Digestive enzyme profiles
reveal digestive capacity and potential energy sources in fed and starved
spiny lobster (Jasus edwardsii) phyllosoma larvae
D.J. Johnston, A.J. Ritar, C.W. Thomas-2004
Comparative Biochemistry and Physiology, part B: Biochemistry and Molecular
Biology, 138(2): 137-144
Abstract:
The impact of starvation on the digestive enzyme
(protease, trypsin, lipase and amylase) activities of Stage I and IV Jasus
edwardsii phyllosoma larvae was used to identify the nutrients
metabolised or conserved during food deprivation, highlighting the most
critical energy reserves. Protease activities increased significantly in
both Stages I and IV phyllosoma, suggesting that protein catabolism provided
energy during food deprivation. Lipase activity decreased significantly in
starved Stages I and IV larvae indicating that lipid may be spared for
fuelling later developmental moults. The use of protein, while sparing
lipid, may provide immediate energy but not at the expense of long-term
lipid energy stores which are known to be important during their lengthy
larval phase. The preferential use of protein during short-term periods of
starvation suggests that particular attention must be given to providing
sufficient protein in artificial diets at all times. Amylase activity in
starved Stage I larvae was lower than in fed animals, suggesting that the
starved animals are not gaining sufficient carbohydrate. However, amylase
activity was similar in fed and starved Stage IV larvae, possibly due to the
catabolism of accumulated glycogen stores that were not sufficiently
developed in Stage I animals.