Classification of laboratory animals
The lab animals are categorized based on level of
sentience, shelter and the research procedure approving consultant as:
1. Small
laboratory animals
2. Large
laboratory animals
1. Small
Laboratory Animals
The animals that can be kept in cages are named small
laboratory animals.
For example, Rat, Mouse, Rabbit and guinea pig
A rat is an average-sized to large rodent, with a pointy
nose, long slim and hairless tail, and nimble forepaws. Mice are relatively small
in size & their weight is around 20-35 gm. Mice have huge ears and long
tails compared to the body. The Institutional Animal Ethics Committee (IAEC) consents
to the research procedure to use small animals in research.
2. Large
Laboratory Animals
The animals that cannot be kept in cages are classified
as large laboratory animals.
For example, Dogs and Monkeys.
They can only be kept in open run places. The procedures
used in research that comprise these animals are sanctioned by CPCSEA, while the
IAEC is only an endorsing authority.
Laboratory animals can also be categorised as:
·
Rodents include rats, mice, gerbils,
hamsters, guinea pigs etc.
·
Non-rodents i.e. lagomorphs, non-human
primates, cats, dogs, sheep, goats, cattle, poultry, birds, fishes, amphibians
etc.
Laboratory
Animals vs. Sentience
The
laboratory animals can be categorised based on their level of emotion. An emotional
being has some capability to:
·
Estimate the activities of others concerning
themselves and third parties.
·
Reminisce some of its activities and their
values.
·
Evaluate risks and remunerations.
·
Have some emotional state.
·
Have some extent of consciousness.
The
level of emotion upsurges from invertebrates to birds, rodents, canines, felines,
to bovines/equines to primates.
Also read:- History of the usage of laboratory animals in India
Important Laboratory Animals
1. Zebra
Fish
There are typical zebra strips consecutively along the body and the fins, hence the name. The lifetime of zebrafish is around 2-3 years. It is inferior in size (up to 6.4 cm) and hence culturing is comfortable. Zebrafish are matured from a fertilized egg to an adult outside the female in an obvious egg. This makes it achievable to see transformations in emerging embryos.
Research use of Zebrafish
·
Gene expression prototypes and gene
functions can be studied by using zebrafish embryos. Their embryos are apparent
and we can see vigorous gene expression in numerous tissues and organs in vivo deprived
of killing.
·
Used for exploring the growth of organs
like heart, muscle, ocular etc. and nerve development.
·
Used as a favourable animal model for
human ailments like cardiac diseases, cancer and behavioural experiments.
·
Used as a biosensor for ecological toxicants.
2. Mouse
A mouse is a very broadly used lab animal with greater
than 85% of the total biomedical research is accompanied using a mouse. There
are higher than 400 genetically well-defined inbred strains and many transgenic
strains. Conversely, the most regularly used stain is albino with a white coat shade
and pink eyes.
The existence of typical characteristics amongst inbred
stains makes them appropriate as lab animals. The mouse is a common animal; consequently,
it is housed in a small group of its types. Mice are night-time, investigating and
climbing animals.
They spot their zones with urine. The normal lifecycle of the mouse is 1.5-2.5 years. Female mice have a conception period of 19-21 days giving the average litter size fluctuating from 6-to 12 in number. Mouse-like nesting so offering good nesting material is a good option to forward the welfare issues.
Research use of mouse
Both inbred and out-bred strains are used extensively in
biomedical research because of their short pregnancy period, large litter size,
great genetic variety and being inherently closer to humans.
Mostly used in the study for immunological drug assessment,
genotoxicity, infectious diseases like malaria, CNS (Central Nervous System) complaints,
anti-prothrombin study, antiviral experiment, anxiety, TB testing, Alzheimer’s disease,
atherosclerosis, metabolic disorders (diabetes, obesity) etc.
3. Rat
The research laboratory rats are obedient social
animals and are most usually used next to the mouse in a research laboratory.
They are most pleased if preserved in groups to gather the safety needs of the establishment
of the animal’s kind. They have enormously developed sense organs and can feel personal
contact (touch), voice, smell and are accessible. They like excavating, piling,
repeating, raring, worrying, scavenging etc. in the cage. Like the mice, they
are also night-time animals and spot their regions with urine. They have an average
lifetime of 2-3 years. Female rats undertake 21-23 days of gestation phase giving
average litter size fluctuating from 8-10 in number.
The rat is desired for experimentation as of the subsequent
benefits:
·
Small size compared to other animals so
drugs are obligatory in small quantities.
·
The vomiting centre is deficient and so
drugs can be administered orally.
·
Due to the lack of gall bladder in rats,
there is an unceasing flow of bile into the intestine. This expedites the study
of drugs proceeding on bile, cholesterol re-absorption etc.
·
The pancreas is dispersed, therefore, challenging
to conduct a pancreatectomy.
·
In the stomach, fundus and pyloric parts
have distinct linings and the gastric acid unremitting is continuous.
