Of Mice and Mammaries, Part 2: Breast cancer in a dish?

In light of Breast Cancer Awareness Month, Justin Varholick traces how mice have helped breast cancer research over the past century. In the second post of this 4-part series, we look at advances made from 1960 to 1975 when scientists were studying a virus in the milk.

Last week, in Part 1 of this series, we discussed how scientists from the early 1900s studied the growth and spread of mammary tumors in mice. We also walked through an experiment discovering how the breast milk from mother mice carried “something” that was more responsible for breast cancer than the genes the mother had passed down to her pups. This week we learn how scientists determined that this new “something” was a virus, and this virus could only be found in mice – it was never found in humans.

1940 to 1960 — What’s in the milk?

After Dr. John Bittner found out that there was “something” in the milk, many scientists wanted to figure out what it was. A first thought was to filter the milk and see if it still showed the same effects as Dr. Bittner’s experiments. Scientists took very special filters used to filter out bacteria, and ran mouse milk from “high tumor” mothers through these filters. Despite filtering, the results remained the same – filtered milk from “high tumor” mothers still led to tumors in pups fed the milk.

Then in the early 1950s scientists started using electron microscopes to compare “high-tumor” mouse breast milk with normal “low tumor” mouse breast milk. The electron microscopes gave scientists the power to magnify the milk 2,000,000x the normal size – magnification beyond what the bacteria filters could filter out. After comparing the types of milk, Dr. Leon Dmochowski found many small particles in the “high tumor” milk and very few of these particles in the “low tumor” milk. After other scientists repeated these experiments, they concluded that these particles were the “something” in the milk that may be responsible for tumors in the pups. Many scientists looked for these particles in human breast tissue and milk, but could never find it – only mice have this “something” in the milk. It was interesting, however, that the particles were in both “high tumor” mothers and “low tumor” mothers, albeit in different amounts, which indicated that both types of mothers were at risk to have the mammary tumors – “high tumor” mothers just had a higher risk.

While all this science with electron microscopy was going on, scientists studying mammary tumor cells in mice determined that the something in the milk acted very much like a virus and gave it the name mouse mammary tumor virus, or MMTV for short.

Cover of “Immunity against the mouse mammary tumor virus” by Paula Creemers. Electron microscope image of MMTV with a sketch of two mice with mammary tumors.

1960 to 1975 — Can we grow the milk virus in a dish?

Now that scientists had established that a virus in the milk was responsible for mammary tumors in mice, they wanted to see if they could grow the virus in a petri dish. Scientists had already grown viruses in a dish that were responsible for cancer in chickens, and other viruses that were responsible for skin cancer in humans, so they believed they would be able to grow MMTV in the dish. Unfortunately, growing the milk virus dish proved very difficult.

In the 1970s many scientists tried to grow the virus in a dish and were unsuccessful. One group of scientists at the Cancer Research Genetics Laboratory (CRGL) of the University of California, Berkeley showed that the virus could be grown in a dish, but it was too cumbersome for many scientists to use for research. Because MMTV could not be easily grown in a dish, scientists interested in mammary tumors in mice knew they had to find a new method if they wanted to continue using mice to understand more about breast cancer.

To be continued…

Tune in next week, to learn how scientists started using new methods with stem cells to make genetically engineered mice and how they validated that the mouse could be used as a model for humans!

Justin Varholick


  1. Cardiff R, Kenney N. (2011). A compendium of the mouse mammary tumor biologist: From the initial observations in the house mouse to the development of genetically engineered mice. Cold Spring Harb Perspect Biol. 3(6).


Research Roundup: Snail venom and cancer, reversal of advanced heart failure and more!

Welcome to this week’s Research Roundup. These Friday posts aim to inform our readers about the many stories that relate to animal research each week. Do you have an animal research story we should include in next week’s Research Roundup? You can send it to us via our Facebook page or through the contact form on the website.

  • Secrets found in snail venom may help treat cancer. Cone snails are marine mollusks that are found worldwide in warm climates. Usually reclusive, cone snails will produce a venomous sting when threatened using a single, harpoon-like tooth. They also use this venom to immobilize their prey, which are often much bigger and faster than the snails themselves. By examining the molecular makeup of cone snail venom, researchers are learning how a single toxin, which typically only affects the central nervous system, can also impact the immune system. This information may help develop therapies for cancers that involve uncontrolled overproduction of certain cells, such as gastric, breast, and lung cancers. Published in Scientific Reports.

