SELENIUM BIOACUMULATION AND DISTRIBUTION IN
TISSUE OF Litopenaeus vannamei
Silva, E.(¹); Araújo, L.N.C.P.(¹); Oliveira, H.M (¹); Viana, Z.C.V.(²); Santos,
V.L.C.(²) [email protected]
(1)
Universidade Federal de Campina Grande - UFCG, Campus de Patos – PB, Brasil;
(2)
Universidade Federal da Bahia - UFBA, Salvador – BA, Brasil, CNPq, FABESB.
ABSTRACT
Selenium is the very narrow margin between nutritionally beneficial and
potentially toxic levels for vertebrate animals. It is less toxic to most plants
and invertebrates in comparison to vertebrates, particularly with birds and fish.
In this study, concentrations of selenium in tissues (muscle, exoskeleton, and
viscera) of major aquaculture shrimp species (Litopenaeus vannamei; Boone,
1931) farming and zone natural coastal located in the northeastern Brazil were
investigated. The selenium determination was performed by optical emission
spectrometry with inductively coupled plasma (ICP OES). There was
significant variation in the levels of selenium accumulation among tissues.
The following ranges of concentrations in the tissues were obtained in µg g-1
dry weight: muscle: 1.07 - 4.00, exoeskeleton: 0.08 - 7.23; viscera: 8.46 - 9.81.
The distribution of Se concentration in tissues showed much variation between
locations, and the concentration levels found in shrimp muscles of wild
samples were high, indicating evidence of selenium bioaccumulation.
Keywords: Trace Elements, Shrimp, ICP OES.
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RESUMO
O selênio tem uma margem muito estreita entre os níveis nutricionalmente
benéficos e potencialmente tóxicos para os animais vertebrados. Ele é menos
tóxico para a maioria das plantas e invertebrados, em comparação com
animais vertebrados, em particular, com as aves e peixes. O objetivo desse
trabalho foi investigar as concentrações de selênio nos tecidos (músculo,
viscera, exoesqueleto) da espécie de camarão Litopenaeus vannamei (Boone,
1931) de carciniculturas e de origem natural da zona costeira do nordeste do
Brasil (Baia de Todos os Santos). A determinação do selênio foi por
espectrometria de emissão óptica com plasma indutivamente acopladom (ICP
OES). Houve variação significante (p<0.05) nas concentrações de selênio
entre os tecidos, sendo determinado as seguintes faixas de valores (µg g-1 peso
seco): músculo: 1,07 - 4,00, exoesqueeleto: 0,08 - 7,23; víscera: 8,46 - 9,81. A
sua concentração também apresentou muita variação entre as localidade. Os
valores encontrados nas amostras de camarões da zona costeira indicam
evidência de bioacumulação do selênio.
Palavras-chave: Elemento Traço, Camarão, ICP OES.
INTRODUCTION
Selenium is a no metallic element with naturally occurring and typically
found in uncontaminated water at concentrations of 0.1 to 0.4 ug L-1
(LEMLY, 1985; DOBBS et al. 1996). It is an essential micronutrient
that is vital to biological systems in small amounts, but there is a narrow
range between the essential exposure dose and toxicity in fish
(DANABAS and URAL, 2012).
It is a component of glutathione peroxidase. Glutathione is an enzyme
that acts as an oxidizing agent free radical that attacks the cell
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(GOYER, 1995). This enzyme has four selenium atoms, and also
biochemical functions in the reduction of hydroperoxides in cells,
plasma and gastrointestinal tract. Selenium from organic sources is
absorbed by amino acids can be incorporated directly into body
proteins, where they are stored, thereby reducing its excretion and
contamination of the environment (Paiva, 2006). Its antioxidant activity
may play an important role in cancer prevention. This preventive action
is due to its role in the liver, where carcinogenic compounds are
metabolized by a group of oxidases (CORREIA, 2001). In this study,
concentrations of trace elements in tissues (muscle, exoskeleton, and
viscera) of major aquaculture shrimp species (Litopenaeus vannamei;
Boone, 1931) farming and zone natural coastal located in the
northeastern Brazil were investigated.
MATERIAL AND METHODS
Shrimp samples (Litopenaeus vannamei) were collected directly from
the four sites: three shrimp farms (Guaibim – L1, Salina das Margaridas
– L2, Santo Amaro – L3) and a sampling site of wild shrimp caught in
the natural coastal zone (Mar Grande – L4 e L5) in the Todos os Santos
Bay, between December 2005 and January 2006. Composite subsamples of muscle tissue, exoskeleton and viscera from 76 to 120
individuals were used for analysis. The samples were stored
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individually in sterile polyethylene vials at 20 oC, freeze–dried and
homogenized.
