STUDY ON SOME MINERALS CONTENT IN NILE FISH

Five fish species ( Oreochromis niloticus, Bagrus bayad, Lates niloticus, Clarias gariepinus, and Mormyrus kannume ) "25 of each" were collected from Assiut fish markets between January and December 2021 to determine the proximate composition (moisture, dry matter, fat, and ash), as well as some minerals: macro (calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na), potassium (K); and micro minerals (iron (Fe) and zinc (Zn). Results of proximate composition revealed moisture mean values were (79.40, 81.22, 80, 76.20, and 78.75%, respectively) in samples of Oreochromis niloticus, Bagrus bayad, Lates niloticus, Clarias gariepinus, and Mormyrus kannume , dry matter mean values were (20.60, 18.81, 19.29, 23.80, and 21.25%, respectively); fat mean values were (1.54, 1.48, 1.29, 2.28, and 3.28%, respectively), and ash mean values were (1.02, 0.91, 0.97, 1.32, and 0.93%, respectively). A noteworthy distinction (P<0.05) was discovered between the mean value (g/100g) of proximate items for some studied fish species. Results of minerals content declared that calcium mean values were (494.34, 156.34, 159.99, 249.85, and 187.11, respectively) in the investigated samples of Oreochromis niloticus, Bagrus bayad, Lates niloticus, Clarias gariepinus, and Mormyrus kannume; phosphorus mean values (mg/100g) were (151.41, 159.20, 133.98, 232.13, and 265.30, respectively); magnesium mean values were (22.04, 15.12, 19.37, 19.29, and 13.81, respectively); sodium mean values were 1462.47, 1465.27, 1395.11, 1993.46, and 1673.54, respectively); and potassium mean values were 217.21, 394.28, 151.88, 347.72, and 239.79, respectively), iron mean values were (2.70, 3.48, 4.58, 6.88, and 2.63, respectively), and zinc mean values were 4.57, 2.48, 3.67, 3.41, and 3.79%, respectively). A significant difference between some studied fish species was found regarding their macro and microelement content. In conclusion, fishes under investigation are an excellent source of vital minerals, and it was observed that Claris gariepinus displayed superior mineral content and proximal quality.


INTRODUCTION
Fishes come in a variety of sizes, forms, habitats, and biological characteristics.Usually, they are found close to the summit of the food chain (Parveen and Gaikwad, 2018).Fish is one of the possible sources of animal protein and vital nutrients for the upkeep of a healthy physique in emerging nations (Fawole et al., 2007).
Because of delicate flesh, low cholesterol, and good palatability fish is well accepted (Eyo, 2001).In addition, they are a significant source of calcium, iodine, iron, selenium, and other minerals as well as vitamins.There is a wealth of evidence supporting the importance of fish consumption for a child's brain development and learning, for maintaining eye health and eyesight, and for preventing certain cancers and cardiovascular disorders (Sanker et al., 2013).
The assessment of fish's moisture, protein, fat, and ash levels; is referred to as its "proximate composition" (Rani et al., 2016).A variety of factors, including food composition, feeding and eating habits, feeding rate, age, size, sex, habitats, genetic characteristics, and season/migration, may influence the proximate composition of various fish species (Begum et al., 2012).To make the most of fish, one must be aware of its makeup.When it comes to giving children, patients, and the elderly easily accessible sources of low-fat, highprotein diets, nutritionists and dieticians can benefit greatly from knowledge about the mineral and chemical compositions of freshwater fish (Foran et al., 2005).Approximately twenty different minerals are necessary for the human body to function effectively (Williams 2006).These components fall under the categories of macro and micro-minerals.The macrominerals calcium (Ca), phosphorous (P), magnesium (Mg), sulfur (S), sodium (Na), chloride (Cl), and potassium (K) are required in doses more than 100 mg/day.Micro-minerals, which are required in less than 100 mg/day, consist of elements like iron (Fe), manganese (Mn), zinc (Zn), iodine (I), selenium (Se), and a few more (Mahan and Escott-Stump 2005).These components are necessary for the sustenance of life, development, and reproduction (Alsafwah et al., 2007).Anemia, osteoporosis, goiter, stunted growth, and genetic problems are examples of mineral deficiency diseases that can occur when the body does not receive enough of these elements, primarily from food intake (Bhandari and Banjara, 2015).
The current study set out to look into the mineral content and proximate makeup of a few different species of Nile fish.

