Welcome to STEMology – Show Notes
Season 1, Episode 16
Sleepy sharks, Bird-brain song, FISSTING hiccups, and the diets of rodents
In today’s episode of STEMology…
We’ve finally discovered how sharks sleep, researchers have translated brain activity into artificial bird song, FISST has been invented to cure hiccups and the food lab rats are being fed could be disrupting our scientific discoveries
What they’ve basically discovered is that sharks hanging out in a certain place so that they can kind of surf the ocean currents in a conveyor belt figuration, which allows them to take turns resting.
Their ultimate goal is to come up with this communications prosthetic that allows people to speak if they’re not able to speak. And they’re studying this in zebra finches, because this is a species that produce song…. and it’s very complicated, which make them quite a good model for figuring out how to turn the activity of the sensory motor cortex, which is where the speech comes from into song.
There are some people who actually get hiccups through no fault of their own. you’ve got patients who have maybe brain and stroke injury. What I didn’t realize was that some kinds of chemotherapies cause hiccups, there’s all these people who actually suffer from hiccups.
Turns out that potentially by feeding our lab mice and rats the wrong kinds of food, we are possibly confounding variables in experiments …. we are kind of forcing a different outcome, maybe accidentally.
This is a “kind of, sort of, vaguely close” copy of the words that David & Sophie speak in this episode.
IT IS NOT 100% accurate. We are very sorry if we have spelt something completely incorrectly. If it means a lot to you to have it corrected, email us at firstname.lastname@example.org
[00:00:00] [00:00:00] David: [00:00:00] Welcome to episode 16 of STEMology.
[00:00:02]Sophie: [00:00:02] A podcast sharing some of the interesting fun, and sometimes just patently bizarre news in science, technology, engineering, or maths
[00:00:11]David: [00:00:11] Your hosts are Dr. Sophie Callabretto and Dr. David Farmer. On today’s episode, we’re talking about sleepy sharks, bird brain song,
[00:00:18] Sophie: [00:00:18] FISSTing hiccup and the diets of rodents.
Sleepy sharks [00:00:22] hi Dave. I love sharks.
[00:00:25]David: [00:00:25] you do love sharks.
[00:00:26] And every time we get a shark story in the mix, you get much happier than you are when there’s not a shark story in the
[00:00:31] Sophie: [00:00:31] I know, I just think it means that I’m easily controllable. It’s like, show me a shark or dinosaur and I’ll do anything you want me to do, which is a problem.
[00:00:38]David: [00:00:38] Basically. So, uh, this is some work at Florida International University, looking at sleepy sharks and specifically the great reef shark, which is a species of requiem shark, I learned. And basically these researchers were interested in why these sharks hang out, where they choose to hang out and they find that they tend to hang out in [00:01:00] these weird updrafts zones
[00:01:01] Sophie: [00:01:01] Yeah, they do. So this is all about, uh, sharks, not dying a little bit and sleeping a little bit, and this is why they choose to hang out where they do it. Yeah. So there’s, I guess. Two kinds of sharks. No, there’s not two kinds of sharks. There’s many different kinds of sharks, but in terms of shark breathing, there are two main ways to breathe as a shark, which is what I learned this week.
[00:01:21] So basically what we want is we want water to pass over the gills in order to receive oxygen. And so you can do that just by swimming through the water. So that’s known as Ram ventilation and That’s what grey reef sharks do, but there’s also another kind of breathing that sharks do. And it’s for like the kind of lazy bottom dwellers. Like they don’t move as much. And so they do this thing called buccal pumping, and so apparently this is the sole means of inflating lungs in an amphibian. So this is what amphibians do. And basically they just kind of open their mouth and close their mouth and that forces water over the gills.
[00:01:58] David: [00:01:58] Oh, so, to clarify, it’s not [00:02:00] buckle as in belt buckle, it’s buckle as in B, U C, C A L as in the mouth.
