Carotenoids of Sea Angels Clione limacina and Paedoclione doliiformis from the Perspective of the Food Chain

Abstract

Sea angels, Clione limacina and Paedoclione doliiformis, are small, floating sea slugs belonging to Gastropoda, and their gonads are a bright orange-red color. Sea angels feed exclusively on a small herbivorous sea snail, Limacina helicina. Carotenoids in C. limacina, P. doliiformis, and L. helicina were investigated for comparative biochemical points of view. β-Carotene, zeaxanthin, and diatoxanthin were found to be major carotenoids in L. helicina. L. helicina accumulated dietary algal carotenoids without modification. On the other hand, keto-carotenoids, such as pectenolone, 7,8-didehydroastaxanthin, and adonixanthin were identified as major carotenoids in the sea angels C. limacina and P. doliiformis. Sea angels oxidatively metabolize dietary carotenoids and accumulate them in their gonads. Carotenoids in the gonads of sea angels might protect against oxidative stress and enhance reproduction.

Carotenoids as natural functional pigments

“…The next example involves carotenoids in the gonads of the sea angel Clione limacine [12]. The sea angel is a small, floating sea slug belonging to the class Gastropoda.…”

“…By introducing a carbonyl group at C-4′ in diatoxanthin, the carotenoid changes color from yellow to red and shows enhanced antioxidative and photo-protective activities. Therefore, the sea angel accumulates pectenolone in the gonads as an anti-oxidant and a photo-protector [12].…”

Anti-Oxidative Activity of Mytiloxanthin, a Metabolite of Fucoxanthin in Shellfish and Tunicates

“…Many crustaceans oxidatively convert dietary β-carotene to astaxanthin [ 1 , 2 ]. The scallop and sea angel also oxidatively convert dietary diatoxanthin to pectenolone [ 2 , 16 ]. By these oxidative metabolic conversions, the anti-oxidative activities of dietary carotenoids are increased.…”

The Sea Urchin Arbacia lixula: A Novel Natural Source of Astaxanthin

“…In this species, astaxanthin was as the main ketocarotenoid synthesized through biosynthetic reactions starting from the precursor β-Carotene [ 37 , 38 ]. Considering that carotenoids found in animals can be directly accumulated from food and/or partially modified through metabolic reactions [ 39 , 40 ], it is very important to find a way to enhance metabolic pathways in order to optimize the production of bioactive compounds. Spirulina platensis has been proved to be a valuable source of carotenoids enhancing the pigmentation in fish [ 41 , 42 , 43 , 44 ] and shrimps [ 45 , 46 ], and its inclusion in broodstock diet is recommended to avoid carotenoid deficiency-related problems in shrimp hatcheries [ 47 ].…”