In the wild, cone snails harpoon their prey as it swims by. In the lab, the cone snail has learned to exchange venom for dinner. Here, a snail extends its proboscis and discharges a shot of venom into a latex-topped tube.
Credit: Alex Holt/NIST

  • Scientists reverse advanced heart failure. Heart failure is one the most common reasons for hospital admittance in individuals 65 years or older. It occurs when the heart is unable to pump blood sufficiently to maintain the body’s needs. This week, researchers were able to reverse severe heart failure in a mouse model, by silencing the Hippo pathway. The Hippo pathway is associated with cell death, which occurs, for example, when heart tissue is starved of oxygen. Dr. James Martin, the corresponding author on this study states “Heart failure remains the leading cause of mortality from heart disease. The best current treatment for this condition is implantation of a ventricular assist device or a heart transplant, but the number of hearts available for transplant is limited”. This mouse model, which mimics the human condition of advanced heart failure, is therefore an exciting new avenue for further investigation into measures which limit the debilitating consequences of heart failure. This study appears in the journal Nature.
  • Zebrafish recover faster from stressful situations when housed together. Zebrafish are a small, schooling minnow-like species increasingly used in many aspects of biomedical research. A new study shows that when zebrafish are housed together after a stressful procedure, they recover faster, resume normal behaviours and even have lower levels of stress hormone than fish housed alone. The study also demonstrated that stress hormone levels can be measured non-invasively by sampling the water directly from fish tanks. Refining how we work with zebrafish, and discovering better ways to provide for their welfare needs are important aspects of doing valuable life-saving research with these animals. This research was published in the journal Animal Behavior.

Zebrafish: Wellcome Trust Sanger Institute

  • The link between caesarean sections, the microbiome, and obesity. Caesarean section, a.k.a. C-section, is a life-saving practice for delivering 10-15% of human newborns. However, C-section is also overused in the developed world with some regions delivering 43% of newborns by C-section. Although this practice is quite common, scientists and medical doctors understand little about the long-term effects of C-section. This week, scientists have uncovered evidence that being delivered by C-section is linked to an increased risk of obesity in mice. This link between C-section and obesity deals with the gut microbiome. When humans, or laboratory mice, are delivered normally they travel through the vaginal canal and get exposed to vaginal microbiota. C-section circumvents the vaginal canal and thus the newborns do not get exposed to this vaginal microbiota. Research published this week in Science Advances indicates that mouse pups born by C-section weigh significantly more than those born normally. They also have a different gut microbiomes. This research does not necessarily mean humans born by C-sections are at higher risk for obesity, because human newborns often get antibiotics immediately after delivery and mice are fostered to new mothers after being delivered by C-section. Nonetheless, this is a great step towards further understanding the consequences of C-section deliveries.
  • The validity of studies on the transplantation of tumours to mice questioned. This week ,a study published in the journal Nature Genetics, described changes in the genome of tumor tissue implanted into immunodeficient mice that may affect interpretation of research results. Human tumors can be studied in cell culture medium or by implanting cultured cells into immunodeficient rodent models. However, the process of ‘immortalization’ of cells grown in artificial culture medium alters the cells in ways that limit their usefulness as a model in tumor biology.  As an alternative, tumors collected from patients can be implanted directly into rodents (PDX or patient-derived xenograft avatars) to study their activity and response to therapeutic drugs.  This approach has been thought to better replicate the behavior of tumors in human patients with improved predictability of the model as a desired outcome. However, the study in Nature Genetics by Uri Ben-David and colleagues found that the unstable genome in many tumors continues to change after implantation into the mouse, and can accumulate mutations that differ in behavior and response to chemotherapeutics from the original patient tumor. These findings do not negate the value of the PDX avatar model, but do highlight the need for further investigation to determine how the genomic changes that occur affect the interpretation of results derived using this type of model.

If you don’t want to miss a thing

Thanks to the incredible work of the SR committee, the amount of news we produce has risen to the point that there are posts almost every other day. Our end-of-week Research Roundup allows readers to keep abreast of the week’s animal science news, while we also cover news from animal rights groups, worldwide statistics, and more.  Our hard work is being rewarded, Speaking of Research are increasingly being quoted in the media, and our calls to action are being taken up by hundreds of scientists (For example, Christine Lattin has already received over 300 comments of support).

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We’ve always assumed he was talking about Speaking of Research too!