[00:02:05] Sophie: [00:02:05] Yes, as in relating to the mouth or cheeks. And so, so there are some other sharks that can do that, but there were some sharks that these obligate Ram ventilators as, and if they stop moving, they will die. And so that’s like great whites and hammerheads and threshes and whale shark, and bull sharks, which is interesting because that’s also a type of Requiem shark, like the gray reef shark, but even some fish Dave, so tuna and Benito and a bunch of other fish also are these Ram ventilators.
[00:02:30] So if they ever stop moving, they’ll die as well. But anyway, getting back to the science in a way from all the shark things I learned this week. So yeah, what they’ve basically discovered is that sharks hanging out in a certain place so that they can kind of surf the ocean currents in a conveyor belt figuration, which allows them to take turns resting.
[00:02:50] So while they’re resting, they’re still moving, which means that they’re still breathing and they’re not dying.
[00:02:55]David: [00:02:55] Yeah. So it seems like this was happening during the daytime, which is when they’re kind of minimally [00:03:00] active. And these researchers observed that the shark were kind of minimally active. they were just that they were literally like not moving their fins very much.
[00:03:07] And of only swimming occasionally and they kind of notice that they were in these weird updraft regions. So what also is happening during the day was that the tide was coming in. So they were this region on the ocean shelf for water was coming up and they would kind of drift forward on it. down towards the ocean floor, I guess, and further out to sea.
[00:03:26] And then a particular time when they were getting to near the edge of the updraft, they would kind of move their fins a bit so that they were drift themselves back to the start of the thing and then repeat the process again. And it turns out that this is consistent with them using these updrafts to do Ram ventilation and so spend less energy.
[00:03:45] Sophie: [00:03:45] Yeah, exactly. so I think they were looking at the hunting habits, right, of these gray,nurse sharks originally. That’s what, this is one of these science things where they were looking at one thing and then they noticed another thing and they decided to go down that path and they found that.
[00:03:57] Yeah. So where they were hunting at night time, then they [00:04:00] would sort of hang around in these channels during the day, but yeah, in these particular updraft regions. And so then they got into These floating conveyor belt sharks. Um, and they used a combination of acoustic tracking tags, animal, born cameras, and then their own underwater observations to kind of monitor these behavior and they created this biomechanical model to calculate the energy expenditure of sharks, swimming in the updraft. And I had a bit of a look at the model and it was fine to be honest, Dave.. It was just, it was like some solid maths. I’m very pleased with it I’ve got no criticisms. Yeah, basically, it’s just a function of hydrodynamic drag, like shark speed, the hydrodynamic propulsion efficiency of the shark this emerge way. They did all this stuff and they then could go and look at, you know, using this model and the sharks and the different places. They found that the sharks, the ones that would hang out and surf these slopes, they cut their energy use by at least 15% doing this, which is like not insignificant.
[00:04:56]David: [00:04:56] No, it’s not, it’s absolutely not. And what I really loved that they did is they use [00:05:00] this. So they made this observation and they made this model. And then they actually did the next step, which was, they went out into the ocean and used multibeam sonar, which sounds really cool and kind of is, and that’s basically where you use multiple beams of sonar shooting and a fan-like pattern from the bottom of your boat to map the ocean floor and basically found regions where based on their model, you would expect to see updrafts of the kind that they’d spotted in French Polynesia where they originally seen
[00:05:29] Sophie: [00:05:29] In the Fakarava Atoll I believe Dave,
[00:05:32] David: [00:05:32] Careful, now. Yeah.
[00:05:33]Sophie: [00:05:33] I looked up the pronunciation and that’s how you say it.
[00:05:36] David: [00:05:36] Excellent work. And so they found a spot where they would reckon That you would see when the tide comes in this same kind of updraft and phenomenon, and sure enough, the predicted sharks were they’re doing exactly the same thing. So they made this observation. Then they made this model. Then they said, well, basically, let’s go out and look for a spot where this should be true, found one, and it was true, which is a really nice result.
[00:05:59]Sophie: [00:05:59] it’s a [00:06:00] really good result. Right? It’s like science imitating art. and then life imitating science. I don’t know. No, it was really, really good. like, I thought yeah, that was perfect. They went, we made this model and that’s why I think that it was a stellar model. Like there’s nothing bad or I was really good.
