Could someone tell me how antibiotics promotes weight gain in livestock? Is the use of antibiotics only a necessity because so many animals are kept in close quarters? What about antibiotics causing weight gain in humans?
Consider how many of these steps involve cell growth and or tissue damage that needs to be repaired: https://www.youtube.com/watch?v=zQGOcOUBi6s
TLDR; Low dose antibiotics don't eliminate infections, but by reducing their growth the immune system puts far less effort into defense.
Also, this is why if your doctor prescribes a course of antibiotics you should always complete the entire course, even if you feel fine. Stopping the antibiotics early can select for resistant strains.
1. http://learn.genetics.utah.edu/content/microbiome/resistance...
Fascinating stuff. People can read more about it here: https://en.m.wikipedia.org/wiki/Protein_structure_prediction
This is a common experience in combinatorics ( https://en.wikipedia.org/wiki/Combinatorics ).
Similar things happen when beginner programmers (like me!) try to solve chess by recursing/looping through possible moves (there are about 10^123 separate paths, if duplicate configurations are merged together), or brute-force a cryptographic hash/key (2^k possibilities for keys of length k; keys of length 2048 and above are common).
The "standard big number" that gets thrown around when pop-sci articles talk about this stuff is the number of atoms in the observable universe, which is estimated at around 10^80. It irks me that this is used so much for comparison, since combinations of things are so overwhelmingly larger than collections of things that it feels like a category error to compare them.
After all, "the number of atoms in the observable universe" isn't a particularly intuitive quantity; unlike, say, "football field" as a unit of length or "bag of sugar" as a unit of mass/weight (UK media loves to use the latter; since a bag of sugar is 1kg, it shows off both their laziness and lack of faith in their audience...).
Also, picking "the number of atoms in the universe" is really trying hard; yet these combinatorial numbers (protein foldings, chess positions, etc.) are actually small, everyday examples! People have no problems (either conceptually or practically) with playing board games, choosing passwords, etc. despite these large numbers lurking in there.
The "atoms in the universe" number would be a hopeless comparison if we really tried to make a big combinatorial number. For example, "the number of binary sequences that can be represented by all the world's computer storage"; a quick Google search estimates the world's data storage as 295 exabytes, so that makes this number around 256^(295 * 10^18)
I think this is the core of the issue. "Atoms in the universe" is only such a relatively 'small' number if you assume that the way they're arranged is unimportant.
2^2048 is so astronomically large a number it has no universe sized meaning, its likely way way more than any discrete chunking you can do of stuff in the whole universe.
Something like 2^128 or 2^256 are more common 'brute' force type numbers, which would correspond to trying every key in a symmetric cipher like AES or a public key signature in ECDSA
2^256 is similarly quite large, but we can practically estimate this to be about the number of atoms in tens of thousands of galaxies.
Some people are claiming this is not supported by evidence: http://www.bmj.com/content/358/bmj.j3418.full
Previous HN discussion: https://news.ycombinator.com/item?id=15311274
If you get 5 day subscription stop on day 3, then take the rest next week that's bad.
I'm glad for all the research into causes of antibiotic resistance, and if medicine comes up with a better way to treat infections and minimize resistance, I'm all for it.
1. https://www.ncbi.nlm.nih.gov/pubmedhealth/behindtheheadlines...
Whether or not people understand, believe the concerns are overblown or believe that we'll always be one step ahead, or will only stop when things get really bad, amounts to the same thing; misuse of anti-biotics.
It's a very human behavior to prefer a pound of cure to an ounce of prevention. It's magnified when you won't be responsible for the cure or the cost of it yourself. It's a weight that will be borne by all of society.
http://edis.ifas.ufl.edu/an285
There is also other growth promotion due to antibiotics.
source: https://www.nature.com/articles/nature11400
abstract: Antibiotics administered in low doses have been widely used as growth promoters in the agricultural industry since the 1950s, yet the mechanisms for this effect are unclear. Because antimicrobial agents of different classes and varying activity are effective across several vertebrate species, we proposed that such subtherapeutic administration alters the population structure of the gut microbiome as well as its metabolic capabilities. We generated a model of adiposity by giving subtherapeutic antibiotic therapy to young mice and evaluated changes in the composition and capabilities of the gut microbiome. Administration of subtherapeutic antibiotic therapy increased adiposity in young mice and increased hormone levels related to metabolism. We observed substantial taxonomic changes in the microbiome, changes in copies of key genes involved in the metabolism of carbohydrates to short-chain fatty acids, increases in colonic short-chain fatty acid levels, and alterations in the regulation of hepatic metabolism of lipids and cholesterol. In this model, we demonstrate the alteration of early-life murine metabolic homeostasis through antibiotic manipulation.