P. Mayzaud et al., THE INFLUENCE OF FOOD QUALITY ON THE NUTRITIONAL ACCLIMATION OF THE COPEPOD ACARTIA-CLAUSI, Journal of marine systems, 15(1-4), 1998, pp. 483-493
The influence of food quality on the nutritional metabolism of Acartia
clausi was studied experimentally using four different diets: (1) dia
tom cells of Thalassiosira weissflogii, (2) detritus prepared from the
same culture, (3) 50:50 mix on a protein basis of the two previous di
ets, and 4) dinoflagellate cells of Prorocentrum micans. For each trop
hic, ingestion, gut transit time, trypsin activity and K-m (half satur
ation constant) were measured at limiting and saturating concentration
. Assimilation rates were also estimated for both pure diatoms and mix
ed live-detrital cell diets. Ingestion followed a Holling type 2 respo
nse for diets 1 and 4, a linear one for detritus and an intermediate r
esponse for diet 3. Gut transit time displayed different adaptive chan
ges with food regime depending on protein concentration. Trypsin activ
ity was lower for detrital food and trypsin K-m significantly decrease
d with increasing concentration of live diatoms. Assimilation rates we
re higher for live food than for mixed live-detrital food. Results ill
ustrated that Acartia-type copepods optimize nitrogen or protein uptak
e. They suggest that besides chemoreception-mediated selectivity, inte
rnal controls by digestion and assimilation also regulate ingestion (f
eed-back). (C) 1998 Elsevier Science B.V. All rights reserved.