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Of Mice and Mammaries, Part 1: There’s something in the milk

In light of Breast Cancer Awareness Month, Justin Varholick traces how mice have helped breast cancer research over the past century. In the first post this 4-part series, we look at advances made from 1854 to 1940, including the understanding of the role of breast milk in causing certain types of tumors. 

Image credit: Jackson Labs

Breast cancer is one of the most serious forms of cancer facing women. Each year, over 300,000 women in the U.S. will be diagnosed with breast cancer, and it is estimated that 40,610 women will die from it in 2017 alone. Thankfully, death rates from breast cancer have dropped almost 40% from 1989 to 2015, and there are over 3.1 million breast cancer survivors living in the U.S. today.

Breast cancer grows and spreads through many stages, and can start in different parts of the breast. Some types of breast cancer cause lumps, others form no lumps. Some forms of it spread very quickly throughout the body, while others spread more slowly. Because breast cancer spreads and forms at different rates and in different areas of the breast, treating it is no easy task. It is also unlikely that we will one day have a “cure” for breast cancer — one size cannot fit all.

Despite the complicated nature of breast cancer, scientists feel a responsibility to understand it as much as possible in efforts to find new treatment methods and forms of a cure. Over the years they have made great strides in their research by studying mice. These mice serve as an essential step between early research on mammary cells and clinical trials in humans.

Over the course of this month, I will highlight some of the key findings scientists have discovered about breast cancer through their studies in mice.

1854 to 1903 — The first mouse mammary tumors

The first discovery of a mammary tumor in a mouse was in 1854. In these early days, scientists were able to find tumors spontaneously growing in female mice kept as pets and in the wild. Although they were able to detect and describe these tumors, it was difficult to understand where they came from, and how they grew and possibly spread or metastasized.

Thankfully in 1903, Dr. Carl Jensen developed a line of “high tumor” mice that readily grew mammary tumors, which could be easily transplanted to other mice. By transplanting the tumors in other mice, they could measure how and where the tumors spread, in otherwise healthy mice.

During this time in history, 1.2* women per 1,000 died from breast cancer in the U.S. Today it is around 0.13 women per 1,000. (*at this time we only had reports on the number of white women in the U.S.).

1933 to 1940 — There’s something in the milk

After bringing mice into the laboratory and thoroughly studying their biology, a great discovery was made — there was something in the milk. This discovery was made by Scientists at Jackson Laboratories, in Bar Harbor, Maine. They bred “high tumor” mice with “low tumor”* mice and found that offspring were more likely to get mammary tumors if they had a “high tumor” mother. Although some scientists were able to replicate this finding in other labs, very few were convinced there was something in the milk — they believed it was passed down through the genes. (* an extremely low number of “low tumor” mice were found with mammary tumors; because of this scientists could not call them “no tumor” mice.)

To answer whether there was either something in the genes or the milk, Dr. John J. Bittner did a more complex study 3 years later. In this key study, Bittner cross-fostered mouse pups from “high tumor” and “low tumor” mice to opposite mothers (see diagram). This method allowed him to determine whether the parent’s genes or the foster mother’s milk lead to mammary tumors. If it was the genes then “high tumor” offspring would have tumors whether they had “high tumor” or “low tumor” foster parents. If it was the milk then any offspring nursed by “high tumor” mothers would get tumors.

Through this experiment, Bittner found out that milk was a key factor. “Low tumor” pups cross-fostered to “high tumor” mothers had many mammary tumors, while “high tumor” pups cross-fostered to “low tumor” mothers had very few tumors. “High tumor” pups nursed by their own mothers, however, had the highest rates of tumor growth. It didn’t always matter who the parents were, it also mattered who nursed the pups. This verified that indeed there was something in the milk. This something was labeled as the Mouse Mammary Tumor Virus (MMTV).

Dr. Bittner was often heard stating that he only studied the milk because nobody else wanted it — they all wanted to study the genes.

To be continued…

Tune in next week to read what we learned about the milk virus, MMTV, and what we did with this new power!

Justin Varholick


  1. Cardiff R, Kenney N. (2011). A compendium of the mouse mammary tumor biologist: From the initial observations in the house mouse to the development of genetically engineered mice. Cold Spring Harb Perspect Biol. 3(6).
  2. Holen I, Speirs V, Morrissey B, Blyth K. (2017). In vivo models in breast cancer research: progress, challenges and future directions. Dis Model Mech. 10(4).
  3. Tarone RE, Chu KC. (1992). Implications of birth cohort patterns in interpreting trends in breast cancer rates. J Natl Cancer Inst. 84(18).

