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.
This may well be the way forward in manufacture of uncontaminated vegetable protein and includes Omega 3's. As we need Omega 3's in our diet and it's not present in most freshwater fish, the fish food manufactured from this algae will be a healthy addition to AP and be a large factor toward it's sustainability for the future.
I did a bit of looking into the Omega ratios of some of the freshwater fish. I learned that there is a huge difference in the omega ratios between farm raised catfish and wild caught catfish. The wild caught catfish was far healthier to eat according to the omega 3 ratios. I think this has mostly to do with the other parts of the commercial fish feed than the fish meal.
Well one step in improving the Omega ratio in fish like catfish and tilapia will probably be in pushing for a different basis for the feeds. Current US fish feeds are mostly corn, and soy in addition to the fish meal and vitamin admixtures. Well corn and soy tend to have about the worst omega ratios so it stands to reason that the farm raised fish who eat it will also have poor omega ratios while the wild caught counter parts do have better ratios from their wild diet.
And the wild caught catfish are not eating ocean fishmeal to get the better omega ratio (granted it isn't like they are one of the prized omega 3 type fish.) Wild catfish have a pretty varied diet as do many types of fish and that diet will vary with age. Plankton, zoo plankton, algae, insect larva, insects, invertebrates, crustations, amphibians, and small fish are all on the menue for many types of fish at different stages in life. Now how to provide that in proportions that will make for healthy fish to eat while not costing more than the house will be a challenge.
I am hopeful that some of the research into algae cultures will help fill the needs. There are many plant sources that have some good levels of the precursors to the Omega 3s that may be useful as well if not as a feed for us or our food fish, perhaps as a feed for the food for our food fish.
Yea, I'm reading "In Defense of Food" and yea, all our western re-invention of food in an effort to be healthier seems to be backfiring on us. Trying to get back to more whole foods and and less refined (stripped) and re-fortified foods may well be a key to health and the same may hold true for the foods we eat as in your example of grass fed beef as opposed to feed lot grain/corn/soy fed beef.
Sylvia Bernstein said:
Hi TC. Missed you. A travelling stint? Your reply was well said. Sounds mighty parallel to what is happening in the beef industry, etc. Beef used to be a reasonable source of Omega 3 when it was grass feed. I guess the "grass" equivalent to catfish is the diet you listed above. The lesson that we need to keep learning from nature rather than reinventing her keeps getting driven home...
Oh, it is easy to strive for an ideal, but we humans can rarely achieve them. While at home, I can eat good food but when you notice I'm not online much for a time, I rarely manage to eat well while working my other jobs. (Tends to be even worse since it is often at or traveling to those jobs when I have time to read actual books)
Anyway, yes a very good book.
Sylvia Bernstein said:
Isn't that a great book? I'm a huge Michael Pollen fan. He came to Boulder a couple years ago and we got to hear him speak - I highly recommend it if you get the chance. I had a bunch of 1/2 sheets printed with his motto for healthy eating "Eat food, not too much, mostly plants" and asked him to sign them. Then we framed them and gave them away as Christmas gifts. Sometimes the most profound wisdom comes in the simplest thoughts! Given what we've learned of you, TC, I can't imagine you are too far away from an ideal, whole diet...
I have seen the good result of eating a lot of green vegetables and fruits, also drinking a lot of water on a daily basis help our body keep fit and healthy.