Comparative Study of the Lipid and Fatty Acid ...

Malaya Journal of Biosciences 2015, 2(1):57-74 ISSN 2348-6236 print /2348-3075 online

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Comparative Study of the Lipid and Fatty Acid Composition of Two Shell Fish: Lagoon and Fresh Water Crabs Emmanuel Ilesanmi Adeyeye Department of Chemistry (Analytical Unit), Ekiti State University, PMB 5363, Ado-Ekiti, Nigeria. *For correspondence e-mail: [email protected] Article Info: Received 12 Jan 2015; Revised: 27 May 2015; Accepted 01 June 2015

ABSTRACT Lipid and fatty acid composition of two species of shell fish (Sudananautes africanus africanus and Callinectes latimanus) are reported. Crude fat varied from 0.870 to 1.83 g/100 g on dry weight basis. SFA varied from 18.6 to 23.8 % of total fatty acid weight and MUFA varied from 37.5 to 43.9 %. PUFA (n-6+n-3) ranged from 37.5-39.4 %. The following quality ratios were noted to have the following values: PUFA/SFA (1.66-2.02), MUFA/SFA (1.58-2.36), EPSI (0.853-1.03), AA/DGLA (6.93-13.5), LA/ALA (3.98-454) and EPA/DHA (0.986-1.58). Total energy value was low at 23.1-48.3 kJ/100 g. Phospholipid values were high at 271-423 mg/100 g with lecithin predominating in the two samples having values of 141-243 mg/100 g or 52.157.4 %. Sterol levels were generally low with total value of 88.8-100 mg/100 g and cholesterol predominated in both samples with values of 87.5-99.5 mg/100 g or 98.6-99.3 %. Statistically, it was shown that significant differences existed at r = 0.05 in the samples in their SFA and MUFA, PUFA (n-6 and n-3), phospholipids, and sterols. S. africanus africanus was more concentrated than C. latimanus in crude fat, SFA, PUFA, phospholipids and sterols (i.e. 5/6 or 83.3 % parameters). Keywords: Sudananutes africanus africanus; Callinectes latimanus; lipid composition

1. INTRODUCTION Crab is an outstandingly successful form of Crustacean whose number of species has multiplied to such an extent that within the order Decapoda (which includes Lobster, Prawn, Shrimp) some 4,500 of the 8, 500 species are crabs [1]. The typical crab is thought of as a creature which scuttles sideway across the sea bottom or beach; and many crabs answer to this description. However, there are also swimming crabs and land crabs, and the range of sizes and configurations is huge. The tiny oyster (pea) crab is the size of a pea, whereas the giant Japanese spider crab may measure 3.6 m (12´) from claw tip to claw tip. The constant feature is possession of two claws

and eight walking or swimming legs or ‘feet’, and that the whole creature is, like other crustaceans, contained within a hard exoskeleton which serves as protective armour except at those time when it has to be shed, as its occupant grows, and replaced by a new larger one [1]. Nigeria is among the protein and minerals deficient nations in the world. Most of the animal protein sources (cattle, goat, chicken, etc.) are inadequate and costly due to drought, disease, exorbitant cost of feeds, etc. Aquatic food is a broad component with major categories, finfish and shell fish, aquatic foods

Comparative Study of the Lipid and Fatty Acid Composition of Two Shell Fish: Lagoon and Fresh Water Crabs Copyright © 2015 MJB 57

Emmanuel Ilesanmi Adeyeye, 2015 / Malaya Journal of Biosciences 2015, 2(1):57-74

most especially sea-foods are nutritionally important in the supply of protein, especially the nine essential amino acids [2]. The lipid content of sea foods is primarily in the form of triglycerides or triacylglycerols and is the only major source of highly unsaturated fatty acids [2]. Sea fish ingests and accumulates omega-3 fatty acids through the food chain algae and phytoplankton, the primary producers of omega-3 fatty acid. Several crabs are prized as food. They include the Alaska king crab (Paralithodes camtschatica); the blue crab (Callinetes sapidus), which is the commercially important crab occurring along the East and Gulf coasts of the United States [3]; the Dungenes crab (Cancer magister), which are present in Europe-nonswimming crabs used as food [3]; and the giant mangrove swimming crab (Scyllia serrata) which is popular in pacific waters from the East Coast of Africa to India and as far away as Japan [4].

following constituted it: cheliped (muscle and exoskeleton), carapace, thoracic sternum and the other four pairs of walking legs and then dried at 105 o C. The Callinectes latimanus samples were collected from the fish trawlers from the Lagos lagoon and treated like the S. africanus africanus. The samples were separately blended and stored in plastic containers pending analyses.

The crab is usually consumed by individuals and it is often recommended for pregnant women. Literature is available on the chemical composition of the nutritionally valuable parts of male and female common West African fresh water crab, Sudananautes africanus africanus [5]; the relationship in the amino acid of the whole body, flesh and exoskeleton of S. africanus africanus [6]; proximate and mineral composition of whole body, flesh and exoskeleton of male and female S. africanus africanus [7]; proximate and mineral compositions of common crab species [Callinectes pallidus and Cardisoma armatum] of Badagry creek, Nigeria [2]. There is paucity of information on the lipids composition of Nigeria crabs. The study reported in this article is an attempt to assess the quality of lipids composition of common West African fresh water crab Sudananautes africanus africanus (fam. Potamidae) and the lagoon crab Callinectes latimanus (fam. Portunidae). It is hoped that this will contribute information to food composition tables.

2.1.2. Preparation of fatty acid methyl esters and analysis

2. MATERIALS AND METHODS 2.1. Collection and treatment of samples Sudananautes africanus africanus samples were collected from the banks of River Osun, located at Ikere-Ekiti, Ekiti State, Nigeria during the onset of the rainy season (they normally hibernate in the dry season). Six pieces of matured fresh crabs were selected from more than 12 crabs caught in holes along the river banks. The samples were stored under freezing at -10 oC. Two whole crabs were separated fresh. Whilst the internal organs were discarded, the other separated parts were dried in the oven at 105 oC until constant weight. For the whole body sample, the

2.1.1. Determination of ether extract An aliquot (0.25 g) of each sample was weighed in an extraction thimble and 200 ml of petroleum ether (4060 oC boiling range) was added. The covered porous thimble containing the sample was extracted for 5 h using a Soxhlet extractor. The extraction flask was removed from the heating mantle when it was almost free of petroleum ether, oven dried at 105 oC for 1 h, cooled in a desiccator and the weight of dried oil was determined.

A 50 mg aliquot of the dried oil was saponified for 5 min at 95 oC with 3.4 ml of 0.5 M KOH in dry methanol. The mixture was neutralized by 0.7 M HCl and 3 ml of 14 % boron trifluoride (BF 3) in methanol (Supelco Inc., Bellefonte, PA, USA) was added [8]. The mixture was heated for 5 min at 90 oC to achieve complete methylation. The fatty acid methyl esters (FAME) were thrice extracted from the mixture with redistilled n-hexane (2x3 ml) and concentrated to 1 ml for analysis and 1µl was injected into the injection port of the GC. The fatty acid methyl esters were analysed using these GC conditions: HP 5890 series II autosampler 7673, powered with HP3365 ChemStation rev. A09.01 [1206] software; HewlettPackard Co., Avondale, PA, USA fitted with a flame ionization detector. Injection type was split injection, split ratio was 20:1 and carrier gas was nitrogen. The inlet temperature was 250 oC, column type was HP INNOWAX, capillary column (30 m, 0.25 mm i.d., 0.25 µm film thickness) (Supelco, Inc. Bellenfonte, PA, USA). The oven programme was: initial temperature at 60oC, first ramping at 10 oC/min for 20 min (260 oC), maintained for 4 min; second ramping at 15oC/min for 4 min (320 oC) maintained for 10 min. The injection temperature was 250 oC and the flame ionization detector (FID) was used and the detector temperature 320 oC. Hydrogen pressure was 22 psi and compressed air was 35 psi. The peaks were identified by comparison of their retention times with authentic standards of FAME.

