A. Garciaortega et al., BIOCHEMICAL AND ENZYMATIC CHARACTERIZATION OF DECAPSULATED CYSTS AND NAUPLII OF THE BRINE SHRIMP ARTEMIA AT DIFFERENT DEVELOPMENTAL STAGES, Aquaculture, 161(1-4), 1998, pp. 501-514
Decapsulated Artemia cysts were used to study the factors which induce
the superior performance of live organisms as food for fish larvae. T
he biochemical composition, the in vitro protein digestibility, and th
e total proteolytic and trypsin activities in cysts and nauplii of Art
emia were determined at different developmental stages as a function o
f incubation time. Six different incubation times were studied: 1, 6,
ii, 16, 21 and 25 h of development, which cover cyst and early nauplii
stages. The individual dry weight of Artemia decreased through develo
pment. The individual protein and lipid content (mu g ind(-1)) remaine
d constant during development until the time of hatching after which t
hey decreased slightly. However, no significant incubation effect was
found. Small changes in amino acid and fatty acid composition were fou
nd during development, but is assumed that they are too small to be of
nutritional importance to fish larvae. No major changes were observed
in protease activities measured at acid and alkaline pH during the fi
rst 25 h of development. From the alkaline proteases, no significant c
hange in trypsin activity was detected during cyst and early nauplii d
evelopment. From the point of view of exogenous enzyme contribution to
fish larvae, there seems to be no difference whether feeding decapsul
ated cysts or newly hatched nauplii, since no difference in qualitativ
e protease composition was found during the first 25 h of Artemia deve
lopment. The relative contribution of Artemia proteases to the digesti
on of food by fish larvae is discussed. (C) 1998 Elsevier Science B.V.