Lab Animals Flashcards
Animals frequently used for research
- Mice
- Rats
- Pig
- Rabbit
- Zebrafish
- Chicken
- Cattle/sheep
- Various wildlife
AT USASK, highest used species is chickens, then mice
Specific pathogen free (SPF) animals
- Animals bred to eliminate certain pathogens, reduce disease outbreaks, reduce zoonosis, increases research
- Bred by C-section, dam-fostering
Acclimation
- Lab animals often need a week to adjust to new environment before use. This will allow for cortisol levels to go back to normal
- Expose to routine handling and common procedures to familiarize animals. Includes Classical and operant conditioning (positive reinforcement training)
Positive reinforcement training (PRT)
- Operant conditioning
- Reduces stress on the animals for procedures
Ex. mice tunnel handling
Laboratory animal allergies (LAA)
Workers have allergic symptoms when exposed to allergenic proteins from lab animals. If allergic to one, often become allergic to others over time
- Urine, dander, saliva, bedding, feed, mold, insects
Zoonosis risk with lab animals
- Few zoonoses from SPF rodents and rabbits besides LAA and fecal bacterial exposure
- Chance of mycobacterial exposure from fish if you have open cuts or sores
Mouse/rat housing
- Ventilated vs. static caging
- Barrier facilities to prevent wild rodent disease transmission
- Workers can’t have rodents at home
- Controlled temperature, humidity, lighting
- Bedding, nesting material, environmental enrichment
Most common mouse strains
C57BI/6, Balb/c, Nude
Catching mice with tube
- Can use tube, place around edge of cage. Mice will run around edge into tube
- Pick up tube and tip mouse backwards into your hand
- Don’t chase mouse with tunnel
- Handling should be quick, don’t be hesitant
Restraint of mice
- Use scruffing; don’t hold upside down by tail
1. One-handed restraint
–> 3 finger hold. Scruff mouse but support body with other fingers while mouse is upside down on palm
2. Two-handed restraint
**Can use scruff guard
Scruffing
Don’t scruff with 2 fingers and create longitudinal fold, as this causes choking/pressure on throat INSTEAD use 3 fingers and create different angle of fold
Support body
Injections for mice and rats
- Subcutaneous- most common (anywhere in scruff)
- Intramuscular- rare (hind leg)
- Intraperitoneal- common (lower abdomen)
- Intravenous- common (tail vein)
- Intravenous- retro-orbital (stick behind eye)- not as common, need to be anesthetized first
- Oral gavage
Blood collection in mice
- Small circulating volume between 1-1.5ml
- Typically collect 10-100ul per collection
- Repeated collections need rest period to allow blood production and prevent anemia
- Taken at tail vein or artery, saphenous vein, facial vein, jugular vein, cardiac (when under anesthesia), and rarely but can be taken at retro-orbital plexus
Mouse and rat anesthesia
- Isoflurane induction box and mask
- Injection, IP, or IV with top up as needed
Reasons for anesthesia in mice
- Surgery
- Imaging
- Blood collection
- Inoculation
Exams of mice and rats
- Distance exam
- Animal condition, movement, nesting (nest score- good nest would be round structure with a roof on top; will indicate whether mouse is well or not), social interactions, fur, eyes, grimace score, feces, urine - Physical exam
- Abdominal palpation, oral cavity, eyes, anus, prepuce, vulva, skin, tail
Common conditions of mice
Barbering- another mouse picking off fur of another. Need to remove the aggressor
Ulcerative dermatitis- excessive scratching leading to damage of skin
Tail injury
Fight wounds
Congenital conditions
- Hydrocephalus- water on brain
- Eye(s) are smaller or no eyes present
Stereotypies (try to mitigate by providing better environment)
- Barbering
- Chewers
- Backflips
- circling
Poor body condition score
- Degree of hunching- more hunced when not feeling well
- Sunken abdomen
- Thin or fat
Euthanasia of rats and mice
AVMA and CCAC guidelines on euth
Common methods
- Isoflurane
- Cervical dislocation
- Decapitation
- CO2
- Exsanguination
- Anesthetic overdose
- Pentobarbital IV or IP
Rat Common research strains
- Sprague Dawley
- Wistar
- Long evans
Rat Handling/restraint
Rarely scruff
Hold by grabbing neck and shoulders, rest against your body, support hind end. If needed, flip rat onto back, hold shoulders and legs and push inwards so that the rats arms are almost crossed
Prefer full body hold, circle grip or V hold
Towel wrap for aggressive or squirmy rats
Can be acclimated to human interaction and touch very easily
- Tickling
Never lift or hold by the tail as it can cause tail sloughing
Can use tunnel/pvc pipe to transfer
Blood collection in rats
- Small circulating blood volume between 7-10ml
- Typically collect 0.5-1ml per collection
- Repeated collections may need rest period for blood production and to prevent anemia
- Taken at tail vein or artery, saphenous vein, facial vein, jugular vein, cardiac (when under anesthesia), and rarely but can be taken at retro-orbital plexus
Common conditions of rats
- Bumblefoot- common with barred cages
- Obesity
- Ringtail- constrictions in tail results in ring shape
- Porphyrin staining
- Mammary tumour
- Importance of Body condition scoring
- No mycoplasma due to SPF status
Examination of rats
Distance exam, physical exam, grimace score
Housing and husbandry for rabbits
- Floor housed or cage housed
- Individual vs. social housing
- Need environmental enrichment (companion, chew toys, floor time/exercise)
Restraint for rabbits
- Arm holds
- Towels
- Bags
- Covering eyes
Injections in rabbits
- Subcutaneous- common in scruff or back
- Intramuscular- rare (hind leg)
- Intravenous- common (ear vein, cephalic vein)
- Intraperitoneal (rarely performed)
Blood collection in rabbits
- Sites: marginal ear vein, ear artery, saphenous vein, cardiac (terminal only)
- Often collect 1-5ml per collection
Rabbit anesthesia
- Injectable or inhalant
- Isoflurane and sevoflurane common +/- sedation given prior
- Full total injectable anesthesia rare, if so then use ear vein catheter
- They tend to breath hold so need to keep mask on for quite a while
Examination for rabbits
Distant exam- Animal condition, movement, social interaction , fur, eyes, grimace score, feces, urine production
Physical exam- abdominal palpation, palpate jaw, legs, back oral cavity
Grimace score- look at ears, cheeks, whiskers, nostrils, orbital
Common conditions of rabbits
- Pasteurella
- Foot lesions
- Fight wounds
- Overgrowth of incisors and molars
- Broken back
- Anorexia- especially after transport
Environmental needs of zebrafish
- May need rocks? Plants? Objects can lead to dominance as they fight over them
- Treated water tanks, remove chloride
- Circulation of water
Zebrafish Examination
Distance exam
- Animal condition
- Movement
- Social interactions
- Scales
- Where in water column
- Breathing
- Body condition, skeletal condition
Blood collection of zebrafish
Anesthesia: MS-222, metomidate immersion in water
injections of zebrafish
- Intraperitoneal
- Exposure in tank water
Common conditions of zebrafish
- Popeye
- Mycobacteriosis
- General ill-health
Most often related to water quality