Comparative Study of the Lipid and Fatty Acid Composition of Two Shell Fish: Lagoon and Fresh Water Crabs 58


2.1.3. Sterol analysis For the analysis of sterols, the GC conditions of analysis were similar to the GC conditions for the FAME analysis. 2.1.4. Phospholipid analysis Modified method of Raheja et al. [9] was employed in the analysis of phospholipids. A weight of 0.01 g of the extracted fat was added to each test tube. To ensure complete dryness of the oil for phospholipid analysis, the solvent was completely removed by passing a stream of nitrogen gas on the oil. A volume of 0.40 ml of chloroform was added to the tube followed by the addition of 0.10 ml of chromogenic solution. The tube was heated at 100 oC in water bath for about 1 min 20 sec. The content was allowed to cool to the laboratory temperature and 5ml of hexane was added and the tube shaken gently several times. The hexane layer was recovered and concentrated to 1. 0 ml for analysis. The phospholipids were analysed using an HP 5890 powered with HP gas chromatograph (HP 5890 powered with HP ChemStation rev. A09.01[1206] software [GMI, Inc, Minnesota, USA]) fitted with a pulse flame photometric detector. Nitrogen was used as the carrier gas with a flow rate of 20-60ml/min. The oven programme was: initial temperature at 50oC, first ramping at 10oC/min for 20 min (250oC), maintained for 4min, second ramping at 15oC/min for 4 min (310oC) and maintained for 5min. The injection temperature was 320oC. A polar (HP5) capillary column (30m, 0.25mm i.d., 0.25µm film thickness) was used to separate the phospholipids. Split injection type was used having a split ratio of 20:1. Hydrogen pressure was 20 psi and compressed air was 30 psi. The peaks were identified by comparison with standard phospholipids. 2.2. Quality assurance Standard chromatograms were prepared for sterols, phospholipids and FAME which were then compared with respective analytical results; calibration curves were prepared for the standard mixtures and correlation coefficient was determined for each fatty acid, sterol and phospholipid. Correlation coefficient ≥ 0.95 was considered acceptable. It was performed with Hewlett Packard Chemistry (HPCHEM) software (GML Inc 6511 Bunker Lake Blvd Ramsey, Minnesota, 55303, USA). Fatty acids were listed with the chain length and double bond numbers.

2.3. Calculation of fatty acids as food per 100 g sample At the data source and reference database levels, values for individual fatty acids are usually expressed as percentages of total fatty acids since this is the most common form of analytical presentation. (It was used here.) At the user data base level, values per 100 g of food are required. (Value of each fatty acid present in 100 g of each sample was calculated.) At all level of data management both modes of expression are useful for comparative evaluation. A conversion factor derived from the proportion of the total lipids present as fatty acids is required [10] for converting percentages of total fatty acids to fatty acids per 100 g of food. (Crude fat level was multiplied by conversion factor of 0.70 to convert it to total fatty acids [10]). For fatty acids expressed in g per 100 g total fatty acids, precision is best limited to the 0.1 g/100 g level, with trace being set at 0.06 g/100 g of fatty acids [11]. Total lipid level (crude fat) was multiplied by conversion factor as follows: S. africanus africanus (1.83 x 0.70 = 1.28 g/ 100 g) and C. latimanus (0.870 x 0.70 =0.609g/100g). 2.3.1.

Statistical analysis

Statistical analysis [12] was carried out to determine the mean, standard deviation, coefficient of variation in per cent. Also calculated were linear correlation coefficient (rxy), coefficient of determination (rxy2), linear regression coefficient (Rxy), coefficient of alienation (CA) and index of forecasting efficiency (IFE). The rxy was subjected to the Table (critical) value at r = 0.05 to see if significant differences existed in the values of fatty acids, sterols and phospholipids between the two crab samples.

3. RESULT AND DISCUSSION 3.1. Crude fat and fatty acid levels The crude fat levels of the samples are shown in Table 1. Also shown are the true total fatty acids and the energy range (kJ/100 g) of each sample. The range was 0.870 – 1.83 g/100 g and true total fatty acid range was 0.609-1.28 g/100 g with energy range of 23.1-48.7 kJ/100 g. In all these parameters the S. africanus africanus had the higher values whereas the C. latimanus occupied the lower position in all the parameters. The difference between each of the parameters is high as shown by the coefficient of variation in per cent (CV %). The samples will all serve as sources of low density for calorie provision.



Table 1. Crude fat, true fatty acids and total energy levels of the S. africanus africanus and C. latimanus Parameter

S. africanus africanus

C. latimanus

Mean

SD

CV %

Crude fat (g/100 g)

1.83

0.870

1.35

0.679

50.3

True fatty acids (g/100 g)a

1.28

0.609

0.945

0.474

50.2

Total energy (kJ/100 g)b

48.7

23.1

35.9

18.1

78.4

a

S. africanus africanus (1.83 x0.70); C. latimanus (0.870 x 0.70); SD = standard deviation; CV % - coefficient of variation;bTrue fatty acids x 38kJ/g (for each fatty acid value).

Table 2. Saturated and monounsaturated fatty acid profiles of the S. africanus africanus and C. latimanus crabs (% total fatty acid weight) Fatty acid


SD

CV %

Hexanoic acid (C6:0)

0.00

0.00

0.00

-

-

Octanoic acid (C8:0)

0.00

0.00

0.00

-

-

Decanoic acid (C10:0)

0.00

0.00

0.00

-

-

Lauric acid (C12:0)

0.128

0.524

0.326

0.280

85.9

Myristic acid (C14:0)

5.57

0.413

2.99

3.65

122

Palmitic acid (C16:0)

14.8

11.2

13.0

2.55

19.6

Stearic acid (C18:0)

0.881

6.44

3.66

3.93

107

Arachidic acid (C20:0)

1.18

0.024

0.602

0.817

136

Behenic acid

1.09

0.022

0.556

0.755

136

Lignoceric acid (C24:0)

0.135

0.003

0.069

0.093

135

Total SFA

23.8

18.6

21.2

3.68

17.3

Myristoleic acid (C14:1cis-9)

0.388

0.028

0.208

0.255

122

Palmitoleic acid (C16:1cis-9)

6.03

7.44

6.74

0.997

14.8

Petroselinic acid (C18:1cis-6)

10.6

8.74

9.67

1.32

13.6

Oleic acid (C18:1 cis -9)

7.84

16.4

12.1

6.05

49.9

Gondoic acid (C22:1 cis-11)

11.6

11.1

11.4

0.35

3.12

Erucic acid (C22:1 cis-13)

0.376

0.008

0.192

0.260

136

Nervonic acid (C24:1 cis-15)

0.135

0.158

0.147

0.016

11.1

Total MUFA (cis)

37.0

43.9

40.5

4.88

12.1

Trans-Petroselinic acid (C18:1 trans-6)

0.426

0.009

0.218

0.295

136

Elaidic acid (C18:1 trans-9)

0.039

0.001

0.020

0.027

134

Vaccenic acid (C18:1 trans-11)

0.00

0.00

0.00

-

-

Total MUFA (trans)

0.464

0.010

0.237

0.321

135

Total MUFA (cis + trans)

37.5

43.9

40.7

4.53

11.1

(C22:0)

C. latimanus

Mean

SFA = saturated fatty acid; MUFA = monounsaturated fatty acid.



