ABSTRACT
BACKGROUND: Sea cucumbers are highly prized seafood in Asia, where the demand for them has increased dramatically in recent years. However, nutritional information is only available for only a few of the commercially traded species. METHODS: In this study, the biochemical composition of the sea cucumber Australostichopus mollis was evaluated in terms of the major functional components: collagen, amino acid and fatty acid content using standard analytical procedures. RESULTS: The collagen, mostly type I, formed a homogeneously clustered network constituting 1.4% of the wet weight of adult A. mollis which is lower than for some other species of sea cucumber. The collagen consisted ofα1andα2 chains (around 116 kDa),αchain dimers,ßchains (around 212 kDa), and small amounts of γ components.The most abundant amino acids were glycine, alanine, threonine, serine and proline (lysine/arginine ratio of 0.1).Threonine was the most abundant essential amino acid, followed by methionine and valine, while glycine was the dominant non-essential amino acid. The sea cucumbers had a low lipid content (0.2 and 0.1% of wet weight forthe viscera and body wall, respectively) which is below the range reported for most other species of sea cucumber.The lipid contained high levels of PUFA (54%) compared to MUFA (23%) and SFA (24%). The dominant PUFA was arachidonic acid in both the body wall and viscera, followed by eicosapentaenoic acid. CONCLUSIONS: Overall, the Australasian sea cucumber has strong potential as a functional food due to its high levels of PUFA and essential amino acids, comparing favourably with the most commercially valuable sea cucumbers.
Subject(s)
Animals , Amino Acids , Fatty Acids, Omega-3 , Nutritive Value , Sea Cucumbers/chemistryABSTRACT
The trilobite larvae of C. rotundicauda were tested to determine their colour preference and light sensitivity until their first moulting (25 days post hatching) under laboratory conditions. Maximum congregation size of the trilobite larvae was found in the white zone respectively where (n= 12) followed by yellow (n= 8) and orange (n= 8), which showed the larval preference for lighter zones. Morisita’s index calculation showed a clumped/aggregated distribution (yellow, blue, orange and white) and uniform/hyper dispersed distribution (green, red and black) for various colours tested. Trilobite larvae showed least preference for brighter regions while tested in the experiment [black; (n=4) and red; (n=5)]. Experiments done to determine the light sensitivity of trilobite larvae showed that the larvae had more preference towards ultraviolet lights. The maximum congregation size of 38.8 and 40.7% of the larvae was encountered under ultraviolet light, when the light sources were kept horizontal and vertical, respectively. Overall, results suggested that the trilobite larvae of C. rotundicauda, preferred light source of shorter wavelengths (UV light) and colours of lighter zone (white, yellow, orange), which might be due to their adaptation to their natural habitat for predator avoidance, prey selection and water quality.