Mirea (Ciortan) C. et. al./Scientific Papers: Animal Science and Biotechnologies, 2013, 46 (2)
Hematological and Biochemical Characterization of Nile
tilapia (Oreochromis niloticus, Linnaeus, 1758) Reared
Intensively in a Recirculating Aquaculture System
in Relation to Water Temperature
Catalina Mirea (Ciortan), Victor Cristea, Rodica Iulia Grecu,
Lorena Dediu, Vasilean Ion
“Dunarea de Jos” University of Galaţi, Aquaculture, Environmental Sciences and Cadastre Department
800008-Galati, Domneasca, 47, Romania
Abstract
The aim of this study was to obtain a basic knowledge of the hematological response of Oreochromis niloticus
mantained in different tchnological condition induced by different temperatures. Nile tilapia (Oreochromis niloticus,
Linnaeus, 1758) with average weight of 33.5±1.0 g, they were stocked in 12 rearing units at 20, 24, 30 and 28oC
(control) water temperature for 30 days. Diet of 41 % protein was offered as feed, 3 times daily. The sampling of
Oreochromis niloticus blood from the four variants before and after the experimental trial allowed determination of
hematological indices. Red blood cel count (RBCc), hematocrit values (Hct), hemoglobin concentration (Hb), mean
corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular concentration (MCHC),
glucose and protein from blood were measured and analysed, with routine methods udes in fish hematology.
Keywords: biochemical, hematology, Nile tilapia, Oreochromis niloticus, recirculating aquaculture system,
temperature
1. Introduction
represent an important argument for rearing this
species in a super intensive recirculation system in
order to obtain tilapia for consumption purposes.
The temperature can negatively affect a series of
biological functions: metabolism, breading
performance, resistance to disease and health
condition.
The optimum temperature range in rearing
systems is 25–31oC [2].
At water temperature of 16oC, tilapia stop feeding,
under 20oC do not spawn while sever mortality
occurs at 12oC. That why is not recommended
introduction of this species in traditional systems
of our countries with environmental conditions
outside of its limits of tolerance [3].
The purpose of this study was to present the effect
of different temperature on hematological indices
and biochemical parameters of the blood of Nile
tilapia (Oreochromis niloticus).
Tilapia are the second most commonly cultured
fish in the world, and are a food staple in many
parts of Africa, Asia and South America.
Aquaculture of tilapia, as with other species of
finfish, is adversely affected by production related
disorders and infectious disease [1].
The research carried out at a global level on the
species Oreochromis niloticus have brought up
that, is not very demanding when it comes to
environmental condition, it have a high level of
fodder assimilation , grows rapidly in captivity it
is resistant to disease. Technological aspects

* Corresponding author: Catalian Mirea (Ciortan)
Tel: 0040742069549
Email: [email protected]
[email protected]
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Mirea (Ciortan) C. et. al./Scientific Papers: Animal Science and Biotechnologies, 2013, 46 (2)
2. Materials and methods
Experimental design. The fish was stocked into
12 rearing units at 20, 24, 30 and 28oC (as
Control). Automatic heaters with thermostat were
used to obtain the temperatures. The number of
tilapia stocked in the rearing units was in a rate of
15 fish per unit for 30 days with three replicates
for each treatment.
Commercial diet was used in the experiment; the
pellets size was 2 mm, which had 41% crude
protein.
Table 1 present the statistical and biometrical data
at the beginning of the experiment and the four
treatments applied in this experiment.
Fish biomass used in this study was represented
by Oreochromis niloticus, reared into a
recirculating aquaculture system from Department
of Aquaculture, Environmental Science and
Cadastre, University “Dunarea de Jos” of Galati.
Nile tilapia (Oreochromis niloticus) used in this
experiment were 33.7±5 g mean average weight
and 12±0.8 cm of length. Fish were homogenous
in size, body weights and healthy. They were fed
on the same diet like in the experiment for 2
weeks before the study to adapt them to the
experiment conditions. Through the adaptation
period the week and the dead fish were eliminated
daily.
Table 1. Biometrical and statistical data at the beginning of the experiment
T2 (T=30oC)
T3 (T=24oC)
Experimental variant
T1 (T=28oC)
Indicator/tank
B1
B2
B3
Initial biomass (g)
505.33
505.67
506.67
Initial number of fish
15
15
15
Initial average weight (g/ex)
33.68
33.7
33.77
Standard deviation
226.87
227.02
227.48
T4 (T=20oC)
B4
50.3
15
33.68
226.85
were calculated (mean corpuscular volume-MCV,
mean erythrocyte hemoglobin-MCH, mean
erythrocyte hemoglobin concentration-MCHC).
