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. 2023 Feb 28;9(3):e14031. doi: 10.1016/j.heliyon.2023.e14031

Nutritional composition, heavy metal contents and lipid quality of five marine fish species from Cameroon coast

JCK Manz a, JVF Nsoga a, JB Diazenza b, S Sita b, GMB Bakana b, A Francois b, M Ndomou a,∗, I Gouado a, V Mamonekene c
PMCID: PMC10015189  PMID: 36938409

Abstract

The nutritional value, heavy metal content and lipid quality of five marine fishes from, Cameroon coast were be investigated. Fish samples from Ilisha africana, Sardinella, maderensis, Cyprinus carpio, Arius parkii and Ethmalosa fimbriata were collected at, the Douala sea port, carried to the laboratory, washed with distilled water and, processed. Proximal composition, minerals, lipid quality and heavy metal analyses, were performed using AOAC standard methods. Results show that proteins (18.43%), and lipids (3.69%) contents were higher in Ilisha africana. Cyprinus carpio had the, highest ash content (4.59%). Contents of minerals and heavy metals were found as, follows: P > Mg > K > Ca > Na > Fe > Zn > Cu > Mn and Hg > Pb > Cd > As. Oils extracted from C. carpio, A. parkii and E. fimbriata were semi-siccative while those of I. africana and S. maderensis were siccative. Thus, these fish species are good sources of proteins and, minerals that can be used for managing mineral deficiencies in humans and animals.

Keywords: Nutritional composition, Heavy metal, Lipid quality, Fish species

1. Introduction

World fish production rose to 179 million tons in 2018 with an estimated annual supply consumption of 20.5 kg per capita [1]. Fish is a food rich in proteins of high nutritional value, lipids, minerals and vitamins. Proteins are used to synthesize digestive enzymes, hormones and to repair and maintain tissues, such as skin, muscles and bones. Fish oils are rich in PUFAs especially omega 3 which have therapeutic properties such as antidiabetic, antioxidant, hypotensive, anti-inflammatory and antihyperlipidemic effects [[2], [3], [4]]. Fish flesh is one of the main sources of minerals to cover needs and prevent several deficiencies that can help reduce the chronic condition of patients suffering from cardiovascular diseases [5]. Minerals control the water balance, maintain the acid-base balance and enter into the constitution of certain structures (bones, teeth), enzymes, hormones and catalyze many metabolic reactions [6]. Vitamins are involved in several biological processes. The water-soluble vitamins, in this case the B-complex vitamins, are the precursors of the coenzymes involved in the metabolic pathways. Cameroon, with a coastline of 402 km on which artisanal and industrial fisheries are practiced have an annual fish production estimated at 252,764 tons in 2016, with an average consumption of 19.4 kg per capita [7]. A variety of products come from these fisheries, such as fish from the Clupeidae, Ariidae and Cyprinidae families. The Clupeidae are pelagic species native to the coasts, beaches, lagoons and estuaries of West Africa. They are distributed along the tropical zone of the Atlantic Ocean. Some prefer shallow water. They feed on phytoplankton, benthic invertebrates, fish, detritus and fish eggs [8]. Three fish species belonging to each of these families were choosen for this study: Ilisha africana, Sardinella maderensis and Ethmalosa fimbriata. The Ariidae are demersal species that include catfish from fresh, brackish or salt water in temperate and tropical regions. They are of great importance both in terms of specific and biogeographical diversity. Species in this family feed on shrimp, parasites, planktons and numerous benthic invertebrates buried in the mud and are qualified as complete omnivores [9]. The Cyprinidae represent the largest family of freshwater fish, only a few species are able to venture into the brackish waters of estuaries. They are stomachless fish with toothless jaws. Most cyprinids are omnivorous with a herbivorous tendency, feeding mainly on benthic invertebrates and plants, probably due to the lack of hard teeth and stomach [10]. Cyprinus carpio is the species of this family targeted for the study. These fish species are easily accessible to all social strata and occupy an important place in the fishing catches and diet of Cameroonians. Fish is a good indicator of heavy metal contamination in aquatic systems because they belong to different levels of the food chain [11]. Heavy metals were of particular concern due to their toxicity and ability to bioaccumulate in aquatic ecosystems, as well as their persistence in the natural environment. The sources of natural aquatic system contamination of heavy metals are mostly man-made activities, domestic sewage, agricultural activities and discharges of petroleum products [12]. Among the different metals analyzed, lead (Pb), cadmium (Cd), mercury (Hg), chromium (Cr) and arsenic (As) are classified as hazardous chemicals and maximum residual levels have been prescribed for humans [13]. Heavy metal pollution in the aquatic environment has become a serious factor in the decline of aquatic sediments and fish quality [14]. Lots of studies have been done on fish and fishery products in Cameroon [7,[15], [16], [17], [18], [19]]. There are limited information about heavy metals pollution and proximate composition of Clupeidae, Ariidae and Cyprinidae from Cameroonian coast. Therefore, considering the various health risk and the nutritional benefits associated with fish consumption; it was important to evaluate fish's heavy metals content and proximate composition and to assess their health status in order to establish the safety level of these commercially important species prior their consumption. This study contributes to the valorization of fishery products from the Cameroonian coasts by evaluating the nutritional value, heavy metals and lipid quality of the five fish species namely I. africana, S. maderensis, C. carpio, Arius parkii and E. fimbriata.

2. Materials and methods

2.1. Material

Fifty fresh fish of each specie (Ilisha africana, Sardinella maderensis, Cyprinus carpio, Arius parkii and Ethmalosa fimbriata) were purchased on the boats as soon as they arrived at the Douala fishing seaport in July 2021. The Animal Industries officers from the Ministry of Livestock, Fisheries and Animal Industries of Cameroon identified fish using FAO fish identification sheets. The fish samples (Fig. 1) were placed in iceboxes containing ice with a fish/ice ratio of 1:2 (w/w) and transported to the Laboratory of Food Sciences and Nutrition at the Faculty of Sciences of University of Douala. An ichtyometer and a precision balance were used respectively to measure the lenght and weight of each fish. Average weight and length of the fish used in this study were 97.74 ± 19.73 g and 21.23 ± 1.50 cm; 108.50 ± 29.88 g and 23.1 ± 2.32 cm; 405.41 ± 84.63 g and 28.44 ± 4.09 cm; 895 ± 271.29 g and 46.62 ± 7.82 cm; 286 ± 53.32 g and 25.36 ± 3.41 cm for Ilisha africana, Sardinella maderensis, Cyprinus carpio, Arius parkii and Ethmalosa fimbriata respectively.

Fig. 1.

Fig. 1

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The experimental fish samples collected from Douala fishing seaport.

2.2. Sample preparation

After morphometric measurement, the fish were dissected with a cleaned stainless steel knife. Heads and visceras were discarded. The edible flesh and skin and other parts consumed by the local population were cut into small pieces. The central vertebra was removed thoroughly. The fresh edible part was used for lipid analysis. For proteins, ash and mineral analyses, the samples (edible part or clean central vertebra) were dried in an oven at 45 °C for 48 h and were homogenized thoroughly in a food blender equipped with stainless steel cutters.

