Discus questions

[TNT77]

The findings were “cross checked” in lay terms. That is, the results obtained by the above method were compared to results of molecular weight “markers” for proteases. What was found is that discus stomach and intestine contain two groups of digestive enzymes with the ones in the stomach working best at a pH of 2.0 while the group in the intestines worked best at a surprising pH range of 7.5 - 9.0 and at a second range of 11.5 – 12.5. The pH ranges further confirmed the findings of the intestines containing the proteases Trypsin and Chymotrypsin and Metalloproteases while the low pH of 2.0 inhibited the functioning ( if present ) of these proteases in the stomach. The discus stomach pH confirmed the finding of “pepsin-like proteases” in the stomach, which require a pH range of 2.0 – 3.0 to fully process proteins consumed by the fish. The high level of Chymotrypsin ( .61 average ) and Trypsin ( .79 ) matches or exceeds the levels in the intestines of other “carnivorous” and “omnivorous” fish. Also matching the profile of “carnivorous” fish is the low presence ( .09 - .03) of these proteases in the stomach of discus. Further matching a carnivorous fish’s “enzyme profile” is the actual “activity” of Trypsin above the level ( nearly double ) of Chymotrypsin which would be reversed for a fish able to sustain itself on plant material / vegetable material. In total, 8 specific proteases were identified, located and “activity” noted.
Do believe you have completely ignored the fact that even though discus can digest plant matter they mainly utilize the proteins. The fact that the enzymes are comparable to those of a carnivore plus the way the way they digest and utulize food suggests higher proteins levels throughout life. Robert Winfree wrote that even adult discus should have protein levels up to 49.99%. The above information was not linked for the levels but for the digestion references which you have completely ignored. But I am not in this to argue. Anyone can feed what they will. But take into account that RD has been banned from a discus site I know for certain reasons.
Plus the op does have 1.5" and the above material you are promoting for juvie growth is for up to 3" discus. So your call op. I wish you the best of luck.

 

[RD.]

The enzymes that you are referring to, are those produced by 10 week old fish, not semi-adults, and not adults. There are plenty of nutrients that can & are gleaned from plant matter, besides just protein. Unlike Fred Goodall, I'm not fixated on just protein when it comes to the optimum level of nutrients that a fish requires for optimum long term health.

There is nothing in any of those studies that suggests that an adult discus requires 50% protein, anymore than an adult piscivore requires 50% protein. You might want to broaden your horizons a bit before making claims such as that. Robert Winfree can write & say whatever he likes, unless he has conducted some long term feed trials to support that hypothesis that's all it is, a hypothesis with no credible data to support it.

Nor did I ignore the digestion levels, none of this is anywhere near the black/white that some people have postulated on various discus forums. Most don't even understand the basic fundamentals, and have based their comments (such as Fred has) due to their obvious bias towards beef heart. Clearly from the studies performed over the years by Chong et al it is quite obvious that certain plant matter can indeed be digested, and utilized by a discus, even a juvenile discus.

In which study does it state that a discus will mainly digest/utilize just the protein portion of ALL plant matter? Please share that little nugget of information, as I'm almost certain that outside of a few select terrestrial based plants no such data exists. Are we now to believe that a discus cannot utilize the vitamin & mineral content of a food stuff such as spirulina, or other aquatic algae? Really?

As previously posted:

"The alimentary canal of Symphysodon is characterized by a poorly defined stomach and an elongate intestine, some 300 mm long and 3 mm wide (in a 180 mm SL specimen). This intestinal morphology is typical of a cichlid with a dominantly vegetarian, detritivorous, or omnivorous diet."

This species feeds predominantly on algal periphyton, fine organic detritus, plant matter, and small aquatic invertebrates.

That's real data, from discus collected in their natural environment.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000400008

You think that all those fish are pulling out of all of the plant matter & algae is protein?


From one of the studies previously linked to in this discussion.

Jonas et al. (1983) reported that trypsin activities were generally higher compared to chymotrypsin for carnivorous fishes while in omnivorous and herbivorous species, activities of chymotrypsin were higher. However, both types of proteases are believed to play a collaborative role in protein digestion at the intestinal tract Cohen et al., 1981; Uys and Hecht, 1987; Glass et al., 1989.

See how that works? This isn't a simple case of black or white, there are always shades of grey involved in these types of studies. Even carnivores (at least those that have been studied) are in fact capable of producing enzymes that allow them to assimilate a certain amount of plant matter, both aquatic based, and terrestrial based plant matter, and not just for protein content. A carnivores enzyme activity is generally much lower than a herbivores, which simply means they can not digest as much plant matter as a herbivore can. Even Asian arowana are capable of digesting a certain amount of plant matter. This only makes sense as the prey of most carnivores is often gut loaded with plant matter, and thousands/millions of years of evolution has allowed carnivores to fine tune their digestive systems so that little to nothing of what they eat goes to waste.

But take into account that RD has been banned from a discus site I know for certain reasons.

Now that was certainly entertaining. What does my status on some discus forum have to do with anything in this discussion?

FYI - It was a self imposed ban, as in I asked Al to remove my account last year so as not to further upset the status quo in his perfect little politically correct discus world. I had actually been a member there for 7 or 8 yrs. Their loss, not mine.

Cheers!

 

[TNT77]

I do not wish to have further discussions with someone who feels they need to degrade others. I believe that a breed specific site that has been running for such a long period of time and endorsed by a great deal of top breeders should given the credit it deserves. To the op I do wish you the best of luck with your new babies. Post pics when you can.

 

[RD.]

I see, yet you felt perfectly fine about making sure that everyone here knew that I had been banned from that site, as though that had anything to do with this discussion. Funny how that works.

 

[arowanas lover]

op i been following this thread and all i have to say is do what you believe is smart. whether its listening to an expert that can sell out over 500 fish in less than 2 weeks or someone who saids you should have a variety yet turns around tells you discus can be finicky eaters and you should try different flakes.

no point in discussing this any longer as it only add fuel to the fire and no matter what is posted someone who insists they are right can not be proven wrong

good luck with you fish dont forget to do the water change