Food quality related to nutrient dificiency signs?

[Kobus Jooste]

I have recently started experiencing an interesting problem with my micro-nutrient balance in the micro system.  Since I started running the system in different configurations in 2008, I have not seen this problem and was wondering if others have experienced the same.  One of the cornerstone assumptions of AP is that if you start off with a GOODquality fish food, you should have all the trace elements needed in the system, barring Molybdenum and Boron.  In terms of fish food in South Africa, it is not all that easy to shop around.  We have one established and one new supplier, and the range of pellets that they do is rather limited.  In the past to date, I have used three different food types in my system, all from the same established manufacturer.  I ran the system from set-up to late 2009 on a high grade koi pellet, as the tilapia feed is only sold in bulk and I was not going to buy a huge amount of food and watch 80% of it spoil.  I had 20 fish! When I moved the system, I bought new tilapia stock (gave the old away when I took the system down) and got a kg of the tilapia food used by the supplier to set them up.  When this ran out, I decided to get a bulk bag of tilapia food from the supplier, but could not get a match to what I was using.  Protein content went up from 35% to 41% (way too high in my opinion) and the pellet was smaller and lighter in colour.  The manufacturer does not print exact nutrient break-downs on the packaging, thus I am in the dark about what I am using.  Since I switched to the current bag, I have seen every type of difficiency except nitrogen and Molybdenum manifest itsself in the system.  At first I was at a bit of a loss, but I have had enough time to run troubleshooting to the point that I want to blame the food.  I do not lime excessively, supplement potassium every now and then, have a 6.5 pH  and the fish are feeding very well.  When I add chelated iron and trace elements, the problems go away.

 

Has anyone else found these problems and what, other than supplementing, has been done to fix the problem?  My options are limited in terms of food source.   

[Kobus Jooste]

I'm sure you were Francois, but they have moved off the 4 mm sinking and now do a smaller one that floats.  41% protein, and I do think their quality has gone backwards

Francois Lemmer said:

Hi Kobus
I use to feed my fish on a 4mm pellet that was developed by the Stellenbosch university.
I had to buy in 25 kg bags + transport....
cost of food was very expensive due to transport
was I using the same brand fish food as you...
francois

Kobus Jooste said:

I see a blog topic coming up.  I don't have an issue with supplementing, but to get back to a system health and commercial system point of view, the feed you pick has to have eveything the fish require at least, and having 10% too much protein and likely a lack in trace elements could influence the health of the fish.  I have not lost any of the tilapia, but if their growth is not optimal and if I am tossing in supplements all the time, my already slim margins will look even worse here in South Africa.

Harold Sukhbir said:

And I thought it was just me, something i was doing wrong.Thanks for bringing this up Kobus. Two cucumber plants, got to fruit and started to wither and died. What got me is that they really took off and in just a few weeks started fruit, looked just the picture of health, and within one week, yellowed and died. I've read that they do extremely well in raft and I'll be trying that next for sure. I too switched fish food and noticed about 30%-40% better growth. Trace and macro elements are easy to add as a supplement to any system but I think fish need high quality protein to grow, and as they grow the system will mature.

[Harold Sukhbir]

Here's a great article all about fish food, makes good reading

http://www.americanaquariumproducts.com/Quality_Fish_Food.html

[Kobus Jooste]

So, it would seem that for us to grow a sustainable food with high nutrient value for our AP systems, we should be looking at having Lemna and Spirulina as two main components.  Anyone tried to do Spirulina yet?

Harold Sukhbir said:

Here's a great article all about fish food, makes good reading

http://www.americanaquariumproducts.com/Quality_Fish_Food.html

[Harold Sukhbir]

Then there's the Omega 6-3 problem. Seems there's no getting around the fact that fish must eat fish. If AP has to takes us into the future we'l have to figure out a way to make it truly sustainable. Wild fish stock are depleting and slowly becoming toxic with mercury, cadmium, lead, arsenic, pcb's etc. Fish meal will pose the threat of bio-magnification in our tank fish, if it is not doing so already.

[Kobus Jooste]

One option is go for vegetarian fish species such as Carp.  Obviously you want a fish that contains the omega fatty acids as you need those for your own diet.  Plant sources of these nutrients are not deemed as great as the fish derived alternatives, thus we are a little bit stuck there.  If you really get down to it, you may consider culturing a fish species in your AP system that is a great source of these Omega 3 (and 6?) fatty acids - Jade perch (Scortum barcoo).  I'm just not sure what base diet thay need to be on in order to yield the best Omega levels.  Anyone out there with an answer?

Harold Sukhbir said:

Then there's the Omega 6-3 problem. Seems there's no getting around the fact that fish must eat fish. If AP has to takes us into the future we'l have to figure out a way to make it truly sustainable. Wild fish stock are depleting and slowly becoming toxic with mercury, cadmium, lead, arsenic, pcb's etc. Fish meal will pose the threat of bio-magnification in our tank fish, if it is not doing so already.

[Eric Warwick]

If we were to create a food chain of some fish converting plant mater to fish protein and feed that to our food source fish we could improve food quality. However there is the 10% rule, so keep the amount of organisms to the food source (eating fish) to a minimum.


Harold Sukhbir said:

Then there's the Omega 6-3 problem. Seems there's no getting around the fact that fish must eat fish. If AP has to takes us into the future we'l have to figure out a way to make it truly sustainable. Wild fish stock are depleting and slowly becoming toxic with mercury, cadmium, lead, arsenic, pcb's etc. Fish meal will pose the threat of bio-magnification in our tank fish, if it is not doing so already.

[Sylvia Bernstein]

Eric, I'm curious about the 10% rule you are referring to.  Can you talk more about that?