2.3. Proximate analysis

2.3.1. Moisture content

Moisture content was determined using a hot air oven (Binder-78532). Samples were dried at 105 °C ± 2 °C to constant weight [20]. The difference between the fresh weight and the dry weight was calculated and expressed as a percentage relative to the fresh material.

2.3.2. Lipid content

Total lipid was determined by Bligh and Dyer [21] method using chloroform/methanol/water 2:2:1.8 (V:V:V). About 100 ± 0.5 g of edible portion of fresh fish were mixed with 100 ml of chloroform and 200 ml of methanol in a mixer (WARING COMMERCIAL LABORATORY BLENDER) for 2 min 100 ml of chloroform and 100 ml of distilled water were then added and mixed for 30 s. The mixture is filtered under vacuum. Total extraction is ensured by adding chloroform to the retentate, respecting a final solvent ratio of 2:2:1.8 (V:V:V) of chloroform: methanol: water. The mixture is decanted in a funnel until separation into two phases. The lower organic phase is collected in a weighed flask after adding anhydrous sodium sulphate to eliminate all traces of humidity. The solvent was then evaporated in a rotary evaporator (BÜCHI ROTAVAPOR R-205). The lipid residue is weighed and the result is expressed as (%) of the fresh material.

2.3.3. Crude protein content

Crude protein content was determined using Kjeldahl's method which determines the amount of nitrogen and uses the conversion factor 6.25 to infer the total amount of protein. In tubes, 0.1 g of sample, 7 ml of a mixture of concentrated sulfuric acid and salicylic acid and 0.2 g of Merk catalyst were respectively introduced. This mixture was then heated on a digestion plate under a ventilated hood for 3 h until a light green or light brown solution was obtained. The product resulting from the mineralization was placed at the inlet of an automatic micro Kjeldahl type still (BÛCHI Distillation Unit K-355), then 20 ml of 40% NaOH were added (until the copper color appeared) to neutralize acidity due to sulfuric acid, and above all increase the pH above 9 to facilitate the evaporation of ammonia. At the outlet of this apparatus, an Erlenmeyer flask containing 20 ml of boric acid and a few drops of colored indicators (methyl red and bromocresol green) was placed so as to immerse the outlet of the condenser to capture the distilled ammoniac. The distillation was stopped when the distillate reached a volume of 200 ml in the Meyer Erlen. The titration was carried out by noting the volume of 0.01 N HCl which changes the light green color of the distillate to purplish pink. At the same time, a blank test was carried out under the same conditions and the burette descent volume noted, in order to detect traces of nitrogen coming from the reagents.

2.3.4. Ash content

Ash content was obtained by burning away of organic content for 5 h at 450 °C [20]. The various samples, previously dried in an oven at 105 °C, were ground in a mixer (SWISS LINE SWITZERLAND UNIVERSAL MIXER SW-1354-P) to obtain fine particles or powders that were easy to handle. Each sample thus prepared was placed in stainless steel capsules and labeled. Cooling in a desiccator for 30 min was performed to prevent the samples from re-wetting. With a precision balance (METTLER TOLEDO PL403), 2.50 g of sample were weighed as well as the Pyrex beakers in which they were introduced. They were placed in a muffle furnace for calcination for 5 h at 450 °C. At the end of this phase, ashes characterized by their grayish powder appearance were obtained and cooled in a desiccator, then weighed and the ash content was determined.

2.3.5. Total carbohydrates

Carbohydrate was determined by subtracting the sum of fat, protein, ash and moisture contents from 100 in equation 1 [20]. % Carbohydrates = 100 - % Moisture -% Proteins - % Fat -% Ash (1).

2.3.6. Value of energy

The average value of energy was calculated using equation 2. The Atwater general factor system includes energy values of 4 kcal per gram (kcal/g) for protein, 4 kcal/g for carbohydrates and 9 kcal/g for fat. AE = (4 x Carbohydrate content) + (9 x Fat content) + (4 x Protein content) (2) AE: Average Energie.

2.4. Mineral analysis

2 g of sample were weighed as well as the Pyrex beakers in which they were introduced. They were placed in a muffle furnace for calcination for 5 h at 450 °C. After incineration of the fish meal, the ashes obtained were transferred to 100 ml beakers in which 10 ml of concentrated nitric acid were introduced to digest the rest of the organic matter. The different beakers were placed in a boiling water bath for 30 min for optimal digestion. The solution was filtered through WHATMAN paper into a 100 ml volumetric flask and then the volume made up to the gauge mark. Calibration was performed using stock solutions. The absorbance of these solutions was read by atomic absorption spectrophotometry (PerkinElmer Atomic Absorption Spectometer Pinnacle 900T, Perkin Elma, USA) at 623 nm for calcium, 422.7 nm for potassium, 285.2 nm for magnesium, 213.9 nm for sodium, 248.3 nm for iron, 213.9 nm for zinc, 324.7 for copper and 279.5 for manganese. Phosphorus content was determined by spectrophotometry (PerkinElmer, Norwalk CT, USA) at 860 nm. The concentration of a sample is obtained using a linear regression of the concentrations against the absorbance of the standards. The calibration curve and the calculation of the concentrations, expressed in mg/100 g of dry matter, are established using Excell software.

2.5. Heavy metal analysis

The filtrate obtained during the digestion of the ashes was used for the determination of heavy metals. The standards were prepared from stock solutions of cadmium (Cd), lead (Pb), mercury (Hg) and arsenic (As) prepared at 1000 ppm. The concentration levels of cadmium (Cd), lead (Pb), mercury (Hg) and arsenic (As) in the digested sample solutions were determined by using Atomic Absorption Spectrophotometer (AAS ZEEnit-700P). The concentration of a sample is obtained using a linear regression of the concentrations against the absorbance of the standards. The calibration curve and the calculation of the concentrations, expressed in mg/Kg of dry matter, are established using the Excell software. All analyses were done in triplicate and used as quality control. Analytical procedure was ensured using certified standard scientific research approved by National Standard Agency (ANOR).

2.6. Chemical index analyses of fish oil

2.6.1. Acid index

Acid index (AI) was determined according to method described by AFNOR [22]. 1 g of oil was introduced into a 250 ml beaker, then 100 ml of 95 °C ethanol were introduced. Two drops of 1% phenophthalein solution are added to the contents of the beaker and the whole titrated with a 0.1 N potassium hydroxide solution. This titration is also made with the blank test and the volume of KOH used is noted. The Acid index was expressed as mg KOH/g of oil.

2.6.2. Saponification index

Saponification index (SI) was determined according to method described by AOAC [20]. 2 g of oil was dissolved in a solution of ethanolic potass (0.5 N) in ethanol, the whole introduced into a flask with a ground joint. The flask is connected to a reflux condenser and boiled for at least 60 min, stirring occasionally. The excess KOH was titrated with a hydrochloric acid solution (0.5 N), in the presence of phenolphthalein. A blank test was prepared following the same procedure. The saponification index was expressed as mg KOH/g of oil.

2.6.3. Iodine index

The iodine index (II) was determined using the wijs method, as described in the AOAC [20]. 0.2 g of oil was weighed into a flask into which 15 ml of carbon tetrachloride solution and 25 ml of Wijs' reagent. The hermetically sealed bottle is gently shaken and placed in a dark box for 1 h, then 20 ml of aqueous solution of potassium iodide (10%), 15 ml of distilled water and 5 drops of 1% starch will be added to it. The solution in the flask was titrated with 0.1 N sodium thiosulfate solution and the volume of sodium thiosulfate used to turn the solution (disappearance of blue color) from the flask noted. This titration was also made with the blank test. The II was expressed as g I2/100 g of sample.