[00:06:12] And, um, I’ve just got a fact for you though, Dave. So this particular sharks, they get interested in sharks. So these are the kinds of sharks that you will actually see. They do exist in Australia. So they start. Uh, from central Western Australia and they kind of go the whole way up the coast around the tropical north and south, and then around to Southern Queensland.
[00:06:30] They’re also known as the black V Whaler fallers Whaler shark Chrysler shark graceful way, the shark, Lemnos black tail shark and a bunch of other sharks, but Dave, they will attack people. So just be careful as of 2008, the international shark attack file listed seven unprovoked and six provoked attacks from this species.
[00:06:49] Uh, and none of them were fatal.
[00:06:51]David: [00:06:51] Okay, well, that’s good. I have a fact as well, in addition to the non fatality of these attacks and which is I got interested because these are great reef sharks, which are a species of [00:07:00] Requiem shark. And, the name. Requiem may be related to the French word for shark, which is requin,
[00:07:06] Sophie: [00:07:06] Did I spoil your joke?
[00:07:08] David: [00:07:08] No, no, no, not at all. Because that would mean that they’re called shark shark,
[00:07:12] Sophie: [00:07:12] Oh Yeah.
[00:07:14] David: [00:07:14] um, which is of disputed etymology in France, apparently. but one derivation may be from the Latin Requiem, which is, you know, the original word and rest, which would make a cyclic etymology. Cause you go from Requiem to requin to Requiem again. to call the shark requin. or it may be from the old French verb, rechigner, to grimace while bearing teeth, which I also like
[00:07:39] Sophie: [00:07:39] Oh, I mean, that makes sense as well. I feel like that’s what sharks do a lot as well,
[00:07:43]but yeah, this was, um, cool result. And so they found that yeah, incoming tides with stronger updrafts, the sharks do their conveyor belt thing, you know, shuttling along and also tend to go deeper because that’s where the current is weaker and then outgoing tides where there’s more turbulence, the sharks move closer to the surface for a smoother ride and do a [00:08:00] Little bit less of this belt shuffling.
[00:08:02] So Dave, it turns out that the way that the sharks use those updrafts is actually similar to the way that birds stay aloft with minimal energy expenditure. And I want to talk to you about birds right now, but in a completely different way.
[00:08:25] David: [00:08:25] what just a magical segway of the sort that we very rarely managed to master on this show. And yes.
[00:08:32]Sophie: [00:08:32] Yeah. So people, there are a bunch of researchers from the university of California, San Diego, think it’s possible to recreate a bird song by reading only its brain activity, but also something else. Because if you’re on the read its brain activity, it doesn’t quite work.
[00:08:47]David: [00:08:47] Yes, it’s astonishingly complicated. So these are some researchers who are interested in developing communication prosthetics for people who are perhaps mute. And they pointed out that the gold standard in this is communication [00:09:00] prosthetics and implantable devices that allow you to generate text. Um, and they say the gold standard is 20 words per minute, but we’ve recently covered on STEMology, device that does it at 90 words per minute.
[00:09:09] So that’s a bit better, but still text is not as good as actually just being able to speech. Being able to speech, it’s not as good as being able to just speak. So their ultimate goal is to come up with this communications prosthetic that allows people to speak if they’re not able to speak. And they’re studying this in zebra finches, because this is a species that produce song, which is learned. It’s a learned behavior. And it’s very complicated, which make them quite a good model for figuring out how to turn the activity of the sensory motor cortex, which is where the speech comes from into song.
[00:09:42] Sophie: [00:09:42] Yeah. So I think that, cause the idea is often when they do this kind of neural prosthesis research, they use primate models and stuff. Right. But, a primates speech patterns really aren’t particularly complicated when you compare them to a human. But these, um, the zebra finches are, and I’ve, looked up separate, finished singing Dave, and it turns out [00:10:00] that they are loud and boisterous singers and their calls can be a loud beep, meep, Oi or aha. So I presume when they say that as a bird in like different tones in different combinations, that makes a song. but just before we get into it, these are weird. They’re amazingly weird communicators. So apparently zebra finches use an acoustic signal to communicate to embryos. So they, it gives them an incubation code to the eggs when the weather is, and it says hot, but it says above like 26 degrees, so warm.