Kobus, I am also quite intrigued with Jade Perch!  Can't find them here for some reason (does anyone know why?), but here is a great blog post that Frank Gapinski at EcoFilms wrote last summer on them - http://www.ecofilms.com.au/2010/08/02/jade-perch-the-perfect-aquapo...

Harold, I wonder if the answer lies in using discarded fish - bi-catch and the waste from fish processing - as our future source of fish meal rather than harvesting fish specifically to create fish meal.  Would need to know a lot more about the quantities available vs what is needed, but could it be as simple as hooking up the guys doing the fishing and processing with the guys seeking the fish meal?  

[Kobus Jooste]

I'll let Eric handle the 10% rule, as I may get it too convoluted - basically I think it relates to the number of trophic levels that feed on contaminated food items before you get to the fish you use as feeder stock.  Each step increases the amount of toxins that magnify up the food chain.

 

In terms of Jade perch, it is an excellent AP candidate - found in large areas of the tropical zones around Australia, it can take terrible water conditions.  In the Queensland area it inhabits the billabongs that only gets seasonal water input.  It is an omnivore but will do well on a predominantly plant diet, and has more Omega fatty acids in it than Salmon.  You may have an invasive risk attached to the species in similar parts of the US.

Sylvia Bernstein said:

Eric, I'm curious about the 10% rule you are referring to.  Can you talk more about that?

Kobus, I am also quite intrigued with Jade Perch!  Can't find them here for some reason (does anyone know why?), but here is a great blog post that Frank Gapinski at EcoFilms wrote last summer on them - http://www.ecofilms.com.au/2010/08/02/jade-perch-the-perfect-aquapo...

Harold, I wonder if the answer lies in using discarded fish - bi-catch and the waste from fish processing - as our future source of fish meal rather than harvesting fish specifically to create fish meal.  Would need to know a lot more about the quantities available vs what is needed, but could it be as simple as hooking up the guys doing the fishing and processing with the guys seeking the fish meal?  

[Eric Warwick]

Almost Kobus, the 10% rule is an mean taken to describe how much energy (calories in this case) gets lost to physical activity such as swimming and repairing cells. So basically the higher you go in the food chain the less animals you can have in that trophic level. That is why you want to keep a food chain length to a minimum for maximum efficiency.

Kobus Jooste said:

I'll let Eric handle the 10% rule, as I may get it too convoluted - basically I think it relates to the number of trophic levels that feed on contaminated food items before you get to the fish you use as feeder stock.  Each step increases the amount of toxins that magnify up the food chain.

In terms of Jade perch, it is an excellent AP candidate - found in large areas of the tropical zones around Australia, it can take terrible water conditions.  In the Queensland area it inhabits the billabongs that only gets seasonal water input.  It is an omnivore but will do well on a predominantly plant diet, and has more Omega fatty acids in it than Salmon.  You may have an invasive risk attached to the species in similar parts of the US.

Sylvia Bernstein said:

Eric, I'm curious about the 10% rule you are referring to.  Can you talk more about that?

Kobus, I am also quite intrigued with Jade Perch!  Can't find them here for some reason (does anyone know why?), but here is a great blog post that Frank Gapinski at EcoFilms wrote last summer on them - http://www.ecofilms.com.au/2010/08/02/jade-perch-the-perfect-aquapo...

Harold, I wonder if the answer lies in using discarded fish - bi-catch and the waste from fish processing - as our future source of fish meal rather than harvesting fish specifically to create fish meal.  Would need to know a lot more about the quantities available vs what is needed, but could it be as simple as hooking up the guys doing the fishing and processing with the guys seeking the fish meal?  

[Kobus Jooste]

How dare I neglect the laws of thermodynamics :)

Eric Warwick said:

Almost Kobus, the 10% rule is an mean taken to describe how much energy (calories in this case) gets lost to physical activity such as swimming and repairing cells. So basically the higher you go in the food chain the less animals you can have in that trophic level. That is why you want to keep a food chain length to a minimum for maximum efficiency.

Kobus Jooste said:

I'll let Eric handle the 10% rule, as I may get it too convoluted - basically I think it relates to the number of trophic levels that feed on contaminated food items before you get to the fish you use as feeder stock.  Each step increases the amount of toxins that magnify up the food chain.

 

In terms of Jade perch, it is an excellent AP candidate - found in large areas of the tropical zones around Australia, it can take terrible water conditions.  In the Queensland area it inhabits the billabongs that only gets seasonal water input.  It is an omnivore but will do well on a predominantly plant diet, and has more Omega fatty acids in it than Salmon.  You may have an invasive risk attached to the species in similar parts of the US.

Sylvia Bernstein said:

Eric, I'm curious about the 10% rule you are referring to.  Can you talk more about that?

Kobus, I am also quite intrigued with Jade Perch!  Can't find them here for some reason (does anyone know why?), but here is a great blog post that Frank Gapinski at EcoFilms wrote last summer on them - http://www.ecofilms.com.au/2010/08/02/jade-perch-the-perfect-aquapo...

Harold, I wonder if the answer lies in using discarded fish - bi-catch and the waste from fish processing - as our future source of fish meal rather than harvesting fish specifically to create fish meal.  Would need to know a lot more about the quantities available vs what is needed, but could it be as simple as hooking up the guys doing the fishing and processing with the guys seeking the fish meal?  

[Sylvia Bernstein]

I learned something new today.  Thanks, guys.

[Harold Sukhbir]

The short chain vegetable Omega acids aren't a substitute for the ocean produced. I saw this article on a company in Australia growing algae in ponds which is new and will fit the bill. Here's the link;

 

 http://www.aurorainc.com/aurora-algae-introduces-the-industry%E2%80...