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International Journal of Marine Science 2015, Vol.5, No.9, 1-4
http://ijms.biopublisher.ca
1
A letter Open Access
Cold Lugol’s solution as an alternative of formaldehyde-base preservative in
preserving stomach content of shellfish
Tan Kar Soon, Julian Ransangan
Borneo Marine Research Institute, University Malaysia Sabah, Jalan UMS, 88400, Kota Kinabalu, Sabah, Malaysia
Corresponding author email
International Journal of Marine Science, 2015, Vol.5, No.9 doi: 10.5376/ijms.2015.05.0009
Received: 05 Jan., 2015
Accepted: 25 Jan., 2015
Published: 10 Feb., 2015
Copyright
©
2015
Soon and Ransangan, This is an open access article published under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Soon and Ransangan, 2015, Cold Lugol’s solution as an alternative of formaldehyde-base preservative in preserving stomach content of shellfish, International
Journal of Marine Science, Vol.5, No.9 1
-
4 (doi
Abstract
Formaldehyde has long been the standard preservative for stomach content of bivalves in the feeding preference studies of
the animal. However, formaldehyde-base preservatives are highly toxic and carcinogenic to human. Many other preservatives
particularly Lugol’s solution and alcohol are known to be effective in preserving phytoplankton sample in water. However, the
performance of these preservatives in preserving phytoplankton in the gut of mussels is not fully understood. Current study compared
the preservative efficiency of formaldehyde, Lugol’s solution, alcohol and filtered seawater on the phytoplankton in the stomach of
green mussel. Mussel samples were collected from green mussel farm at Marudu Bay and preserved in mixture of 5% formaldehyde
and glutardialdehyde (3:1), 1% Lugol’s solution, 70% alcohol and filtered seawater, then stored in 4°C. The phytoplankton
composition in the gut of mussels was identified and counted according to different preservatives. The result demonstrates that the
preservative performance of cold alcohol and filtered seawater is not encouraging. However, the cell abundance and composition
preserved in Lugol’s solution is similar to that in the mixture of formaldehyde and glutardialdehyde, suggesting Lugol’s solution can
be used as a safe alternative to formaldehyde-base preservative.
Keywords
Alternative preservative; Gut content of mussel; Phytoplankton; Formaldehyde; Lugol’s solution
Introduction
Cilliary-mucus suspension feeder is known to
preferentially ingest certain group of phytoplankton
(Ciocco and Gayoso, 2002; Ren et al., 2000). The
selective behavior of bivalves is usually examined on
the basis of comparison between the phytoplankton
composition in gut and water column (Tan and
Ransangan, 2014). Indeed, it is always the best to
examine samples as early as possible after collection.
However, in some circumstances, particularly
sampling sites are too far from the laboratories and it
needs few hours for the transportation, it is necessary
to preserve the sample with suitable preservative that
can ensure the samples in good condition before
analyzing.
Bivalve specimens are commonly preserved in
formaldehyde-base preservative (Navarro, 2005).
However, the hazardous fumes of formaldehyde are
extremely harmful to human (Titford and Horenstein,
2005). Formaldehyde is highly soluble in water. It
reacts with the active hydrogen of many compounds
in biological systems such as ammonia, amines and
phenols to form bis-chloromethyl ether, a known
carcinogen to human (Infante et al., 1981). Therefore,
a safe alternative to formaldehyde in preserving the
gut content of bivalve is urgently needed.
Apart from formaldehyde, Lugol’s solution and
alcohol are commonly used preservatives for plankton
samples from water column (Mohammad-Noor et al.,
2014; Gaytan-Herrera et al., 2011; Adam et al., 2011).
However, the effectiveness of Lugol’s solution and
alcohol as a preservative in the present of enzyme in
the gut of bivalve is yet to be studied. Therefore,
current study was carried out to investigate whether
cold filtered seawater, Lugol’s solution and 70%
alcohol could be used to replace formaldehyde in
preserving stomach content of bivalve.
1 Materials and Methods
1.1 Sample collection and preservation
Twenty mussels with the shell length of 5.0±0.5 cm
were collected randomly from a green mussel farm at
Kota Marudu, Sabah, Malaysia. The mussels were