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International Journal of Aquaculture, 2014, Vol.4, No.14, 85
-
88
http://ija.biopublisher.ca
85
A letter Open Access
Endocrine Disruption by the Consumption of Fish (
Tilapia oreochromis
) from
Heavy Metals Polluted River Sites and its Reversal Using Zinc
Bolawa O.E. , Gbenle G.O., Ebuehi O.A.T.
Department of Biochemistry, College of Medicine, University of Lagos, Lagos Nigeria
Corresponding author Email
International Journal of Aquaculture, 2014, Vol.4, No.14 doi: 10.5376/ija.2014.04.0014
Received: 17 Feb., 2014
Accepted: 18 Mar., 2014
Published: 02 May, 2014
Copyright © 2014
Bolawa et al., 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
:
Bolawa et al., 2014, Endocrine Disruption by the Consumption of Fish (
Tilapia oreochromis
) from Heavy Metals Polluted River Sites and its Reversal Using
Zinc, International Journal of Aquaculture, Vol.4, No.14: 85-88 (doi: 10.5376/ija.2014.04.0014)
Abstract
Background:
Metals can disrupt hormonal functioning by binding to the receptor site and this can lead to various hormonal changes.
Objectives:
This research paper present the changes in hormonal levels due to the consumption of Tilapia fish (
Oreochromis
niloticus
) gotten from heavy metals polluted riverine sources and its reversal using Zinc.
Methods:
Twenty –one rabbits of mean weight 6.30kg + 0.5 were randomly grouped. The first group consists of seven rabbits fed
with 100g of fish from Carter Bridge riverine site together with rabbits pellets. The 2
nd
group was fed with 100g of fish from Makoko
Riverine site together with rabbits pellets while the third group which is the control group was fed with just rabbits pellets. The
duration of the experience was three months. The level of hormones (progesterone, lutenizing hormone (LH), follicle stimulating
hormone (FSH), prolactin) were investigated using the blood samples. A similar experiment was conducted on another set of twenty-
one rabbits grouped and fed in the same way as the previous set but this time the second group consists of rabbits fed 100g of fish
from Carter bridge site together with rabbits pellets and 0.133g (extrapolated from their weights) of zinc. Also the levels of hormones
were investigated.
Results:
Progesterone levels significantly decreased from 1.60 ± 0.05 to 0.03±0.01ng/ml while FSH level also decreased from
1.60±0.01 to 1.10±0.05 IU/ml. The ratio of FSH to LH was greatly altered. Prolactin levels increased significantly from 1.10±0.02 to
1.80±0.03 ng/ml. The progesterone levels of zinc supplemented rabbits shoots up from 0.03±0.02 to 6.80±0.70 ng/ml.
Conclusion:
Data of this study suggest that ingestion of fishes from heavily polluted sites by animals is capable of inducing low
progesterone levels and prolactinaemia which can lead to infertility. Also the ingestion of a daily supplement in form of zinc can
reverse this change.
Keywords
Progesterone; Prolactin; LH; FSH;
Tilapia oreochromis
; Cater bridge site; Makoko riverine site
Introduction
Endocrine disruptors are substances that interfere
with the synthesis, secretion, transport, binding or
elimination of natural hormones in the body that are
responsible for the maintenance of homeostasis,
reproduction, development and or behavior. Many
endocrine disruptors are thought to mimic hormones.
They have chemical properties similar to hormones
that allows binding to hormone specific receptors on
the cells of target organs. Endocrine disruptors include
pesticides, dioxins, polychlorinated biphenyls (PCBS),
heavy metals, phenols etc (EPA, 1998).
Health effects attributed to endocrine disrupting
compounds include a range of reproductive problems
(reduced fertility, reproductive tract abnormalities),
changes in hormone levels, early puberty, brain and
behavior problems, impaired immune functions and
various cancers (Crisp et al., 1998; Krimsky, 2001).
Hormones travel throughout the body and act as
chemical messengers. They interface with cells that
contain matching receptors in or on their surfaces. The
hormones bind with the receptor. The endocrine
system regulates adjustments through slower internal
processes, using hormones as messengers. The endocrine
system secretes hormones in response to environmental
stimuli and to orchestrate development and reproductive
changes. The adjustments brought on by the endocrine
system are biochemical, changing the cell chemistry to
bring about a long term change in the body. These
systems work together to maintain the proper
functioning of the body through its entire life cycle.
Hormones work at very small doses (Krimsky, 2001).