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In the current/latest edition there is a mini article pertinent to all panaque lovers and deals with the long held belief on the consumption of wood.
It challenges the validity of manufacturers putting wood in foods (in particular lingin) and also technically states they are eating degraded/rotting wood whilst grazing for other 'stuff'
The article is a good read, gets you thinking and by Dr Donovan german

Cool, thanks Ian, will have to get it.

I've seen this article and I’m not too convinced. How can wood in a lab really replicate its natural environment? I think they are many things that have not have been took into consideration, from wood type to species etc. Also many studies from wild specimens show there diet is mainly all wood.

Personally its good to see research being done into panaques but I doubt you can conclude it in a paragraph.

Skilldeft said:

I've seen this article and I’m not too convinced. How can wood in a lab really replicate its natural environment? I think they are many things that have not have been took into consideration, from wood type to species etc. Also many studies from wild specimens show there diet is mainly all wood.

Personally its good to see research being done into panaques but I doubt you can conclude it in a paragraph.

Click to expand...

The article states whilst feeding on whats ON the wood their teeth take in a lot of wood but don't necessarily digest it all.
Aren't we always saying they poop loads of saw dust? That says to me it passes right through them (bit like sweetcorn in us:lol

Here is my summarised version of it:

When Panaque nigrolineatus (and Pterygoplichthys disjunctivus) were fed wood in a laboratory both lost weight and had use their own protein reserves.

Around 70% of their daily intake is decaying wood, they cannot survive on wood alone.

They cant efficiently digest cellulose. However they are very efficient at digesting wood degradation products such as disaccharides produced by microbes degrading the wood.

Most loricariids are grazers consuming the Epilithic Algal Complex (EAC) which is a loose assemblage of bacteria, cyanobacteria, filamentous green algae, diatoms and detritus.

However the enlarged teeth of Panaque and Hypostomus dig into the wood and consume a considerable amount of it, only efficiently digesting the degradation products.

Aquarium foods with added Lignin (plant 'cement') serve no real purpose as it is very difficult to breakdown, just acts as filler. May even reduce digestibility of food due to covalent bonding.

Extra food should include algae wafers and other fish faeces.

The type of wood is important, decaying wood of riparian trees from the Amazon basin, not pine or exotics. Get degraded wood from a river/creek that is not polluted.

Also, tannins need to be investigated. Loricariids are most abundant and diverse in non tannin stained water so tannin laden water could be a problem over time. However, no health problems observed in P. nigrolineatus for more than 2 years.

Hi all,
It is an interesting paper, I've had a long think about it, and I've cross-posted (apologies for the cross-post) the link to Matt's thread on PF, as there are a few more comments about Dr German's paper there.

<http://www.plecofanatics.com/forum/showthread.php?t=81356>

Cheers Darrel

Dr Germans reply - Panaque & wood

Hi all,
With apologies with re-opening this old post, but I've just had an email from Donovan German, and it makes interesting reading. One point of interest was that he observed the Panaques feeding on a wide range of woody debris.
It was a long email with lots of detail, but he did include a summary.

Dr Germans summary:

"So, just to summarize what I think these fish are doing… the wood-eating catfishes dig into decaying wood and efficiently digest wood degradation products that environmental microbes are making available as they degrade wood. The fish also have elevated digestive enzyme activities (e.g., N-acetyl-b-D-glucosaminidase) suggestive that they digest fungi within the wood matrix. Thus, they likely get “energy†from the degraded wood. The stable isotopic signatures (carbon and nitrogen) of wild-caught wood-eating catfishes certainly suggest that they get their protein from fungi and amorphous detritus, and we find periphyton and amorphous detritus in their guts (in addition to the wood; see the “inside the guts†paper where I do a detailed gut content analysis of wild-caught fish). Basically, the fish have to get their nitrogen from somewhere other than the wood detritus (there isn’t much N in wood anyway). The fish certainly ingest wood, they just don’t use the same “pathway†to obtain energy from it as a termite. Rather than harbouring an endosymbiotic community, they let the microbes in the environment do the work for them. This may be a function of living in an aquatic environment."

cheers Darrel

Thanks for that, interesting update

Thanks for that Darrel very interesting
It does make you wonder if they are getting anything from the bogwood that we put in for them
Pete

Hi all,
Pete it probably depends upon the state of the wood. Very hard bog/mopani wood won't provide any/many nutrients, but may have other important functions in the fish. They certainly didn't evolve teeth like that for fun.

I think Donovan is saying that the wood that we would reject to go in the aquarium e.g the soft, rotted fungal bits, are probably what the fish really wants.

I'd keep the structural wood in, but also feed small amounts of rotted wood, you could literally collect any fallen non-coniferous wood, and pile it up in a damp corner of the garden, once it's started to break down and you can see the fungal mycelia transfer it in to the tank. So really just treat it like another vegetable, and take it out before it fouls the water.

A thought occurs that you could culture Oyster mushrooms, shiitake etc on a log, and feed the spent logs to your fish.
<http://www.ragmans.co.uk/products/index.html>

cheers Darrel