The nutritional values of different species of sea cucumber are greatly concerned because of their dietary and curative properties. In this study, two species of sea cucumber, Holothuria edulis, a low-valued noncommercial species, and Holothuria scabra, a high-valued commercial species were selected to compare its proximate composition and fatty acids. H. edulis a prevalent species in coastal water of Sabah is not commercially importance like H. scabra. Sea cucumbers were captured live from the Sabah marine habitat. All samples were immediately eviscerated, freeze-dried and stored at 4°C in until analyzed. Silylating agent N, O-Bis(trimethylsilyl) trifluoroacetamide (BSTFA) was used to derivitization of fatty acid prior to gas chromatography-mass spectrometry (GC-MS) analysis. Proximate compositions (%), such as moisture, crude protein, crude lipids and ash were carried using standard methods. Major fatty acids in H. edulis and H. scabra were saturated fatty acid (SFA) accounted for 83.95% and 98.60%, respectively and dominated with Palmitic acids. Polyunsaturated fatty acid (PUFA), arachidonic acid of 16.05% was found only in H. edulis, but absent H. scabra. Proximate compositions (dry weight) were varied greatly within these two species. Moisture, crude protein, crude lipids and ash of 85.5%, 70.5%, 1.37% and 1.27% respectively were obtained in H. edulis. On the other hand 84.5% of moisture, 51.2% of crude protein, 0.27% of crude lipids and 4.44% of ashes were determined in H. scabra. Significantly higher protein (p < 0.05) content and detection of PUFA in H. edulis compare to H. scabra could be the choice of option for the utilization of this non commercial species as nutraceutical industry and also alternatives to reduce the pressure on heavily exploited species of H. scabra.
Malaysia coastal water are preferable habitat for diversity of marine fauna and flora due to its tropical climate. Sea cucumbers are predominant and widely harvested in Sabah, Malaysia. In 2013, total of 284 tonnes sea cucumbers were harvested both commercial and natural sectors in Malaysia, out of which 292 tonnes were from Sabah [
Poly Unsaturated Fatty Acids (PUFA) were the primary fatty acid in sea cucumber of which Eicosapentaenoic acid (EPA) [
Benthic feeder sea cucumbers with microbial-enriched detritus are generally contained branched chain fatty acids such as saturated fatty acid [
Holothuria edulis was collected from, Sepanggar Bay, Sabah, Malaysia using scuba diving whereas Holothuria scabra was collected from the bay adjoining Kampung Baru-Baru, Tuaran, Sabah with the aid of local artisanal fisherman. Twenty five samples for each species were collected during dry season. Collected sea cucumbers were kept in ice box and taken back to Borneo Marine Research Institute, University Malaysia Sabah laboratory for freezing at −20˚C prior to homogenization. Samples were identified to assure the desired species according to identification guidelines as described [
All samples were eviscerated before by hand. Post-lacerated body weight of sea cucumber were taken and directly dried in oven until constant weight for the determination of moisture content. Samples were freeze-dried and blended to fine powder form for the determination of total crude protein, total crude lipids, ashes and profiling fatty acids. Samples of sea cucumber were diced into small pieces (1 cm) and dipped into distilled water for 45 minutes to de-saline samples. Desalination process repeated for five times. Prior to freeze-drying, samples were kept in −80˚C for two days. Freeze dried samples were blended with a lab scale blender into fine powder form to increase total surface area for better extracting process. Finally blended samples were kept in 4˚C to avert dried samples from rehydration and oxidization.
Total crude protein (%) of sea cucumber was determined by a KjeltechTM2300 auto analyzer (Foss Tector, Sewdeen). Total crude lipid (%) was analyzed using the petroleum ether extraction method (Soxtec TM System 2043 Extraction Unit of Foss Tecator, Sweden). Ash (%) and moisture (%) were determined according to standard methods [
Lipids from body wall of sea cucumber were extracted using a modified method of Folch [
The trimethylsilyl (TMS) derivatives samples were injected into a GC-MS system consisting of an Agilent 7890A gas chromatograph system coupled with an Agilent 5975C mass spectrometry detector. Modified setting of GC-MS with reference was used [
Independent T-test at 5% confidence was used to test the proximate analyses and fatty acid composition between H. edulis and H. scabra using SPSS v22.
A total of seven types fatty acids were detected from the two species of sea cucumber as shown in
Total three types of fatty acids, palmitic, stearic acid (SFA) and arachidonic acid (PUFA) were detected in H. edulis. On the other hand six types of fatty acids detected in H. scabra. Four of them myristic, pentadecyclic, palmitic, and stearic acid were belongs to saturated fatty acids while palmitoleic acid and nonahex-
Fatty acids | H. edulis | H. scabra | Significance |
---|---|---|---|
Saturated fatty acids (SFA) | |||
Myristic acid C14:0 | n.d | 5.08 ± 0.55 | |
Pentadecylic acid C15:0 | n.d | 2.08 ± 2.48 | |
Palmitic acid C16:0 | 43.67 ± 1.70a | 49.57 ± 3.59b | <0.0001 |
Stearic acid C18:0 | 40.32 ± 4.01a | 41.87 ± 5.84a | >0.05 |
Σ SFA | 83.95 ± 4.76a | 98.60 ± 2.42b | <0.001 |
Monounsaturated fatty acid (MUFA) | |||
Palmitoleic acid C16:1 | n.d | 0.48 ± 6.23 | |
Σ MUFA | n.d | 0.49 ± 4.25 | |
Polyunsaturated fatty acid (PUFA) | |||
Arachidonic acid C20:4(n-6) | 16.05 ± 4.59 | n.d | |
Σ PUFA | 16.05 ± 4.59 | ||
Long chain fatty acid (LCFA) | |||
Nonahexacontanoic acid C69:0 | n.d | 0.93 ± 1.87 | |
Σ LCFA | n.d | 0.93 ± 1.87 |
Values in the same row with different letters are significantly different at P < 0.05; n.d.: not detected; SFA: saturated fatty acid, PUFA: polyunsaturated fatty acid, MUFA: monounsaturated fatty acid and LCFA: Long chain fatty acid.