The farmed shrimps were collected using a non-metallic net, and the
wild shrimp were bought from local fishermen. Each white shrimp
weighed 19 - 26 g, all market size. The humidity percentage was 78 ±
2%.
To minimize contamination, all the materials used in the experiments
were previously washed in ultra pure water, and a stainless steel knife
was used to cut the tissues.
Masses of 200 mg of samples were directly introduced into PTFE
closed vessels with volumes of 23 mL. A volume of 2.0 mL of ultrapure
nitric acid solutions was added to each vessel. Then, a volume of 2.0
mL of H2O was also added to each reaction vessel. Parr bombs were
sealed and put in a muffle furnace set at 110 ± 10ºC and remained at
this temperature during 12 h. After cooling down at room temperature,
solutions were transferred to glass volumetric flasks and volumes were
made up to 10 mL with water.
An inductively coupled plasma optical emission spectrometer (ICP
OES) with axially viewed configuration (VISTA PRO, Varian,
Mulgrave, Australia) equipped with a solid state detector, a cyclonic
spray chamber, and a concentric nebulizer was employed for selenium
determinations. The ICP OES condition used for this study was as
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follows: RF power: 1.3 kW; gas: argon; plasma flow: 15 l/min;
auxiliary flow: 1.5 l/min; nebulizer flow: 0.75 l/min; instrument
stabilization delay: 15 s; pump rate: 15 rpm; sample uptake delay: 70 s;
number of replicates: 3; read time: 5 s; read: peak height; rinse time: 30
s.
The precision and accuracy of the method employed for the
determinations were validated by analysis in triplicate of certified
reference materials (CRM), from National Research Council Canadá
(BCR-422, Cod Muscle), using the same analytical procedure. The
recovery rates was 104% (µg g-1/dry weight). Analytical blanks were
run in the same way as the samples and the concentrations were
determined using the standard solutions prepared in the same acid
matrix.
All reagents were of analytical grade unless otherwise stated. Ultrapure
water (Milli-Q®, Millipore, USA) with conductivity lower than 18.2
mΩ cm-1 was used throughout. The multielement reference solutions
were prepared daily from 1000 mg L-1 stock solutions of each element
(Titrisol®, Merck, Germany).
Each reported result was the average value of the three analyses. The
results were offered as means ± SEM. Kruskal–Wallis H test, which
was followed by comparisons of particular pairs of samples by Mann–
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Whitney U test to compare the data by locations and by tissues. Results
were considered significant at p <0.05.
RESULTS AND DISCUSSION
The measured levels of Se ranged from 1.07 - 4.00 µg g-1 (dry weight)
in muscle, 0.08 - 7.23 µg g-1 in exoskeleton and 8.46 - 9.81 µg g-1 in
viscera (Table 1).
Table 1. Concentrations (µg g-1 dry weight) of trace elements in Litopenaeus vannamei
tissues from the Todos os Santos Bay, Bahia, Brazil
Amostra
Síte 1
Síte 2
Síte 3
Síte 4
Síte 5
cA
3.97 ± 0.02
cA
4.0 ± 0.03
cA
3.68 ± 0.41
cA
3.84 ± 0.62
cB
5.45 ± 0.5
cB
6.59 ± 0.21
dB
7.07 ± 0.62
dB
7.23 ± 0.34
aC
9.72 ± 0.34
aC
8.46 ± 0.06
aC
9.81 ± 0.34
aC
8.56 ± 0.06
MUSCLE
A1
A2
A1
A2
aA
1.09 ± 0.05
a.A
1.07 ± 0.17
aB
3.97 ± 0.03
aB
3.83 ± 0.69
aA
bA
1.47 ± 0.38
2.33 ± 0.47
aA
bA
1.46 ± 0.01
2.10 ± 0.25
EXOESKELETON
bB
aB
0.08 ± 0.006
3.84 ± 0.06
bB
aB
0.09 ± 0.007
3.76 ± 0.17
VISCERA
A1
<LD
<LD
ND
A2
<LD
<LD
ND
The mean±SD for elements designated by different lowercase superscript letters
are significantly different from other samples in the same row.
The mean±SD for elements designated by different uppercase superscript letters
are significantly different from other samples in the same column.
<LD – Below limit of detection (< 4,1 ng g-1); ND – Not determined.
The highest concentrations of Se were found in wild shrimp tissues. The
distribution of Se concentration in tissues showed many variations
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between sites. In the wild shrimp (Sites 4 and 5), the descending order
of concentration in tissues was: viscera > exoskeleton > muscle. While
this sequence of distribution in tissues of shrimps collected in other
sites presented the order: exoskeleton > muscle > viscera.