Collection of specimens:
A total of 125 samples, 25 of each of the following species, were collected from fish markets in Assiut city: Al Weledya, Riad Street, and Al Magzob: Oreochromis niloticus, Bagrus bayad, Lates niloticus, Clarias gariepinus, and Mormyrus kannume.The Laboratory of Meat Hygiene Section, Department of Food Hygiene, Safety and Technology, Faculty of Veterinary Medicine, Assiut University, received each sample individually packed in a polyethylene bag, collected in an icebox, and transferred for preparation and analysis.Samples that are thought to have been taken and examined while still fresh (with brilliant red gills, transparent eyes, and intact scales).

Preparation of samples (AOAC, 2000):
After the fish's head and fins were removed, they were deboned.We took about 40g of the fresh fish flesh and ground it up in a mortar.
Two separate analyses of the samples were conducted.Every sample underwent proximate analysis, which included measurements of moisture, dry matter, fat, and ash.Additionally, the samples' mineral contents, including phosphorus, calcium, sodium, magnesium, potassium, zinc, and iron, were examined.

Moisture content determination (AOAC, 2000):
A 10 gram sample of the prepared wet sample was dried at 65°C for 24 hours and subsequently at 105°C for 6 hours in a hot air oven (Fine Tech, Shinsaeng, Korea).
Moisture percentage = (W 1-W2)/w1 x 100 W1= The sample's weight before drying W2= The sample's weight following drying Note: The dry matter percentage was determined using the following method: Moist%dry matter% = 100

Calculating the proportion of fat using "ether extract" (AOAC, 2000):
After weighing one gram of the dried sample, it was placed in the thimble of the Soxhlet apparatus and wrapped in filter paper with a given weight.
Petroleum ether (60/80) was used for the extraction, which lasted for 17 hours.
The following formula was used to get the fat percentage: The crucibles were placed in a Muffle Furnace (Thermolyne, 6000 Furnace) and burned for six hours at 550°C, producing a grayish-white ash.
The following formula was used to get the ash content: Ash% is equal to (ash weight) / (sample weight) x 100.• One gram of the dry sample was taken in crucible and was ashed at 500-550°c for 6 hours, and after cooling, 10 ml Nitric acid 1+2 (v/v) (one volume from Nitric acid 65% with two volumes of double distilled water and mixed well) was added.The solution was covered with watch glass and heated in a boiling water bath for 30 minutes then cooled.The content was transferred to a 100 ml volumetric flask and diluted to the mark with water (deionized water) then mixed well.The dilution was filtered through filter paper and the first 5 -10 ml of the filtrate was discarded.The filtrate was collected in a brown glass bottle and the sample was ready for minerals estimation.

Calcium content:
According to procedures of Calcium O-CPC kits "Spectrum-diagnostics, Germany IFUFCC07".

Magnesium content:
According to procedures of Magnesium kits "Spectrum-diagnostics, Germany IFUFCC94".

Sodium content:
According to procedures of Sodium kits "Spectrum-diagnostics, Germany IFUFCC94".According to procedures of potassium kits "Spectrum-diagnostics, Germany IFUFCC53".
Where: *39.098 = conversion factor, which relates to the molecular weight of potassium **10 = conversion factor (L to dl)

N.B.
• The obtained results on a dry-weight basis were converted on wet wetweight basis using the following equation according to Jurgens and Bregendahl ( 2007): Nutrient wet basis%= (nutrient dry basis% X dry matter %)/ (100) • The color absorption was measured at the central laboratory, Faculty of Veterinary Medicine, Assiut University using a spectrophotometer (Unic, UV-2100 Spectrophotometer).

