Discussion
From
our experiments we can conclude that doses of nicotine
between 0.25 mg and 1.0 mg have adverse effects on chick
embryo development. All chick embryos treated with 1.0 mg of
nicotine were dead within 3 days. This outcome is in
accordance with Gilani's observations that exposure to 1.0
mg of nicotine results in high instances of embryonic
death.
When
the treatment concentration of nicotine was decreased to 0.5
mg and 0.25 mg we still observed high instances of death. It
is known that high amounts of nicotine reduces essential
nutrients and oxygen supply to fetal tissues (Lambers and
Clark 1996). This suggests that any dose of nicotine over
0.25 mg fatally interferes with embryonic development.
Although, the treatment population was severely reduced due
to casualties, two eggs survived until day 13 of
development. Egg #8 exhibited significant underdevelopment
compared to the controls. This can be attributed to the fact
that nicotine inhibits the absorption of calcium, vitamin C,
and essential minerals (Nash and Persaud 1989). Staining
with Alcian green confirms this as large amounts of
cartilage was observed in egg #8, whereas the control limbs
exhibited evidence of further bone development.
Nicotine
also has an affect on the circulatory system. Nicotine is a
known stimulant that can lead to an increase in heart rate
as our evidence suggests. It is also known to narrow the
diameter of the blood vessels, thus slowing down the blood
flow. Nicotine also increases the tendency of the blood to
clot (Lambers and Clark 1996). The red skin color of egg #9
could be a result of these factors. We
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