The feeding mash: the bio-reactor for our Acropora

Beyond plain food: bacterial pre-digestion

If we think our Acropora are happy with a pinch of powder poured into the current, we are ignoring their physiology. As Yuri Sorokin teaches us, the coral is a holobiont that makes the most of its energy only if the food is bioavailable.

The feeding mash (in Italian, "pappone") is not a recipe: it is a biochemical process.

The premise: why do we prepare it this way?

In nature Acropora live in a "soup" of bacterioplankton and organic matter that is already partly broken down. In the aquarium, dry food is too "hard" and inert.

The goal: to turn solid particles (POM) into dissolved nutrients (DOM) and live bacterial biomass.

The trick is time: the 4-5 hours of soaking set off enzymatic hydrolysis. Proteins are "taken apart" into free amino acids (DFAA) that the coral absorbs directly by pinocytosis, without even using its mouth!

The gladiator's ingredients

Three key components are needed to forge this nutritional weapon.

SPS powders (the base): freeze-dried zooplankton, rotifers and algae. They are the bricks.

Amino acids (the signal): they trigger the feeding response (the polyps opening) and feed the tissues.

Live bacteria (the turbo): this is the magic touch. The bacteria start colonising the powder in the glass, making it "alive" and rich in vitamin B12 and organic phosphorus.

1. 1SPS powders · the bricks freeze-dried zooplankton, rotifers and algae
2. 2Amino acids · the signal make the polyps open (feeding response) and feed the tissues
3. 3Live bacteria · the turbo colonise the powder and make it alive, with vitamin B12 and organic phosphorus

The mucus captures, the polyp conveys.

The ingredients of the feeding mash.

The capture mechanics (Sorokin style)

Many people ask: "But bacteria are tiny, how does the polyp eat them?"

The mucus net: while soaking, bacteria and powders form a colloidal mixture. Once in the tank, this mix gets caught in the sticky mucus of the Acropora.

The conveyor belt: microscopic cilia on the polyps push this mucus, loaded with "bacterial mash", straight into the animal's mouth.

The mucus captures, the polyp conveys.

1. 1The mucus net bacteria and powders get caught in the sticky mucus
2. 2The conveyor belt the cilia push the mash-laden mucus towards the mouth
3. 3The mouth the polyp swallows the bacterial mash

Even the smallest bacteria reach the mouth, carried by the mucus.

Operating protocol: how to enter the arena

Preparation: in a glass of tank water, mix powders, amino acids and your dose of bacteria.

Incubation: leave it to stand for 4-5 hours. During this time the bacteria "pre-digest" the food for the coral.

Feeding: pour it into the tank. Do not switch off the circulation pumps. As Martin Hovland says, the flow must break up the coral's boundary layer so that the mucus can intercept the feast.

Export: skim wetter to remove the excess, once the holobiont has feasted.

1. 1
   Preparation

   In a glass of tank water: powders, amino acids and bacteria.

2. 2
   Incubation 4-5 hours

   The bacteria "pre-digest": proteins become free amino acids.

3. 3
   Into the tank, pumps on

   The flow breaks the boundary layer and the mucus intercepts the food.

4. 4
   Export

   Wetter skimming to remove the excess, after the feast.

From solid particles (POM) to dissolved nutrients (DOM) and live bacterial biomass.

The feeding mash protocol, step by step.

Conclusion

The feeding mash is the secret to going from a tank of Acropora that are "alive" to a tank of explosive Acropora. We are giving the holobiont exactly what Sorokin studied on the reef: a ready-to-use source of organic nitrogen and phosphorus that does not pollute but builds tissue.

Who wrote this article

Sources

1. Grover R., Maguer J.-F., Allemand D., Ferrier-Pagès C. (2008). Uptake of dissolved free amino acids by the scleractinian coral Stylophora pistillata. Journal of Experimental Biology 211(6): 860-865.