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)