Between 30 and 50 shrimp, depending on the development stage, were collected at
M , PL , PL , and PL stages from each treatment for enzyme assays. All samples
were collected between 10:00 and 12:00 h, 2–4 h after feeding. Shrimp were washed
with distilled water and immediately frozen at 2708C in 1-ml micro-test tubes until
enzyme assays were done. Frozen samples were homogenized in 500-ml ice-cold
de-ionized water. Homogenates were centrifuged at 16 0003g for 6 min at 48C. Part of
the supernatant was diluted in 10 volumes of ice-cold de-ionized water. Homogenates
(crude or diluted) were immediately used for enzyme analysis.