Backyard Aquaponics
A place to discuss aquaponics

The introduction of seed crop as an alternative protein feed for aquaculture is commonly weighed up taking into account the following

The nutritional content and composition of the feed
The anti-nutrient content and composition of the feed
The digestable portion of all feed contents

What scientists are then looking for is performance – the energy and growth value of the food - the amount of fats, carbohydrates, proteins and anti-nutrient content that are actually absorbed and utilised by the fish, in relation to the amounts present in the diet.

Lupins have performed well alongside fishmeal, rapeseed, cornmeal and soymeal as fish nutrition.

Fish live more off the fats and protein in their diets being rather poor at assimilating carbohydrates. Two specific amino acids present in most protein sources, l-lysine and l-methionine, are crucial to fish development and health. Both amino acids are present in lupin cultivars Angustifolius and Albidus. The protein digestibility varies with the percentage of lupin present in the diet, and hulled seed further enhances the percentages of digestible protein.

The adverse affects of anti nutrients in seed crops (specifically in this case oligosacharrides) will vary at differing levels and species of vegetable protein supplementation.

Oligosacharrides are virtually indigestible without the presense of a-galactosidase enzymes. Various lupin cultivars have present a-galactosidase enzymes (EC 3.2.1.23)

Protein efficiency begins to be inhibited over 50% of Lupin in diet. It is debatable as to the cause of this, whether it is due to L-methionine and L-lysine being insufficient with high lupin dietary content, or due to anti nutrients present reaching levels where adverse effects are seen.

Lupins have a unique dietary value – the phosphate retention is considerably higher than other feed sources. This is good news for the planet dealing with the wastes of conventional Aquaculture, but for Aquaponics, what does it mean?

There are two notable things happen in the digestion of lupins that makes the waste a bit different to what would normally be encountered in Aquaculture.

1. High Cellulose waste.

2. Lower Phosphate waste.

High cellulose requires algal enzymes, they are the only thing capable of breaking down lignin, or fibre.

Low phosphate dictates less proteins for the formation of enzymes needed to deal with high cellulose waste.

Conclusions - Much to be learnt yet.
Lupins are a good fish food.
L-Angustifolius has been proven an excellent strain.
Hulled seed is better than whole seed.
Lupins should only be a supplement for AP fish so other foods with higher phosphate waste ensure the correct balance to break down the fibre content of waste.

Huge write up AA.
TimC and I were talking about this somewhere.TimC put a link in i think to a PDF. will look and see.

I read a pdf I got off the net and wrote this. Probably the same one if it was the same/similar title.

About 120 pages odd?

I like stripping the pdf's down give us a chance to see what they say before the screen goes all hazy and words blur and...

you know...

Fair call, It did make interesting reading but reads better condensed

A lot of pig feed in Australia uses lupins as a major component.

(I have read somewhere or other that some school kids in Australia did some really nice research on using it as a food for humans.)

I have fed tilapia on pig feed pellets ( a quick whizz in a coffee grinder to make the particles a little more granular (like chick crumbs) (I used pig feed cos it is very cheap) - supplemented with azzolla, duckweed and the odd worm or two ... no problems at all.

As with humans, I think a varied diet is good.

So lupins mixed with other inexpensive, high protien things would be a great way to go.

(Don't feed them cottonseed though! .. cottonseed contains a substance known as "gossypol" which, in chickens turns the yolk an appetizing black colour. YUK! I think poor people in India have been known to use cottonseed meal as a natural method of birth control.)

Lupins get a thumbs up from me!

(Mixed with other ingredients to form a well balanced feed... 2 thumbs up!)

Formulating feeds is quite an art, should involve lots of experimental feeding trials and would depend very much on the type of fish being raised. Much research and feed trials have been carried out to optimise returns for commercial ventures where the dollar is the goal.

In regard to backyard aquaponocs and fish feeding, I guess the idea is feed them whatever we can get our hands on, variety is the spice of life, if it costs little or nothing, so much the better, and if the feed is healthy then go fer it!

Good memory Gnash06...

Repost if anyone is interested... http://www.fish.wa.gov.au/docs/op/op031/fop031.pdf

You are right though I only read the contents page and looked at the pictures and graphs.

AA,
Thanks for the Reader's Digest version. I wouldn't have made it through 120 pages.

Thanks people, I love to read and even I find the PDF's hard. Thought it'd be a nice contribution though, so soldiered on. Yes it's the same PDF thanks Tim.

And Johnnie, always ahead of the 8 ball!

Thanks mate, excellent feedback and information.

AA- I skimmed that a few weeks ago, and it made me think that one of the better fish foods we could use would be sprouts. A combination of Lupins, (a legume), other legumes, alfalfa, and grains.

I have been trying to figure a way to sprout fish food, even better would be to make it automagically sprout, then dribble into the tank, with little or no additional intervention.

automagically? Neat word!

I like it! It best describes how I would like things to run, (but they unfortunately seldom do!

hehehe, yeh I like it too - hope this doesn't mean we need to start up an AP dictionary

your turn Les, I did the toolkit

You taking lessons from Steve (dob in les to do it)

you brought it up! I thought you were volunteering!