Research Roundup: Cure for blindness, DNA delivered antibodies and more!

Welcome to this week’s Research Roundup. These posts aim to inform our readers about the many stories that relate to animal research each week. Do you have an animal research story we should include in next week’s Research Roundup? You can send it to us via our Facebook page or through the contact form on the website.

  • Rare benign tumors hold the ‘genetic recipe’ to combat diabetes. Researchers at the Icahn School of Medicine at Mount Sinai are studying insulinomas — benign tumors that contain a mechanism for regeneration of insulin-producing human beta cells, in mice and humans. They are hopeful that this may hold the key to the development of better drugs for the millions living with diabetes. Dr. Andrew Stewart, Director of the Diabetes, Obesity, and Metabolism Institute at the Icahn School of Medicine and lead author of the study said, “For the first time, we have a genomic recipe—an actual wiring diagram in molecular terms that demonstrates how beta cells replicate.” He and a team of international researchers analyzed the genomics and expression patterns of 38 human insulinomas and found a map for beta cell replication. These cells are required for insulin secretion which regulates sugar in the bloodstream. Lack of insulin leads to diabetes causing severe disease and even death.  The identification of this map offers a target for new drugs to help these patients.  This study was published online in Nature Communications.

  • DNA-delivered antibodies used to fight bacterial infections. Monoclonal antibodies are antibodies made by identical immune cells — basically clones of a unique parent cell. In the present experiment, mice were injected with the genetic sequence for a monoclonal antibody which targeted Pseudomonas aeruginosa, a life-threatening, multidrug-resistant bacterial pathogen. This approach allows antibodies to be produced in vivo within the host, and is in contrast to current methods which require large quantities to be delivered via intravenous drip. Mice were successfully inoculated using this approach, “providing a proof-of-concept for a potentially cheaper and faster alternative to current monoclonal antibody treatments.” This research was published in Nature Communications.

CRISPR–Gold is composed of 15 nanometer gold nanoparticles that are conjugated to thiol-modified oligonucleotides (DNA-Thiol), which are hybridized with single-stranded donor DNA and subsequently complexed with Cas9 and encapsulated by a polymer that disrupts the endosome of the cell.

FDA response to Goodall letter found lacking

On September 25, 2017, Dr. Scott Gottlieb , Commissioner of the U.S. Food & Drug Administration (FDA) replied to a scathing letter from Dr. Jane Goodall, where Goodall denounced what she called the “cruel and unnecessary nicotine addiction experiments on monkeys”. We previously evaluated that letter from Goodall and now do the same with Commissioner Gottlieb’s letter.

The FDA Commissioner’s letter starts with an acknowledged appreciation of Goodall’s opinion and a re-statement of the FDA’s commitment to compliance with the rules and guidance governing the use of animals for research. It is indeed admirable that Commissioner Gottlieb places emphasis on compliance with the long-standing regulatory framework and guidance governing animal research in the US. What is unacknowledged in the letter is that all studies involving animals used in research, including the one that Goodall references, are continually monitored with respect to such compliance.

Gottlieb writes:

“After learning of concerns related to the study you referenced, I directed the Agency to place a hold on the research study earlier this month. Accordingly, at this time, all experimentation involving the monkeys in the study you referenced has been halted.”

Several things are surprising about this approach. Foremost, the vague reference to “concerns” when coupled with the failure to mention the review and oversight mechanisms in place, can give a public impression that is confusing. For example, is Gottlieb saying that his response is driven by Goodall and WCW? Speaking of Research, like the scientific community, supports an effective oversight system that has mechanisms for investigation and correction of animal welfare issues. In this letter, however, the Commissioner appears to bow to celebrity opinion, halting an ongoing experiment without providing evidence or acknowledgement of the continual monitoring that surrounds research. In fact, subsequent media coverage of Gottlieb’s response also conveys the impression that the decision was made directly in response to Goodall’s letter.

This is alarming on many levels. There is, for example, no acknowledgement of contact with the research institution’s federally-mandated review board (Institutional Animal Care and Use Committee, IACUC), no mention of the FDA’s process for review of research, or evaluation of records. Instead, the letter suggests that the federal agency’s decision is a bow to celebrity pressure from Goodall, who is acting on behalf of an anti-animal research organization (White Coat Waste, WCW).

Gottlieb continues:

“I asked for a medical team of primate experts to conduct a site visit to evaluate the safety and well-being of the monkeys and to understand whether there are additional precautions needed.”