2.6.4. Peroxide index

Peroxide index was conducted according to method described by Santha and Decker [23].In a glass test tube of 10 ml volume containing 50 mg of oil sample, 9.8 ml of a chloroform-methanol mixture (7:3 v/v) is added, and the mixture vortexed for 2–4 s. Then 50 μl of a 30% aqueous solution of ammonium thiocyanate was added and the mixture again is vortexed for 2–4 s, followed by the addition of 50 μl of an aqueous solution of iron chloride II. The mixture is again vortexed for 2–4 s. After 5 min of incubation at room temperature, the absorbance of the reaction mixture is read at 500 nm against a blank containing all the reagents except the oil, using a spectrophotometer (PerkinElmer, Norwalk CT, USA). The peroxide value was expressed as milliequivalents of O2/kg of oil.

2.6.5. Anisisdine value

Anisidine index (AnI) was determined according to the method described by AOCS [20]. 1 g is weighed into a 25 ml volumetric flask, then dissolved and diluted with isooctane to the mark. The solution obtained is stirred well and its absorbance measured at 350 nm using a spectrophotometer (PerkinElmer, Norwalk CT, USA) using isooctane as a blank. With a pipette, 5 ml of this solution was taken and introduced into a test tube. In a second tube, the same volume of isooctane was added. Subsequently, in each of these tubes, 1 ml of a 0.25% p-anisidine solution prepared in glacial acetic acid was added and the mixture vortexed for a few seconds. After 10 min of incubation at room temperature, the absorbance (As) of the solution from the first tube was measured at 350 nm using the solution from the second tube as a blank.

2.6.6. Thiobarbituric acid number

Thiobarbituric acid number (TBA) was evaluated by method described by Drapper and Hadley [24]. 1 g of oil was weighed into a 10 ml test tube, then an aqueous solution of 0.1% trichloroacetic acid was added and the mixture vigorously vortexed. Subsequently, 1 ml of a 0.375% thiobarbituric acid solution, 1 ml of a 15% trichloroacetic acid solution and 1 ml of a 0.25 N hydrochloric acid solution were successively added to this tube, and the contents of the tube shaken again before being incubated in a water bath at 95 °C for 30 min. After removing the tubes from the bath and cooling them to room temperature, the aqueous phase was sampled and its optical density measured at 532 nm using a spectrophotometer (PerkinElmer, Norwalk CT, USA) against a white. The TBA was expressed as mg of malondialdehyde (MDA) per kg of oil.

2.6.7. Thiobarbituric acid number

The total oxidation (TOTOX) values of oil samples were obtained using the following equation 3: TOTOX = 2PI + AnI (3) according to Shahidi and Wanasundara [25] where TOTOX = total oxidation number, PI = peroxide index and AnI = Anisidine index.

2.7. Statistical analysis

All measurements were done in triplicates. Data were expressed as mean ± standard deviation. One-way ANOVA was performed to test the differences between species. Significance was established at P < 0.05. Fisher's PLSD (Protected Least Significant Difference) (post hoc comparison test) was used to make comparisons between the different groups when the ANOVA p-value was significant. Statistical analyses were performed using SPSS 16.0 for windows (SPSS, Chicago, IL, USA).

3. Results and discussion

3.1. Proximate composition

Table 1 shows macronutrient contents. Water content varies significantly (P < 0.05) in I. africana and E. fimbriata compared to A. parkii and S. maderensis. Values were within 70–80% as defined by Ackman [26]. Water is therefore the major component of fresh fish and could explain its susceptility to rapid alteration. Similar results were obtained by Tsegay et al. [27] on C. carpio (77.24). Erkan et al. [28] obtained 69.40 on S. maderensis which is lower than shown in this result in this study. Different results were reported by Aiyeloja and Akinrotimi [29] on E. fimbriata (71.67) sold in Harcourt port in Nigeria. The protein content varies significantly (P < 0.05) between the different fish species. I. africana and C. carpio have the highest (18.48) and lowest (13.68) values respectively. These results show that these fish species could be a good source of protein. Indeed, proteins are used for the synthesis of digestive enzymes and hormones, improve insulin sensitivity and increase absorption of carbohydrate in the body [30]. Different results were obtained by Abraham et al. [31] on E. fimbriata (14.46), Ahmed et al. [15] on A. parkii (18.81). According to Nomwine et al. [32], the protein content of fish products could be influenced by diet.

Table 1.

Proximate composition of the edible parts of different fish (%).

Macronutrients Ilisha africana Sardinella maderensis Cyprinus carpio Arius parkii Ethmalosa fimbriata
Moisture 75.66 ± 0.88a 79.66 ± 0.34b 78.96 ± 3.81ab 79.91 ± 1.98b 75.90 ± 1.19a
Protein 18.43 ± 0.16e 14.92 ± 0.04b 13.68 ± 0.23a 15.32 ± 0.06c 16.45 ± 0.21d
Lipid 3.69 ± 0.16d 2.72 ± 0.14bc 1.78 ± 0.18a 2.55 ± 0.05b 2.79 ± 0.00c
Ash 2.01 ± 0.08a 2.38 ± 0.14b 4.59 ± 0.08d 2.13 ± 0.03a 3.35 ± 0.25c
Carbohydrate 0.20 ± 0.00b 0.30 ± 0.07c 0.98 ± 0.16d 0.08 ± 0.01a 1.49 ± 0.07e
Energy (Kcal/100g WW) 107.77 ± 0.97d 85.46 ± 1.24b 74.69 ± 1.25a 84.62 ± 0.14b 96.97 ± 0.99c
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Mean values in the same line with different superscript letters are significantly different (P < 0.05). N = 3. WW: wet weight.

Total lipid content ranges from 1.78 to 3.69 with I. africana having the highest lipid content. Lipid contents varies significantly (P < 0.05) between the species E. fimbriata, A. parkii, C. carpio and I. africana. Diet, water salinity and temperature could explain this range between species [33]. According to the classification of Ackman [26], C. carpio is classified as a lean species while E. fimbriata, A. parkii, S. maderensis and I. africana are semi-fat species. Different results were obtained on S. maderensis (6.15) caught in the Mauritanian coasts [28]. Ahmed et al. [15] obtained a lower lipid content on A. parkii (1.35) caught in Lake Lagdo in Cameroon. Tenyang et al. [16] reported different results on C. carpio (4.09) from Lake Maga in the Far North of Cameroon. Goswami and Kuntal [34] found different results on fresh Tenualosa ilisha (21.22) sold in the local Battala market in India. Mobilization of energy stock during migration and fishing periods could explain this difference [35].

Table 1 shows that C. carpio is the most ash-rich species. The ash content varies significantly (P < 0.05) in C. carpio, E. fimbriata and S. maderensis compared to A. parkii and I. africana. Ashes give idea on the quantity of mineral elements present in food. The results obtained by Ayanda et al. [12] on Chrysichthys nigrodigitatus (7.56), Abraham et al. [31] on E. fimbriata (8.18) were greater than those obtained in our study. The amount of minerals in the water could justify this difference. According to Norhazirah et al. [36], mineral content found in fish varies with dietary habits, physiological state and the ability to absorb minerals.