Table 3. PUFA n-6 and n-3fatty acid profiles of the S. africanus africanus and C. latimanus crabs (% total fatty acids) Fatty acid


C. latimanus

Mean

SD

CV %

Linoleic acid (LA)(C18:2 cis-9,12)

3.90

10.3

7.10

4.53

63.7

Gamma-linolenic acid (GLA) (C18:3 cis-6,9,12)

0.858

0.029

0.444

0.586

132

Eicosadienoic acid (C20:2 cis -11,14)

0.168

0.003

0.086

0.117

136

Dihomo-γ-linolenic acid (C20:3 cis 5, 8,11,14)

1.38

0.381

0.881

0.706

80.2

Arachidonic acid (AA)(C20:4 cis-5,8,11,14) 9.56

5.15

7.36

3.12

42.4

Docosadienoic acid (C22:2 cis-13,16)

0.135

0.304

0.220

0.120

54.4

n-6 PUFA (cis) (total)

16.0

16.2

16.1

0.141

0.878

Rumenic acid (RA) (C18:2 cis-9, trans-11)

0.499

0.010

0.255

0.346

136

n-6 PUFA+RA (total)

16.5

16.2

16.4

0.212

1.30

Alpha-linolenic acid (ALA) (C18:3 cis-9,12,15)

0.980

0.023

0.502

0.677

135

Eicosatrienoic acid (ETE) (C20:3 cis-11, 14,17)

0.724

0.015

0.370

0.501

136

Timnodenic acid (EPA) (C20:5 cis-5,8,11,14,17)

10.9

13.0

12.0

1.48

12.4

Cervonic acid (DHA) (C22:6 cis-4,7,10,13,16,19)

10.3

8.25

9.28

1.45

15.6

Total n-3

22.9

21.3

22.1

1.13

5.12

n-6 + n-3(total)

39.4

37.5

38.5

1.34

3.49

In Table 2, fatty acid profiles of the crab samples in % total fatty acid are shown for the saturated and monounsaturated fatty acids. The following fatty acids had 0.00% total fatty acid each: C6:0, C8:0, C10:0 and C18:1 trans-11 in both samples. The most concentrated SFA was C16:0 in the samples with values of 14.8 % (S. africanus africanus) and 11.2 % (C. latimanus) with a CV % of 19.6. Next SFA was C18:0 in C. latimanus (6.44 %) but it was C14:0 in S. africanus africanus (5.57 %). SFA was reported further in C12:0, C20:0, C22:0 and C24:0 with concentration of the SFA being more in the S. africanus africanus than C. latimanus in C20:0, C22:0 and C24:0. The overall SFA was 23.8 % (S. africanus africanus) > 18.6 % (C. laitmanus) and CV % of 17.3. Among the monoenoic acids, C20:1 cis-11 occupied the highest position in S. africanus africanus (11.6 %) and followed by C18:1 cis-6 (10.6

%) in the same sample; whereas C18:1 cis-9 occupied the highest position in C. latimanus (16.4 %) and followed by C20:1 cis-11 (11.1 %) in the same sample. The CV % (3.12) of C20:1 cis-11 was the least in both SFA and MUFA. The MUFA with least significant level was C22:1 cis-13 (0.008 %) in C. latimanus. All the trans fatty acids: C18:1 trans-6, C18:1 trans-9 and C18:1 trans-11 had no significant values (0.00-0.009 %) in C. latimanus whereas such values ranged from 0.00-0.426 % in S. africanus africanus. On the whole, the concentration of MUFA was in contrast to SFA in the samples with C. latimanus (43.9 %) > S. africanus africanus (37.5 %). The SFA in S. africanus africanus (23.8 %) was close to the value of 25.4 % in ram; also the MUFA in C. latimanus (43.9 %) was close to the value of 45.5 % (ram) and 41.5 % (bull) [13].



Short-chain (SC) fatty acids (C4-C6) and mediumchain (MC) fatty acids (C8-C12) recorded 0.00 % in all the samples (except in C12:0; 0.128-0.524 % and CV % 85.9). The first member of LC is C14:0, it is a ubiquitous component of lipids in most living organisms but usually at levels of 1-2 % only. In the present samples it has values of 0.413 % (C. latimanus) -5.57 % (S. africanus africanus) with a CV % of 122. In the organs (liver, muscle and brain) of domestic pig (Sus scrofa domesticus) we had C14:0 values of 2.23-4.97 % [14]. Myristic acid is also found in palm kernel oil, coconut oil, butter fat and is a minor component of many other fats [15]. It is also found in spermaceti, the crystallized fraction of oil from the sperm of whale. Palmitic acid (C16:0) is usually considered the most abundant SFA in nature, it is found in appreciable amounts in the lipids of animals, plants and lower organisms. It comprises 20-30 % of the lipids in most animal tissues and it is present in amounts that vary from 10-40 % in the oils. The present results of 11.2-14.8 % were lower than the range of 20-30 % of the lipids in most animal cells; it is 21.2-24.9 % in domestic pig organs [14]; however, the bull’s head and chicken head brains contained no detectable level of C16:0 [16]. Stearic acid (C18:0) is the second most important SFA in nature and again it is found in the lipids of most living organisms. In these samples C18:0 occupied the second concentrated SFA with a value of 6.44 in C. latimanus with overall range of 0.881-6.44 % and CV % of 107. In the domestic pig organs C18:0 range was 7.70-10.4 % [14]. Long-chain (LC) fatty acids have 14-18 carbon atoms and can either be saturated, monounsaturated or polyunsaturated. C14:0, C16:0 and C18:0 had been discussed above. Oleic acid (C18:1 cis-9) is by far the most abundant monoenoic fatty acid in plant and animal tissues, both in structural lipids and in depot fats. Whilst it formed the highest concentrated MUFA in C. latimanus (16.4 %), it formed the third position in S. africanus africanus (7.84 %). Olive oil contains up to 78 % oleic acid and it is believed to have especially valuable nutritional properties as part of the Mediterranean diet. Oleic acid is the biosynthetic precursor of a family of fatty acids with the (n-9) terminal structure and with chainlengths of 20-24 or more. In the present report petroselinic acid had value range of 8.74-10.6 %. Studies in vitro by Weber et al. [17] revealed that triacylglycerols containing petroselinoyl [18:1(n-12)] moieties are hydrolysed by pancreatic lipase at much lower rates than other triacyglycerols. Consumption

of coriander (Coriandrum sativum) oil compared with the other oils, led to significantly greater liver weights. No significant differences were observed among the groups fed various levels of oleic acid in body weight, the weights of heart, liver, kidneys, spleen or testes, lipid content of heart, or total cholesterol, HDL cholesterol and triacylglycerol concentration of blood plasma. Ingestion of coriander oil led to incorporation of 18:1 (n-12) into heart, liver and blood lipids and to a significant reduction in the concentration of arachidonic acid in the lipids of hearts, liver and blood with a concomitant increase in the concentration of linoleic acid compared with results for the other groups. The data show that petroselinic acid from dietary triacylglycerols is absorbed by rats as readily as oleic acids, but the former reduces the concentration of arachidonic acid in tissue lipids suggesting [in view of earlier studies (18)] petroselinic acid-mediated inhibition of arachidonic acid synthesis. Another monounsaturated fatty acid is the 16carbon palmitoleic acid which has strong antimicrobial properties [19]. It is found almost exclusively in animal fats; it formed a range value of 6.03-7.44 % in the samples. Palmitoleic acid (C16:1 cis-9) is also found in rich amounts in macadamia nut, olive, canola and peanut oils. This MUFA is beneficial in reducing bad cholesterol (LDL) and it behaves like a saturated and not as an unsaturated fatty acid in its effect on HDL cholesterol [20]. It also reduces the fat deposition in blood vessels and reduces blood clot formation [21]. Gondoic acid [11cis eicosenoic acid (11-20:1) or 20:1 (n-9)] is a common if minor constituent of animal tissues and fish oils, often accompanied by the 13-isomer. It is also found in rapeseed oil and seed oils of related species. Its value ranged from 11.1-11.6 % and CV % of 3.12 in the present samples. Erucic acid (22:1 cis13) is a fatty acid that is apparently responsible for a favourable response of persons with nervous system disorder [22]. The administration of erucic acid in the diet will reduce the serum levels and brain accumulation of very-long-chain of SFAs (such as C26.0) responsible for demyelination [23, 24]. The level of erucic acid in the present samples ranged from 0.008- 0.376 % and CV % of 136. Accumulation of certain long-chain FAs is associated with degenerative diseases of the central nervous system , such as behenic acid (C22:0; 0.0221.09 %) but about 1 % in beef fat [25] and lignoceric acid (C24:0; 0.003-0.135 %) but about 1 % in beef fat as well as that of the unsaturated members of C22



