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 [15] . After identification the sea cucumbers were cleaned and removed their entrails. Only the body wall and muscle band were taken for analyses due to the fact that majority of nutritional values were found in body wall and muscle [6] .

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 [16] .

Lipids from body wall of sea cucumber were extracted using a modified method of Folch [17] . A total of 2 g of the powder sea cucumber sample was dissolved into 19 ml of solvent mixtures of chloroform, methanol and water in the ratio of 1:2:0.8 0 volume basis [18] . The extractions steps were repeated for three times to ensure complete extraction of total lipid content. The organic layers were combined and partitioned with 10 ml chloroform and 10 ml of 5% NaCl to remove any non-lipid impurities such as salt and urea. The lower layer which was the chloroform layer was siphoned when a clear separation was seen. Collected chloroformlayer was dried using sodium sulphate, during collected layer appeared to be cloudy which indicate contamination of water. Silylating agent N,O-Bis(trimethylsilyl) trifluoroacetamide (BSTFA) was used to derivitization of fatty acid prior to gas chromatography-mass spectrometry (GC-MS) analysis.

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 [19] . A capillary column HP-5MS (30 m × 0.25 mm) of 0.25 μm film thickness of coated material was used. Fatty acids were identified by the retention time with reference to known standards. Analysis was carried out in triplicate, together with a blank solvent and each replicate was tested for three times. The obtained results were reported in relative abundance of the fatty acid compositions.

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 Table 1.

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-

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 (Table 1).

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 (Table 2). The total crude protein of 70.35% in H. edulis was significantly higher (P < 0.05) than the crude protein of 51.21% obtained in H. scabra. Low amount of crude lipids of 1.37% and 0.27% were determined in H. edulis and H. scabra respectively (Table 2).

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.

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) [5] .

The percentage of SFA, MUFA and PUFA in H. scabra was 37.71, 25.43 and 36.84 respectively [13] , and 71.26, 7.69 and 21.06 respectively [12] [20] . In this study majority of fatty acid obtained in H. scabra were belongs to SFA (98%) higher than the SFA obtained by previous researchers.

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 [21] and species Apostichopus japonicas after fed when they were less in diets [22] .

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 [33] . However, the nutritional values of the sea cucumber were regularly neglected. In this study, Holothuria edulis and Holothuria scabra were investigated whether their nutritional value reflects their commercial importance or not. H. edulis is a low commercial valued species while the H. scabra is a highly valued species.

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% [24] , 83% to 86% in Isostichopus sp [34] , 81% to 85% for H. tubulusa [9] , even higher than present study as reported 89% to 90% in Parastichopus sp [35] and 87% to 90% in Cucumaria frondosa [31] . Moisture percentages in various studies can be link to due to collection time of year, environmental factors, geographical variations and feeding behaviour of respective species [35] . Sea cucumbers generally contain higher moisture in their body wall than marine fish and shellfish [24] and deemed as tonic food that has high content of water and low fat [14] .

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 [7] . The crude protein contained in Isostichopus sp varies within month (2.74% to 6.63% on wet weight basis) as the highest protein values were found to relate with breeding season [35] of sea cucumber. The crude proteins in different species were in the range of 2.5% to 13.8% in Parastichopus sp [34] , 1.13% to 3.99% in Apostichopus japonicas [24] and relatively higher (16.644%) and 12.94% for Thelenota pineapple and Acaudina molpadioides respectively [36] . Seasonal variation could have effect on the chemical compositions of sea cucumber [9] , as the percentage of protein (dry weight basis) dramatically fluctuations with the highest values from June (6.17%) to October (4.64) at its maximum increase in July (6.63%) and the lowest of 2.74% in the month of April [35] . Crude protein of 9.53% and 5.78% of H. scabra in the spring and summer [37] indicating that these fluctuations may be related to the physiological characteristics, seasonal variations, the life cycle of the species and the and the study region.

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 [36] . The total lipid content in both species was much lower than those obtained by other researchers. The total lipid for two species Stichopus japonicas was 0.56% to 2.3% and 0.28% to 0.33% for Apostichopus japonicas [24] . While lower than present study was also reported 0.27% for Thelenota ananas and 0.03% for Acaudina molpadioides. On the other hand lower value of 0.09%, 0.15% and 0.18% in total lipid were obtained from the species of H. tubulosa, H. polii and H. mammata respectively [9] . In general all holothurians may have wide variations in lipid concentrations (and polyunsaturated fatty acids) and these variations might be due to reproductive pattern and the type of species, feed and feeding pattern as well as on environmental conditions [24] . The variations of total lipid between H. edulis (0.27%) and H. scabra (1.37%) are probably due the temperature of water in respective habitat. Temperature fluctuations were known to be influential factor of lipid content of fishes [38] . Total lipids contents of Apostichopus japonicas under the fluctuating temperatures are lower than those under the corresponding constant temperatures [39] . H. scabra which prevalent in coastal sand flat where diet and seasonal temperature fluctuations happened, has lower total lipid than H. edulis which inhabit in reef flat where temperature is usually constant.

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% [35] was above the values reported by [36] to T. ananas and A. molpadioides. However the values obtained in present study are lower than the ranged value (5.13% to 7.85%) obtained for H. polii, H. tubulosa and H. mammata [9] . The total ash content was apparently a measure of mineral content and other inorganic matter in biomass. The distinctive difference in ash content of both species was highly due to the deposition of ossicles in cellular vesicles of the body wall of sea cucumber [40] . Ossicles are composed of calcium carbonate which might contribute to the high mineral content in body wall of sea cucumber.

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 [41] . As a benthic deposit feeder, microbial enriched detritus attribute much to their body compositions. Selectivity of food sources by holothurian do prevail and it has profound influence on body compositions. Parastichopus parvimensis does not directly utilize plant detritus which consist of large energy reserve prior to decomposition by bacteria or fungi, thus suggesting the importance of ecological niche of decomposer (bacteria and fungi) in replenish marine sediment [42] . The preferential habitat for H. scabra after observation on the gut content containing were mostly of muddy particles with size of 125 - 250 μ that high in organic matter [43] . Both Stichopus tremulus and Mesothuria intestinalis favor finer sediment and nutritionally rich, pigment-enhanced, food patches [44] . Diets of Apostichopus japonicus show that sea mud and seaweed combination diet with ratio of (7:3) has significant effect on the body composition and with addition of corn leaves, it will boost growth rate and feed conversion ratio [45] . In addition to diet temperature could affect the proximate body composition of sea cucumber. Crude lipid contents under the fluctuating temperatures were lower than those under the corresponding constant temperatures [39] . Thus, projections of further studies are essential to boost and improve the nutritional values of sea cucumber.