The Effects Of Tetracycline On Chick Embryos Essay, Research Paper
THE EFFECTS OF TETRACYCLINE
ON GALLUS DOMESTICUS
TRIMESTER 3
Professor J. P. Ellis
T.A. Tom Pinard
Bryan Dumanski
Mike Hale
Dean Tower
Heather Mammon
Joe Hull
July 15, 1996
Abstract
Our Embryology lab experiment was performed to observe the effects of tetracycline on
the development in chicken embryos, such as bone and beak growth. Five control and
seven experimental eggs were used for the experiment. The five control eggs were not
injected with tetracycline, six of the experimental eggs were injected with 0.05 mg of
tetracycline, and one of the experimental eggs was injected with 0.2 mg of tetracycline.
On the seventeenth day of embryo development, all eggs were opened and observed.
Good conclusive results were noted. Out of the seven injected eggs, all had some sort
of abnormality. Conversely the control group eggs appeared normal.
Table of Contents
I. Introduction
II. Methodology
III. Results and Observations
IV. Discussion and Conclusion
V. Bibliography
I. Introduction and Review
Tetracycline, an antibacterial drug, is used to treat many infectious diseases such as
gonorrhea, syphilis, sinusitis, upper respiratory infections.
The usual adult dosage ranges from 100mg to 200mg once a day. Possible allergic
reactions include: 1) swelling of the face, 2) skin rash, 3) loss of appetite with vomiting,
4) soar throat, and 5) abdominal cramping. There are more serious side effects , such
as anaphylactic reactions, liver and renal damage, discoloration of teeth with
malformation in children under 8 years of age.
Results of animal studies shows that tetracycline class drugs cross the placenta and
are found in fetal tissues. This has toxic effects on developing fetuses. These effects
include retardation of skeletal development, decreased white cells, and increased
eosionophils. Due to the findings, it is advisable to completely avoid tetracycline class
drugs during pregnancy and breast feeding.
Tetracycline drugs are used specifically in chick embryos autoradiographic studies.
The chick’s bones have the ability to fluoresce tetracycline at the active sites of
calcification.
Tetracyclines have effected not only chick embryos, but also weight and bone formation
in the offspring of rats and mice. It causes reduction in fetal size with serious physical
defects.
II. Methodology
The effect of tetracycline infections were demonstrated on twelve New Hampshire Red
Chicken eggs. The control group included five eggs numbered eight through twelve
and were not injected. The injections were given on June 12, 1996 to seven eggs
numbers one through seven. Eggs one though six received 0.05mg of tetracycline and
egg seven was given an increased amount of 0.2mg tetracycline. All of the eggs were
incubated at an ideal temperature of 101 degrees, sixty to eighty percent humidity in
the incubator (model no. 624-E) for seventeen days. The eggs were turned twice daily
before being sacrificed on the seventeenth day June 28, 1996.
III. Results and Observations
Experimental Group Amount of
Tetracycline injected Eggs Number Embryo Weight
No fertilization, pseudo white
masses, no development
0.05mg
1
N/A
Twice as large as control
group, no malformations
0.05mg
2
23.8g
Twice as large as control
group, slightly malformed feet
0.05mg
3
22.5g
Twice as large as control
group, no malformations
0.05mg
4
22.0g
Twice as large as control
group, no malformations
0.05mg
5
22.5g
Twice as large as control
group, no malformations
0.05mg
6
20.95g
Twice as small as control
group, not fully developed,
internal organs exposed,
malformed legs, dead
0.2mg
7
16.9g
III. Results and Observations (con’t)
Control Group Amount of
Tetracycline injected Eggs Number Embryo Weight
Normal development, medium
size
N/A
8
18.6g
Normal development, medium
size
N/A 9 18.8g
Not fertilized; pseudo white
masses present
N/A 10 N/A
Normal development, medium
size
N/A 11 19.3g
Not fertilized;pseudo white
masses present
N/A 12 N/A
IV. Discussion and Conclusion
The results of the experiment were compared and found to be conclusive.
Distinguishing characteristics were noted between the control group and the
experimental group which included size of embryo, overall weight, feather growth, and
bone development. Internal development was not observed in this experiment.
Weights of embryos two through six injected with 0.05mg of tetracycline were: 23.8g,
22.5g, 22.0g, 22.5g, and 20.95g, respectively. These embryos appeared to be
abnormally larger than the control group embryos. Embryo number three also had
external defects; malformed legs. We also noted that all of these embryos had more
feather growth than the control group.
Embryos number seven, injected with 0.2mg of tetracycline showed the most dramatic
results. This embryo was smaller and weighed significantly less than the other
experimental embryos (16.9g). In addition, the external organs were exposed, there
was no feather growth and the embryo died during the experimental period.
Our experiment found that three embryos did not fertilize (embryos 1, 10, and 12) and
were not part of the conclusions.
In conclusion, our experimental findings showed that tetracycline is inhibitive to normal
embryo growth as found in embryos two through six. Further, higher dosages of
tetracycline are detrimental to embryonic growth as noted in embryos seven.
If future testing is done, more embryos should be injected at the higher 0.2mg dosage
to validate the findings from embryo seven and an internal study of embryos two
through six (with 0.05mg tetracycline) should be conducted to determine possible
contributing factors to the abnormally large growth of these embryos.
.
V. Bibliography
Beckman, D., Brent, R., Mechanisms of Teratogenesis, Ann Rev. Pharmacol Toxicol,
No. 24, p. 483-500. (1984)
Greene, G.: Tetracycline in Pregnancy, New England Journal of Medicine, Vol. 295,
No. 9, (1976)
Halme, Jouko, Aer, J: Effect of Tetracycline on Synthesis of Collagen and Incorporation
of Calcium into Bone in Foetal and Pregnant Rats, Biochemical Pharmacology,
Vol. 17, p. 1479-1484.
Hoolingsworth, M.: Drugs and Pregnancy, Clinic in Obstetrics and Gynecology, Vol. 4,
No. 2, p. 503-520 (1977)
Long, J., Rybacki, Doxycycline, The Essential Guide to Prescription Drugs, p. 461-464,
(1994).
Saivin, S., Houin, G., Clinical Pharmacokinetics of Doxycycline and Minocycline,
Clinical Pharmacokinetics, No. 15, p. 355-366 (1988)