This statement and the announcement of “halting” the study, absent any other information, imply that animal health and well-being are in immediate jeopardy. The evidence for that claim is not presented. If the animals were in immediate jeopardy, we would expect that the facility’s personnel would be taking action. Whether that is the case or not cannot be ascertained from Gottlieb’s letter. At the very least, the commissioner’s letter should acknowledge any ongoing efforts by his agency’s personnel—including those at National Center for Toxicological Research (NCTR).

Squirrel monkey. Source: Wikipedia Commons.

The letter can leave readers with the several wrong impressions by leaving out any information about the expertise of the existing veterinary, animal care, and scientific staff at the federal facility. Readers may be left with impression that primate experts—including scientists and veterinarians — are absent at the long-standing federal research facility, the NCTR. That is unlikely to be the case. Further, even when people with a high level of expertise and experience are present, adverse events that require thoughtful review and modifications in procedures sometimes occur. Animal research, like all human endeavors, has potential for error. Research teams, IACUCs, and regulatory bodies all play a role in making sure that those errors are addressed and corrected. Thus, in light of full transparency, actions taken by the institutional IACUC, the scientists, and the facility’s veterinarians, along with further information including the timing and venue for a public report of findings before decisions are taken need to be specified.

Gottlieb’s letter continues:

“I also appointed an independent FDA review team, led by senior career experts and with the guidance of primate veterinarians, to assess the science and integrity of the animal research process for this study. I also asked this team to evaluate whether the re-initiation of the study you referenced is necessary to fulfill FDA’s public health responsibilities, or if the study should be halted indefinitely.”

This is one of the more troubling aspects of the FDA commission’s letter as it is unclear whether he is aware that firstly, this study must have gone through rigorous review in terms of scientific merit, evaluation of the risks to the animals being used as well as the proposed benefit to humans, when it was funded. Secondly, the IACUC at this institution will have vetted all procedures being performed on these animals, including consideration of response and correction should an adverse situation occur.

Finally, separate to this letter, but parallel to this issue, an FDA spokeswoman is quoted as stating, “the agency is also considering creating a wider-ranging function that would provide for even greater oversight of the care of animals in the agency’s possession.”

This statement is alarming in its lack of specificity and requires clarification. Does it mean that FDA is conducting a re-assessment of the existing federal structure for reviewing and conducting all animal research? If so, what is the impetus for the review? How is it different from existing policies? Who is involved in the review? What is the process by which public interests in scientific research that informs public health policy will be protected and scientific objectives balanced with animal welfare? How will the public be assured that the full range of relevant expertise is included in the review? There are many additional questions—all raised by the statement, none addressed, as far as we are aware, by any other materials provided by the FDA.

Finally, it is also important, in light of full transparency that the FDA provides an update about its ongoing lawsuit with WCW. The WCW suit appears to have arisen as a consequence of the FDA’s response to a WCW freedom of information (FOIA) request for records about the NCTR research. At this time, it is unclear whether the FDA’s decision to suspend this ongoing and already scientifically-justified funded research is related to this lawsuit. The Washington Post writes:

“Goodall was enlisted in the fight against the monkey tests by the White Coat Waste Project, an advocacy group that says its goal is to publicize and end taxpayer-funded animal experiments. In January, the organization obtained 64 pages of documents on the nicotine-addiction research from the FDA under the Freedom of Information Act. It is suing the agency to get more information on the research’s costs, as well as veterinary records and photographs and videos of the experiments.”

Speaking of Research is not the only organization concerned with the FDA response. The American Psychological Association (APA), the American College of Neuropsychopharmacology (ACNP), and the College on Problems of Drug Dependence (CPDD), have jointly penned their own letter to the FDA demanding a clear explanation for the suspension of the nicotine research project. Part of it is quoted below:

“As you may be aware, Dr. Goodall’s letter to you came at the behest of an organization, White Coat Waste Project (WCW), that is fundamentally opposed to all research with nonhuman animals. Your decision to suspend the research is extremely troubling because it appears to have occurred without any substantive input from experts in the scientific community who have deep knowledge and understanding of research on substance use disorders. Furthermore, the methods and technologies used in this study have been rigorously validated and commonly used in studies of substance use disorders, including research that is funded by other federal agencies, such as the National Institute on Drug Abuse (NIDA) and National Institute on Alcohol Abuse and Alcoholism (NIAAA).”