The carbohydrate content ranges from 0.20% to 1.49%. Carbohydrate contents varied significantly (P < 0.05) between the different species probably due to the amount of glycogen stored in the muscles. Indeed, the more glycogen is stored in the muscles, the sweeter the fish tastes [33]. These results were lower than those of Tsegay et al. [27] on C. carpio (3.30). Temperature, salinity, age and sex could justify these results (Oladosu-Ajayi et al., 2020).

I. africana and C. carpio species were the richest and the poorest in energy respectively. The energy value varies significantly (P < 0.05) between species C. carpio, E. fimbriata and I. africana compared to A. parkii and S. maderensis. This result could be justified by the ecological niche and the different food habits. Nsoga et al. [37] obtained different results on smoked I. africana (357.35). According to Nomwine et al. [32], the energy value of fish is linked to its chemical composition which in turn is influenced by environmental factors.

3.2. Mineral content

3.2.1. Macroelement contents

Table 2 shows that the fish species with the highest calcium content is S. maderensis. This content varies significantly (p < 0.05) in I. africana and E. fimbriata compared to A. parkii, S. maderensis and C. carpio. These calcium values are lower than those obtained by Tenyang et al. [16] on some fish from Lake Maga in northern Cameroon. The calcium content on C. carpio is higher than that obtained by Tsegay et al. [27] on C. carpio (981.24). The recommended daily intake (RDA) of calcium for an adult is approximately 800 mg. The consumption of 100 g of S. maderensis could cover 34.70% of the RDA. Calcium is involved in the strengthening of bones and teeth, blood clotting and muscle contraction. It is also involved as a cofactor in metabolic and enzymatic processes [7].

Table 2.

Mineral contents in the edible parts of different fish (mg/100 g DW).

Micronutrients Ilisha africana Sardinella maderensis Cyprinus carpio Arius parkii Ethmalosa fimbriata
Ca 462.78 ± 34.85b 1364.47 ± 36.24d 1232.98 ± 31.62c 219.12 ± 20.08a 468.05 ± 21.15b
Mg 839.31 ± 48.38a 2101.81 ± 13.62c 4678.54 ± 34.30d 2104.35 ± 34.32c 1583.15 ± 35.19b
K 993.19 ± 4.79c 1072.52 ± 41.20d 657 ± 17.01b 1347.62 ± 37.85e 614.70 ± 7.95a
P 2548.32 ± 57.96c 2170.09 ± 15.26b 4767.49 ± 47.16e 2324.27 ± 78.62d 1569.43 ± 86.57a
Na 161.60 ± 6.20e 111.93 ± 5.54d 43.37 ± 1.24b 72.50 ± 0.47c 35.76 ± 1.62a
Na/K 0.16 ± 0.00c 0.10 ± 0.00b 0.06 ± 0.00a 0.05 ± 0.00a 0.05 ± 0.00a
Ca/P 0.18 ± 0.01b 0.62 ± 0.01d 0.25 ± 0.00c 0.09 ± 0.00a 0.29 ± 0.02c
Zn 1.29 ± 0.23a 2.25 ± 0.16b 12.39 ± 0.49d 10.28 ± 0.56c 12.41 ± 1.84cd
Cu 4.35 ± 0.30e 3.82 ± 0.15d 2.42 ± 0.38b 1.90 ± 0.13a 3.10 ± 0.20c
Mn 0.83 ± 0.03b 0.72 ± 0.03a 1.82 ± 0.11c 2.14 ± 0.07d 3.17 ± 0.14e
Fe 6.55 ± 0.41a 10.68 ± 0.50d 7.69 ± 0.49bc 8.38 ± 0.50c 7.36 ± 0.20b
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Mean values in the same line with different superscript letters are significantly different (P < 0.05). N = 3. DW: dry weight.

Values of phosphorus contents varies from 1569.43 for E. fimbriata and 4767.49 for C. carpio). They are greater than those obtained by Tsegay et al. [27]; Tenyang et al. [16] on C. carpio. Phosphorus contributes in the uptake of calcium by bones. It is a constituent of nucleic acids, nucleoproteins and intervenes for the release of energy. The recommended daily intake of phosphorus is approximately 800 mg. About 79.75 g of C. carpio and 100 g of I. africana could cover 100% and 77.53% of the recommended daily requirement respectively. The high levels of phosphorus compared to calcium in all the different species studied give low Ca/P ratios for these fish. This ratio in food is established at around 1. This ratio is important because it is a good indicator of the level of calcium binding to the bones. Phosphorus facilitates the uptake of calcium by bones and teeth.

Magnesium content laid between 839.31 and 4678.54. C. carpio is the richest species in magnesium. These results are superior to those obtained by Tenyang et al. [38] on Chrysichthys nigrodigitatus. This difference could be due to the availability of minerals in their living environment and to the physiological state of fish. Magnesium participates in neuromuscular excitability, energy metabolism reactions and protein synthesis. The consumption of 35.55 g of C. carpio and 100 g of I. africana would respectively cover 100 and 58.34% of the RDA in magnesium (350 mg) [33].

The sodium content varies significantly (p < 0.05) between the different species. This content ranges from 35.76 (E. fimbriata) to 161.60 (S. maderensis). These results are different from those obtained by Tenyang et al. [16] on C. carpio (141.33), Goswami and Kuntal [34] on Tenualosa ilisha (163.1). The recommended daily allowance for this mineral is approximately 500 mg. Taking 100 g of I. africana would cover 7.86% of the RDA. Sodium helps maintain osmotic pressure, acid-base balance and enzyme activation [7]. Potassium is involved in enzyme activation, muscle contraction, osmotic regulation, membrane transport, maintenance of osmotic pressure and acid-base balance.

The results in Table 2 show that A. parkii had the higher content in potassium. This content varies significantly (p < 0.05) between the different species. The potassium RDA is approximately 2000 mg 100 g of A. parkii would cover 13.53% of the RDA. These results are higher than the data reported by Tenyang et al. [16] on Chrysichthys nigrodigitatus (644.05) and lower than the results of Tsegay et al [27] on C. carpio (17276.21). The living environment, the fishing period and the physiological state of the fish could explain this difference. The Na/K ratio is between 0.05 and 0.16 and varies significantly (p < 0.05) between the I. africana and S. maderensis species in relation to the species. In food, this ratio is generally less than 1. The results show that these fish could be recommended for monitoring human hypertension and cardiovascular diseases [33].

3.2.2. Microelement content

Zinc content varies significantly (p < 0.05) between the species I. africana, S.maderensis,

C. carpio and A.parkii. This content is between 1.29 and 12.41 and the highest content was found in E. fimbriata. The results obtained by Dama et al. [7] on fish of the genus Pseudotolithus are greater than those found in this study. Consumption of 100 g of E. fimbriata could cover 19.93% of the RDA in zinc. This mineral participates in perception of taste, fetal development, and in the synthesis of genetic material. Zinc deficiency leads to immune function abnormalities and muscle wasting [16]. According to the results recorded in Tables 2 and I africana stands as the fish with greater content in copper and this content varies significantly (p < 0.05) between the different species. This difference could be due to food habits, living environment and fishing season. The copper content varies from 1.90 to 4.35. These results are superior to those obtained by Tenyang et al. [16] on four fish (0.63–0.71) from Lake Maga in the Far North of Cameroon. The required daily amount of copper being 1.5–3 mg, the consumption of 100 g of these fish could cover these intakes. Copper is involved in the metabolism of iron and collagen. It also helps to fight against oxidative stress and is part of many oxidation-reduction enzymes [33].