Blood sampling and analysis
0.5 ml of blood was sampling from fish of each
variant by caudal venous puncture using lithium
heparin as anticoagulant at the beginning and at
the end of the experiment. Blood was analyzed
with routine methods used in fish hematology.
The red blood cell counts (RBCc, x 106/µl) was
determined by counting the erythrocytes from 5
small squares of Neubauer hemocytometer using
Vulpian diluting solution.
Blood hemoglobin concentration [Hb (g/dl)] was
determined quantitatively, by colorimetric
method,
with
Drabkin
reagent,
at
SPECTROCORD
210
Analytikjena
Spectrophotometer, at a wavelength of 540 nm.
If for determination of above hematological
indices, heparinized blood was used, for
measuring biochemical indices (serum glucose
and protein) blood without heparin was used.
Thus, to obtain blood serum, the blood without
anticoagulant was centrifuged 10 minutes, at 3500
rotation/min.
Serum glucose was calorimetrically dosed with otoluidine at a wavelength λ=635 nm. Serum
proteins were determined spectrophotometric by
Biuret method, at wavelength λ=546 nm.
After determining hematological indices, using
standard formulas [4, 5], erythrocyte constants
Statistical analysis
Hematological parameters were statistically
analyzed using Microsoft Excel 2010 statistical
computer program, from which we used the
following statistical tests: descriptive statistics,
parametric t-Student test.
3. Results and discussion
In order to underline as faithful as possible the
physiological response of blood to the stressing
action of the environmental technological factors
(temperature, stock density), there used the
dynamic analyses of the hematological indicators
value and eritrocitary constants, at the end of the
experiment, between the control and the
treatments.
The literature reveals that the erythrocyte count
among fishes ranges from lowest of 0.84
million/cu.mm in carps (Barron et. al., 1956) [6]
to the highest count of 6.48 million/cu.mm in
Acanthurus bahianus (Saunders, 1966) [7],
however Tayler (1960) [8] has reported a count of
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Mirea (Ciortan) C. et. al./Scientific Papers: Animal Science and Biotechnologies, 2013, 46 (2)
0.66
million/cu.mm
in
Trematomus
borchgrebinkl, which is lowest RBC count for a
teleost fish.
Table 2. Changes in hematological parameters of Nile tilapia during the experiment
Hematological parameters (Avarage and standard deviation)
Experimental version
Ht (%)
Hb (g/dl)
RBCc ×106/µl
MCV (µm2)
MCH (pg)
MCHC (g/dl)
T1(Control) Avarage
23.67
8.41
2.23
115.02
37.66
*35.85
(T=28oC)
St, dev
2.58
0.61
0.69
32.58
8.84
3.58
T2
Avarage
22.00
8.35
2.63
*85.46
31.70
*38.50
(T=30oC)
St, dev
2.94
0.59
0.45
16.16
12.90
4.74
T3
Avarage
22.11
8.18
2.53
*88.63
32.31
*37.41
(T=24oC)
St, dev
2.73
0.49
0.33
15.02
15.00
3.81
T4
Avarage
26.44
8.04
2.26
123.19
35.64
*31.53
(T=20oC)
St, dev
6.53
0.48
0.69
32.44
7.07
4.72
Reference intervals
22 37
7.0–9.8
1.91–2.83
115-183
28.3–42.3
22-29
The values with * are not in the reference intervals described by Terry C. Hrubec [7], and can describe an incipient
anaemia.
experimental stocking densities tested to the
values originally recorded (Figure 1).
The analysis reveals that the variation of
hemoglobin quantity (respiratory pigment having
the capacity of transporting the oxygen to the
blood) under the action of thermal stress, is having
a tendency to decreases with decreasing the
temperature with insignificant differences between
the control and the other three treatments.
The important reduction of hemoglobin can
modify the oxygen quantity from tissue and can
lead to the slowdown of the metabolic ratio and to
smaller production energy [9].
The decrease of hemoglobin can be caused by the
increase of the destruction rate of Hb or the
reduction of its synthesis rate [10].
The hematocrit (Ht) under stressing effect of the
temperature, records increasing value in T4 (20oC)
comparing with the T1 (28oC-Control) (Table 2).
Mean Corpuscle Haemoglobin (MCH)
The value of MCH at O. niloticus was 37.66±4.22
pg indicating an decrease of 31.7±2.54 pg. In
hypochromic anaemia there is a decrease in cell
haemoglobin and thus the MCH value will be
decreased. However, in macrocytic condition the
MCH will be increased (Table 2).
