Bisbal and Bengtson. Starvation in early life stages of Paralichthys dentatus 



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 Figure 2 



Summer flounder, Paralichthys dentatus, 16-day-old larvae. Morphometries, gravi- 

 metric, and biochemical changes during ad libitum feeding ( ) or starvation ( • ). 

 (A) standard length; (B) dry weight; (C) eye diameter/head height ratio; (D) pec- 

 toral angle; (E) RNA:DNA ratio; (F) total proteins. Symbols represent the arith- 

 metic mean of samples of 9-10 animals iStandard Error. Asterisks indicate a 

 statistically significant difference between fed and starved groups at a particu- 

 lar sampling time. 



of starved juveniles remained consistently lower than 

 those of fed juveniles at all times (^=3.05, P=0.007, 

 at 72 h; Fig. 4E). During the experimental period, 

 fed fish maintained a mean ratio between 8 and 9. 

 In contrast, the ratio in starved fish dropped from 

 an initial value of 8.49 to a final value of 4.86, a 68% 

 difference from the fed group. Differences in mean 

 total proteins were significant at 72 hours U 17 =3.46, 

 P=0.003) and 216 hours (i 18 =2.71, P=0.014; Fig. 4F). 



Histology 



The trunk musculature in fed larvae was striated, 

 closely packed, and composed of parallel myofibrils 

 over the lateral surfaces of the notochord (Fig. 5A). 

 However, under starving conditions, the fibrils were 

 not distinguishable and their parallel orientation was 

 disrupted. Further, muscle fibers were widely sepa- 

 rated because of shrinkage of the cells (Fig. 5B). In 6 



and 16-day-old larvae, degradation of skeletal muscle 

 was evident after 24 hours of starvation. In 33-day- 

 old larvae and 60-day-old juveniles, this effect was de- 

 tected after 72 and 144 hours of starvation, respectively. 

 Hepatic tissue of fed larvae appeared continuous 

 and compact, composed of hepatic cells organized in 

 typical liver cords (Fig. 5C). The hepatocytes had a 

 bulky cytoplasm with low staining affinity, several 

 vacuolar inclusions, and round nuclei in their cen- 

 ters. Conversely, liver tissue of starving larvae was 

 fractionated and exhibited loss of the cellular cord 

 arrangement and contained wide intercellular spaces 

 (Fig. 5D). The cytoplasm was severely collapsed and 

 deeply stained (there were no vacuolar spaces) and 

 contained heavily pigmented eccentric nuclei of ir- 

 regular shape. Liver deterioration was detected af- 

 ter 24, 48, 120, and 144 hours of food deprivation in 

 6, 16, 33-day-old larvae, and 60-day-old juveniles, 

 respectively. 



