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ABSTRACT.
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Key words:
Los sistemas de recirculación de acuicultura afectan los parámetros hematológicos y aumentan
la susceptibilidad a los ectoparásitos en la tilapia del Nilo Oreochromis niloticus
RESUMEN.
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Palabras clave:
Recirculating aquaculture systems affects hematological parameters and
increases ectoparasite susceptibility in Nile tilapia Oreochromis niloticus
Rodrigo Stallbohm Marco Shizuo Owatari
Evoy Zaniboni-Filho Maurício Laterça Martins
Marine and
Fishery Sciences
MAFIS
Marine and Fishery Sciences 37 (4): 609-618 (2024)
®
Oreochromis niloticus
Stallbohm et al.: Hematological parameters and parasitism in tilapia raised in RAS
μ
NitrosomonasNitrobacter
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Marine and Fishery Sciences 37 (4): 609-618 (2024)
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56
Stallbohm et al.: Hematological parameters and parasitism in tilapia raised in RAS 613
The average amounts of feed oered in the morn-
ing period were signicantly lower (p < 0.05)
(1,755.22 ± 475.8 g) when compared to the af-
ternoon period (1,927.64 ± 408.55 g), resulting
in an average consumption of 3,682.86 ± 693.37 g
of feed daily. According to Timmons and Ebe-
ling (2010), 3% of feed supplied daily to sh will
be converted into TAN, i.e. for every 1,000 g of
feed, 30 g of TAN will be produced in the sys-
tem; and for every 0.3 g of TAN generated in the
system, 1.0 m² of specic surface area is needed
for the adhesion of nitrifying bacteria to eciently
oxidize ammonia to nitrate. Therefore, the RAS
must be equipped with a biolter that allows the
development of healthy colonies of nitrifying bac-
teria, capable of carrying out ammonia oxidation.
In the present study, the inoculation of nitrifying
bacteria such as those of the genera Nitrosomonas
and Nitrobacter, which obtain their energy from
the oxidation of ammonia or nitrite (Owatari et al.
2022a), probably accelerated the biolter matura-
tion process and maintained the concentrations of
nitrogenous compounds in the stocking sh phase
within acceptable limits in the RAS.
Water quality standards may vary depending
on the target species (Arana 2010). However, the
deterioration of such water quality standards is
one of the main factors aecting sh health (Dara
et al. 2023), causing changes in the blood count
(Fazio 2019), as well as increasing the presence
of parasites (Lacerda et al. 2018). The hematolog-
ical analysis is a bioindicator of the health of sh
and the environment in which they live, and this
assessment elucidates changes and morphologi-
cal disorders of blood cells caused by aggressive
agents (Fazio 2019). Thus, in the erythrogram it
is possible to identify potential anemic processes,
while the leukogram provides information about
infectious processes and other states of homeostatic
imbalance (Tavares-Dias et al. 2009). Hematolog-
Table 1. Water quality variables during the maturation phase of the biological lter and after 54 days of cultivation of Nile tilapia
in a recirculating aquaculture system (RAS). Mean values are presented as mean ± SD. BB = before the biolter. AB =
after the biolter. TAN = total ammonia nitrogen. NH3 = toxic ammonia. NO2 = nitrite. NO3 = nitrate. (*) Asterisk indicates
signicant dierence.
Variables Maturation phase Stocking sh phase p-value
Dissolved oxygen (mg l-1)* 7.61 ± 0.20 5.53 ± 0.24 0.0079
Temperature (°C) 27.24 ± 0.22 27.99 ± 0.19 0.3046
pH* 6.92 ± 0.59 7.48 ± 0.21 0.0486
Alkalinity (mg CaCO3 l-1)* 28.99 ± 5.44 33.35 ± 2.45 < 0.0001
Hardness (mg CaCO3 l-1) 36.73 ± 3.26 36.85 ± 2.57 0.5282
Salinity (‰)* 0.17 ± 0.08 0.37 ± 0.07 0.0373
Electric conductivity (μS cm-1)* 385.44 ± 163.76 732.57 ± 52.87 0.0331
TAN (BB) (mg l-1)* 3.12 ± 6.28 0.274 ± 0.15 0.0089
TAN (AB) (mg l-1)* 1.635 ± 4.26 0.02 ± 0.013 0.0002
NH3 (BB) (mg l-1)* 0.285 ± 0.90 0.007 ± 0.01 0.0021
NH3 (AB) (mg l-1)* 0.041 ± 0.14 0.001 ± 0.00 0.0161
NO2 (BB) (mg l-1)* 3.263 ± 3.79 0.042 ± 0.03 0.0399
NO2 (AB) (mg l-1)* 1.353 ± 2.16 0.022 ± 0.04 0.0321
NO3 (BB) (mg l-1)* 42.56 ± 2.09 34.73 ± 2.47 0.0451
NO3 (AB) (mg l-1)* 46.04 ± 3.73 35.83 ± 3.61 0.0071
Marine and Fishery Sciences 37 (4): 609-618 (2024)
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Centropomus undecimalis
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Stallbohm et al.: Hematological parameters and parasitism in tilapia raised in RAS
Declaration of interest
Author contributions
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Marine and Fishery Sciences 37 (4): 609-618 (2024)
Centropomus un-
decimalis
Oreochromis niloticus
Oreochromis niloticus
Stallbohm et al.: Hematological parameters and parasitism in tilapia raised in RAS
Oreochromis niloticus
Oreochromis niloticus
Aero-
monas hydrophila
Saccharo-
myces cerevisiae
Streptococcus agalactiae
Oreochromis
niloticus
Marine and Fishery Sciences 37 (4): 609-618 (2024)
Dactylogyrus
vastator