Mean corpuscular Haemoglobin Concentration
(MCHC)
The control value obtained in the present study in
Oreochromis niloticus was 35.8±3.14 g/dl. An
increase of 38.5 value has been observed in the
treated fish. The increase in the MCHC value is
due to macrocytic anaemia (Table 2) .
Determinations of blood glucose and serum
proteins are the most effective and least expensive
stress evaluation [12]. Thus, for this experiment
the steady growth serum proteins for all four
Figure 1 and 2. Protein and glucose level
at the end of the experiment
Serum protein similar experiment determined at
the end 2.75 g/dl in literature. Keeping a steady
blood glucose control is the finest fish
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Mirea (Ciortan) C. et. al./Scientific Papers: Animal Science and Biotechnologies, 2013, 46 (2)
2. Bucur, C., Costache, M., Oprea, D., Marica, N.,
Studies and Observations on the Spawning of
Oreochromis niloticus Species Reared at SCDP Nucet–
Dambovita. Scientific Papers: Animal Science and
Biotechnologies, 2012, 45 (2)
3. Coadă, M.T., Patriche, N., Cristea, V., Antache, A.,
Placintă, S., Mocanu, M., Petrea, M. Șt., The effect of
feeding with different dietary protein levels on
hematological profile and leukocytes population of
juvenile paddlefish, Polyodon spathula, Scientific
Papers: Animal Science and Biotechnologies, 2012,
45(2), 7-13.
4. Ghergariu, S., Pop, A., Kadar, L., Veterinary Clinical
Laboratory Guide, 1985, pp.82-90.
5. Svobodova, Z., Stress in fishes (a review). Bull
VURH Vodnany, 2001, 4, 169-191.
6. Barron, D. H., Hart, F. H., Kisch, B., Osgood, E. S.,
Punden, E., Root, R. W and Young, I. M., Erythorcyte
and platelet values; vertebrates in Hand Book of
biological data (W.S. Spector., ed.) W. B. Saunders,
Philadelphia, 1956
7. Saunders, D. C., Differential blood cell counts of
121sps of marine fishes of Puerto rico. Trans.
Am.Microsc.Soc., 1966, 85, 427-449
8. Tayler, J. C., Stanford Ichthyol Bull., 1960, 7, 199
9. Misăilă, C., Misăilă, E. R., Dumitru, G., Influence of
thermal and parasitary stresson the erythtrocytary
hemoglobin (index m) in some culture cyprinids,
Modern animal husbandry strategies, opportunities and
performance, 2011, 55(16), 301-305.
10. Molnar, G., Tamassy, E., Study of the haemaglobin
content of a single erythrocyte (Mindix) in various
cultured fish species, J. Fish. Biol., 1970, 2, 167-171.
11.Terry, C. Hrubec, D. V. M., PhD; Jenifer L.
Cardinale, DVM; Stephen A. Smith, DVM, PhD,
Hematology and plasma Chemistry reference intervals
for cultured tilapias (Oreochromis Hibrid), Veterinary
Clinic Pathology, 2000, 1, 1-17
12. Patriche, T., Patriche, N., Bocioc, E., Determination
of some normal serum parameters in juvenile Sevruga
sturgeons Acipenser stellatus (Pallas, 1771), Archiva
Zootechnica, 2011, 14(1), 49-54
13. Patriche, T., Fish Imunity, 2008, Didactic and
pedagogical, ISBN: 978-973-30-2070-7
homeostasis involving the liver, extra hepatic
tissues and a number of endocrine glands. Glucose
decreased at the end of the experiment proteins
showing significant differences between the
variants but the value are in the optimum range of
the species, glucose level being a stress indicator;
the values are lower between control and variants
[13], so if we take only the glucose indicator we
can say that the individuals are stressed in T2 and
T4 that are the higher ant the smaller temperature.
4. Conclusions
Therefore the blood parameters might be
considered as potential bio-indicators in assessing
the physiological status of fish and the data
obtained in this regard might also provides
substantial information on the quality of the water
body as such.
Consequently, the water temperature resulted to
influence the homeostatic power, favouring the
damege of tilapia physiological response
mechanisms.
In conclusion the water temperature can affect the
individuals because the blood indicators leed us to
say that they may be affected by an incipient
macrocytic anaemia, and from the biochemistry of
the blood we can observed that high and low
temperature affect Nile tilapia beeing a stressor
factor for the fish.
Acknowledgements
The work of Catalina (Ciortan) Mirea was supported by
Project SOP HRD–TOP ACADEMIC 76822/2010.
References
1. Global Aquaculture Advocate, November/December
2011, pp. 25-29
237