Table 2 shows that the manganese content varies significantly (p < 0.05) between the different species. This content varies from 0.72 (S. maderensis) to 3.17 (E. fimbriata). These results are lower than those obtained by Dama et al. [7] on three species of fish of the genus Pseudotolithus. 100 g of E. fimbriata could cover 100% of manganese RDA.

Manganese helps prevent protein-energy malnutrition, allows the activation of pyruvate carboxylase and the fixation of minerals. The highest iron content was found in S. maderensis (10.68). These results are greater compared to those obtained by Goswami and Kuntal [34] on Tenualosa ilisha (3.1). The daily iron requirements are 10, 15 and 30 mg for men, women and pregnant women respectively. The consumption of 100 g of S. maderensis could cover 7.24% of iron RDA. Iron deficiency leads to anemia. Iron is the major constituent of hemoglobin, assuming good tissue oxygenation. Iron is involved in the synthesis of hormones and neurotransmitters [33].

3.3. Heavy metal content

The heavy metal contents are given in Table 3. A. parkii is the species with the highest cadmium content. The cadmium content varies significantly (p < 0.05) between A. parkii and E. fimbriata species. This difference could be due to eating habits and living environment. This value is lower than that recommended by the International Atomic Energy Agency (IAEA) [39] which sets a maximum value of 0.18 mg/kg of dry matter. These results are similar to those obtained by Erkan et al. [28] on S. maderensis from the Mauritanian coasts and lower than those of Helmy et al. [40] who reported a cadmium content between 0.14 and 0.25 of some fresh fish from the Qaliobia governorate market in Egypt. Younis et al. [11] reported a cadmium content between 1.70 and 5.10 of some fresh fish from the Jeddah coast in Saudi Arabia. This result shows the degree of pollution of the corresponding water and could be a consequence of human industrial activities [13]. The lead content is between 0.146 and 0.194. This content varies significantly (P < 0.05) in I. africana compared to A. parkii and E. fimbriata. This difference could be explained by the living environment of each species. The results are lower than those of the European Union [41] which are 0.3 mg/kg of fresh fish. Ayanda et al. [12] showed that the lead content of some fish from the Ogun River in southwestern Nigeria was between 12.5 and 20.1. Tasnim et al. [42] reported lead content between 0.5 and 1.9 in some marine fish from the southeastern part of Bangladesh. Younis et al. [11] reported a lead content between 0.70 and 0.80 of some fresh fish from the Jeddah coast in Saudi Arabia. Lead has deleterious effects on hematopoiesis, nervous, reproductive and urinary systems. Table 3 shows that the mercury content is between 0.128 and 0.161. I. africana is the species with the highest mercury content. The Egyptian Organization for Standardization [43] recommends a maximum value of 0.5 mg/kg of fresh fish. Similar results were obtained by Stancheva et al. [44] on Sprattus (0.12) caught in the towns of Balchik and Nessebar in Bulgaria.

Table 3.

Heavy metal contents in the edible parts of different fish (mg/Kg DW).

Métaux lourds Ilisha africana Sardinella maderensis Cyprinus carpio Arius parkii Ethmalosa fimbriata
Cd ND 0.068 ± 0.013ab 0.069 ± 0.009ab 0.090 ± 0.026b 0.056 ± 0.015a
Pb 0.146 ± 0.015a 0.176 ± 0.025ab ND 0.194 ± 0.007b 0.180 ± 0.015b
Hg 0.161 ± 0.009b 0.135 ± 0.005a 0.157 ± 0.008b 0.133 ± 0.01a 0.128 ± 0.011a
As 0.022 ± 0.003a ND 0.021 ± 0.002a ND 0.024 ± 0.002a
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Mean values in the same line with different superscript letters are significantly different (P < 0.05). N = 3. DW: dry weight; ND: non determined.

These results are lower than those obtained by Helmy et al. [40] on some fish from Egypt (0.73–1.62). Ingestion of high doses of mercury would cause damage of the brain, kidneys, fetal development, reproductive problems and coma [14].

The arsenic content does not vary significantly (p > 0.05) between the species I. africana, C. carpio and E. fimbriata. Arsenic was not determined in the species A. parkii and S. maderensis because the levels are below the detection limit. The results obtained by Erkan et al. [28] on S. maderensis (4.19) from the Mauritanian coasts, Stancheva et al. [44] on Sprattus (0.73) were higher than those found in this study. Chronic exposure to arsenic could induce disorders in the hematopoiesis, the cardiovascular system, the nervous, respiratory and renal systems, liver and prostate cancers, hyperpigmentation [45].

3.4. Chemical indexes of oils extracted in fresh fish

Table 4 shows the chemical indexes characteristic of the oils extracted from the species of fish studied. The iodine index (II) varies significantly (P < 0.05) between the different species. I. africana and C. carpio show the highest and lowest iodine indices respectively. The iodine number provides information on the degree of unsaturation of the oil and makes it possible to classify them into non-drying oils (II < 100), semi-drying oils (100 < II < 130) and drying oils (II > 130). Therefore, the oils extracted from C. carpio, A. parkii and E. fimbriata are semi-drying while those extracted from I. africana and S. maderensis are drying. Manz et al. [46] obtained different results on Ilisha africana (162.09) and Sardinella maderensis (180.45). These iodine indices are higher than those obtained by Tenyang et al. [47] on Oreochromis niloticus (39.65). The fishing period, diet and environment could explain this difference [35]. The saponification index (SI) of these fish species ranges from 96.04 to 194.05. This index varied significantly (P < 0.05) in the species Ilisha africana, Sardinella maderensis compared to the species Cyprinus carpio, Arius parkii and Ethmalosa fimbriata. The IS obtained by Manz et al. [46] on Ilisha africana (190.26) and Sardinella maderensis (192.12) are higher than those of this study. The SI takes into account the length of the hydrocarbon chains of the fatty acids and the quantity of saponifiable oil. Indeed, the more carbon atoms the fatty acid molecules have, the lower the saponification index is [48]. Oil weathering indices, such as acid (AI), peroxide (PI), anisidine (AnI) and thiobarbituric acid (TBA) indices did not vary significantly (P > 0.05) between the different species. AI measures the amount of free fatty acid in a fatty substance. These results are below the standard (4 mg of KOH/g of oil) recommended by the Codex Alimentarius [49]. This could be explained by a low hydrolytic activity of triglyceride lipases [17]. PI and AnI measure the primary and secondary products of oxidation, respectively, taking into account the non-volatile aldehyde compounds in the oil. Tenyang et al. [50] obtained a peroxide index (3.77) in the oil extracted from Cyprinus carpio higher than those of this study. The PI and AnI values obtained in this study are lower than those recommended by the Codex Alimentarius [49], which stipulates that for virgin fats and oils, the peroxide and anisidine indices must be less than 10 and 20 respectively. The thiobarbituric acid index quantifies the secondary oxidation compounds of lipids, particularly Malondialdehyde (MDA). Different results were obtained by Tenyang et al. [47] on smoked Oreochromis niloticus (12.46). Exposure of oil to high temperatures during smoking could justify this difference [48]. The total oxidation index (TOTOX) varies significantly (P < 0.05) between Cyprinus carpio and the other species. This index makes it possible to better assess the oxidation state of the fat, taking into account the different forms of fatty acid oxidation. These results are below the standards set by the Codex Alimentarius [49] which recommends a value below 26 for virgin fats and oils.