Laboratory studies with fish species have demonstrated that selenium in
excess tissues of aquatic organisms results in a variety of toxic effects
such as decreased growth, tissue damage, reproductive effects and
increased mortality. (HODSON and HILTON 1983; LEMLY, 1993).
The characteristic of selenium toxicity is the appearance of teratogenic
deformities in offspring of females exposed to this toxicity, resulting
from deposition of selenium in their eggs. Teratogenesis is restricted to
the larval development when larvae egg yolks using contaminated with
selenium (LEMLY, 1997).
Selenium is the very narrow margin between nutritionally beneficial
and potentially toxic levels for vertebrate animals. It is less toxic to
most plants and invertebrates in comparison to vertebrates, particularly
with birds and fish (WHITE et al., 2012).
Lemly (1995) proposed a protocol of selenium accumulation profile in
the food chain to evaluate the toxicity of its concentration in fish and
aquatic birds. According to their classification, selenium levels found in
the muscles of the samples investigated show low risk of toxicity for
shrimp farm (Sites 1, 2 and 3) samples and moderate risk for samples of
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wild shrimps (Sites 4 and 5). Thus, according to the protocol proposed,
wild shrimp samples analyzed showed evidence of selenium
bioaccumulation in the food chain and can cause adverse effects on
populations of fish and birds. For human consumption, the values found
for selenium concentration in all shrimps are below the tolerance limit
set by ANVISA - 0.30 mg/L (ANVISA, 1965).
CONCLUSION
The tissues analyzed from L. vannamei shrimp species showed different
trends of selenium bioaccumulation.
The highest concentrations of the majority of elements have been found
in the tissues of viscera.
The distribution of selenium concentration between tissues showed
many variations between locations
The concentration levels found in muscles of wild shrimp samples were
high, indicating evidence of selenium bioaccumulation in the food
chain.
For human consumption, the values found for selenium concentration in
all shrimps are below the tolerance limit set by ANVISA.
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REFERENCES
CORREIA, P. R. M., Determinação Simultânea de manganês/selênio e cobre/zinco
em soro sanguíneo por espectrometria de absorção atômica com atomização
eletrotérmica. Dissertação de mestrado (Mestrado em Química Analítica). Instituto
de química,USP. 2001.
DANABAS, D., URAL, M. Determination of Metal (Cu, Zn, Se, Cr and Cd)
Levels in Tissues of the Cyprinid Fish, Capoeta trutta (Heckel, 1843) from
Different Regions of Keban Dam Lake (Euphrates-Turkey). Bulletin of
Environmental Contamination and Toxicology. 2012; 89:455–460
DOBBS, M. G., CHERRY, D. S., CAIRNS, J. Toxicity and bioacumulation of
selenium to a three-trophic level food chain. Environmental Toxicology and
Chemistry. 1996; 3, 340-347.
GOYER, R. A. Nutrition and metal toxicity. The American Journal of Clinical
Nutrition. 1995; 61; p. 646-650.
HODSON, P.V. e HILTON, J.W. The nutritional requirements and toxicity to fish
of dietary and waterborne selenium. Ecology Bulletin. 1983; 35: 335-340.
LEMLY, A.D. Toxicology of selenium in a freshwater reservoir: Implications for
environmental hazard evaluation and safety. Ecotoxicology and Environmental
Safety. 1985;10: 314-338.
LEMLY, A.D. Ecosystem recovery following selenium contamination in a
freshwater reservoir. Ecotoxicology and Environmental Safety. 1997; 36: 275-281.
LEMLY, A.D. Teratogenic effects of selenium in natural populations of
freshwater fish. Ecotoxicology and Environmental Safety. 1993;26: 181-204.
LEMLY, A. D. A. Protocol for Aquatic Hazard Assessment of Selenium.
Ecotoxicology and Environmental Safety. 1995; 32, 280-288.
PAIVA, F.A. Avaliação de fontes de selênio para ovinos. Tese de doutorado
(Doutorado em Zootecnia e Engenharia de Alimentos). Faculdade de Zootecnia e
Engenharia de Alimentos, USP.2006.
9
Resumos Expandidos do I CONICBIO / II CONABIO / VI SIMCBIO (v.2)
Universidade Católica de Pernambuco - Recife - PE - Brasil - 11 a 14 de novembro de 2013
WHITE, R. R., HARDAWAY, C. J., RICHERT, J. C., SNEDDON, J. Selenium–lead
interactions in crawfish (Procambrus clarkii) in a controlled laboratory
environment. Microchem. J. 2012; 102, 91-114.
AGÊNCIA DE VIGILÂNCIA SANITÁRIA - ANVISA, Brasil. Decreto nº 55871, de
26 de março de 1965. http://e-legis.bvs.br/leisref/public/showAct.php?id=22 Acesso
28 de outubro de 2012.
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