[00:10:31]and they also give another one near the end of the incubation period. And the call alters the growth and behavior of the chicks like, is that not.
[00:10:38]David: [00:10:38] So the call is you are cooked.
[00:10:40]Sophie: [00:10:40] Yeah. Yeah. Like it’s getting real warm, like maybe expand like less energy or like we’re getting to the end of this time of you being in the shell, maybe get ready to poke your little wee head out
[00:10:51] David: [00:10:51] Come on out. you’re almost ready I’ve ironed your jeans. you some breakfast. Uh, come on out of the egg it’s time.
[00:10:59] Sophie: [00:10:59] It’s worms [00:11:00] and they’re in my stomach for they’ll be in yours soon. But yeah, so what they did is they got four male adult zebra finches, and they put Silicon electrodes in them and then they monitored the birds neural activity while they sang. So the idea was, um, connecting the singing to what was going on in the brain, but that was a bit simplistic. It’s turned out.
[00:11:19]David: [00:11:19] Basically, that didn’t work. So from my understanding of the paper, which is a really complicated paper, the complexity of the audio signal and the complexity of the neural signal were just too complicated to map together in a meaningful way without requiring much more computational power than they had available.
[00:11:34] So there was an intermediate step and to get the intermediate step, I had to go back to their previous paper, which was published 10 years ago and plus computational biology. So wait, actually I have to explain a little bit about how the bird sing.
[00:11:47] So songbird sings by using a structure called the syrinx, which is kind of like your voicebox, except it’s at the branch point of your, windpipe, but further down your chest. And they have two of these valve [00:12:00] structures. So it’s like they have two voice boxes, one on each side of their lungs.
[00:12:03]And basically that means they can valve the airflow and produce sounds on both sides, which is how they’re able to songbirds in general are able to flutter back and forth between songs and make that really complicated noise. Um, anyone in to show, you can think about a magpie. There are songbirds, and they make that amazing warbling noise where they float between stuff.
[00:12:19] And that’s how that works. So in this previous paper, what they actually did was they actually put in a pressure transducer and measured the pressure below the syrinx, while the bird sang and then could map the, pressure changes to the song itself. So they were able to map the pressure changes to the song, using machine learning algorithm, and then what they managed to do in that paper was they actually muted the bird. So they removed, the ability of the bird to sing. So the bird was singing. yeah.
[00:12:49] Yeah. And then use the machine learning algorithms. So they had the bird not singing, but producing the pressure changes. And then the pressure changes producing the song through a computer that the [00:13:00] bird could then hear. So it was effectively still singing. It was just singing using this virtual apparatus.
[00:13:04] Sophie: [00:13:04] I mean, that’s amazing. And just really bit bleak as well.
[00:13:09]David: [00:13:09] so what’s, amazing about it though, is that it’s basically enabled this research because in able to get that pressure sensor part of the thing to work, they had to model the way that the birds’ breathing apparatus works.
[00:13:19] They couldn’t like look at it very specifically. They had to make a kind of what they call a low dimensional model of it. And, but one that is basically good enough. That means they don’t need as much computation. So there, what they did was the bird sang. They took the pressure readings and then mapped that onto the song using machine learning here, they’ve taken it one step further to somewhere quite wild, which is they’ve taken the neural activity of the bird, which they’ve measured using tungsten electrodes placed into the brain, map that activity onto the model of the, you know, the birds breathing and song making apparatus with the pressure information from the previous time and how that model works [00:14:00] and then use that to produce the song. So it’s basically like previous where they had the pressure onto the song and now they put the brain onto the pressure onto the song. And it’s just really complicated and really amazing that they’ve managed to do this.
[00:14:13]Sophie: [00:14:13] Yeah. So I looked at the kind of, yeah, so that the birds vocalization pattern in you know as you said, you met them at a lower dimensional model, which was kind of like a simple representation of changes in the pressure and whatever they’ve got this like set of mathematical equations that model this change.
