A comparative Study of Blood Physiological Characteristics in Common Carp Fish Reared in Earthen Ponds in Different Locations at the Tigris and Euphrates Rivers in Central Iraq

This study was conducted with the aim of showing the effect of location and water quality on the blood and physiological characteristics of Common Carp fish. This study was carried out in four different sites in central Iraq for the period from 1/June 2022 to 30/November 2022, where the sites of Dujail and Suwayrah at the Tigris River were used, and the sites of Fallujah and Al-Mahawel at the Euphrates River. 120 fish were collected from the four sites, 30 fish for each site, and some traits were measured. The physiology of fish blood represented by the number of red blood cells, white blood cells, compacted blood volume, and hemoglobin concentration. The findings revealed that there were very substantial changes in the amount of compressed blood, the number of red and white blood cells, and the number of red and white blood cells between the Dujail and Fallujah locations, as it recorded 2.0 cells × 10 6 / mm3 and 32.8 cells × 10 3 / mm3 and 38.4 cells, respectively, in the Dujail site, and it recorded 1.8 cells × 10 6 / mm3. mm 3 and 30.9 cells × 10 3 / mm 3 and 37.3, respectively, in the Fallujah site, while there were no significant differences between the sites of Al-Suwaira and Al-Mahaweel. The results showed that there were highly significant differences in hemoglobin concentration between Dujail, Suwaira and Fallujah, as it recorded 12.0, 11.1 and 9.0, respectively. While there were no significant differences between the site of Al-Suwaira and Al-Mahaweel in hemoglobin concentration.


Introduction
Fish is one of the most important sources of food since the ancient man knew it, and it still enjoys a prestigious position in all countries of the world, and as a result of the large increase in the number of the world's population in recent years, the eyes of countries have turned to exploiting various types of wealth to secure the food needs of their people [1].The World Health Organization stresses the need for an individual to obtain 20 kg / year of fish meat [2].The shortage of animal protein made the researchers' eyes turn towards fish in order to compensate for it, especially after the global financial crisis, the increase in extreme weather phenomena, and the increasing number of the world's 1259 (2023) 012080 IOP Publishing doi:10.1088/1755-1315/1259/1/012080 2 population that is not compatible with limited natural resources, as natural fisheries and aquaculture provided the world with about 214 million tons of fish during the year 2020 [3].The Common carp (Cyprinus carpio L.) is one of the most important types of fish farmed in freshwater and loves warm waters [4] ; [5].It is one of the most widespread types of fish in the world because of its adaptation to various environmental conditions.It achieves a large spread in many regions of the world and is bred In stagnant and running waters, in ponds, lakes, and cages, in addition to the ease of breeding them, their ability to withstand difficult conditions, the diversity of their nutrition, and their rapid growth are key factors in their success [6].The process of fish farming in Iraq has begun to face many difficulties due to significant environmental changes, such as low water levels, increased pollutants, the use of illegal means in fishing, and the lack of interest by government institutions and decision-makers in the problems of fish breeders [7].The main goal of fish aquaculture is Increasing production and not relying on natural fisheries through the establishment of earthen ponds and choosing the appropriate site that is characterized by the ability to increase productivity per unit area and good management in providing processed food that increases the speed of growth for these large numbers through the provision of good water and the possibility of monitoring the health condition through a study Blood characteristics represented by the number of red blood cells, white blood cells, compressed blood volume, and hemoglobin, thus obtaining a good economic return and preserving the water environment from pollution [8] ; [9].

Materials and Methods
The study was conducted in four different sites for fish farms in central Iraq near Baghdad governorate, which were represented by the Dujail site on the Tigris River, the Fallujah site on the Euphrates River, the Suweira site on the Tigris River, and the Mahaweel site on the Euphrates River.(replicates), the area of one pond is five dunums and laboratories in Musel university Ethical approval No. um.VET.2021.5.Using a plastic syringe with a 3 ml capacity, blood samples were taken from the caudal vein of the test fish.The blood sample from each fish was divided into two parts.The first part was placed in tubes containing an anticoagulant (heparin) to perform blood image examinations, which included each of the cell counts.The red blood RBC, the number of white blood cells (WBC), the volume of packed blood cells (PCV%), the concentration of hemoglobin (Hb) and depending on the method mentioned [10].

Calculating the Number of Red Blood Cells
02 microliters of blood were drawn using the Sahli haemoglobinometer's pipette, and 0.98 ml of Modified Dacie's fluid was added.After the mixture had been completed, 0.1 mm of the mixture was collected and put in a Hematology chamber with its unique glass cover.The quantity of red blood cells per milliliter of blood was calculated by counting the red blood cells at a 400x magnification in the four corners and the center, then multiplying the resultant figure by 2500.

