The proximate composition of the edible part of different fishes analyzed in the present study is depicted in Table 2. The statistical results revealed that the moisture content varied (p < 0.05) from 65.03–87.27%. These results are in agreement with those reported by Ravichandran et al. [7], Younis et al. [8] and Bogard et al. [9]. Of all the analyzed fishes, Catfish had the highest value of moisture (87.24%), which is slightly higher than the values given by the FAO [10] and USDA [11] for the fresh fish samples (66–81%). The occurrence of an osmotic shift, when fish reared in brackishwater or salt/sea water is transferred to a freshwater or melted ice for a short period of time before being euthanized for processing would be a reason for obtaining the higher moisture content. Sea bass, Grouper and Parrotfish had the moisture content of 77.16–78.09% and there was no significant difference between them. The moisture content of Tilapia, Emperor and Milkfish was almost similar and was in the range of 74.44–75.57%. Rabbitfish had 72.81% of moisture and the lowest value was observed in Sea bream (65.03%). Though no negative impact is reported so far due to the higher moisture content of fish in relation to human nutrition, in bottom line having a lower moisture content would be ideal for obtaining the higher nutrients, in particular protein. Notwithstanding, the lower moisture would be beneficial in reducing the deterioration of fish when they stored for a longer time [12].
The highest (p < 0.05) crude protein content in fish edible portion was observed for Tilapia, Emperor and Milkfish (21.39–21.77%) followed by Sea bass, Grouper, and Parrotfish (19.34-21.012%). However, there was no significant difference was observed for Rabbitfish (18.68%) with Grouper and Parrotfish. The crude protein content was significantly (p < 0.05) low in Sea bream (16.45%) compared to the above said species and was just 10.29% in Catfish. In general, the moisture content of fish is inversely related to nutrients, especially crude protein. As the moisture content of catfish increased to 87.24%, which resulted in decreasing the crude protein content to 10.29% proportionally. Though Sea bream had less moisture (65.03%), still the crude protein content was significantly (p < 0.05) decreased to a level of 16.45% rather increasing. This would be attributed to the highest body lipid content of Sea bream (Table 2). The crude lipid content in edible portion of fishes analyzed in the present study significantly (p < 0.05) varied among them and was drastically high (p < 0.05) in Sea bream (17.08%) compared to all other species. This result is almost similar to those reported by Bonaldo et al. [13]. Next to Sea bream, Rabbitfish has shown the highest crude lipid content of 6.63%, followed by Tilapia (2.00%), Grouper (1.41%) and Catfish (1.12%), whereas other species had lesser than 1% of crude lipid (0.31–0.87%). These results are corroborated with the findings of Ewaidah [14]. Ali [15] documented that the body lipid content of aquatic species could be varied due to various reasons, including species, age, sex, capture season, feeding habits, reproduction etc. Fauconneau et al. [16] stated that genetic origin is also one of the factors affecting the body lipid content in fish.
Generally, the carbohydrate content of fishes is low and it is agreed with the results of the present study. The total carbohydrate content was not remarkably varied (p = 0.199) among the fishes used and was in the range of 0.43–1.06%. Chrisolite et al. [17] suggested that the lower carbohydrates would be related to the fact that glycogen does not contribute much to the reserves of fish tissue. Though the total ash content was statistically (p < 0.05) differed among the fishes analyzed in our study, the values were relatively similar and was above 1.2%, except Sea bream (0.96%). These results were as expected, and similar to the findings of Erkan and Ozden [18]. But in contrast to our study, Younis et al. [8] found significant variations in total ash content of six different fishes collected from the Arabian Gulf Coast of Saudi Arabia. The differences between the studies would be attributed to the variation in feeding behavior, environment and migration [17]. The gross energy in the edible portion of fishes differed significantly (p < 0.05) among them. The highest energy value was found in Sea bream (2563.11 Cal/g), which would be due to the higher content of body lipid (Table 1), while the least value was noticed for Catfish (692.02 Cal/g) due to the higher moisture content.
The recommended daily allowance (RDA) was computed based on FAO/WHO/UNU guidelines to provide adequate nutrient required for a healthy person, but this value may differ between children, adult males and females. In the present study, 100 g of fish (edible) has been taken into an account to calculate the daily value of food (%) for an adult man weighing 70 kg (Fig. 1). The FAO/WHO/UNU reports as cited by Dayal et al. [5] stated that the daily value of nutrients with > 70% is rated as outstanding, 50 to 70% as excellent, 20 to 50% as very good, 10 to 25% as good and < 10% as poor. The results revealed that there was a significant (p < 0.05) difference in the daily values of fishes for both protein and lipid. The daily values of protein for all the fishes were grouped under the category of very good and were ranged from 22.28–47.11%. Of all the fishes analyzed here, Tilapia, Emperor and Milkfish had the highest (p < 0.05) daily value for protein (46.30-47.11%) and the least value was noticed for Catfish (22.28%), while others had the values between 35–45%. Except Sea bream, the daily value of lipid for all the fishes was in the range of 0.40–8.51% and were listed under the category of poor one as they have < 10% daily values. However, Sea bream was placed in the category of good as it had a daily value of 21.91%.
Table 2
Edible composition of different finfishes imported by the Kingdom of Saudi Arabia from certain Asian and Arab countries (% wet basis)
Particulars | Proximate composition | Gross energy (Cal/g) |
Moisture | Crude protein | Crude lipid | Carbohydrates | Total ash |
Grouper | 77.16b | 19.34bc | 1.41d | 0.79a | 1.30bc | 1257.57de |
Rabbitfish | 72.81d | 18.68c | 6.63b | 0.40a | 1.47a | 1698.79b |
Parrotfish | 78.09b | 19.72bc | 0.31g | 0.64a | 1.24c | 1168.94f |
Catfish | 87.24a | 10.29e | 1.12de | 0.12a | 1.23c | 692.02g |
Emperor | 75.57c | 21.39a | 0.87ef | 0.67a | 1.50a | 1317.22d |
Tilapia | 74.44c | 21.77a | 2.00c | 0.43a | 1.36b | 1436.43c |
Milkfish | 75.47c | 21.40a | 0.61fg | 1.06a | 1.45a | 1309.52d |
Sea bream | 65.03e | 16.45d | 17.08a | 0.48a | 0.96d | 2563.11a |
Sea bass | 77.34b | 20.12b | 0.80ef | 0.40a | 1.31bc | 1229.46ef |
SEM (±) | 0.256 | 0.217 | 0.028 | 0.078 | 0.001 | 1064.812 |
p-value | < 0.001 | < 0.001 | < 0.001 | 0.199 | < 0.001 | < 0.001 |
CV (%) | 0.087 | 3.265 | 6.372 | 66.244 | 3.828 | 3.050 |
The values are means of three replications Means bearing same superscript in a column do not differ significantly (p > 0.05) Carbohydrates analyzed by a difference |