and C24 group [25]. Accumulation occurs because enzymes needed to maintain turnover of those fatty acids are lacking [26]. Behenic acid has been detected to be a cholesterol-raising SFA factor in humans [27]. The total trans-MUFA concentration was generally low at 0.010-0.464 % whereas cis-MUFA total ranged from 37.0-43.9 % and CV % of 12.1. Literature sources of MUFA are 48 % (beef fat), 39% (lamb fat), 41 % (pork fat), 42 % (chicken, meat and skin), 54 % (duck, meat and skin) and 54 % (calf liver) [28]. Literature SFA were: 43 % (beef fat), 50 % (lamb fat), 37 % (pork fat), 33 % (chicken, meat and skin), 27 % (duck, meat and skin) and 30 % (calf liver) [28]. Many studies have suggested that SFA raise TC, LDL and HDL, and that PUFA lower them. But certain SFA (as consumed in our daily diet) are better than others in terms of their impact on the LDL/HDL ratio. Fats rich in 12:0+14:0 (e.g., milk fat, coconut oil and palm kernel oil) raise LDL the most. Stearic acid (18:0) is not very prevalent in saturated fats, but it is neutral in its effect on blood cholesterol when consumed in natural fats. Considering the influence on the lipoprotein profile, 16:0 is intermediate, that is, it can be neutral when placed on a triglyceride molecule with MUFA, PUFA or 18:0, or cholesterolraising when attached along with 12:0 +14:0. In high amounts, 16:0 can even raise TC and LDL when substituted for 18:0, MUFA or PUFA in people who already have elevated TC or who eat large amounts of cholesterol. Accordingly, the advice has been to remove as much SFA from the diet as possible. But this is not practical because the manufacture of many food products requires SFA (or some facsimile thereof, such as trans fatty acids (TFA), and extreme removal of dietary SFA is not prudent because their deletion from the diet surprisingly exerts an adverse effect on the LDL/HDL ratio [29] but concluded that the best SFA are 16:0 and 18:0 from natural fats. In Table 3 is depicted the PUFA n-6 and n-3 fatty acid profiles of the crab samples. In the n-6 PUFA, concentration in the two samples was of different fatty acids. The highest concentrated n-6 PUFA in S. africanus africanus was C20:4 cis-5, 8, 11, 14 with a value of 9.56 %, second was C18:2 cis-9, 12 (3.90 %) and third was C20:3 cis-8, 11, 14. In the C. latimanus, C18:2 cis-9, 12 (10.3 %) was the most concentrated n-6 PUFA, second was C20:4 cis-5, 8, 11, 14 (5.15 %) and third was C20:3 cis-8, 11, 14 (0.381 %). On the whole, n-6 PUFA in the samples was about the same at 16.0-16.2 % and very low CV % at 0.878. The C18:2 cis-9, trans-11 was not significant in C. latimanus (0.010 %) whereas the

fatty acid was of significant level in S. africanus africanus (0.499 %). Both crab samples had good values of n-3 PUFA. In C20:5 cis- 5, 8, 11, 14, 17 (EPA) was the most concentrated fatty acid with values of 10.9-13.0 % and CV % of 12.4, followed by C 22:6 cis-4, 7, 10, 13, 16, 19 (DHA) with values of 8.25-10.3 % and CV % of 15.6. Total n-3 PUFA in S. africanus africanus was 22.9 % > in C. latimanus of 21.3%. On the whole n-6 + n-3 (total) in S. africanus africanus was 39.4 % and in C. latimanus it was 37.5 % with CV % of 3.49. The major important polyunsaturated fatty acids in the samples were linoleic acid (LA), arachidonic acid (AA), alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA (C18:3) is classified as a short-chain omega-3 fatty acid and is also found in nuts and seeds. EPA and DHA are found predominantly in foods of marine origin and are classified as long-chain omega-3 fatty acids. LA is also found in corn, sunflower oil, safflower oil and soybeans whereas AA is found in brain, liver, glandular and egg lipids (both acids belong to the omega-6 family of fatty acids) [25]. The concentration of both EPA and DHA were each very close in both crab samples showing that fresh water animal samples could also be good sources of EPA and DHA. Today we know that there are two series of essential fatty acids (EFAs) which cannot be synthesized by animals or humans and must be supplied in the diet [30]. The n-6 series are derived from linoleic acid (LA), and the n-3 series from linolenic acid (ALA). Physiologically more important than these parent fatty acids are their elongated and desaturated derivatives or metabolites. Whilst the desaturation steps (especially the first one) tend to be slow, the elongation steps proceed rapily. The EFAs affect the fluidity, flexibility and permeability of the membranes, they are the precursors of the eicosanoids, are necessary for maintaining the impermeability barrier of the skin and are involved in cholesterol transport and metabolism. There are several interactions between the n-6 and the n-3 fatty acids (FAs) [31]. Knowledge of the significance of the long-chain PUFA of the n-3 type, particularly EPA and DHA, for human health has increased considerably since the 1970s [32]. As is well known, they are abundant in fish oils. Many health disorders are linked with an undesired overproduction of eicosanoids [33]. These are hormone-like compounds which include prostaglandins, thromboxanes and leukotrienes. Several eicosanoids originate from AA which can be



synthesized from LA. By virtue of their competitive inhibition in the enzyme systems, FAs of n-3 type, especially EPA and DHA, can slow down the eicosanoid overproduction and thus prevent or cure health disorders (Figure.1) [33].

Figure 1. Competition between n-3 and n-6 polyunsaturated fatty acids can slow down the eicosanoid formation [33]. There can be very little doubt, that the n-3 fatty acids have antiatherosclerotic efficacy [34]. This is mainly based on: inhibition of synthesis of the vasoaggressive low density lipoproteins (LDL), acceleration of LDL elimination, non-influences on the vasoprotective high density lipoproteins (HDL) or even enhanced HDL production, decrease in the total serum triglycerides, shifting the eicosanoid balance in favour of the antiaggregatory fraction, reduction of the platelet aggregation of bleeding time, reduction of blood pressure. In many highly developed countries cardiovascular diseases pose a serious health risk and often rank first among the causes of death. Thus, for many years, in Germany more than 500 per 100 000 inhabitants (1989:586) have been dying annually of heart and circulatory disorders. Compared with this, carcinoma ranks “only” second with about 260 deaths per 100 000 [35]. Death rates from ischemic heart disease (in percentage of all deaths) in the United States of America, Denmark and Greenland are 40.4, 34.7 and 5.3, respectively [36]. The low rate of deaths from cardiovascular disease in Greenland has been linked with the consumption of marine oils [37]. There is evidence suggesting that long-chain n-3 PUFAs also have beneficial effects on diseases other than those of the heart and of the blood vessels. They include [37]: inflammatory diseases, arthritis, nephritis, lupus erythematosis, multiple sclerosis, strokes, cancer, skin diseases and asthma. Total PUFA in the samples ranged from 37.5 – 39.4 %; in the bull and hen brain, it was 83.5 – 85.0