[00:14:27] I went, oh, that’s fun. I went and looked at it and. It was like a, this was definitely like a little bit complicated, but what I really liked is they use of Helmholtz resonators, which I just get really excited about a Helmholtz resonated. It’s not like that exciting. It’s like, you know, everyone at home when you have a bottle and you blow across the top of the bottle and it makes us sound like that’s Helmholtz residents, basically.
[00:14:46] It’s true. just like air resonance in a cavity, but they use that exactly to model the oropharyngeal and esophageal cavity. But I guess it kind of makes sense the way that you’ve described the way that the birds sing like that, it kind of makes perfect sense.
[00:14:59]so I [00:15:00] think it’s interesting cause I said the next step is, to demonstrate that their system can reconstruct this bird song from your activity in real time. Cause they make a very, interesting point that if there’s any delay so in a person, if you are talking and then you hear yourself speaking with a delay like that, actually you’ll start to stutter.
[00:15:17] Like, and it’s funny, I had this exact experience yesterday having a phone conversation with someone and I could hear myself, but a second later in the phone conversation and you just can’t say anything, you get to the point where, you know, your voice is about to start and you’re trying to ignore it.
[00:15:30] And then you hear yourself speaking. And then the thing that you are saying in real time, you just like, forget it or it gets really, yeah, I don’t know. So that would be the difficulty right now. And apparently the same thing is going to happen to those birds theoretically is if they’re hearing the song with a delay
[00:15:45]David: [00:15:45] it’ll have to be time and it’ll have to be really, really, really real-time because in hearing delays of 10 or a hundred milliseconds are a really long time, which is why, you know, we can listen to music and listen to drums and we can detect when someone’s playing out of time, because if it’s out by even a [00:16:00] little bit, we can tell, cause we’re really, really, really good at hearing.
[00:16:02]So, this is really cool. And the reason that it’s really exciting that they did the brain activity is because that will presumably make it more applicable to humans because just recording the pressure in someone’s chest is never going to give you speech because so much of speech is motor control.
[00:16:16] You know, it’s what you’re doing with the muscles and your mouth and your throat. so we need to have that information and the best way, the least invasive way of getting that information is from the brain probably. so I think this is really cool.
Fissting Hiccups [00:16:27]So from the oropharyngeal cavity of birds, to the diaphragms of humans, which are inexplicably and repeatedly contracting against our wells in the form of a hiccup, Sophie, we’ve got a story about hiccups here.
[00:16:52] Sophie: [00:16:52] I loved everything about it. Um, so yeah, Dave work coming out of the University of Texas Health Science Center at [00:17:00] San Antonio, they have come up with a new science-based intervention for hiccups.
[00:17:05] David: [00:17:05] Right now we can’t get them, but we can get straight to my first problem with the paper, which is the phrase science based, which I take to mean science, like,
[00:17:16] Sophie: [00:17:16] science, like, look, unfortunately, there was a huge amount of detail lacking almost everywhere, but they have come up with something that’s called the Forced Inspiratory Suction and Swallow Tool or FISST and in fact, fist has been patented and branded as hic away. So if anyone finds something in the shops code, hic away, you’re really using one of these FISST tools.
[00:17:39] And so there’s, a good motivation behind it though, Dave, because you could be a person like me who gets hiccups quite frequently just because they don’t learn. So I love me like a soda water in our family. We call it spicy water because my niece, when she was really young, it was like, the bubbles were a bit spicy.
[00:17:53]I’ve got a soda stream. I drink soda water every day. If you do a new bottle of soda stream water, and you drink it really [00:18:00] quickly and it’s very bubbly, you will without fail, get hiccups. And I do it all the time and I haven’t learned, but there are some people who actually get hiccups through no fault of their own. you’ve got patients who have maybe brain and stroke injury. What I didn’t realize was that some kinds of chemotherapies cause hiccups, there’s all these people who actually suffer from hiccups. Whereas I am suffering from a lack of an ability to learn, I think is really my problem.
