Frequently Asked Questions about Animal Research
Is animal research necessary? Don't alternatives like cell culture and computer modelling exist?
While non-animal methods like cell culture and computer models can be excellent systems for understanding particular types of questions, they have limitations. For example, computer modeling can only be done if we already have information to put into the model. There is often no way of acquiring this information other than using living organisms. In vitro experiments using cell cultures are very useful for shedding light on mechanisms that happen inside the cell, but are usually not sufficient for understanding how different cells, tissues and organs interact inside the body. This means that we must use live animals to answer many of the most important scientific questions related to human health, and to understand behavior, physiology, and neurobiology in other animals. However, many animal researchers, including all members of the Lattin Lab, strive to adhere to the 3Rs principle when using animals in research - reduce, refine, and replace. This is part of the reason why we have pioneered new techniques in sparrows that allow for less invasive ways of studying stress, such as Dr. Lattin’s work validating a technique for extracting hormones from feathers, and her research using PET, CT and SPECT imaging techniques to study the brain and body. To learn more about Dr. Lattin’s personal reasons for studying animals, please see this editorial in the LSU student newspaper.
Why study stress in songbirds?
While stress helps animals and humans survive and cope with challenges, too much stress is bad and causes health problems. Yet we still don’t have a clear understanding of how and why stress switches from being helpful to harmful, or why some individuals, or some species, are relatively resilient to the negative effects of stress while others are more vulnerable. To address these questions, our research uses a combination of lab and field studies, and techniques from hormone sampling to behavioral analysis. Understanding stress in wild animal populations is important because stressors like habitat destruction, climate change, and species invasions now affect most, if not all, animal species. Knowing more about how these different kinds of stressors affect animals may allow us to save some species that might otherwise go extinct. Stress is also a major risk factor for depression, heart disease, drug abuse, and suicide in humans. ~8% of Americans will experience post-traumatic stress disorder at some point in their lives. Understanding more about the physiology of stress could help lead to the development of new medicines and procedures to reduce stress in humans and animals.
Why study house sparrows and European starlings in particular?
First of all, because house sparrows and European starlings have been so successful at invading new habitats, we know that natural selection has favored stress resilience in these species. There is a long history of research on both species, so there is a solid foundation of scientific knowledge we can build upon. Also, we can’t completely understand stress by only studying animals that were born in a cage. Captive-born animals don’t have the same range of physiological and behavioral responses to stress that wildlife and humans show.
What regulations protect wild birds used in research?
Every study we do must first be approved by a university Institutional Animal Care and Use Committee (or, IACUC). This federally-mandated committee provides regular updates on its practices and procedures to federal agencies that include the U.S. Department of Agriculture (USDA) and the U.S. Public Health Service (USPHS). Our work complies with all existing laws and regulations and the Ornithological Council's Guidelines for the Use of Wild Birds in Research. The labs, imaging facilities, and animal rooms where sparrows are housed are regularly inspected, and sparrows are monitored by researchers and vets to make sure they stay in good health and don’t lose too much weight in captivity. Researchers, veterinarians, and veterinary technicians strictly adhere to the Federal Animal Welfare Act. Research with wild birds also requires state and in some cases federal permits, which creates another level of oversight.
Why bring wild birds into captivity?
Wild animals experience stress in many situations, including escaping from predators, fighting rival birds for territories and mates, and surviving severe storms. Some of our current research focuses on one type of stressor that has direct implications for the conservation of endangered and threatened species - bringing birds into captivity. The transition from the wild to captivity is a strong psychological stressor, even if birds have unlimited food and water and large clean cages. We are trying to understand why this is, and why certain individuals do better in captivity than others. This work could help us identify which individuals are most likely to be successful in captive breeding programs or translocations.
What do you do to the birds in your studies?
To measure the animals’ responses, we take blood samples to measure hormones, keep track of the birds' weight, and observe their behavior using video recordings. Some birds are put to sleep using anesthesia and put into medical scanners (PET/CT/SPECT). These are non-invasive ways to study the brain and body, and are techniques commonly used in people. While they are asleep, the birds are kept warm using heating pads, and after their scans are done they wake up within just a few minutes. To study receptors in the brain and body, we sometimes have to euthanize animals, which is done under anesthesia.
Why did you do a study where you gave sparrows small skin punctures?
This study was designed to investigate the role of stress hormones in the healing process. Wild birds commonly receive small wounds from insect bites, predators, and rival birds, but we know little about how stress hormone receptors in the skin change during healing. To examine this question, we used a 4 mm biopsy punch to make a small incision in the skin of sparrows' legs. Birds were anesthetized during this procedure, which is frequently done to human beings. From this study, we learned that birds with a small puncture had decreased numbers of one type of stress hormone receptor in the wounded skin, suggesting that reducing the amount of receptors in the skin is necessary for successful healing.
Why did you do a study where you rolled sparrows on a cart, tapped on their cages, and played radio in the animal room?
In this study, we were trying to understand how chronic stress affects concentrations of stress hormone receptors in different tissues in the body. Understanding what is happening with receptors is really important because for a hormone to have any effect, it first has to bind to a receptor. Using multiple unpleasant stimuli is a well-established approach to studying stress, called chronic mild stress, that has been used in biomedical research for over 30 years. You can read more about how important this model has been for understanding stress in this open-access review paper. In this project, we found that chronic mild stress exposure caused an increase in receptors in several tissues that could potentially be used as indicators of chronic stress, and may help us understand some of the negative effects that can result from prolonged stress hormone exposure.
Why did you do a study where you put oil in sparrows' food?
We know that large amounts of oil are toxic to wildlife, but this study was designed to test whether very small amounts of oil could act as an endocrine disrupting chemical. Endocrine disrupting chemicals block or interfere with normal hormone actions in the body that are necessary for health and survival. Most research on endocrine disrupting chemicals has focused on chemicals that disrupt estrogen activity (like bisphenol A, and PCBs). However, a few studies have shown that the adrenal glands, which secrete stress hormones, are also very sensitive to certain endocrine disrupting chemicals. We wanted to know whether small amounts of exposure to oil could disrupt animals' normal stress response, and if a disrupted stress response could potentially act as a biological indicator of oil exposure in wildlife. To study this, we mixed very small amounts of oil (equal to 1% of food weight) into sparrows’ food. Doing this research in a lab environment allowed us to control a lot of things that might vary in the wild and make it hard to draw clear conclusions about cause and effect. While there were no obvious outward signs this had any effect, and many potential biomarkers of oil exposure in the blood were also normal, blood sampling revealed that birds were not able to secrete normal concentrations of stress hormones after exposure to a standardized stressor (a brief period of restraint in a clean, breathable cloth bag) and an injection of adrenocorticotropic hormone. In our publications on this research, we suggested that stress hormone concentrations could be used as a biological indicator of oil exposure in wildlife. This research is being used by other scientists as evidence that some health problems and deaths they saw in wild dolphins and sea turtles after Deepwater Horizon were due to oil exposure.