% [16]; in three land snails it was 25.5 – 38.7 % [38]; in the bush pig it was 18.9 – 23.1 % [39]; in domestic pig it was 23.9 – 30.1 % [14]. Total PUFA in beef fat was 4%, in lamb fat was 5 %, in pork fat was 15 %, in chicken (meat and skin) 19 %, in duck (meat and skin) 12 %, in calf liver (26 %)[28]. Literature value for C20:4 were (% total fatty acids): rabbit, lean (0.7), brain, sheep (4.2), liver, ox (6.4), liver, sheep (5.1), liver, pig (14.3), liver, calf (9.0), whereas in C22:6, we have brain, sheep (9.5), liver:ox (1.2), sheep (2.4), pig (3.8), calf (2.5)[10]. Table.4 shows the summary of the quality parameters which are characteristics of the fatty acids in the crab samples. The MUFA + PUFA was 76.9 % (S. africanus africanus) and 81.4% (C. latimanus) showing that the samples were more unsaturated than saturated in their fatty acids. n -6/n-3 range was 0.721 - 0.761; PUFA/SFA was 1.66 - 2.02; MUFA/SFA range was 1.58 - 2.36; essential PUFA status index (EPSI) was 0.853 – 1.03; AA/DGLA was 6.93 – 13.5; LA/ALA was 3.98 – 454; EPA/DHA was 0.986 – 1.58 showing that C. latimanus fatty acid was better in many of these parameters than in the S. aficanus aficanus. The relative values of PUFA in all the samples made them important in diet. A deficiency of n – 6 fatty acids in the diet leads to skin lesions. A deficiency of n–3 fatty acids leads to subtle neurological and visual problems. Deficiencies in PUFA produce growth retardation, reproductive failure, skin abnormalities and kidney and liver disorders. However, people are rarely deficient in those fatty acids [40]. The relative amounts of PUFA and SFA in dietary oils is important in nutrition and health. The ratio of PUFA/SFA (P/S ratio) is therefore important in determining the detrimental effects of dietary fats. The higher the P/S ratio the more nutritionally useful is the oil. This is because the severity of atherosclerosis is closely associated with the proportion of the total energy supplied by SFA and PUFA salts [41]. The PUFA/SFA was much better for C. latimanus than the S. africanus africanus. The essential fatty acid ratio (n-6/n-3) have critical roles in the membrane structure and as precursors of eicosanoids. Since n-6 and n-3 compete for the same enzymes and have different biological roles, the balance between the n-6 and n-3 FAs in the diet can be of considerable importance. Because of the low content of n-6 FAs in marine fish, the ratio of total n-3 to n-6 fatty acids (essential fatty acid ratio) is high, varying between about 5 and more than 10 [37]. The ratio of n-6 and n-3 in the diet should be between 5:1 and 10:1 [42] or 4-10 g of n-6 FAs to 1.0g of n-3 FAs [43]. As LA is almost always present in foods, it tends to be relatively more abundant in animal tissue. This is supported in the present report in both samples (n-6 =



3.90 – 10.3 % and n-3= 0.023 – 0.980 %). Looking at n-6/n-3, none of the samples fell within the expected ratio; we had 0.721 in S. africanus africanus and 0.761 in C. latimanus and in LA/ALA, we had 454 :1 in S. africanus aficanus and 3.98:1 in C. latimanus. Both LA and ALA need adjustment from other food sources. The relative proportion of MUFA/SFA is an important aspect of phospholipid composition and changes to this ratio have been claimed to have effects on such disease states as cardiovascular disease, obesity, diabetes, neuropathological conditions and cancer. For example, they have been shown to have cyto-protective actions in pancreatic -cells. Cis – Monoenoic acid have desirable physical properties for membrane lipids in that they are liquid at body temperature, yet are relatively resistant to oxidation. They are now recognized by nutritionists as being beneficial in the human diet [38]. Present results in the samples were good enough. A high ratio between AA and DGLA as an indicator of Δ-D desaturase activity in the skeletal muscle phospholipids has been related to good insulin sensitivity; the AA/DGLA in the samples were good results. For the assessment of the essential PUFA status of an individual, the total amount of the various EFA and PUFA in plasma or erythrocyte phospholipids is a useful indicator [44]. The following are further used as additional markers to reliably assess the functional PUFA status [45]. The best known marker is Mead acid [trivial name for all cis – icosa – 5,8,11 – trienoic acid (C20:3n-9)]. The synthesis of this fatty acid is promoted if there are insufficient concentration of LA and ALA to meet the need for the synthesis of long-chain PUFA. EPA and DHA inhibit Mead acid synthesis; the presence of Mead acid indicates a general shortage of all essential PUFA. The present results had ratios of EPA/DHA as 0.986 – 1.58 and no Mead acid was produced. Another suitable indicator of essential PUFA status is the essential PUFA status index (EPSI), which is the ratio between all essential PUFA (the sum of all n-3 and n-6 FAs) and all non-essential unsaturated FAs (the sum of all n-7 and n-9 FAs). The higher the EPSI status index the better the essential PUFA status. The present result had values of EPSI range of 0.853 – 1.03 which were above average. Finally, if there is a functional shortage of DHA, the body starts to synthesise the most comparable long-chain PUFA of the n-6 family, osbond acid (22:5 n-6). Therefore, under steady state conditions, the ratio between DHA and osbond acid is a reliable indicator of the functional DHA status [46]. Hence, the PUFA in the crab samples cannot cause functional diseases.

The values produced from SFA, MUFA and PUFA had this trend, SFA: S. africanus africanus > C. latimanus; MUFA: C. latimanus > S. africanus africanus; PUFA: S. africanus africanus > C. latimanus (Fig. 2). The calculation accounted for all the total fatty acids as calculated by crude fat x the conversion factors for the samples: 0.609/0.609 (C. latimanus) but 1.27/1.28 (S. africanus africanus; difference of 0.01 g/100 g due to various approximations). The National Institute of Health has published recommended daily intakes of FAs; specific recommendations included 650 mg of EPA and DHA, 2.22 g/day of ALA and 4.44 g/day of LA. However, the Institute of Medicine has recommended DRI (dietary reference intake) for LA at 12-17 and ALA at 1.1-1.6 g for adult women and men, respectively. Both crab samples had high percentage levels of PUFA.

Figure.2. Fatty acid composition of S. africanus africanus and C. latimanus compared.

3.1.1.

Fatty acids as food

Table 5 contains the fatty acids distribution per 100 g samples as food. The values produced from SFA, MUFA and PUFA followed the pattern shown in Tables 2, 3 and 4. SFA was 305 mg/100 g as food in S. africanus africanus, it was 113 mg/100 g in C. latimanus; for MUFA, it was 480 mg/100 g in S. africanus africanus and 267 mg/100 g in C. latimanus; n-6 PUFA (total) in S. africanus africanus was 212 mg/100 g and in C. latimanus it was 98 mg/100 g as food; in n-3 total, S. africanus africanus was 285 mg/100 g but 130 mg/100 g in C. latimanus; n-6 + n-3 (total) had 497 (S. africanus africanus) and 288 mg/100 g (C. latimanus) but total unsaturated FAs had 964 mg/100 g as food in the S. africanus africanus and 496 mg/100 g as food in C. latimanus. Total food source from the samples gave the values as SFA + MUFA + PUFA in S. africanus africanus (1270 mg/100 g) and in C. latimanus (609 mg/100 g),



these gave similar values as the values for true fatty acids in the samples (Table 1). The PUFA content of some selected foods for LA are (mg/100 g): beef (muscle only), 80; calf’s kidney, 61; chicken (breast), 980; chicken (leg), 370; horsemeat (average), 160; pork (muscle only), 110; turkey (breast), 180, turkey

(leg), 750; veal (muscle only), 197. For ALA (mg/100 g): present result (13.0 in S. africanus africanus and 0.00 mg/100 g in C. latimanus); calf’s kidney, 61; chicken (breast), 2.7; chicken (leg), 10; horse meat (average), 260; pork (muscle only), 25 and veal (muscle only), 9.1 [47].

Table 4. Summary of the quality characteristics of the fatty acids profiles Fatty acid


C. latimanus

Mean

SD

CV %

Total PUFA n-6

16.5

16.2

16.4

0.212

1.30

Total PUFA n-3

22.9

21.3

22.1

1.13

5.12

Total PUFA (n-6 + n-3)

39.4

37.5

38.5

1.34

3.49

MUFA total (cis)

37.0

43.9

40.5

4.88

12.1

MUFA total (trans)

0.464

0.010

0.237

0.321

135

MUFA

37.5

43.9

40.7

4.53

11.1

C16:0/SFA %

60.1

62.2

61.2

1.48

2.43

C18:0/SFA %

34.6

3.70

19.2

21.8

114

SFA total

23.8

18.6

21.2

3.68

17.3

MUFA + PUFA

76.9

81.4

79.2

3.18

4.02

n-6/n-3

0.721

0.761

0.741

0.028

3.82

PUFA/SFA

1.66

2.02

1.84

0.255

28.8

MUFA/SFA

1.58

2.36

1.97

0.552

28.0

C18:1 (cis-9)/MUFA (cis) %

37.3

21.2

29.3

11.4

38.9

EPSI

0.853

1.03

0.942

0.125

13.3

AA/DGLA

13.5

6.93

10.2

1.73

17.0

LA/ALA

454

3.98

229

318

139

EPA/DHA

1.58

0.986

1.28

0.420

32.7

PUFA/MUFA

0.853

1.03

0.942

0.125

13.3

Ratio

1:1

1:1

-

-

-

SFA+MUFA+PUFA

100

100

-

-

-

total

EPSI = essential PUFA status index.