[00:18:24]David: [00:18:24] Okay. So to clarify, I agree with all of this. I agree that it’s for a worthy cause and they’ve done a good thing. To clarify, in this cross-sectional study FISST was offered worldwide to volunteers through an online Kickstarter campaign. so they’re interested in whether this thing works, but we have to be worried about sources of bias. And one potential source of bias is the fact that everyone who has one of these things bought it. So they’re quite invested in the outcome.
[00:18:49]Sophie: [00:18:49] Yeah.
[00:18:49]David: [00:18:49] and basically the only thing that they’ve measured is customer satisfaction.
[00:18:54] Sophie: [00:18:54] Yeah. A hundred percent. So everything here is it’s also for evaluated. [00:19:00] Yeah. So basically, you said there was an online Kickstarter campaign in 2020, globally 674 participants that said with hiccups volunteer to receive the device but only the 290 participants, which is 43% of the people who received this FISST straw provided a written consent to participate in the study.
[00:19:19] So it’s a study of 290 people who put their hands up to be in the study. So, um, you know, potentially we don’t have a good overview of maybe a society and hiccups sufferers.
[00:19:29] David: [00:19:30] they got 249 responses with a mean age of 30.9, which is the demographic that you and I are in. And that makes sense to me because this is exactly the kind of thing I see adverts for my Instagram feed.
[00:19:40]Sophie: [00:19:40] I mean, yeah, to be honest, one of these straws so I drink, I drink my soda water through it. So, but yeah, we should say that. So this FISST device is basically a rigid drinking tube. So a straw, as we would know, it
[00:19:52] David: [00:19:52] if you will, yeah
[00:19:53] Sophie: [00:19:53] yeah with an inlet valve that requires forceful suction to draw water from a cup into the mouth.
[00:19:58] So the whole idea is the [00:20:00] suction swallow simultaneously stimulates two nerves, the phrenic and Vagus nerves to relieve hiccups, but then complete lack of description, but also maybe that force will suction induces like the diaphragm, um, we know what the diaphragm is and the suctions fully prompts the epiglottitis to like close, which also helps stop hiccups.
[00:20:19] Basically you have to suck really hard and swallow at the same time. And apparently that cures hiccups with the straw.
[00:20:25]David: [00:20:25] they say, that stimulates the phrenic nerve and the vagus nerve, which is kind of right, like the phrenic nerve. Sure. Because that’s the muscle you use to breathe in. But saying that you switched the vagus nerve on it’s like saying Hoddle street is busy in Melbourne and meaning that every single possible car that could fit onto Hoddle street is on Hoddle street.
[00:20:42] Like the vagus nerve is a nerve that does a million different things from closing the epiglottitis to slowing the heart down to making you digest things faster. It does a million things to saying that, to switch this Nirvana doesn’t really mean anything
[00:20:56] Sophie: [00:20:56] Imagine if you were drinking there, Dave, and it made your heart go [00:21:00] slow and you digest really quickly. And you’re like, I just wanted to get rid of the hiccup.
[00:21:03] David: [00:21:03] That’d be great. but here’s my, maybe my biggest problem with the whole thing. Right. Here’s maybe my biggest problem. FISST stopped hiccups and nearly 92% of cases. Right? First of All over what? Timescale over how long cause Sophie, do you have the hiccups right now?
[00:21:19] Sophie: [00:21:19] I haven’t
[00:21:20] David: [00:21:20] you had, have you had the hiccups in the past? So have I, but you know what, in a hundred percent of cases, my hiccups went away. So in 92% of cases, hiccups went away over what timescale, what is this? What does this even mean? It’s less effective than nothing.
[00:21:39] Sophie: [00:21:39] Users self reported, so they could still be lying. Like it doesn’t even, but yeah, Dave, but apparently 226 of the 249 participants. That’s 90.8% rated FISST more feasible than home remedies and they’ve listed home remedies to be breath holding, recycled [00:22:00] breathing in a paper bag and drinking water from the far side of a glass.
[00:22:04] Because the problem with these home remedies, they’re played by unclear instructions, inconsistent performance, and for effective.
