Re: water weight

[Sarah Ralston <ralston@AESOP.RUTGERS.EDU>]

At 10:33 AM 12/21/99 -0700, you wrote:
>Hmmm, I read this in Stephen Duren's article on 
Feeding the Endurance Horse and thought gut water 
content might be used to support blood plasma levels
>(and ward off dehydration).  Nutrients move across
 the membrane - is water not able to move through?
>
>"The additional water and electrolytes in the 
>digestive tract of the high fiber animals is probably 
>due to the high water holding capacity of plant fiber. 
>More importantly, the water and electrolyte pool 
>created by a high fiber diet can be used to combat dehydration and
electrolyte >imbalances which derail so many endurance horses."
>

The large intestine is a major site of water absorption-ingesta in the
colons are normally <10% solids whereas by the time the horse lifts it's
tail, those fecal balls are over 20% dry matter (I've done a lot of
digestion trials and have reems of data on fecal dry matter-it's a S$$%Y
job but someone had to do it ;-)). There have been several studies
documenting the fact that both water and electrolytes are absorbed from the
large intestine in horses. What needs to be verified is whether increased
amounts are absorbed during prolonged exercise. Also how much stress
induced diarrhea (ah, we've all seen this at rides!) affects the overall
picture. 

By the way-Steve Duren recently told me he and his wife have started
competing in distance rides. Heads up, Ridecampers in Oregon! Steve is one
tough competitor AND an extremely nice guy (And a superb nutritionist).

Sarah
Sarah


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