Table 5. Fatty acid levels in crab samples (per 100 g as food) Fatty acid C6:0 C8:0 C10:0 C12:0 C14:0 C16:0 C18:0 C20:0 C22:0 C24:0 SFA C14:1 cis-9 C16:1 cis-9 C18:1 cis-6 C18:1 cis-9 C20:1 cis-11 C22:1 cis-13 C24:1 cis-15 MUFA (cis) C18:1 trans-6 C18:1trans-9 C18:1trans-11 MUFA (trans) MUFA(total) C18:2 cis-9,12 C18:3 cis-6,9,12 C20:2 cis-11,14 C20:3 cis-8, 11,14 C20:4 cis-5, 18,11,14 C22:2 cis-13,16 n-6 PUFA (cis) C18:2 cis-9, trans-11 n-6 PUFA (total) C18:3 cis-9, 12, 15 C20:3 cis-11,14,17 C20:5 cis-5,8,11,14,17 C22:6 cis-4,7,10,13,16,19 n-3 PUFA (total) n-6 + n-3 (total) MUFA + PUFA (total) Total (SFA + MUFA +PUFA)

S. africanus africanus 0.002 0.071 0.190 0.011 0.015 0.014 0.002 0.305 0.005 0.077 0.136 0.100 0.149 0.005 0.002 0.474 0.005 0.00 0.00 0.006 0.480 0.050 0.011 0.002 0.018 0.123 0.002 0.206 0.006 0.212 0.013 0.09 0.131 0.132 0.285 0.497 0.964 1.27

C. latimanus 0.003 0.003 0.068 0.039 0.00 0.00 0.00 0.113 0.00 0.045 0.053 0.100 0.068 0.00 0.00 0.267 0.00 0.00 0.00 0.00 0.267 0.063 0.00 0.00 0.002 0.031 0.002 0.098 0.00 0.098 0.00 0.00 0.079 0.050 0.130 0.228 0.496 0.609

Mean 0.003 0.037 0.129 0.025 0.061 0.095 0.100 0.109 0.371 0.00 0.00 0.374 0.057 0.010 0.077 0.002 0.152 0.155 0.105 0.091 0.208 0.363 0.730 0.940

SD 0.001 0.048 0.086 0.020 0.023 0.059 0.00 0.057 0.146 0.151 0.009 0.01 0.06 0.00 0.076 0.081 0.037 0.058 0.110 0.190 0.331 0.467

CV % 28.3 130 66.9 79.2 37.1 62.1 52.5 39.5 40.3 16.3 113 84.5 50.2 52.0 35.0 63.7 52.8 52.5 45.3 49



3.1.2.

Energy density of fatty acids

The energy density in the samples due to fat ranged as 23.1-48.3 kJ/100 g as shown in Table 6 for the SFA +MUFA +PUFA (TFAE). A close look at the Table 6 would reveal that the energy contribution per parameter tallied with the percentage level of the fatty acids components in the samples. This then meant that energy in SFA, MUFA, n-6 PUFA, n-3 PUFA, total PUFA, MUFA + PUFA and TFAE in S. africanus africanus > in the C. latimanus. The energy in food is held in form of fat, protein, carbohydrate and alcohol. Each gram of fat contains approximately 9 kilocalories (38 kJ) [48]. This value was used to calculate the energy levels of the two fat samples. The 1990 Canadian RNI (Recommended Nutrient Intakes) included specific amounts for 3n-3 FAs and 2n-6 FAs. For n-3 FAs, the RNI is 0.5 % of total energy or 0.55 g/1000 kcal; for n-6 FAs, the RNI is 3 % of total energy or 3.3 g/1000 kcal [49]. In the energy contribution in the samples, the followings were observed: S.africanus africanus (PUFA > MUFA >SFA); C. latimanus (MUFA > PUFA >SFA). Remember, total energy contribution by the samples ranged from 23.1- 48.3 kJ/100 g. These values were much less than what could result into deleterious effects on excess fat consumption. 3.1.3.

Statistical analysis of SFA and MUFA, PUFA n-6 and n-3

In Table 7, the statistical analysis of the results from Table 2 and 3 is shown. From Tables 2 and 3, the correlation coefficient rxy was statistically significant at r = 0.05. Also the coefficient of alienation (C A) was slightly above 50 % in both results from Tables 2 and 3 with corresponding lower values ( cephalin > phosphatidylserine > phosphatidylinositol > lysophosphatidylcholine; also the percentage levels followed similar trend. Phospholipids intervene in prostaglandin signal pathways as raw material used by lipase enzymes to produce the prostaglandin precursors. In plants they serve as the raw material to produce jasmonic acid, a plant hormone similar in structure to prostaglandins that mediate defence responses against pathogens. The quantities of phospholipids in the human diet are not fully known. The total phospholipids intake of eight healthy Swedish women ranged from 1.5-2.5 mmol/day. Of the total dietary fatty acids, 13-33 mg/g were consumed as phospholipids [50]. Further research has been carried out on the consumption of phosphatidylcholine and its group choline. Zeisel et al [51] estimated that the adult population in the USA consumed about 6 g of phosphatidylcholine per day. Phosphatidylcholine in the present report ranged between 141-243 mg/100 g. There is evidence that phosphatidylserine (PS) (third most concentrated in the samples) influencies cognition. Phosphatidylserine plays an important role in the function and homeostasis of neuronal cell membranes. PS is able to improve age associated behavioural alteration in animal models, so it was thought that it may also have a positive impact on cognition in humans, particularly on those functions that are impaired during aging, such as memory and language achievement, as well as learning and concentrative [52, 53]. Therefore it was assumed that phosphatidylserine may be useful in the prevention and treatment of age related cognitive decline such as Alzheimer’s disease, and in depression and other cognitive disorders [54].

Table 6. Energy contribution (kJ/100 g) of the crab samples



Table 6. Energy contribution (kJ/100 g) of the crab samples Fatty acid


C. latimanus

Mean

SD

CV %

SFA

11.6(24.0 %)

4.29(18.6 %)

7.95

5.17

65.1

MUFA (cis)

18.0(37.3 %)

10.1 (43.8 %)

14.1

5.59

39.8

MUFA (trans)

0.228 (0.472 %)

0.00(-)

-

-

-

MUFA (total)

18.2(37.8 %)

10.1(43.8 %)

14.2

5.73

40.5

n-6 PUFA

7.83(16.2%)

3.72(16.1%)

5.78

2.91

50.3

n-3 PUFA

10.4(21.5 %)

4.94(21.3 %)

7.67

3.86

50.3

PUFA (total)

18.9(39.1%)

8.66(37.4 %)

13.8

7.24

52.5

MUFA + PUFA

36.6(75.9 %)

18.8(81.4 %)

27.7

12.6

45.4

SFA +MUFA + PUFA (TFAE)

48.3

23.1

35.7

17.3

4.85

Table 7. Statistical analysis of the variances Statistics

SFA and MUFA S. africanus africanus/C. latimanus

PUFA n-6 and n-3 S. africanus africanus/C. latimanus

Correlation coefficient (rxy)

0.8164*

0.8401*

Coefficient of determination (rxy2)

0.6666

0.7057

Regression coefficient (Rxy)

0.4472

0.0494

Mean of S. africanus africanus (X)

3.83

3.58

X ± SD

4.93

4.41

CV %

129

123

Mean of C. latimanus (Y)

3.91

3.41

Y± SD

5.46

4.92

CV %

140

145

Coefficient of alienation (CA)

0.5774

0.5425

Index of forecasting efficiency (IFE)

0.4226

0.4575

Remark

Significant

Significant

Results significantly different at df 14 (Table 2) r = 0.05 (with value of 0.497(Table 2); results significantly different at df 9 (Table 3) r = 0.05 (with value of 0.602 (Table 3); * = significant.



