RAMB - Novembro 2017

nimal

experimentation

: A

look

into

ethics

welfare

and

alternative

methods

ssoc

ras

2017; 63(11):923-928

925

experiments can be conducted while aiming at reducing

pain, suffering and stress inside the enclosure, thereby

promoting animal welfare and consequently increasing

reliability of research data.

Factors causing agony and distress in animals should

be eliminated or controlled so that there is no interference

in data collection and interpretation of results. The need

for more animals, reduced reliability, increased variabil-

ity in results and unnecessary use of lives all stem from

impaired welfare.

Animals should be kept in a safe and appropriate place

in order to reduce experiment data variation arising from

the environment. It is essential to keep variables such as tem-

perature, humidity and airflow at levels that are appropri-

ate for each species, since abrupt variations can cause stress,

decreased resistance and greater susceptibility to infections.

6,13

The space allocated to animals must permit free move-

ment, sleep and contact with other animals of the same

species.

Rats and mice are very sociable animals and,

therefore, should be housed in groups so that they can

develop normal behavior. Laboratory cages are usually

not suitable for the animals’ behavioral needs. Hence,

environmental enrichment is an important feature for

them to express their natural behavior, which will affect

their physiology and defense mechanisms.

The enrichment features should satisfy their curiosity,

provide them with fun activities, and allow for the fulfill-

ment of their physiological and behavioral needs, such

as building nests, exploring, gnawing and hiding. The use

of igloos, cardboard/PVC tubes, cotton, paper towel, paper

strips and disposable masks favors this objective.

When a new animal is placed into the experiment’s

settings, they should go through a period of acclimatiza-

tion (quarantine), as abrupt changes in their living con-

ditions can elicit a pressure response, which, albeit tem-

porary, can lead to distress.

The environment to be used for animal housing must

be constantly controlled by hygiene, disinfection, sanita-

tion and sterilization processes. Several infectious agents

found in vivaria, such as

Sendai

virus,

Mycoplasma pulmonis

and cestoda, are currently becoming increasingly rarer.

However, the mouse hepatitis virus still remains a threat.

uthanasia

The term euthanasia is derived from Greek and means

death without suffering. The Arouca Law (Article 14,

Chapter IV, Paragraphs 1 and 2) states that an animal

shall be subjected to euthanasia, in strict obedience to

the requirements pertaining to each species, whenever

the experiment is terminated or at any of its phases, where

such a procedure is recommended, as well as whenever

severe suffering occurs. If the animal should not be sub-

mitted to euthanasia, it may exceptionally leave the vivar-

ium after intervention and be assigned to suitable persons

or animal protection entities, duly legalized.

Such a procedure is also indicated where the animal’s

welfare is irreversibly impaired and neither pain nor suf-

fering can be controlled with analgesics or sedatives, or

in those cases where the animal constitutes a threat to

public health and a risk to the native fauna or to the

environment.

4,13,15

Euthanasia techniques should result in a rapid loss

of consciousness followed by cardiac or respiratory arrest

and definite impairment of brain function. It is important

to handle the animal calmly and out of its enclosure, seek-

ing to reduce distress, fear and anxiety.

Prior to choosing the most appropriate method, one

must take into consideration the animal species involved,

the animal’s age and physiological status, as well as the

safety of the person euthanizing the animal. Every research

project should contain the description of appropriate

endpoints for the animal species and the procedures that

will be used.

13,15

There are both chemical and physical methods. The

chemical methods available include injectable agents (bar-

biturates, propofol, potassium chloride); inhalable agents

(carbon dioxide, nitrogen, argon); and anesthetics (halo-

thane, isoflurane and sevoflurane). Physical ones comprise:

compressed air gun (non-penetrating) and captive dart

(penetrating); fire gun; decapitation; exsanguination; elec-

trocution; maceration and cervical dislocation.

The physical methods may be classified as either re-

stricted or unacceptable. Therefore, it is important to

search for the appropriate method for the species being

used. After completion of the procedure, death should

be confirmed before the animals’ bodies are discarded.

13-15

lternative methods

The authorized use of animals in teaching activities raises

very controversial issues, especially considering that it often

involves invasive procedures. This is quite questionable in

veterinary educational programs, where its ethical justifi-

cation is to foster the progress of medical knowledge.

Continuing medical education is increasingly chang-

ing, and the search for alternative methods in surgical

training has been increasing, so as to avoid the overuse

of animals, thereby reinforcing ethical principles and

animal rights. Accordingly, educational institutions seek

ways to teach surgical practice without compromising

the quality of teaching.