Table 4.

Chemical indexes of the oils of the species studied.

Chemical indexes Ilisha africana Sardinella maderensis Cyprinus carpio Arius parkii Ethmalosa fimbriata
II (g I2/100g of oil) 154.04 ± 15.76d 148.73 ± 6.73d 105.36 ± 5.42a 116.12 ± 4.31b 128.64 ± 7.51c
IS (mg KOH/g of oil) 186.82 ± 8.75c 194.05 ± 13.47c 121.07 ± 12.68b 108.83 ± 7.05ab 96.04 ± 7.36a
AI (mg KOH/g of oil) 1.04 ± 0.17a 1.38 ± 0.38a 1.45 ± 0.68a 1.14 ± 0.51a 1.04 ± 0.14a
PI (meq O2/Kg of oil) 1.48 ± 0.28a 1.67 ± 0.39a 2.08 ± 0.83a 1.19 ± 0.29a 1.28 ± 0.56a
AnI 0.63 ± 0.07a 0.68 ± 0.09a 0.66 ± 0.08a 0.73 ± 0.17a 0.76 ± 0.10a
TBA (mg MDA/Kg of oil) 0.65 ± 0.23a 0.83 ± 0.03a 0.87 ± 0.11a 1.26 ± 0.85a 1.13 ± 0.29a
TOTOX 3.99 ± 0.73a 4.52 ± 0.54a 5.91 ± 0.25b 3.59 ± 0.61a 3.67 ± 0.54a
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II: iodine index; SI: saponification index; AI: acid index, PI: peroxide index; AnI: Anisidin index; TBA: thiobarbituric acid number; TOTOX: Total oxidation index; MDA: malondialdehyd; meq = milli-equivalent. Mean values in the same line with different superscript letters are significantly different (P < 0.05). N = 3.

4. Conclusion

This study shows that the nutrients contents varies from one fish to another. They are good sources of protein and minerals and the lipids extracted are of good quality. The analysis of heavy metals in these fish revealed pollution thresholds below international standards. According to these results, it would be important to inform the populations about the risks of toxicity linked to the overconsumption of these fish in the long term. The results of the nutrient composition and the quality of the lipids of these fish show that they can be used in the fight against protein-energy malnutrition and mineral deficiencies. Future studies will evaluate the effect of seasonal variation on macronutrients, fatty acid and amino acid profiles and the effect of different local cooking methods on the proximate composition.

Author contribution statement

J.C.K. Manz: Performed the experiments; Analyzed and interpreted the data; Wrote the paper.J.V.F. Nsoga: Performed the experiments, Contributed reagents, materials, analysis tools; Wrote the paper.J.B. Diazenza: Contributed reagents, materials, analysis tools; Wrote the paper.S. Sita: Contributed reagents, materials, analysis tools; Wrote the paper.G.M.B. Bakana: Contributed reagents, materials, analysis tools; Wrote the paper.A. Francois: Contributed reagents, materials, analysis tools; Wrote the paper.M. Ndomou: Conceived and designed the experiments; Wrote the paper.I. Gouado: Analyzed and interpreted the data; Wrote the paper.V. Mamonekene: Conceived and designed the experiments; Wrote the paper.

Funding statement

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Data availability statement

Data will be made available on request.

Declaration of competing interest

The authors declare no conflicts of interest related to this research work.

Acknowledgments

The authors are grateful to the AUF (Agence Universitaire de la Francophonie) Afrique Centrale et Grands Lacs, Yaounde, Cameroon for travel grants to attend the IRSEN of Brazzaville, Republic of Congo.

Contributor Information

J.C.K. Manz, Email: manz2013@yahoo.fr.

J.V.F. Nsoga, Email: valerynsoga@yahoo.com.

J.B. Diazenza, Email: diazenzajeanbaptiste64@gmail.com.

S. Sita, Email: seraphinsita@yahoo.fr.

G.M.B. Bakana, Email: gerlucbakana@gmail7.com.