Statistics:
All statistical analysis was performed using Graph Pad Prism version 8.0.2 (263).The data was analyzed using a one-way analysis of variance (ANOVA).The findings were shown as a mean SE.Group comparisons were conducted using Tukey's multiplerange tests when significant differences were detected at P<0.05.The means in the same column show significant differences (P<0.05) with distinct superscripts.Duplicate analysis on a wet basis.

RESULTS
Chart 1: Average moisture, dry matter, fat, and ash percentages for the 25 fish samples from each species The means in the same column show significant differences (P<0.05) with distinct superscripts.Duplicate analysis on a wet basis.
Chart 2: Average calcium, phosphorus, magnesium, sodium, and potassium content for the 25 fish samples from each species

Dry matter:
The portion of the sample that remains after drying to a fixed weight at a specific temperature and after making up for volatile chemical losses in some feeds is known as dry matter, or DM (Åkerlind et al., 2011).

Fat content:
The beneficial fatty acid profile of fish is largely responsible for its nutritional significance (Sidhu, 2003).Details regarding the oil content of specific species and how it changes depending on the time of year or the area where it is captured are needed (Namaga et al., 2020).Fish lipid composition and moisture content are inversely correlated, according to FAO (1999).This is consistent with the current study's findings; which declared that the lipid concentration decreases with increasing moisture.

Ash content:
Ash content, which is a measurement of the mineral makeup of all food, including fish, is affected by a variety of variables, including the water's biological, physicochemical, and seasonal characteristics at the time of fishing (Akande and Faturoti, 2005).

Clarias
gariepinus represented a significantly higher mean value (P<0.05), while no significant difference was found between the mean values of the other investigated species.
According to Ogata and Shearer (2000), fish chemical composition can be influenced by a variety of factors, including species, environmental conditions, fish size, amount of protein in the diet, and feeding rate.The present study's findings regarding proximate composition revealed significant differences (P0.05) between the studied fish species.

2) Element (Minerals) composition in fish 2.1. Macro-elements: 2.1.1. Calcium content:
The body and its skeleton depend on the mineral calcium.Many metabolic processes, neuromuscular activities (heart in particular), and most importantly, the stiffness of the skeleton are all influenced by calcium.Insufficient calcium causes osteoporosis and decalcification of the skeleton.In pregnant women, it can also result in hypertension, preterm birth, or fetal mortality (Vilain and Baran, 2016).
According to the FAO, the calcium content of fish muscles ranges from 19 to 881 mg/100g.Adults should consume 1000-1300 mg of calcium daily (FAO/ WHO, 2004).

Phosphorus content:
Along with calcium and magnesium, phosphorus is a key component of bones (Masamba et al., 2015).The FAO states that the range of phosphorus in fish muscles is 68-550 mg/100.The recommended daily requirement for adults is 700 mg of P (FAO/ WHO, 2004).The current phosphorus values fall within that stated by FAO.It could be assumed that the 100g flesh of Mormyrus kannume can provide 37.8%, while Lates niloticus can provide 19% of the phosphorus recommended daily intake.

Magnesium content:
Magnesium plays enormous roles in all aspects of life, including immunological, metabolic, neurological, psychological, cardiovascular, and nervous systems (Guerrero-Romero et al., 2023).
The FAO range of 4.5-452 mg/100 g is stated for fish flesh, and the recommended daily intake of magnesium for adults is 220-260 mg (FAO/ WHO, 2004).2017) declared that magnesium content under three different ecosystems was 24.17, 18.83, 46.00 (mg/100 g) for Oreochromis niloticus muscle tissue.

The data in
It was assumed that 100g of Oreochromis niloticus flesh can provide 3-19%, and of Bagrus bayad can provide 4.5 -9.6% of the magnesium recommended daily intake.

Sodium content:
Humans need sodium to keep their bodily fluid systems in balance as well as for the proper operation of their muscles and nerves.Each person's daily intake of salt differs depending on their culture and particular needs (Munteanu et al., 2019).
As stated by FAO sodium level was in the range of 30-134 mg/100 g in fish muscles (FAO/ WHO, 2004).
The higher sodium content found in this investigation might suggest more sodium in the water with increasing water salinity in the areas of capture causing more trophic transfer and accumulation of this mineral in fish meat.The high sodium content is related to public health concerns for example raised blood pressure, increasing the risk of cardiovascular diseases, gastric cancer, obesity, osteoporosis, Meniere's disease, and kidney disease.

