Wood eating loricariids 2

[lfinley58]

Enjoy!

Lee

Inside the guts of wood-eating catfishes: can they digest wood? by Donovan P. German. J. Comp. Physiol. B, June 27, 2009.


Abstract To better understand the structure and function
of the gastrointestinal (GI) tracts of wood-eating catfishes,
the gross morphology, length, and microvilli surface area
(MVSA) of the intestines of wild-caught Panaque nocturnus,
P. cf. nigrolineatus “Marañon”, and Hypostomus
pyrineusi were measured, and contrasted against these same
metrics of a closely related detritivore, Pterygoplichthys
disjunctivus. All four species had anatomically unspecialized
intestines with no kinks, valves, or ceca of any kind.
The wood-eating catfishes had body size-corrected intestinal
lengths that were 35% shorter than the detritivore. The
MVSA of all four species decreased distally in the intestine,
indicating that nutrient absorption preferentially takes
place in the proximal and mid-intestine, consistent with
digestive enzyme activity and luminal carbohydrate profiles
for these same species. Wild-caught Pt. disjunctivus, and
P. nigrolineatus obtained via the aquarium trade, poorly
digested wood cellulose (<33% digestibility) in laboratory
feeding trials, lost weight when consuming wood, and
passed stained wood through their digestive tracts in less
than 4 h. Furthermore, no selective retention of small particles
was observed in either species in any region of the gut.
Collectively, these results corroborate digestive enzyme
activity profiles and gastrointestinal fermentation levels in
the fishes’ GI tracts, suggesting that the wood-eating
catfishes are not true xylivores such as beavers and termites,
but rather, are detritivores like so many other fishes
from the family Loricariidae.

http://www.springerlink.com/content/301 ... lltext.pdf

[MatsP]

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Mats