Table 8. Phospholipids level (mg/100 g) of the S. africanus africanus and C. latimanus crab samples Phospholipid


C. latimanus

Mean

SD

CV %

Cephalin (PE)

119(28.1%)

77.9 (28.7 %)

98.5

29.1

29.5

Lecithin

243(57.4 %)

141(52.1 %)

192

72.1

37.6

Ptd-L-Ser (PS)

53.5(12.6%)

46.8 (17.3 %)

50.2

4.74

9.45

Lysophosphatidylcholine

4.09e-3(0.001 %)

1.24e-2(0.005%)

0.008

0.006

71.3

Ptd-Ins (PI)

7.89(1.86 %)

5.24(1.93 %)

6.57

1.87

28.5

Total

423

271

347

107

31.0

PE = phosphatidylethanolamine; Lecithin = phosphatidylcholine; PS = phosphatidylserine; PI = phosphatidylinositol.

Table 9. Sterol levels (mg/100 g) of the two crab samples Sterol


C. latimanus

Mean

SD

CV %

Cholesterol

99.5(99.3 %)

87.5 (98.6 %)

93.5

8.49

9.08

Cholestanol

4.71 e-5

2.70e-4

1.59e-4

1.58e-4

99.5

Ergosterol

1.46e-3

5.30e-4

9.95e-4 6.58e-4

66.1

Campesterol

7.08e-1(0.706%)

1.26(1.42%)

0.984

0.390

39.7

Stig-masterol

1.16e-3

4.82e-5

8.34e-4 1.11e-3

133

5-Avenasterol

8.85e-3

4.57e-4

4.65 e-3 5.93e-3

128

Sitosterol

6.40e-3

5.93e-6

3.20e-3 4.52e-3

141

Total

100

88.8

94.4

8.39

7.92

Table 10. Statistical analysis of variances Statistics

Phospholipids

Sterols

0.9926

0.99997

0.9853

0.9994

Regression coefficient (Rxy)

5.56

-0.118

Mean of X

84.7

12.7

X ± SD

100

33.0

CV %

119

260

Mean of Y

54.2

14.3

Y ± SD

58.1

37.6

CV %

107

262

Coefficient of alienation (CA)

0.1211

0.0073

Index of forecasting efficiency (IFE)

0.8789

0.9927

Remark

Significant

Significant

Correlation coefficient (rxy) Coefficient of determination

(rxy2)

Results significantly different at df 3 (phospholipids) at r = 0.05 (with value of 0.878) and at df 5 (sterols) at r = 0.05 (with value of 0.754)



3.3. Steroyl levels In Table 9, the sterol levels are shown. Only cholesterol had significant concentration range from 87.5-99.5 mg/100 g or 98.6-99.3 %. Total sterol levels ranged from 88.8 -100 mg/100 g or 94.4 ± 7.92 mg/100 g and CV% of 8.39. The good aspects of cholesterol included being present in mammalian cell membranes where it is required to establish proper membrane permeability and fluidity, a precursor molecule for the biosynthesis of bile acids, steroid hormones and several fat soluble vitamins. Cholesterol does exert one negative influence in the body, however. On its way into cells from the blood stream, some cholesterol forms deposits in the artery walls. These deposits lead to atherosclerosis, a disease that causes heart attacks and strokes. Complex lipids are bonded to other types of molecules. Because lipids are mostly insoluble in water, the movement of lipids from organ to organ through the bloodstream is facilitated by plasma lipoproteins. Dietary patterns also affect the metabolism of cholesterol. However, diet low in SFA, trans fat and cholesterol encourage the uptake of LDL by the liver, thereby removing LDL from the blood stream and decreasing the ability of scavenger cells to form atherosclerotic plagues in the blood vessels. The two samples under discussion had low SFA, high PUFA, very low trans-fat and low cholesterol which all encourage the uptake of LDL by the liver, hence, decreasing the ability to form atherosclerotic plagues in the blood vessels. 3.4. Statistical analysis of phospholipid and steroyl levels Table 10 contains the statistical analysis of the results from Table 8 (phospholipids) and Table 9 (sterols). There was a high positive significant correlation coefficient in both the phospholipids and sterols with rxy range of 0.9926-0.99997. Also the CA was low to very low in the two parameters with values of 0.0073-0.1211; whilst IFE was correspondingly high at 0.8789-0.9927 thereby making the prediction of relationship much easier between the two samples both in their phospholipids and sterols.

was C20:1 cis-11 (S. africanus africanus) and C18:1 cis-9 (C. latimanus); dominant n-6 was C20:4 cis-5, 8, 11, 14 (S. africanus africanus) and C18:2 cis-9, 12 (C. latimanus); n-3 dominant was C20:5 cis-5, 8, 11, 14, 17 (EPA) in both samples. Most quality parameters were better in C. latimanus than S. africanus africanus. Both samples had reasonable levels of phospholipids and cholesterol although more to the S. africanus africanus than C. latimanus. Both samples are good sources of healthy dietary fat. Conflict of Interest The author declares that he has no conflict of interest.

References 1.

2.

3. 4.

5.

6.

7.

4. CONCLUSION The analytical results of the Sudananautes africanus africanus and Callinectes latimanus showed crude fat to be very low as 0.870-1.83 g/100 g. Fatty acids distribution was SFA < MUFA < PUFA (S. africanus africanus) and SFA < MUFA > PUFA (C. latimanus). In both, dominant SFA was C16:0; dominant MUFA

8.

Davidson A (1999). The Oxford Companion to Food. Oxford University Press, Oxford; 221- 222. Elegbede I O and Fashina-Bombata H A (2013). Proximate and mineral compositions of common crab species [Callinectes pallidus and Cardisoma armatum] of Badagry creek, Nigeria. Poultry Fisheries and Wildlife Sciences; 2: 1-5. Bullough WS (1958). Practical Invertebrate Anatomy. Macmillan Press, London; 483. Muller HG and Tobin G (1980). Nutrition and Food Processing. Avi Publishing, Westport CT; 195-196. Adeyeye EI (2002). Determination of the chemical composition of the nutritionally valuable parts of male and female common West African fresh water crab Sudananautes africanus africanus. International Journal of Food Science and Nutrition; 53: 189-196. Adeyeye EI and Kenni AM (2008). The relationship in the amino acid of the whole body, flesh and exoskeleton of common West African fresh water male and crab Sudananautes africanus africanus. Pakistan Journal of Nutrition; 7: 748-752. Adeyeye EI, Olanlokun JO and Falodun TO (2010). Proximate and mineral composition of whole body, flesh and exoskeleton of male and female common West African fresh water crab Sudananautes africanus africanus. Polish Journal of Food and Nutrition Sciences; 60: 213-216. AOAC (2005). Official Methods of Analysis, 18th ed. Association of Official Analytical Chemists, Washington DC, USA.



9.

10.