Potassium content:
Potassium is necessary for the contraction of muscles, nerve impulse transmission, and the metabolism of sugar (Alas et al., 2014), as well as control of blood pressure (Vilain and Baran, 2016).
Fish muscle has a potassium content between 19 and 502 mg/100 g, which is the daily required amount.(RDA) of K is 800 mg for men in the 25-50 age range (FAO/ WHO, 2004).The results in From the results, it could be seen that 100g of Bagrus bayad flesh can provide 49%, and Lates niloticus can provide 18% of the potassium recommended daily intake.

Micro-elements: 2.2.1. Iron content:
The primary role of iron is in the movement of oxygen from the lungs to the organs.Leukocytes' ability to fight microorganisms strengthens the immune system, while the manufacture of steroid hormones promotes bodily growth.Deficiency can cause altered bodily growth, compromised immunological, neurological, and cognitive systems, and even malfunctioning muscles (Vilain and Baran, 2016).
FAO stated that the iron content in fish muscle was in the range of 1-5.6 mg/100 g, The recommended nutrient intake of iron for female adults between the ages of 19-50 years is 24 mg/day (FAO/ WHO, 2004).The results assumed that 100g flesh of Clarias gariepinus can provide 35.4%, and of Mormyrus kannume can provide 12% of the iron recommended daily intake.

Zinc content:
The body uses zinc extensively for immunity and growth.It is found in all six types of enzymes and plays a role in over 300 catabolic and metabolic activities in addition to a variety of catalytic, structural, and cellular regulatory roles.also engaged in the three-dimensional arrangement of proteins that gives rise to their biological activity.A zinc shortage can cause neurobehavioral impairments (cognitive and memory problems), as well as skin or gastrointestinal concerns in infants.It is harmful and its expression varies with age (Vilain and Baran, 2016).
The FAO stated zinc level in the ranges of 0.23 -2.1 mg/100 g in fish muscle.The zinc recommended dietary allowance for adults is 8-11 mg per day (FAO/ WHO, 2004).
The current values agreed with that found by were higher than those found by Mohamed et al. (2010)  The rate at which these components are available in the water body and the fish's capacity to absorb and convert the necessary nutrients from their food or the water bodies where they reside could be the causes of the variations in the content of the various nutritional components in the fish species and samples that were examined.This is supported by the findings of Martino et al. (2002), Adewoye et al. (2003) and Fawole et al. (2007).

CONCLUSION
People with high blood cholesterol and those experiencing dietary deficits are recommended to eat fish meat.According to the study, fish under investigation are a good supply of important minerals, and the mineral content of fish varies greatly among species.When compared to the other species under investigation, Claris gariepinus had shown superior proximate and mineral content.The general order of mineral concentration in the five investigated species was: Claris gariepinus> Oreochromis niloticus>

(
Porcelain crucibles that had been previously weighted and cleaned were used to weigh one gram of the dry material. These achieved results seem lower than that found byGaber (2000),Premarathna et al.  (2018), and Solomon and Oluchi (2018).However, nearly similar to Oluwaniyi et al. (2017), and Anarado et al. (2023).On the other hand, the obtained results were higher than Mohamed et al. (2010), Adeniyi et al. (2012) and Gana et al. (2020).

Table 1 :
Average values of the fish species samples' proximate composition (n = 25 per sample).

Table 3 :
Micro element mean values of fish species samples analyzed (n = 25 per sample).

:
Average zinc and iron content for the 25 fish samples from each species DISCUSSION1) Proximate analysis:The nutritional profile, which is derived from the proximate components of fish flesh, provides an initial indication of the fish's commercial criteria as needed by food regulations(Marichamy et al., 2012).1.1.Moisture:Food's moisture content serves as a reliable gauge of its calorie, protein, and fat content.Fish with less moisture have more fat and protein in them, as well as more calories per unit(Barua et al., 2012).