A. Francois, Email: antoinefiro@gmail.com.

M. Ndomou, Email: nmathieu2009@yahoo.fr.

I. Gouado, Email: gouadoi@yahoo.fr.

V. Mamonekene, Email: vito.mamonekene@gmail.com.

References

  • 1.FAO (Organisation des Nations Unis pour l’alimentation . Rome; Italie: 2020. La situation mondiale des pêches et de l’aquaculture. La durabilité en action; p. 227. [Google Scholar]
  • 2.Matsuzaka H., Matsuyama H., Tanaka W., Tajiri H., Sakakibara H. Selective consumption of fish oil at end of the day increases the physiological fatty acid compositions of eicosapentaenoic acid and docosahexaenoic acid in mice. Molecules. 2022;27(4):1271. doi: 10.3390/molecules27041271. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.Zou H.Y., Zhang H.J., Zhao Y.C., Li X.Y., Wang Y.M., Zhang T.T., Xue C.H. n-3 PUFA deficiency aggravates streptozotocin-induced pancreatic injury in mice but dietary supplementation with DHA/EPA protects the pancreas via suppressing inflammation, oxidative stress and apoptosis. Mar. Drugs. 2023;21(1):39. doi: 10.3390/md21010039. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.González L.P.F., Rodrigues F.D.S., Jantsch J., Fraga G.D.F., Squizani S., Castro L.F.D.S., Correia L.L., Neto J.P., Giovenardi M., Porawski M., Guedes R.P. Effects of omega-3 supplementation on anxiety-like behaviors and neuroinflammation in Wistar rats following cafeteria diet-induced obesity. Nutr. Neurosci. 2023 doi: 10.1080/1028415X.2023.2168229. [DOI] [PubMed] [Google Scholar]
  • 5.Ali A., Wei S., Ali A., Khan I., Sun Q., Xia Q., Wang Z., Han Z., Liu Y., Liu S. Research progress on nutritional value, preservation and processing of fish. A review. Foods. 2022;11(22):3669. doi: 10.3390/foods11223669. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 6.Ali S., Ali A., Rind R.A., Ali M., Mastoi Z.A., Naz S., Shakir M., Khani R.A.Q. Effect of cooking methods on nutritional and quality characteristics of fish. Pakistan J. Agric. Res. 2021;34(2):325–328. doi: 10.17582/journal.pjar/2021/34.2.325.328. [DOI] [Google Scholar]
  • 7.Dama R.A., Ndomou M., Milong C.S.M., Manz J.C.K., Nchoutpouen M.N., Youogo M.T., Ndombol R.P.N., Nsoga F.V.J., Ngo Tang C., Gouado I., Tchoumbougnang F. Effect of smoking, boiling and freezing on the nutritional value of three species of genus Pseudotolithus commonly consumed in Cameroon. Food Chem. 2021;363 doi: 10.1016/j.foodchem.2021.130229. [DOI] [PubMed] [Google Scholar]
  • 8.Abowei J.F.N. The condition factor, length-weight relationship and abundance of Ilisha africana (Block, 1795) from Nkoro River Niger Delta, Nigeria. Adv. J. Food Sci. Technol. 2010;1:6–11. [Google Scholar]
  • 9.Faye A., Diouf M., Sarr A., Ndiaye W., Mbodj A., Sow D. The Saloum Estuary and Joal (Senegal) Academic; 2017. Growth and exploitation parameters of Ilisha Africana, by-catch of the experimental fishing for the study on selectivity of gill nets for Ethmalosa fimbriata; pp. 14–22. [Google Scholar]
  • 10.Keith P., Allardi J.C. 2001. Atlas des poissons d'eau douce de France, Patrimoines naturels édition. [Google Scholar]
  • 11.Younis M.E., Abdel-Wahab A.A., Nasser A.A., Soltan A.E., Mostafizur R. Nutritional value and bioaccumulation of heavy metals in muscle tissues of five commercially important marine fish species from the Red Sea Saudi. J. Biol. Sci. 2021;28:1860–1866. doi: 10.1016/j.sjbs.2020.12.038. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Ayanda O.I., Ukinebo I.E., Oluwakemi A.B. Determination of selected heavy metal and analysis of proximate composition in some fish species from Ogun River, Southwestern Nigeria. Heliyon. 2019;5 doi: 10.1016/j.heliyon.2019.e02512. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Chowdhury N., Mamunur R. Heavy metal concentrations and its impact on soil microbial and enzyme activities in agricultural lands around ship yards in Chattogram, Bangladesh. Soil Science Annual. 2021;72(2):1–21. doi: 10.37501/soilsa/135994. [DOI] [Google Scholar]
  • 14.Hossain S., Kawser A., Eurida L., Shahadat H., Yeasmin N.J., Jamiul K., Shirin A., Safiur R. A case study on metal contamination in water and sediment near a coal thermal power plant on the Eastern coast of Bangladesh. Environments. 2021;108(8):1–18. doi: 10.3390/environments8100108. [DOI] [Google Scholar]
  • 15.Ahmed A., Dodo A., Bouba A.M.C., Dzudie T. Influence of traditional drying and smoke drying on the quality of three fish species (Tilapia nilotica, Silurus glanis and Arius parki) form lagdo lake. Cameroon. J. Anim. Vet. Adv. 2011;10(3):301–306. doi: 10.3923/java.2011.301.306. [DOI] [Google Scholar]
  • 16.Tenyang N., Ponka R., Tiencheu B., Djikeng T.F., Womeni H.M. Proximate composition, fatty acid and mineral contents of four freshwater fish from Maga lake (Far North region of Cameroon) Adv. J. Food Sci. Technol. 2016;4(3):64–69. doi: 10.12691/ajfst-4-3-2. [DOI] [Google Scholar]
  • 17.Manz koule J.C., Ndomou M., Njinkoue J.M., Tchoumbougnang F., Milong Melong C.S., Djimbie Djopnang J., Soh Oumbe A.V., Nchoutpouen M.N., Foumedzo R., Gouado I. Antihyperlipidemic potential of oil extracted from Ilisha africana on rats. Scientific African. 2020;8 doi: 10.1016/j.sciaf.2020.e00322. [DOI] [Google Scholar]
  • 18.Nchoutpouen M.N., Ndomou M., Manz J.C.K., Milong C.S.M., Dama R.A., Ndombol R.P.N., Nsoga J.V.F., Ngo tang C., Youogo M.T., Peyieno M., Ngock E., Tchoumbougnang F. Effets hypolipidemiques de l'huile extraite du Poisson Ethmalosa fimbriated chez des rattes dyslipidémiques. Int J. Biol. Chem. Sci. 2020;14(6):2193–2203. doi: 10.4314/ijbcs.v14i6.21. [DOI] [Google Scholar]
  • 19.Simo B.N., Tchabong S.R., Deutchoua D.A.D., Dongho D.F.F., Ngamga F.H.N., Ronice Zokou R., Tamgue O., Ngono R.A.N., Tchoumbougnang F. Chemical characterization and antibacterial properties of fontitrygon margarita (günther, 1870) liver oil. Journal of Lipids. 2022;2022 doi: 10.1155/2022/9369387. Article ID 9369387, 10 pages. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20.AOAC (Official . fifteenth ed. AOAC International; Washington, DC: 1990. Methods of Analysis of the Association of the Official Analysis Chemists. Association of Official Analytical Chemists; pp. 222–245. [Google Scholar]
  • 21.Bligh Е.C., Dyer W.J. A rapid method of total lipid extraction and purification. Can. J. Biochem. Physiol. 1959;37:913–917. doi: 10.1139/o59-099. https//doi.org/10.1139/o59-099. [DOI] [PubMed] [Google Scholar]
  • 22.AFNOR (Agence Française de Normalisation) 2nd Édition. AFNOR; Paris: 1981. Recueil des Normes Françaises. Corps Gras, Graines Oléagineuses, Produit Dérivés. [Google Scholar]
  • 23.Shantha N.C., Decker E.A. Rapid, sensitive, iron-based spectrophotometric methods for determination of peroxide values of food lipids. J. AOAC Int. 1994;77(2):421–424. [PubMed] [Google Scholar]
  • 24.Drapper H.H., Hadley M. Malondialdehyde determination as index of lipid peroxidation methods. Methods Enzymol. 1990;186:421–431. doi: 10.1016/0076-6879(90)86135-I. [DOI] [PubMed] [Google Scholar]
