The importance of dietary beta-carotene for somatic growth of juvenile green sea urchins (Strongylocentrotus droebachiensis)

摘要

Based on earlier work, we conducted an experiment to determine the somatic growth require-ments of juvenile green sea urchins, Strongylocentrotus droebachiensis, for the pigment beta-carotene. Two different populations of sea urchins (one from British Columbia and one from New Brunswick) were individ-ually housed in tanks with flowing seawater and fed a standard prepared diet containing purified beta-carotene at a concentration of 0, 50, 100 or 250 mg/kg. Results indicated that the lowest concentration of 50 mg/kg significantly increased the growth rate in wet weight of the juveniles over the control (0 mg/kg), but the former treatment was not significantly different from any of the other pigment treatments. There was no difference in growth between the two urchin populations (BC or NB). The morphology of the test changed over time as the relative test height of the control urchins increased more than that of urchins fed diets incorporating beta-carotene, implying that test diameter is not always an independent indicator of growth performance. The gonad dex of the juveniles was found to decrease with increasing concentrations of beta-carotene while the test index increased, suggesting that beta-carotene is beneficial for test growth in juvenile green sea urchins.