acontanoic acid were belongs to unsaturated and long chain saturated fatty acid respectively (
SFA was the major fatty acids in both species, accounted for 83.9% and 98.6% of total fatty acids in H. edulis and H. scabra respectively. Palmitic acid was the major SFA in both H. edulis and H. scabra, accounted of 43.63% and 49.57%, respectively. On the other hand percentage of stearic acid was observed significantly higher (P < 0.05) in H. scabra than the percentage of stearic acid obtained in H. edulis. MUFA and HUFA were not found in H. edulis, while PUFA was not detected in H. scabra.
Generally, both species of sea cucumber have high percentage of protein and moisture, while low lipid content in their body wall. Moisture content in whole body except internal organ of H. edulis and H. scabra were of 85.56% and 84.49% respectively (
So, percentage or protein and lipids in H. edulis were significantly higher (P < 0.05) than values of those obtained in H. scabra. On the other hand, ash content of H. scabra was remarkably higher than ash content obtained in H. edulis.
Parameters (%) | H. edulis | H. scabra |
---|---|---|
Moisture | 85.56 ± 1.23a | 84.49 ± 1.10a |
Crude protein | 70.35 ± 0.29a | 51.21 ± 0.95b |
Crude lipids | 1.37 ± 0.04a | 0.27 ± 0.03b |
Ash | 1.27 ± 0.03a | 4.44 ± 0.31b |
Nitrogen Free Extract | 27.01 ± 0.25a | 44.08 ± 1.25b |
Sea cucumbers are benthic feeder which its food source is microbial-enriched detritus that generally contain branched chain fatty acid such as polysaturated fatty acids (PUFAs), mono saturated fatty acids (MUFAs), and saturated fatty acid (SFAs) [
The percentage of SFA, MUFA and PUFA in H. scabra was 37.71, 25.43 and 36.84 respectively [
Fatty acid composition of sea cucumber can be improved with inclusion level and types of feed ingredients having high content of 18:2n-6, like corn meal and soyabean meal. Fatty acid such as 20:1n-9, 20:2n-6 and 20:3n-3 found in sea cucumber indication the selectivity/or the biosynthesis of these fatty acids by aquatic species [
Saturated fatty acids accounted 71.26% in three species of sea cucumber such as, H. scabra, H. leucospilota and H. atra collected from the east coast of Sabah, Sulu Sea. [
Monounsaturated fatty acid (MUFAs), comprises of palmitoleic acid (C16:1) of 0.48% are only found in body wall of H. scabra but not H. edulis in this study. MUFAs compare to SFA and PUFA, were observed lower in this species of sea cucumber [
Polyunsaturated (PUFA) was not detected in H. scabra, but was found in H. edulis accounted 16.05% (
Proximate compositions were conducted concerning the nutritional value of the sea cucumbers since they are deemed as nutraceutical food resources. Grading of sea cucumber in marketed product are according to species, abundance, appearance, taste, color, thickness of the body wall and market demand, texture, constituency, dryness [
The average moisture content of 85.56% ± 1.23% and 84.49% ± 1.10% were obtained in H. edulis and H. scabra respectively. Normally the moisture content in most of the sea cucumbers were in the range of 84% to 91% [
Crude protein in fresh samples of sea cucumber contained lower percentage (7.48% in H. edulis and 5.45% in H. scabra) of crude protein. As sea cucumbers are mostly processed into bêche-de mer (dried sea cucumber) as item, their protein content could be relatively higher when measured on dry weight basis. Crude protein in present study measured on dry weight accounted for 70.35% and 51.21% in H. edulis and H. scabra respectively. Crude protein of 68.40% in freeze-dried Parastichopus californicus was reported [
Total lipid in both sea cucumber samples were generally low, 1.37% and 0.27% (dry weight basis) for H. scabra and H. edulis respectively. Most marine organism generally has low lipid content [
Ash content in H. scabra was observed higher (4.44%) than in H. edulis (1.27%). Ash content in the range from 3.16% to 3.81% [
Both H. edulis and H. scabra, are deposit-feeders, widely distributed in the Indo-Pacific. H. scabra is mainly found in sandy to muddy coastal zones whilst H. edulis is ubiquitous in seagrass and coral reef areas [
Results obtained from this study indicates that lipid content of sea cucumber were generally lower in amount compared to protein level in sea cucumber, a common trait of marine organism. H. edulis has higher crude protein than H. scabra which indicate that market value does not necessarily reconcilable with the nutritional value of sea cucumber. The presence of PUFAs in H. edulis also suggested that, a low market price sea cucumber contain beneficial fatty acids than those obtained in high valued species like H. scabra. The nutritional value of the sea cucumber does reflect its market value. This implies that H. edulis has the potential to be a supplementary food. Thus, low valued sea cucumber can be an alternative to mitigate the overexploitation condition.
Al Azad, S., Shaleh, S.R.M. and Siddiquee, S. (2017) Comparison of Fatty Acid and Proximate Com- position between Holothuria edulis and Holothuria scabra Collected from Coastal Water of Sabah, Malaysia. Advances in Bioscience and Biotechnology, 8, 91-103. https://doi.org/10.4236/abb.2017.83007