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

Sections 920.39 (A), 969.33 and 996.06; 970.51. Raheja RK, Kaur C, Singh A and Bhatia IS (1973). New colorimetric method for the quantitative estimation of phospholipids without acid digestion. The Journal of Lipid Research; 14: 695-697. Paul AA and Southgate DAT (1978). McCance and Widdowson’s, The Composition of Foods, 4th ed. HMSO London; 91-92. Greenfield H and Southgate DAT (2003). Food composition data, production, management and use, 2nd ed. FAO, Rome; 83-197. Oloyo RA (2001). Fundamentals of Research Methodology for Social and Applied Sciences. ROA Educational Press, Ilaro, Nigeria; 71-73. Adeyeye EI (2014). Bone marrow: a source of nutritionally valuable fats as typified in the femur of ram and bull. Open Journal of Analytical Chemistry Research; 2: 1-15. Adeyeye EI (2013). Domestic pig organs as good sources of nutritionally important fatty acids and low cholesterol meat. Global Journal of Science Frontier Research: Chemistry Classification; 13: 21-37. IUPAC (2001). Lexicon of lipid nutrition (IUPAC Technical Report), Pure and Applied Chemistry; 73: 685-744. Adeyeye EI (2012). Study of long-chain and n-6 and n-3 polyunsaturated fatty acids and other lipids in brains of bull and hen. Elixir Food Science; 47: 8599-8606. Weber N, Klaus-Dieter R, Schilte E and Mukherjee KD (1995). Petroselinic acid from dietary triacylglycerols reduces the concentration of arachidonic acid in tissue lipids of rats. Journal of Nutrition; 125: 1563-1568. Mohrhauer H, Bahm JJ, Seufert J and Holman RT (1967). Metabolism of linoleic acid in relation to dietary monoenoic fatty acids in the rat. Journal of Nutrition; 91: 521-527. Enig MG and Fallon S (2000). The truth about saturated fats. (Proven Health Benefits of Saturated Fats.), nourishing traditions: the cookbook that challenges politically correct nutrition and the diet dictocrats by S. Fallon with M.G. Enig, Eds. New Trends Publishing. www.newtrendspublihing.com 877-707; 1-39. Nestel P, Clifton P and Noakes M (1994). Effects of increasing dietary palmitoleic acid

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

compared with palmitic and oleic acids on plasma lipids of hypercholesterolemic men. Journal of Lipid Research; 35: 656-662. Grundy SM (1994). Influence of stearic acid on cholesterol metabolism relative to other long-chain fatty acids. American Journal of Clinical Nutrition; 60: 986S-990S. Christensen E, Hagvo TA and Christophersen BO (1988). The Zellweger syndrome: deficient chain-shortening of erucic acid [22:1 (n-9)]. Biochimica et Biophysica Acta; 959: 134-142. Sargent JR, Coupland K and Wilson R (1994). Nervonic acid and demyelinating diseases. Medical Hypotheses; 42: 237-243. Rasmussen M, Moser AB, Borel J, Khangoora S and Moser HW (1994). Brain, liver and adipose tissue erucic acid and very long chain fatty acids levels in adrenoleukodystrophy patients treated with glyceryl tri-erucate and trioleate oils (Lorenzo’s oil). Neurochemical Research; 19: 1073-1082. Whetsell MS, Rayburn EB and Lozier JD (2003). Human health effects of fatty acids in beef, Pasture – Based Beef Systems for Appalachia, Extension Service, West Virginia University, Virginia State, USA; 1 – 8. Lord RS and Bralley JA (2001). Copyright 2001 matametrix Inc. Metametrix is a service mark registered with the United States Patent and Trademark office (www.metametrix.com). Cater NB and Denke MA (2001). Behenic acid is a cholesterol-raising saturated fatty acid in humans. American Journal of Clinical Nutrition; 73: 41- 44. Bender A (1992). Meat and meat products in human nutrition in developing countries: FAO Food and Nutrition Paper 53. FAO, Rome; 3-91. Hayes KC (2002). Dietary fat and heart health: in search of the ideal fat. Asia Pacific Journal of Clinical Nutrition; 11: S394S400. Horrobin DF and Manku MS (1990): Clinical biochemistry of essential fatty acids. In: Omega-6 essential fatty acids Pathophysiology and roles in clinical medicine by DF Horrobin, Ed., Wiley-Liss, New York; 21-53. Mead JF (1971). The metabolism of the polyunsaturated fatty acids. Progress in the Chemistry of Fats and Other Lipids; 9: 159192.



32. Stansby ME (1990). Nutritional properties of fish oil for human consumption –early development. In: Fish oils in Nutrition by ME Stansby, Ed. Van Nostrand Reinhold, New York; 289-308. 33. Lands WEM (1986). Fish and human health, Academic Press, Orlando; 170. 34. Terano T, Hirai A, Hamazaki T, Kobayashi S, Fujita T, Tamura Y and Kumagai A (1983). Effect of oral administration of highly purified eicosapentaenoic acid on platelet function, blood viscosity and red cell deformability in healthy human subject, Atherosclerosis; 46: 321-331. 35. Statistisches Jahrbuch (1992). Fur die Bundesrepublik Deutschland. Statisches Bundesamt, Wiesbadent; 764. 36. Dyerberg J (1982). Observations on populations in Greenland and Denmark, In: Nutritional evaluation of long chain fatty acids in fish oil by SM Barlow and ME Stansby, Eds. Academic Press, New York; 245-262. 37. Steffens W (1997). Effects of variation in essential fatty acids in fish feeds on nutritive value of freshwater fish for humans. Aquaculture; 151: 97-119. 38. EI Adeyeye (2012). Lipid composition of three different types of land snails consumed in Nigeria. Global Journal of Science Frontier Research: Chemistry Classification; 12: 8-22. 39. Adeyeye EI, Adesina AJ and Aladegbami AA (2013). Fatty acids, phospholipids and zoosterols levels of the muscle, skin and liver of bush pig (Potamochoerus larvatus): dietary implications. International Journal of Advanced and Innovative Research; 2: 6590. 40. Tapiero H, Nguyen BG, Couvreur P and Tew KD (2002). Polyunsaturated fatty acids (PUFA) and eicosanoids in human health and pathologies. Biomedicine and Pharmacotheraphy; 56: 215-222. 41. Honatra G (1974). Dietary fats and arterial thrombosis. Haemostasis; 2: 21-52. 42. WHO/FAO (1994). Fats and oil in human nutrition. Report of a joint consultation, FAO Food and Nutrition Paper 57. WHO/FAO Rome; 3-98. 43. Canadian Government Publishing Center (1990). Nutrition recommendations: The report of the Scientific Review Committee. Canadian Government Publishing Center, Ottawa; 24.

44. Hornstra G (1992). Essential fatty acids, pregnancy and complications: A roundtable discussion. In: Essential fatty acids and eicosanoids by A Sinclair and R Gibson Eds. Champaign: American Oil Chemists’ Society; 177-182. 45. Benath P, Peluso G, Nicolai R and Calvani M (2004). Polyunsaturated fatty acids: biochemical, nutritional and epigenetic properties. Journal of the American College of Nutrition; 33: 281-302. 46. Neuringer M, Connor WE, Lin DS, Barstad L and Luck S (1986). Biochemical and functional effects of prenatal and postnatal omega-6 fatty acid deficiency on retina and brain in rhesus monkeys. Proceedings of the National Academy of Sciences USA; 83: 4021-4025. 47. Souci SV, Fachmann W and Kraut H (1990). Food composition and nutrition tables, 1989/1990. Wissenshaftliche Verlagsgellschaft mbH Stuttgart Germany. In: Adeyeye EI (2014). Bone Marrow: A Source of Nutritionally Valuable Fats as Typified in the Femur of Ram and Bull. Open Journal of Analytical Chemistry Research; 2(1): 1 – 15. 48. Royal Society (1972). Metric units, conversion factors and nomenclature in nutritional and food sciences. Report of the subcommittee on metrication of the British National Committee for Nutritional Sciences, London; 23: 1383 – 1391. 49. Whitney EN, Cataldo CB and Rolfes SR (1994). Understanding normal and clinical nutrition, 4th ed. West Publishing Company, New York; 132-168. 50. Akesson B (1982). Content of phospholipids in human diets studied by the duplicate portion technique. British Journal of Nutrition; 47: 223-229. 51. Zeisel SH, Dacosta KA, Franklin PD, Alexander EA, Lamont JT and Sheard NF (1991). Choline, an essential nutrient for human. Federation of American Societies for Experimental Biology; 5: 2093-2098. 52. Pepeu G, Pepeu IM and Amaducci L (1996). A review of phosphatidylserine pharmacological and clinical effects. Is phosphatidylserine a drug for the ageing brain? Pharmacological Research; 33: 7380. 53. Pepeu G (2003). Is there evidence that phospholipids administration is beneficial for your brain?, In: Nutrition and biochemistry of phospholipids by BF Szuhaj



and W Van-nuruwenhuyen Eds. American Oil Ass Press, Illinois; 30-39. 54. Pepping J (1999). Phosphatidylserine, American Journal of Health-System Pharmacy; 56: 2038-2044.