Calculating the Number of White Blood Cells
02 A Sahli haemoglobinometer pipette was used to draw microliters of blood, and after mixing the blood with 0.98 ml of Modified Dacie's fluid, 0.1 mm was collected and put on a counting slide with its unique cover glass on it.The white blood cells in the four side squares were counted, and the result was multiplied by 125 to get the number of white blood cells per milliliter of blood.

Measuring the Volume of Packed Blood Cells (PCV%)
A drop of blood was placed on a glass slide, microhaematocrit tubes with a length of 75 mm were filled with anticoagulant, and one end of the tubes was sealed with synthetic clay.The tubes were then spun at a speed of 10,000 rpm for five minutes after being filled with anticoagulant.. Then I read the result using a ruler Microhaematocrit reader used to measure the length of the packed red cell column and divide it by the entire length of the blood column (cells and plasma) to get the blood volume, then 3 multiply this number by 100%, where the average of all readings was obtained from the different capillaries according to the method mentioned by [11].

Measurement of Hemoglobin Concentration
A Sahli pipette was used to take 0.02 ml of blood, which was then placed in a special measurement tube.The mixture was then mixed with five milliliters of Drabkin's reagent, and it was let to stand for 10 minutes.The amount of hemoglobin in grams per 100 cm3 of blood was calculated from the reading of a spectrophotometer (manufactured by the German company Lamp & Bausch) used to assess the permeability [10].

Statistical Analysis
The statistical program SPSS version 26 was used in data analysis to research how various influences affect the features being investigated.In order to detect significant differences among the various coefficients at a significant level (0.05), the data were analyzed using a complete random design (CRD), and the significant differences between the averages were examined using the Duncan Multiple Range test [12].

Results and Discussion
It is clear from tables (1 and 2) the values of blood parameters for common carp fish in the ponds of the Tigris River before and after Baghdad in Dujail and Suwayra.The maximum numbers of red blood cells, white blood cells, compressed blood volume, and hemoglobin concentration were seen in the Dujail site during the month of August, at 2.3, 35.5, 39.7, and 13.0, respectively.The quantity of compressed blood, the quantity of white blood cells, and the number of red blood cells all had the lowest values.Hemoglobin concentrations were 1.8, 28.5, 32.3, and 10.3, respectively, during October 2022 at the Essaouira site.As for the two tables (3 and 4), the values of the blood parameters of common carp fish in the earthen ponds of the Euphrates River in Fallujah and Mahaweel before and after Baghdad.The greatest values were seen in the quantities of red blood cells, white blood cells, compressed blood volume, and hemoglobin concentration, which were 2.0, 31.6,39.2, and 11.1, respectively, the Al-Mahaweel site in August recorded the lowest values in the number of red blood cells, white blood cells, compressed blood volume, and hemoglobin concentration, which were 1.6, 24.9, 29.0, and 8.2 at the Fallujah site in November 2022, respectively.According to the most recent findings, fish's blood markers increase during hot months and drop during cold months as a consequence of temperature changes.This is due to the large number of pollutants and the decrease in respiration efficiency due to the increase in temperature and seasonal changes in some physical and chemical factors of water such as increased water acidity and lack of dissolved oxygen during the hot months, which is Which results in a reaction in increasing the number of red blood cells, the number of white blood cells, the volume of compressed blood, and hemoglobin.The results of the statistical analysis of the current study, as shown in Table (5), showed that there were no significant differences in the four blood parameters between the two sites (Dujail and Fallujah) before Baghdad and between the two sites (Suwaira and Mahaweel) after Baghdad.While the current results showed that there were highly significant differences at the level of probability (P ≤ 0.01) between the Tigris River and the Euphrates River, as the four blood standards rose during the study period in the Tigris River above the normal limits compared to the Euphrates River, in which the blood standards were within and close to the normal limits.The current results also showed that there were highly significant differences at the level of probability (P ≤0.01) between the Fallujah site and the rest of the three sites, where it was noted that the four blood parameters increased in Dujail, Suwayra and Mahaweel compared to their decrease in the Fallujah site over the length of the study period, and this indicates that The Fallujah site is considered one of the best sites in the level of blood standards because the fish are not exposed to stress and pollutants, the availability of appropriate oxygen and the ideal pH, while other sites have low dissolved oxygen and an increase in pollution and stress rates, and as a result, the fish are encouraged to produce more red blood cells in an effort to adapt to their surroundings.Due to an oxygen deficit, either an immunological response to stress and

Table 4 .
Blood parameters values for common carp fish reared in earthen ponds in Babel Governorate (Al-Mahaweel District) at the Euphrates River for the period from June to November 2022.

Table 5 .
Effect of location, water type and their interaction on blood parameters of common carp fish in the current study for the period from June to November 2022.
• Different letters within one column indicate significant difference.