  • 25.Shahidi F., Wanasundara U.N. In: Food Lipids, Chemistry, Nutrition, and Biotechnology. Akoh C.C., Min D.B., editors. Marcel Dekker Inc.; New York: 2002. Methods for measuring oxidative rancidity in fats and oils; pp. 465–505. [DOI] [Google Scholar]
  • 26.Ackman R.G. Nutritional composition of fats in seafoods. Prog. Food Nutr. Sci. 1989;13(3–4):161–241. PMID: 2699043. [PubMed] [Google Scholar]
  • 27.Tsegay T., Natarajan P., Zelealem T. Proximate and mineral composition of some commercially important fish species of tekeze reservoir and lake Hashenge, Ethiopia. IJFAS. 2016;4(1):160–164. [Google Scholar]
  • 28.Erkan N., İdil C.T., Özkan Ö., Serdar Ü. Nutritional composition and heavy metal concentrations in Sardinella maderensis (lowe, 1838) obtained from the Mauritanian fisheries. J. Appl. Ichthyol. 2020;36:906–911. doi: 10.1111/jai.14143. [DOI] [Google Scholar]
  • 29.Aiyeloja J.O., Akinrotimi O.A. Evaluation of smoking process on proximate composition of some marine fish species. IAR J Agri Res Life Sci. 2021;2(3):90–95. https://www.iarconsortium.org/journal-info/iarjals [Google Scholar]
  • 30.Nsoga J.V.F., Milong M.C.S., Nchoutpouen N.M., Manz K.J.C., Ekwalla M.N.R.J., Tuem S.R., Tchoumbougnang F., Ndomou M. Characterization of smoking activity and perception of smoked fish by households in the city of Douala (Cameroon) IJNFS. 2021;10(6):159–166. doi: 10.11648/j.ijnfs.20211006.16. [DOI] [Google Scholar]
  • 31.Abraham O.V., Olele N.F., Abdullahi U.U. Seasonal variation on the proximate composition of fresh and smoked bonga Ethmalosa fimbriata (bowdich, 1825) obtained from warri river, delta state, Nigeria. Trop. Freshw. Biol. 2018;27(2) doi: 10.4314/tfb.v27i2.6. [DOI] [Google Scholar]
  • 32.Nomwine D.A., Raymond O., Adama O. Relation poids-longueur et facteur de condition de Clarias anguillaris et Sarotherodon galilaeus pêchées dans le lac Bam et le réservoir de la Kompienga au Burkina Faso. Int. J. Biol. Chem. Sci. 2018;12(4):1601–1610. [Google Scholar]
  • 33.Michel Njinkoue Jean, Foumedzo Rodrigue, Marlyse Solange Leng, Justin Djimbie Djopnang. Adélaïde Démassé Mawamba. Marie Modestine Kana. Schweigert Florian J., Gouado Inocent, Tchoumbougnang François. Proximate composition and micronutrient contents of Callianassa turnerana from theWouri Estuary, Cameroon. J. Food Res. 2019;8(1):32–40. doi: 10.5539/jfr.v8n1p32. [DOI] [Google Scholar]
  • 34.Goswami S., Kuntal M. Comparison of the effects of cooking methods on nutritional composition of fresh and salted Tenualosa ilisha. Aquaculture and Fisheries. 2020;5:294–299. doi: 10.1016/j.aaf.2020.01.006. [DOI] [Google Scholar]
  • 35.Dembe H.L.T., Zamba A.I., Goma-Tchimbakala J., Mikembi B.L., Freedom P.N.H., Mamonekene V. Effets saisonniers sur les relations poids-longueurs et coefficients de condition pour 16 espèces de Poissons de la Lagune Mvassa, basse Guinée, République du Congo. J. Anim. Plant. Sci. 2020;44(1):7540–7552. doi: 10.35759/JAnmPlSci.v44-1.1. [DOI] [Google Scholar]
  • 36.Norhazirah A.A., Ahmad S.A., Adiana G., Nurul I.A., Ahmad A., Ong Meng-Chuan. Comparison of proximate composition of raw and cooked intramuscle tissue of Thunnus tonggol from terengganu, Malaysia. Pertanika J. Sci. & Technol. 2021;29(1):629–639. doi: 10.47836/pjst.29.1.33. [DOI] [Google Scholar]
  • 37.Nsoga J.V.F., Ndomou M., Manz K.J.C., Milong M.C.S., Nchoutpouen N.M., Ekwalla M.N.R.J., Ndômbôl N.P.R., Dama A.R., Ngo Tang C.D., Youogo T.M., Gouado I., Tchoumbougnang F. Effects of two smoking and storage methods on the sensory and bromatological quality of Ilisha africana (Bloch, 1795) International Journal of Fisheries and Aquatic Studies. 2021;9(2):280–284. [Google Scholar]
  • 38.Tenyang N., Ponka R., Womeni H.M. Effect of local hot smoking on proximate composition, lipid oxidation, fatty acid profile and minerals content of Chrysichthys nigrodigitatus from Lake Maga in Cameroon. Int. J. Biol. Chem. Sci. 2020;14(4):1214–1227. doi: 10.4314/ijbcs.v14i4.5. [DOI] [Google Scholar]
  • 39.IAEA (International Atomic Energy Agency) Vienne; 2003. Reference Sheet. Reference Material IAEA-407. Trace Elements and Methylmercury in Fish Tissue. [Google Scholar]
  • 40.Helmy A.N., Mohamed A.H., Faten S.H., Ahmed A.M. Detection of heavy metals residues in fish and shellfish. BVMJ. 2018;34(2):255–264. http://www.bvmj.bu.edu.eg [Google Scholar]
  • 41.EU (European Union) vol. 173. Offici. J. Europ. Uni, L.; 2008. (Commission Regulation EC No. 629/2008. Setting Maximum Levels for Certain Contaminants in Foodstuffs). [Google Scholar]
  • 42.Tasnim K.T., Sunjida A., Mohammad S., Waziha F. Fatty acids composition and heavy metals in marine fish samples from the South-Eastern Part of Bangladesh. Org. Chem. 2020;1(2):46–51. [Google Scholar]
  • 43.Egyptian Organization for Standardization (EOS) 2010. Maximum Levels for certain contaminants in foodstuffs, No 7136/2010. Egyptian Standards, Ministry of Industry, Egypt; p. 33. [Google Scholar]
  • 44.Stancheva M.A., Merdzhanova E.P., Petrova D. Heavy metals and proximate composition of black sea sprat (Sprattus sprattus) and goby (Neogobius melanostomus) Bulgarian Journal of Agricultural Science. 2013;19(1):35–41. [Google Scholar]
  • 45.Sarker A., Jang-Eok K., Abu R., Towfiqul I., Muhammad B., Refat J.R., Rakhi N., Mohammed M.R., Islam Tofazzal. Heavy metals contamination and associated health risks in food webs a review focuses on food safety and environmental sustainability in Bangladesh. Environ. Sci. Pollut. Control Ser. 2022;29(3):3230–3245. doi: 10.1007/s11356-021-17153-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 46.Manz K.J.C., Ndomou M., Nchoutpouen M.N., Demasse A.M., Milong M.C.S., Bekwankoa F.G.S., Siewe F.B., Youogo T.M., Dama A.R., Ndombol N.R.P., Nsoga J.V.F., Ngo Tang C., Tchoumbougnang F., Gouado I. Chemical characterization of oil extracted from two species of fish (Ilisha africana and Sardinella maderensis) from the Cameroonian coast. IJNFS. 2021;10(1):14–19. doi: 10.11648/j.ijnfs.20211001.13. [DOI] [Google Scholar]
  • 47.Tenyang N., Zambou G.T., Ponka R., Womeni H.M. Antioxidant effect of plants aqueous extract on lipid stability of Oreochromis niloticus during traditional sun and smoke drying in Far-North Cameroon. Food Nutr. Sci. 2020;11:854–871. doi: 10.4236/fns.2020.118060. [DOI] [Google Scholar]
  • 48.Molla R., Asaduzzaman A.K.M., Rashid A.M., Uddin M., Biswas S., Uddin S. Nutritional status, characterization and fatty acid composition of oil and lecithin isolated from fresh water fish shoul (Channa striata) Int. J. Nutr. Food Sci. 2016;5(1):9–15. doi: 10.11648/j.ijnfs.20160501.12. [DOI] [Google Scholar]
  • 49.Alimentarus Codex. 2017. Normes alimentaires internationales. Normes pour les huiles de poissons. CXS329.6pp. codex@fao. [Google Scholar]
  • 50.Tenyang N., Tiencheu B., Djikeng T.F., Morfor A.T., Womeni H.M. Alteration of the lipid of red carp (Cyprinus carpio) during frozen storage. Food Sci. Nutr. 2019:1–8. doi: 10.1002/fsn3.971. [DOI] [PMC free article] [PubMed] [Google Scholar]

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