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If so. Please share why? Give your 2 cents or provide the proof. Thank you.

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Hello Vlad,

Can you tell me which book you are reading? I would like to check it out.

Thanks

Cliff


Vlad Jovanovic said:

This is from a book I've been re-reading...

"...

Although flavor is not a measured factor for fruit identification, high flavor
(organoleptic properties) sensed by the consumer can result in repeat sales
for labeled fruit of known origin. There are two measured factors that are
associated with “high” flavor, a fruit EC of 5.8 to 6.2 dS/m, and a BRIX
measurement of 4.8 to 5.0. Flavor can be a subjective factor since not everyone
can sense the same thing. In general, high acid- and sugar-containing fruit is
normally judged as “flavorful.” Most of the flavor in the tomato fruit resides
in the gel portion. Therefore, the ratio of gel to wall in the fruit can affect flavor.
High flavor stems from two fruit components, sugar (glucose and fructose)
content and level of volatile organic compounds. Forty-six percent of the dry
weight of fruit is sugar, 12% organic acids, 8% minerals, and the remaining
other organic compounds. The longer the fruit remains on the plant, the higher
will be its flavor. The cooler the air temperature, particularly nighttime temperature,
the higher the fruit flavor. In general, plants under stress produce
higher-flavored fruit; this is the reasoning behind the common procedure of
increasing the EC of the nutrient solution to about 4 dS/m or adding NaCl to
the nutrient solution at a concentration of 35 ppm in solution during the
fruiting period..."

I remember the guy that I used to buy my hoop-house plastic from telling me about this stress/flavor thing 7-8 years ago...



Miguel Afonso said:

That makes sense. Thank you. 

Maybe I should shout at my tomatoes, then reconcile them later so thy don't poison me. 

 

Hello Miguel,

 I've been out for awhile. In terms of fish food, I been playing with various sources including insects, vegetable pulps, and worms in addition to other popular sources. I don't use any part of fish directly nor commercial feed. So far, fishes seems to be doing O.K. (only few months) and I don't have a large scale setup to see whether it is feasible option either. I think I'll do more experiment when spring comes.

Cliff

Miguel Afonso said:

Thanks Clifford. I am kind of hoping for the same results, but I guess is the definitive answers come with doing research. To me it would suffice to measure PH and soluble nutrients in the water to determine the outcome. I am definately a proponent of the idea that what you put in is what you get out. If you are adding fish food. What is it made of? I allow leaves and debri into my system for this reason.Besides seaweed extracts etc. commonly used in aquaponics, I also have been looking at other potential sources of plant nutrients for aquaponics systems. 

Jones, J. Benton, 1930–
Hydroponics : a practical guide for the soilless grower / J. Benton Jones, Jr. — 2nd ed.
p. cm.
Includes bibliographical references and index.
ISBN 0-8493-3167-6 (alk. paper)
1. Hydroponics. I. Title.
SB126 .5 .J65 2005

Though that paragraph I quoted was about all the book had to say on that particular topic...

Apparently, stress will affect the flavor of different cultivars in different ways...Though I'm sure that my AP system will get plenty of stress without me having to induce any of it on purpose 

Wonder if the fish will taste better that way..?Mhuuhaaaahaaahaaa

Clifford Lee said:

Hello Vlad,

Can you tell me which book you are reading? I would like to check it out.

Thanks

Cliff


Vlad Jovanovic said:

This is from a book I've been re-reading...

"...

