Rats (and mice) are often the animals of choice to try and model human conditions, treatment and body functions - even though we know that using animals to try and model people fails over 90% of the time.
Mice and rats are commonly used due to their small size, low maintenance (i.e., they are easy to house and care for), short life cycle, and ability to breed quickly (allowing large numbers to be generated for studies).
They also share many of our genes.1 However, that's not surprising. Even cats share many of our genes.2
Rats are used is some of the most gruesome experiments that involve things like force-feeding, poisoning, oxygen deprivation and invasive surgery.
Rats in NZ have been used for:
- Drug research, including safety and efficiency testing.
- Teaching purposes in schools, mainly dissections.
- Investigating ways of killing wild rats. (i.e., research into effective poisons and traps).
- Medical research, including research into the development of severe diseases (i.e., stroke, diabetes, cancer), modelling neurological disorders (i.e., Schizophrenia, Autism), modelling mood disorders (i.e., example, anxiety, and depression) and research into tinnitus.
- Drug addiction research including research into the development and suppression of addictions and the impacts of drug use.
- Basic biological research, including research into digestion, aging, nerve damage, obesity and how the brain functions.
Places that use rats for science in NZ include crown research institutes, private companies and universities. In fact, most universities have their own breeding colonies. Otago University states on its website that they have a dedicated rat testing room in the Behavioural Phenotyping Unit.3
Rats used for science in NZ are sourced from breeding units, public or commercial sources, the wild (captured) and they are imported from overseas.
Discover real-life examples of how rats have been used in NZ below!
Collecting faeces for lab tests
Colony cats were fed different diets for three weeks before their faeces was collected for analyses.
Measuring thickness of blood vessel walls
Colony cats were anaesthetised, and the blood vessels under their tongue were measured with a special hand-held camera.
Assessing stress reaction to anaesthesia in cats
Cats were put through several anaesthetic infusions with six-day breaks in between. Regular saliva samples were taken 24 hours before and after, and urine was collected through a wire mesh tray.
Testing new toxin in Hawke’s Bay (again)
Toxic bait traps were placed on a property in Hawke’s Bay. Cat population changes were monitored with stationary cameras.
Surveying caregivers on their cat feeding
New Zealand cat caregivers filled in an online survey about their household demographics and what/how they feed their cats.
Testing food preferences of cats
Cats were fasted for two hours in the mornings and then presented with different foods (lamb and beef parts) to measure their consumption.
Sampling cats for feline immunodeficiency virus (FIV)
Buccal swabs (inside the cheek) were collected from almost 200 cats at 15 veterinary clinics.
Testing a cat food supplement for tooth health
Colony cats were anaesthetised, and all plaque was removed from their teeth. Four weeks later, new plaque build-up was measured.
Investigating how worms spread between lambs and calves
Lambs and calves were infected with worm eggs to see if parasites from cattle can infect sheep.
Testing pain meds for disbudding
The horn buds of young calves who were slightly sedated were burned off with a hot iron. Half of them received pain meds beforehand, and blood samples were taken before and after. After 24 hours, the second group received pain meds, too.
Comparing weight gain with different diets
Newborn calves were raised on various milk, pasture, and pellets combinations. They were slaughtered at two years old, and their “quality” was measured.
Checking endometritis rates in dairy herds
Some cows in several dairy herds were selected, and their vaginal discharge was measured and sampled. They were then impregnated as per standard agricultural practice.
Testing a supplement for more calcium intake
Pregnant cows were fed with or without a specific feed additive. After birth, all were fed the same diet. Blood samples were taken in the weeks around birth.
Testing a fertility treatment
Cows with fertility problems were treated with hormones for ten days or left untreated. All were then artificially inseminated.
Studying diarrhea infection
New mother cows had blood samples taken. If the sample was negative for a diarrhoea virus, they were sampled again after a while.
Studying Ikeda infection and treatment
Regular blood samples were taken from cows on three different farms. Only some were treated against the parasite. Milk production and fertility were recorded.
Testing a parasite treatment
After a pilot study with just one dog, six more were given an experimental parasitic treatment. Regular blood samples were taken through a catheter.
Testing the effect of diet on farm dog performance
Working dogs were fed a diet very high or very low in carbohydrates. Their blood glucose and activity were monitored three times over four days each.
Analysing dog movements
Colony dogs were prepared with reflective markers and an activity collar. Their movements on a treadmill at various speeds were recorded.
Testing the eyes of working dogs
Eye examinations were performed on working sheep dogs. Medication for pupil dilation was given, and faeces samples were taken from most dogs.
Transplanting faeces as diarrhoea treatment
A dog with diarrhoea was treated with laxatives and warm water before a faeces sample from a healthy dog was inserted into his colon. Samples were taken before and after.
Investigating farm dogs for four years
Working farms dogs were examined regularly for four years. Health problems and fate were recorded.
