Panda guts not suited to digesting bamboo | Hacker News Reader

Panda guts not suited to digesting bamboo

nature.com

54 pointsbillconan27 comments

The particular bacteria species present (Escherichia, Shigella and Streptococcus bacteria) are typical of carnivores, not herbivores, but we don't know how much (yet) how much those strains have or have not adapted to their cellulose job. From the article:

"Eisen says that some of the microbes in the panda gut might still be highly efficient at breaking down cellulose. He argues that the study's authors examined only microbial composition, not function — and microbes can change function rapidly, making it hard to predict how they perform solely on the basis of the genera of bacteria present. A 2011 study2 found evidence that Clostridium bacteria in panda guts contained genes that resembled those known to produce enzymes that break cellulose down into simpler sugars.

'I’m not convinced at all that there's any limitation to the cellulolytic activity in this system based upon the data they have,' Eisen says of the new study.

The researchers say that the most important question of the study is whether the panda’s carnivore-like microbial structure can still effectively utilize cellulose. More work will help to provide a complete picture."

I was under the impression that in addition to bacteria you would also need a different digestive system, similar to the 4 chambered stomach the cows have. Are there any other animals who have a simple digestive system, like the pandas, but due to their bacterial content can in fact digest cellulose?

Termites can digest cellulose. http://en.wikipedia.org/wiki/Termite#Diet

As can rabbits, apparently, via a form of hindgut fermentation. http://en.wikipedia.org/wiki/Rabbit#Diet_and_eating_habits

Poor pandas. It's as though Mother Nature has been trying to naturally deselect these bears for some time. They're such ineffective competitors that it surprises (and delights!) me that they're still around.

Yes, but these bears have very cleverly evolved the ability to seem irresistibly cute to the current master species of this planet. From personal observations, they seem to emit some sort of aura that induce people (in particular post-puberty to adult females humans who I'm trying to date) to emotionally melt down and make incomprehensible "cooing" noises. This aura increases in strength with increases in proximity to these bears, and is most pronounced in younger bears. The effect is particularly strong and can remain for several hours in the host even if bears are removed. This can and has led the host engaging in questionable (and often regrettable) activities with me she would otherwise refrain from doing.

In any case, for all their microbiome weakness, they've evolved a rather fascinating survival strategy to cope with humans so I don't think these bears will be removed by natural selection any time soon.

I'm not sure whether you're joking, but that's actually what happened to dogs. Unlike wolves and many other beasts, we can empathize with dogs' facial features (apophenia?), thus making us less likely to endanger them. You can think of it as some sort of camouflage.

So pandas were omnivores many years ago, then they became herbivores with physical adaptations to eat bamboo, though their guts didn't keep up with the process.

Can pandas still eat meat? Could you, for example, feed a panda in captivity a carnivorous diet with an expectation that it would thrive?

Pandas do eat some meat in the wild, they've been seen catching and eating birds and rodents.

What about in captivity. Perhaps reintroducing pandas to a meat diet would solve a lot of pandas' problems.

That's what I'm curious about. I don't presume to know better than zoologists, so maybe this has been tried and/or rejected for reasons I don't know about but it seems that it could help. Maybe wild pandas will cease to be, but it may be possible that a diet adjustment could at least keep a population viable in captivity.

Well they have been eating bamboo for 2 million years according to the article. While they are not completely adapted, they have probably made at least some adaptions. So a meat diet may not be optimal.

This is similar to humans. Our diet has changed a great deal in recent evolutionary history. E.g. eating cooked meat, or large amounts of processed grains. But that's not quite as severe as switching to eating bamboo.

Could one do the panda equivalent of a fecal transplant? If so... would this be likely to improve the panda's health and be transmitted to its offspring?

I'd like to know how gut microbes get transmitted from mother to offsprings in other mammals especially humans. I've never thought that the microbes are, in a matter of speaking, hereditary.

If you have a child, you'll read about this. A baby's digestive system is essentially sterile in the womb. There's increasing evidence that important bacteria are passed to the newborn from the vaginal canal during the birthing process – and is an argument against C-sections.

Also related is the resurgent practice of placing a newborn directly against the mother's bare chest immediately after birth, which among other benefits, is supposed to foster bacterial transference through skin-to-skin contact.

As a disclaimer, I'll just say that this field of knowledge seems rife with theories but somewhat lacking credible scientific studies that do long-term tracking of health outcomes. So, I take much of it with a grain of salt.

Here are a couple of studies I found:

Delivery mode shapes the acquisition and structure of the initial microbiota across multiple body habitats in newborns

http://www.pnas.org/content/107/26/11971.full

Influence of mode of delivery on gut microbiota composition in seven year old children

http://gut.bmj.com/content/53/9/1388.2.long

A variety of ways and it varies across species. Some animal young purposefully eat adult feces to seed their guts. Others pick up a sampling during birth from obvious sources. Also none of us wash our hands religiously enough to avoid 100% fecal contamination so babies pick bacteria up indirectly as well. Some people theorize that's behind their "mouthing" behavior.

"He argues that the study's authors examined only microbial composition, not function — and microbes can change function rapidly, making it hard to predict how they perform solely on the basis of the genera of bacteria present. A 2011 study found evidence that Clostridium bacteria in panda guts contained genes that resembled those known to produce enzymes that break cellulose down into simpler sugars."

It sounds the authors identified the bacteria flora in the panda gut via feces, but not the bacterias' specific gene expressions which may vary even if they are known suited more for carnivore digestion (e.g., but may be specialized to digest plants cellulose in panda gut environment).

For those involved in genomics, I'm curious as to how one can obtain the RNA expression (RNASeq) of multiple bacteria present in panda gut; and how do they go from the raw sequence data sequenced from the multiple bacteria composition to match the specific gene and then also its host bacteria?

So what's the panda version of paleo?

This animal has failed at evolution on practically every level. Such a waste of effort to keep them alive while continuing to kill off so many other species. 1000 years from now it will just be us, the cockroaches, and pandas.

This Gizmodo piece pretty much sums up why we should just let them all die.

http://gizmodo.com/5841175/should-we-just-let-pandas-die-off...

They also received a grade of 'F' in their official Animal Review.

https://animalreview.wordpress.com/2008/05/04/pandas/

Pandas were planted by creationists to instill doubt in evolution.

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