoining 



Normal histologic 



mortem change. 



Slight chonge, scattered 



differences. 



AAore advanced cellular chonge with increases in nuclear 



pyknosis, koryrhexis, koryolysis, some cytolysis; loss of 



normal appearance or structure of the tissue or organ. 



Further odvonced change with no normal oppeoring areas. 



Advonced autolytic change, tissue or organ represented 



by cellular debris or by its fibrous or cuticulor stroma. 



Complete outolysis, tissue or organ no longer demon- 



stroble. 



225 