Speaking of Research shares the APA, ACNP and CPDD’s concerns. We hope the FDA will be forthcoming with an explanation of the suspension of the research project in question. We also hope that they will be taking the evidence of experts over the opinions of prominent celebrity scientists and animal rights groups.

Speaking of Research

How many animals were used in Poland and Finland in 2016?

Speaking of Research try to keep on top of the latest statistics coming from governments around the world. This post will look at the 2016 statistical releases in Poland and Finland.


Finland reported that 105,615 procedures were conducted on animals in 2016, a 9% rise from 2015.

According to statistics provided by Finnish authorities (but not required by the EU), 168,548 animals were “bred and euthanized without procedures”. This figure is likely to include both surplus animals bred, and animals bred to supply tissue samples for in vitro studies (but not genetically altered and not undergoing any procedure).

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Animals used in research in Finland in 2016. Click to Enlarge

The rise in numbers mainly comes from the increases in mice (+16%) and birds (104%). This is the second year in which the number of birds used has doubled. Proportionally, Finland uses more dogs than in most countries – 3.8% vs around 0.5% in other EU countries. However, on closer inspection, it turns out that 3,582 procedures were taking blood samples from pet dogs to study genes involved in canine diseases, and 244 procedures were pet dogs participating in (veterinary) patient studies, leaving only 135 dogs used in laboratory settings (nearly all in toxicity and safety tests, nearly all of which were of mild severity). Similarly, all 259 procedures on cats were blood samples from pet cats to study genes involved in feline diseases.

Most research was conducted on mice (66%), rats (12%) fish (10%) or birds (7%), together accounting for 95% of all research procedures. No primates were used.

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Trend over time in animals used in research in Finland. Click to Enlarge.

Over the last decade, the number of animal procedures in Finland has been falling, approximately halving over ten years. Given the relatively small numbers of animals used in Finland (numerous US and UK universities use more animals in a year than all Finnish institutions put together), changes in overall numbers can be the result of just a handful of studies starting or finishing.

CC-BY speakingofresearch.com

Severity of animal research procedures in the Finland in 2016

Finland, like all EU countries, reports the severity of every procedure after they have been completed. Mild and non-recovery accounted for 61.3% of procedures (60.3% in 2015), moderate was 30.1% (down from 33.9% in 2015) and severe was 8.5% (up from 5.8% in 2015). All but one severe procedure was on mice and rats (the last was on pigs).

Finally, 41.1% of procedures involved genetically altered animals (mostly mice and fish), 58.9% did not.

Source of Finnish Statistics: http://www.laaninhallitus.fi/lh/etela/hankkeet/ellapro/home.nsf/pages/BFD5CAFA94D8E7C7C225728A00475B11?opendocument

See previous years’ reports:

Mice are the most common species of animal used in both Finland and Poland.


Poland reported 184,489 procedures on animals in 2016, a 6% rise from the previous year. It should be noted that while we compare to 2015, there were numerous issues relating to that statistical release and as a result these “changes from 2015” should be taken with a pinch of salt.

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Animals used in research in Poland in 2016. Click to Enlarge

The biggest rise has been in fish, which rose 266% from 2015. This was slightly offset by falls in mice (-3%), rats (-10%) and birds (-38%).

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93% of all research in Poland is on mice, rats, birds and fish – similar to most other EU countries. Prcoedures on dogs and cats together add up to less than 0.05% of research (85 procedures), and there were no procedures on primates.

CC-BY speakingofresearch.com

Trend over time in animals used in research in Poland. Click to Enlarge.

There appears to be a downward trend in animal research over the last six years, though errors in previous data should mean that readers should take figures with a pinch of salt. Like Finland, given the relatively small numbers of animals used in Poland (numerous US and UK universities use more animals in a year than all Polish institutions put together), changes in overall numbers can be the result of just a handful of studies starting or finishing.

CC-BY speakingofresearch.com

Severity of animal research procedures in the Poland in 2016. The total number of procedures is higher than previously mentioned as it includes 1,210 animals that had already been involved in previous studies.

Poland reports the severity of every procedure after they have been completed. Mild and non-recovery accounted for 51%% of procedures, moderate was 26%  and severe was 23%. The proportion of severe experiments is higher than in most other EU countries. This may be a result of slightly different guidelines currently in Poland for classifying severity.

Source of Polish Statistics: http://www.bip.nauka.gov.pl/sprawozdania_zwierzeta/

See previous years’ reports:


There was a threefold increase in the number of fish used in Poland in 2016