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International Journal of Aquaculture, 2014, Vol.4, No.13 79
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In the second set of the research work carried out,
progesterone levels of zinc supplemented rabbits
increased significantly from 0.03 ±0.02 to 6.80 ±0.70
(Table 2).
Table 2 Serum progesterone levels of rabbit fed contaminated
fish & zinc supplemented diet
GROUPS
PROGESTERONE (ng/ml)
A–fed with fish diet and rabbit
pellets
0.03 ±0.02
a
B-fed with fish diet, rabbit
pellets & zinc supplements
6. 80 ±0.70
a
Control- fed with rabbit pellets
alone
6.00 ±0.50
Note: Value rep. mean ±S.E.M. (n=5);
a
P< 0.05 ANOVA
3 Discussion
This study confirms the fact that heavy metals
together with other environment pollutants are
endocrine disruptors since they interfere with the level
of progesterone, lutenizing hormone and follicle
stimulating hormone. As the level of environment
pollutant increases, the levels of progesterone & FSH
decreases greatly while the levels of FSH and LH is
being altered. This may lead to early menopausal
period and infertility in females (Lafuente &
Esquifino, 1998).
Marie et al. (2001) investigated the effect of Lead on
the system in lead smelter workers. Median level of
lead in plasma ranged from 0.04-3.7µ/dl in the active
lead workers. FSH levels were lower in the lead
workers than in the control group indicating an effect
of lead at pituitary level. Moderate exposure to lead
was associated with minor changes in the male
endocrine function particularly affecting the
hypothalamic – pituitary axis (Lafuente & Esquifino,
1998; Lafuente et al., 2005). This study is in
agreement with the present study which found low
levels of FSH in the rabbits being studied. Lafuente &
Esquifino (1998) found out that cadmium modify
amine metabolism at the CNS & pituitary hormone
secretions.
This xenobiotic (cadmium) is associated with
deleterious effect on the gonal function and with
changes in the secretory pattern of other pituitary
hormones like prolactin, ACTH & TSH. Lafuente et al.
(2004) analyzed the effect of cadmium on plasma
level of LH, FSH in rats. They reported that the metal
exposure abolished daily pattern of plasma LH levels.
In 2005, they studied the effect of cadmium on
prolactin secretion in rats and observed that the
cadmium exposed animals exhibited variations in
plasma prolactin levels. These finding are inline with
this present study which found altered level in LH &
prolactin levels in the experimental animals studied.
Some of the most dangerous emerging disease facing
the society today are directly related to exposures to
deadly environmental towns. Exposure to heavy metal
toxins such as lead is linked with a 46% increases in
the mortality rate according to the Centre for Disease
Control in Atlanta, USA.
From the study, it was observed that rabbits fed with
zinc supplements had an increase in serum
progesterone level when compared with the control
and the group which had no supplement in their diet.
Zinc supplement do reverse heavy metal effects in the
rabbits as seen from this study. It also increases the
production of progesterone thereby enhancing
ovulation in female rabbits. With zinc supplement,
adverse effects from the consumption of heavy metal
contaminated fish can actually be managed. This also
suggests the fact that zinc supplement may enhance
ovulation as evident from the increase in progesterone
levels.
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