Research Use
Rat is commonly utilised for
regulatory toxicology and pharmacological experiments, osteoporosis, infertility,
hypertension, congestive heart failure (CHF), teratology, nephropathy, cancer
and ageing, autoimmune diseases, diabetes etc.
4. Guinea
Pig
The guinea pig is an obedient, short communal animal that lives together harmoniously throughout life. They improve inflexible habits and displeasure changes i.e. any change in food or water may cause them to discontinue eating. Guinea pigs are extremely sensitive to tuberculosis and penicillin. It needs exogenous ascorbic acid in food. Guinea pigs do not make nests but like to stay in the nest made by others. They have a usual lifetime of 3-5 years. Female complements have a maturation phase of 68 days delivering an average litter size of 3-4 pups.
Research Use
·
Guinea pigs are mainly used in experiments
comprising immunology, infectious diseases, audiology, nutritional and
toxicological studies electrophysiology, antihistaminic activity, and TB
research.
·
They are a well-recognised model for
anaphylaxis (allergic reaction).
·
Also used in the bioassay of digitalis, assessment
of local anaesthetics, the study of histamine and antihistamines, hearing
experiments due to sensitive cochlea and studies on inaccessible tissues
especially, ileum, tracheal chain, vas-deferens etc.
5. Hamster
Hamsters are mice comparable to rodents and they are the third most extensively used study model next to mice and rats. The body is courageous and dense with small furry ears; it is small with a very small tail; has sturdy legs, wide feet with a thick-set body, and protuberant cheek pockets to carriage food and nesting materials. The average lifetime is 2-3 years. The conception phase and average litter size are 16-21 days and 4-7 pups, individually. They show special conduct of hibernation (long physiological insightful sleep).
Research Use
·
Hamster is typically used in
biotransformation analyses as it is vulnerable to Leishmaniosis infection and
metabolic ailments like diabetes mellitus.
·
Research allied to immunology,
implantation studies, cancer toxicology studies, virology and bioassay of
prostaglandin.
·
They are also used to research the influence
of hypothermia.
6. Rabbit
Rabbits are compliant and nervous animals with large ears. The enzyme, atropine esterase is present in rabbit liver and plasma, so it can endure a large dosage of belladonna (atropine). Rabbit urine is generally thick and hazy, with crystalline material. Coprophagy is the species-specific conduct of rabbits that consume their faeces. The normal lifecycle of rabbits is around 4-6 years with a maturation period of 31 days and a typical litter size of 6-8 in number.
Research Use
·
Rabbits are very beneficial models in many
biomedical research zones viz., embryology, toxicology, virology, etc.
·
They are extensively used in toxicity research
and safety analysis (pyrogen, teratogenicity etc.).
·
They are habitually used in serology to make
sera/antibodies in response to a wide selection of antigenic stimuli.
·
They are also utilised in skin and eye
irritation experiments and also studies associated with reproduction
(anti-fertility agents) and local anaesthetics.
Also read:- History of the usage of laboratory animals in India
Dogs
Beagle dogs are the most regularly used in biomedical investigation. The developed, out-bred barrel-chested crossbreeds or wolfhounds are also used as study animals in definite cardiovascular and skeletal research. Dogs are forever directed by their noses across their life, and they are not ever gladder than when monitoring a stimulating scent. Most of the dog strains are happy and fun-loving, but the wolfhounds may be unbending and need patient and original training procedures. Beagle was formerly bred as a scent hound to track small game, typically rabbits and hares.
Research Use
·
Dogs are generally used as a second
(non-rodent) order in toxicity testing.
·
Due to their different genetic, biological
and social features, they are used as models for behaviour analysis and genetic
research.
·
Dogs, like purpose-bred beagles, are exhausted
in cardiovascular experiments, heart and lung research, dental investigation,
genetic studies, age-related research, renal function examinations, pulmonary
studies and also for the improvement of prosthetic devices for hip and knee substitutions.
·
They are utilised to study the plasma
elimination kinetics and assessment of toxicity of drugs.
Non-Human Primates
Non-human primate factions are Prosimians (including lemurs, lorises, galagos and tarsiers) and Simians (monkeys and apes). Monkeys and apes are cardinals that fit the maximum order of mammals. The anatomy of monkey and apes are comparable to that of the human being. The experiments done on monkeys may be honestly transmitted to human beings. Deliberating the welfare aspects, tests in the primates should be done individually in the last stage of the assessment of drugs before clinical trials.
Research Use
·
Physical, physiological and psychological likeness
to humans prepares the non-human primates' most appropriate pre-clinical test
model before advancing to clinical trials in human beings.
·
Non-human primates are usually used in
research on emerging vaccines, infectious, cardiovascular and neurological
diseases, ageing, reproductive biology, gene analysis, drug addiction,
xeno-transplantation (relocation of tissues from one species to the other),
toxicity analysis and study on AIDS.
·
The two most usual primate species used in
studies are the Rhesus and Cynomolgus monkeys also recognised as crab-eating
macaques.
·
Among the Great Apes, the chimpanzees are
the solitary species expended in some specific biomedical investigation systems.
Also read:- History of the usage of laboratory animals in India
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