Using bones of euthanised shelter dogs
Cadavers of dogs killed at an animal shelter were donated. Holes were drilled into leg bones and fitted with screws.
Analysing Greyhound race injury statistics
Historical data on Greyhound races between 2014 and 2019 were analysed. Injuries and deaths were investigated.
Finding a “growth gene” in snappers
Snappers were caught from the wild and bred. Around eighty-thousand of their offspring were hatched and raised. At regular “grading” events, injured and deformed fish were disposed of. At just under a year old, around twenty-two-thousand were left and transported to a sea pen, where they were raised to 17.5 months old before harvesting.
Infecting fish larvae as a potential model for humans
Zebrafish larvae were injected with bacteria to test how their immune system responds. This was repeated to test how well the immune system reacted and how long the effect lasts.
Studying the sleep of sharks
Sharks were caught and kept in outside tanks. For the experiments, they weren't fed for at least 4 days, of which they spent 3 days in a measuring chamber not much bigger than the shark. Oxygen consumption and behaviour were continuously recorded for the last 24 hours.
Studying gut bacteria in fish
Nine fish were caught by underwater spearing and killed so that samples could be collected from their digestion tracts.
Overfeeding Zebrafish to learn about obesity
Normal and transgenic zebrafish were fed normally or way too much. The fish were taken out of the water for glucose tests and blood samples.
Using fish to study the impacts of Climate Change
Fish were either bought or caught and killed so that they could be dissected.
Testing how much fat you can feed fish
Fish in aquaculture were divided into groups and fed diets with different fat content. Fish were anaesthetised and faeces samples squeezed out of them.
Testing nerve reactions to electric stimulation
Young guinea pigs were bled to death. Specific nerves were removed and experimented on.
Questioning vets on pain management
Veterinarians completed a questionnaire regarding pain and pain management in rabbits and guinea pigs.
Studying short-sightedness
Guinea pigs had one eye covered for two weeks before increasing their eye pressure surgically and kill them.
Measuring nerve reactions to gases
Guinea pigs were anaesthetised, and their windpipe and blood vessels were cannulated. They were exposed to different gases and cyanide while measuring breathing and nerve activity.
Studying how anaesthesia affects breathing and heart
Guinea pigs were put in airtight chambers to test the effects of low oxygen. Some were surgically fitted with tubing so blood samples could be taken during the tests. In the end, all were killed.
Testing how heart calcium metabolism is different in species
Guinea pigs and rats were decapitated, and their hearts were quickly removed to study them.
Testing a new tuberculosis vaccine
A new tuberculosis vaccine was tested by injecting guinea pigs with the bacteria, either with or without prior vaccination. After several weeks, all were killed.
Harvesting testicles for studies
Male guinea pigs were killed with CO2 to remove their testicles for experiments.
Studying hormone influences on obesity and fertility
Transgenic mice were bred to have diabetes symptoms. Together with control mice, they were fed a normal or a high caloric diet and compared for their fertility over 150 days.
Researching scoliosis genes
Transgenic mice with a specific gene defect were mated. Pregnant mice were at several time points. The unborn babies were taken, skinned, and gutted to stain their skeletons for better pictures.
Testing motherly instinct towards foster pups
Mice of different “status” (never pregnant, pregnant, new mums) were made to rescue foster pups they didn’t know from several places. Transgenic mice lacking a prolactin brain receptor were tested for anxiety behaviour in the standard elevated-plus-maze.
Testing how hormones influence activity while pregnant
Transgenic and “normal” mice were used to test the influence of pregnancy and hormones on activity and anxiety. They were kept in single cages with running wheels and subjected to behavioural tests. The transgenic mice were killed in the end.
Observing cancer growth with/without treatment
Mice were injected with human breast cancer cells. The growth was monitored and sampled (biopsy). Some were operated on to remove their ovaries and some were treated with drugs before all were killed.
Testing a seizure treatment
Genetically modified mice had wires and a cannula implanted in their brains, and were injected to cause seizures. The next day, their genetic mutation was activated. The test was repeated before they were all killed.
Testing seizure activity in transgenic mice
Mice with specific genetic limitations were bred. Some were killed for dissection, and others were injected with a gene activation drug before they were killed.
Studying movement processing in the brain
Transgenic mice were put through behavioural tests while half of them had a part of their brain-damaged. Some mice had a window put into their skull to take recordings of their brains while awake. They had limited access to water and were forced into a device that stopped them from moving their head. In the end, all were killed.
Studying starch digestion in pigs to try and model humans
Pigs were fed different diets containing durum wheat or rice. Some had regular blood samples taken through a catheter. All the animals were killed at the end.
Testing if pigs can be fed by-products from biofuel and food processing
Pigs were fed a standard diet or a diet containing by-products from other industries. They were slaughtered to compare meat growth and quality.
