Seasonal variation in the carotenoid pigment content and composition of Euphausia pacifica
Date
1989
Authors
Funk, Valerie A.
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Abstract
The carotenoid pigment content and composition of Euphausia paciftca, a preferential herbivore, was determined at monthly intervals from March, 1988 to May, 1989 to determine whether or not season and/or sexual maturity affected the carotenoid content/composition. The total weight specific carotenoid content varied from 306-536 µg/g dry weight over the 15 month period . The maximum occurred in February and March, just prior to sexual maturity and spawning, and the minimum occurred in October, 1988. The weight specific carotenoid content remained relatively constant throughout the summer and ea rly fa ll (June-Nov., 1988) and then increased over the winter as the average dry weight of the euphausiid population decreased. The data suggested that E. paciftca utilized energy stores such as lipid and protein preferentially to carotenoid pigments during times when the food supply was limited. E . paciftca also appeared to accumulate carotenoid pigments on an individual basis during early spring (Feb.-Apr. ,1989) in preparation for spawning. Results from two-dimensional silica TLC and RP-HPLC suggest that 90% of the carotenoid pigments present in E. paciftca consist of astaxanthin , its mono- and diesters each contributing 5, 49, and 40 %, respectively. The astaxa nthin molecules appear to be esterified to only two diffe rent fa tty acids; the combinations producing two monoesters and three diesters. The relative contribution of all the carotenoid fractions isolated from E. paciftca remained remarkably constant throughout the study period suggesting functional importance.