[00:22:10] David: [00:22:10] Yes. So I know um, I want it give it some juice because they do actually say that their study hypothesis is that patients with hiccups would associate FISST with more effective termination of transient hiccups. So all their hypothesis was only about the customer satisfaction.
[00:22:24] which still doesn’t mean that it tells you anything, but they also say the limitations of the study include the absence of a control group and the subject nature of the scoring system, which is absolutely correct. But they have basically included in this study that the limitations of the study are that it can’t tell you anything.
[00:22:39]Sophie: [00:22:39] Um, I mean, having said that I do really, like, I’m not sure if you noticed this in the paper as well, where they’re talking about the sort of satisfaction and the said 183 of 203 participants, which is 90.1% indicated that FISST was effective when they used it. But there were 249 participants in the study, Dave, not 203. And they say that they think that fewer participants [00:23:00] answered that specific question because it was the last one in the survey.
[00:23:03] David: [00:23:03] Oh, yes.
[00:23:04] Sophie: [00:23:04] Everyone got bored and left, but you know what, Dave, no adverse effects were reported. And all I can say is like, I want one of these things.
[00:23:11]You can get me one for Christmas, Dave
[00:23:13] David: [00:23:13] Oh, yeah, I’m not going to do it.
The Diet of Rodents
[00:23:25] So from inappropriate air going into your lungs to appropriate food, going into the stomachs of experimental rodents
[00:23:34] Sophie: [00:23:34] Yeah, Okay. so David turns out that potentially by feeding our lab mice and rats the wrong kinds of food, we are possibly confounding variables in experiments, and getting accidental trash result, not trash results, but you know, we are kind of, um, forcing a different outcome, maybe accidentally.
[00:23:55]David: [00:23:55] Yeah, this is interesting.
[00:23:56] Sophie: [00:23:56] So there was a session at the American Society for [00:24:00] Nutrition meeting Dave. So it’s the ASN meeting. Um, and what did they talk about?
[00:24:03]David: [00:24:03] They were talking about how to make rodent feeding more nutritious and how making it more nutritious and consistent, for specifically consistent would improve animal health um, limit confounding variables and experiments. And this is quite important because in science and particularly in medical science and the biomedical sciences, we have a thing called the reproducibility crisis, which is this problem where people do studies and they get lovely results and publish them in lovely journals.
[00:24:27] But then someone tries to do them again and they can’t do them again. And it doesn’t happen every time, but it happens some of the time and knocking down on the reasons why would be really, really good in terms of science in general and the doing of it correctly.
[00:24:42]Sophie: [00:24:42] Yeah. So this is, I think this discussion actually came from a paper that was written by two guys who work at Research Diets, Inc. in new Brunswick. They are the leading manufacturer of custom purified open-source diets, and scientific instrumentation for biological data acquisition in lab animal models [00:25:00] worldwide.
[00:25:00]and yeah, the idea is prior to the sixties, we sort of had no formulation for rodent food – rodent specifically that we used in these experiments. and then in the seventies, a committee of the American Institute of Nutrition developed A I N 76A which was the first widely accepted, publicly available diet formula for rats and mice and the pellets comprised mostly of sugar and milk proteins enriched with specific concentrations of things like vitamins and minerals and amino acids to meet all the rodent nutritional requirements known at the time.
[00:25:31] Since the early nineties, their researchers have used a slightly modified formula code A I N 93, but apparently even this sort of purified rat formula has shortcomings in terms of what’s in there.
[00:25:43]David: [00:25:43] Yeah. So they basically say there could be unspecified amounts class of hormone, like compounds called phyto estrogens. And these can affect things as varieties, as the onset of puberty, the risk of developing cancer. And that’s not even talking [00:26:00] about the confounding effects that could have on whatever study you happen to be running.
[00:26:03] Right. And they make the point. That’s particularly true if you’re studying a nutrition endpoint, which makes a lot of sense. and they talk about how these non-natural diets, including EIN 93, which contained refined, easy to digest ingredients can lead to abnormalities. Um, just like build up a fat loss of intestinal bacteria and a reduction in the size of the intestines, small colons, Sophie, which apparently is bad.