Harvesting colon tissue for laboratory tests
Pigs were killed and their colon tissue was used for laboratory testing.
Investigating intestine movements
Young pigs and NZ White rabbits were anaesthetised. A part of their intestine was pulled out far enough to record its movements and signalling.
Testing the strain on a temporary surgical implant
A surgical implant was screwed to a severed pig head, and measurements were taken via laser scanning.
Testing the effect of different species’ milk on protein digestion
Piglets were fed different kinds of milk from other species for 15 days. They were killed to dissect their stomachs.
Testing a UV treatment for bacterial eye infection
Pigs’ eyes were acquired for testing a new treatment, followed by tests on live mice, most of whom were killed.
Investigating oxygen content in the gut
Pigs were fed diets with different or no protein sources as a control. After a week, all were killed.
Studying the effects of obesity and mussel powder on bone health
Rats were kept alone and fed different diets containing normal or high amounts of fat or sugar. Some were supplemented with Greenshell mussel powder. X-rays were done, and some rats' ovaries were removed. Ultimately, all were killed by bleeding them out.
Testing the safety of a probiotic supplement
Rats were force-fed with a probiotic solution or control solution. After two weeks, they were killed for dissection.
Studying food intake in an autism "model"
Pregnant rats were injected to cause autism-like symptoms in their babies. The male babies were put through behavioural tests with control animals as well as a feeding study. Some were fasted for 16 hours and killed by flushing their hearts.
Trying to study schizophrenia
Half of a group of pregnant rats were injected to affect their babies' brain development. Some pups were allowed to grow up to test their behaviour.
Testing the effect of diabetes on pregnancy hormones
Rats were anaesthetised, and their brain was accessed through the mouth to measure reactions to stimulation. In the end, all rats were killed.
Testing diabetic rats’ hearts
Genetically diabetic fat rats and their lean littermates were anaesthetised. Ultrasound images were made from their hearts. All were killed and dissected.
Testing a connection between tinnitus and brain function
Rats were anaesthetised and one ear was damaged with noise. Rats were taught that silence meant they would get electric shocks and freeze in fear. This was a test for tinnitus.
Studying the communication between inner ear and brain
Rats were anaesthetised, and their inner ear was partly removed, before parts of their brains were stimulated with wire electrodes. Reactions of the rat's eyes and brain were recorded. In the end, all rats were killed.
Investigating how worms spread between lambs and calves
Lambs and calves were infected with worm eggs to see if parasites from cattle can infect sheep.
Developing “hyperimmune” milk
Sheep were injected with Covid-19 vaccines to see if they produced milk that could be marketed to consumers as providing immunity against certain diseases.
Testing the effects and wash-out of painkillers
Lambs were treated with different painkillers or no painkillers at all before tail docking and castration. Their behaviour was monitored.
Testing the potency of pneumonia vaccines for sheep
Lambs were vaccinated twice and regular blood samples were taken for 34 weeks, to test different pneumonia vaccines for sheep.
Testing the best way to deliver gene therapy drugs
Sheep were anaesthetised. Their heads were drilled into, and their brains injected with test drugs. They were killed after three weeks.
Testing the combination of drugs for congestive heart failure treatment
Sheep were anaesthetised and subjected to surgery. Electrodes were used to pace their hearts faster while testing the effect of different drugs.
Testing if blocking a cell signal can prevent foetal brain injury
Pregnant sheep were anaesthetised, and the foetuses fitted with electrodes. The umbilical cord was blocked for most of them, and half were treated with a test drug. Mothers and unborn lambs were killed three weeks later.
Preclinical testing of a gene therapy for Batten disease
Sheep with and without a specific gene mutation were checked and scanned regularly for nine months. Affected sheep received gene therapy at different ages. Treated sheep were killed.
Investigating intestine movements
Young pigs and NZ White rabbits were anaesthetised. A part of their intestine was pulled out far enough to record its movements and signalling.
Harvesting eyes for lab tests
The eyes of pigs and rabbits killed for experiments were used to analyse the structure of the cornea.
Testing a new vaccine
NZ White rabbits were injected with a new vaccine type several times before being killed.
Causing sinusitis in rabbits as a model
NZ White rabbits were anaesthetised, and a sinus tract in their nose was blocked for four weeks to cause sinusitis. After another ten weeks with regular samples, they were killed.
Harvesting rabbit and pig eyes for lab tests
The eyes of slaughtered rabbits and pigs killed for experiments were used to analyse the structure of the cornea.
Using a new imaging technology
One NZ White rabbit and rats were killed, and their eyes were removed to use for the study.
Testing the toxicity of some substances
Young NZ White rabbits were force-fed different doses of toxic substances. Blood samples were taken before and immediately after killing them at set time points (or to end their suffering).
Mapping wave patterns of the small intestine
NZ White rabbits were anaesthetised, their intestines were used for electrode mapping, and then they were killed.