Although flavor is not a measured factor for fruit identification, high flavor
(organoleptic properties) sensed by the consumer can result in repeat sales
for labeled fruit of known origin. There are two measured factors that are
associated with “high” flavor, a fruit EC of 5.8 to 6.2 dS/m, and a BRIX
measurement of 4.8 to 5.0. Flavor can be a subjective factor since not everyone
can sense the same thing. In general, high acid- and sugar-containing fruit is
normally judged as “flavorful.” Most of the flavor in the tomato fruit resides
in the gel portion. Therefore, the ratio of gel to wall in the fruit can affect flavor.
High flavor stems from two fruit components, sugar (glucose and fructose)
content and level of volatile organic compounds. Forty-six percent of the dry
weight of fruit is sugar, 12% organic acids, 8% minerals, and the remaining
other organic compounds. The longer the fruit remains on the plant, the higher
will be its flavor. The cooler the air temperature, particularly nighttime temperature,
the higher the fruit flavor. In general, plants under stress produce
higher-flavored fruit; this is the reasoning behind the common procedure of
increasing the EC of the nutrient solution to about 4 dS/m or adding NaCl to
the nutrient solution at a concentration of 35 ppm in solution during the
fruiting period..."

I remember the guy that I used to buy my hoop-house plastic from telling me about this stress/flavor thing 7-8 years ago...



Miguel Afonso said:

That makes sense. Thank you. 

Maybe I should shout at my tomatoes, then reconcile them later so thy don't poison me. 

 

Thank you Vlad,

Cliff

Vlad Jovanovic said:

Jones, J. Benton, 1930–
Hydroponics : a practical guide for the soilless grower / J. Benton Jones, Jr. — 2nd ed.
p. cm.
Includes bibliographical references and index.
ISBN 0-8493-3167-6 (alk. paper)
1. Hydroponics. I. Title.
SB126 .5 .J65 2005

Though that paragraph I quoted was about all the book had to say on that particular topic...

Apparently, stress will affect the flavor of different cultivars in different ways...Though I'm sure that my AP system will get plenty of stress without me having to induce any of it on purpose 

Wonder if the fish will taste better that way..?Mhuuhaaaahaaahaaa

Clifford Lee said:

Hello Vlad,

Can you tell me which book you are reading? I would like to check it out.

Thanks

Cliff


Vlad Jovanovic said:

This is from a book I've been re-reading...

"...

Although flavor is not a measured factor for fruit identification, high flavor
(organoleptic properties) sensed by the consumer can result in repeat sales
for labeled fruit of known origin. There are two measured factors that are
associated with “high” flavor, a fruit EC of 5.8 to 6.2 dS/m, and a BRIX
measurement of 4.8 to 5.0. Flavor can be a subjective factor since not everyone
can sense the same thing. In general, high acid- and sugar-containing fruit is
normally judged as “flavorful.” Most of the flavor in the tomato fruit resides
in the gel portion. Therefore, the ratio of gel to wall in the fruit can affect flavor.
High flavor stems from two fruit components, sugar (glucose and fructose)
content and level of volatile organic compounds. Forty-six percent of the dry
weight of fruit is sugar, 12% organic acids, 8% minerals, and the remaining
other organic compounds. The longer the fruit remains on the plant, the higher
will be its flavor. The cooler the air temperature, particularly nighttime temperature,
the higher the fruit flavor. In general, plants under stress produce
higher-flavored fruit; this is the reasoning behind the common procedure of
increasing the EC of the nutrient solution to about 4 dS/m or adding NaCl to
the nutrient solution at a concentration of 35 ppm in solution during the
fruiting period..."

I remember the guy that I used to buy my hoop-house plastic from telling me about this stress/flavor thing 7-8 years ago...



Miguel Afonso said:

That makes sense. Thank you. 

Maybe I should shout at my tomatoes, then reconcile them later so thy don't poison me. 

 

   

     I'm not sure about the idea that a vitamin has to be in the system to end up in fish or plants. There are many essential substances, like vitamin D, that the human body produces on its own. "Good" cholesterol also comes into this category. It is only "Bad" cholesterol when it is from the consumption of another animal or animal product. Living organisms are not just a means of transportation. They also have the characteristics of a laboratory or a factory and can produce many of the things it needs. Do the same kinds of metabolism occur in fish and plants? Also, how you consume your vegetables will have a huge impact on how much nutrition you are gaining. Many of the enzymes and nutrients are destroyed by cooking, so it is recommended that at least %50 of our diet be raw.  A great way to get extra raw greens into your system is green smoothies.  Google it.