[00:26:26]Sophie: [00:26:26] Yeah, well, I mean, I guess you, what you’re really doing is kind of messing with the mouse physiology accidentally by feeding it these diets. And there’s, they also go into a bit more detail in the paper where they say there’s potentially other things that occur and even foods that we eat, but because mice are a lot smaller, I presume it’s more problematic.
[00:26:44] So there’s, you know, arsenic and heavy metals like lead cadmium and mercury potentially there’s mycotoxins, which are the sort of toxins that produced by certain molds. And that we often get them on fruit and veggies and stuff. And like, they’re not good for people. Um, and there’s like even [00:27:00] pesticides and pollutants, like all the things that go into this, you know, lab food, because you’re not just feeding your pet mouse.
[00:27:05] You’re feeding an animal that’s used for science to often draw conclusions in things that will then impact people later on. So the suggested potential improvements are things like modifying the amount of fiber chromium, calcium and protein in the pellet, but then um Marta Fiorotto from the USDA ARS children’s nutrition research center said that if nutrition scientists can reach a consensus that reformulation is necessary. The next step is to properly compile the available research on the issue, identify a group of experts to make recommendations that feed manufacturers could follow. Yeah, I think, cause it sounds like in this particular discussion, some people said maybe a complete overhaul is needed.
[00:27:47] Other people went, look, we might be overreacting a little bit. Like we need to look at this in more detail, but Dave, something else interesting came up that there are lot of scientists who don’t even use these standardized rodent diets often because [00:28:00] of the cost. Right? So it’s like, you know, if you’ve got enough funding to get, your mice and all the other things you need, but not to buy this like very expensive diet, apparently there’s lots of non purified, natural ingredients, such as ground corn, dried beef, pork, fish, you know, all that kind of stuff that they would then feed these mice.
[00:28:16]and often they don’t specifically disclose, you know, the amounts of these specific things. And as you said, this is a question for reproducibility. So if I did something and you know, this thing happened to my mice, but then you did the same experiment and something different happened. It’s like, well, what, yeah, what is the cause of this?
[00:28:33] And so by standardizing the diets that could have, well, if people can’t afford it,
[00:28:37] David: [00:28:37] Yeah, you’re absolutely right. it’s about controlling the variables and the experiment, isn’t it. And the reason you would not do it in a scientist would be cost, but also there’ll be lots of people who just don’t think it will impact their study because of what they happen to be studying.
[00:28:48] I mean, these are nutrition researchers saying this is important for nutrition and probably other research, but if you happen to be studying immune function or, you know, the nerve supply to the kidney [00:29:00] or something, there’ll be lots of people who are just saying, oh, well, it doesn’t really matter.
[00:29:03] So because I’m studying this, which has nothing to do with this, and they may be right, but they may not be right. And that’s, I guess, where it gets tricky.
[00:29:10] Sophie: [00:29:10] Yeah.
[00:29:11] David: [00:29:11] And one thing I found interesting about the improvements to the diet, one of the proposed improvements was improving the fatty acids components.
[00:29:18]because apparently uh the AIN 93 contains soybean oil and the reason it contain soybean oil is because it contains linolenic acid, which is an omega three precursor. But apparently that’s becoming of concern, not because it’s of concern in itself, but because the soybeans, Sophie, they are changing, so soybeans which are produced now for whatever reason have less linolinic acids.
[00:29:42] So there’s less, omega-3 fatty acids going in to the feed and that is apparently a cause for concern.
[00:29:49] Sophie: [00:29:49] that’s interesting. Yeah. I didn’t even think about the fact that crops and things
[00:29:52] David: [00:29:52] Yeah. Yeah, And the other two that they suggested were increasing fiber of all brand, or [00:30:00] maybe, special K
[00:30:01]Sophie: [00:30:01] Yeah, just in very small pieces though.
[00:30:03] David: [00:30:03] Yeah. And at removing sucrose, which makes sense. Cause presumably they think that sugar is bad for the rats and mices in the same way that it’s bad for us.
[00:30:11]Yeah. So we should do this. I think it sounds like we should do it in the interest of standardization and reproducibility and maybe make things better for the mice.