I don't believe aquaponic systems necessarily have high nitrogen levels.

Eric Warwick said:

Aquaponic crops might be less nutritious due to the high Nitrogen levels.

So after reading this conversation, some questions I still have are:

  • Do plants have the ability to manufacture balanced vitamin and mineral contents from a source of fertilizer that is primarily nitrate, adding only photosynthesis and the unique genetics of each vegetable? While nitrogen levels may not be overly high in a balanced system, it is still the most available element compared to P, K, and micronutrients.

  • For that matter, where do P, K, and other nutrients come from in an AP system? Introductions to aquaponics always explain the nitrogen cycle of ammonia --> nitrite --> nitrate, but when I first read that I wondered where the minerals and micronutrients come from. Do the plant's other nutritional requirements come directly from the dissolved components of uneaten fish feed, or do they get carried through in the fish waste as well, perhaps converted by other beneficial microbes that play a lesser role than the nitrosomonas?


If it's all about the feed, I agree with Carey's post about not relying on commercial fish food sources. Not only do commercial feeds contribute to the problems of industrialized farming and overfishing, thereby undermining our noble efforts to get away from those with AP -- but like he said, they will also lack the balanced nutritional profile that we want to come through in our veggies. So if we're feeding black soldier fly larvae, duckweed, organic crops grown for our fish onsite, dead bees from hives positioned over the fish tank, bugs falling from bug zappers, etc -- or at least supplementing our commercial feeds with these things -- that should go further towards improving the nutritional quality of our AP crops. Even small commercial AP operations can incorporate these, as I learned in my workshop with Max Meyers in the spring. So we can certainly work on accomplishing self sufficiency of fish feed at home, with lower stocking densities and lower feeding rates, and focusing on quality over quantity.

I'm just beginning to learn a little about soil science and nutrient cycling, and I guess it works a little differently in aquatic systems. Can't say I know much about nutrition either, but I'm interested in learning more about how these all relate. Instinctively I believe that maximizing life and biodiversity, particularly microbiology, will maximize the health and nutrition of the system, whether it be the soil food web or an aquatic system.

Just because we always focus on the nitrogen cycle in aquaponics, that doesn't mean the fish feed and fish waste doesn't contain all the other stuff.  I mean do you think fish could grow if there was only protein and nothing else in the fish feed?  The nitrogen cycle is simply the cycle we pay attention to when getting the bio-filter up and running since it will tell us if the water is safe for the fish or not.

And commercial fish feeds have been developed to provide complete nutrition for the fish and that usually results in good nutrition for the plants though depending on your source water, certain things sometimes do need to be supplemented.  Iron, potassium, calcium are the most common things to supplement.

I agree that it would be lovely to get away from commercial feeds and am always looking into ways that might be accomplished.  However, trying to cut out the commercial feed in an effort to get better nutrition to the fish and the plants may be more counter productive than you realize.  It may be possible but for the average home aquaponic system, growing ones own fish food and getting a complete balanced diet to the fish is not as easy as it might sound.  No single thing is going to do it and formulating or figuring out what is missing from your fish diet is likely a tall order for the average person.  There are universities and big companies spending lots of money to develop fish feeds that grow fish well without deficiencies and diseases caused by such deficiencies.  Trying to cook that up from your own back yard and kitchen is likely to cost you much in ingredients, time, money, energy, and testing.

That said, the more natural you can make their diet, the better for you it will be to eat those fish.  Corn and Soy are not natural fish foods but they use way too much of them in most commercial fish feeds which means the Omega 3/6 ratios are not good.

There are things other than just worms and BSF larva that you can culture to feed your fish.  Midge larva are actually good food for fish and can improve fish growth.  I like to feed snails to my catfish, I just need to figure out a more efficient way to harvest the snails from my troughs.

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