Live Food Gut Loading Question

[Lowells Fish Lab]

Hi all,

I've got a nerd question I'm struggling to resolve:

When we culture nematodes like microworms in a growth medium, do they consume the medium directly for food or the bacteria that develops in it? I think the answer I've encountered more often is that they consume bacteria but that leaves me wondering, how does that affect efforts to enrich the medium or "gut load"? Are we gut loading the nematodes via the bacteria they would consume or do they get those extra nutrients by consuming the media directly?

Using the microworm example, I've got this odd personal hypothesis that there might be a cleanliness advantage to using something purely starchy as a growth medium because, with the addition of yeast, I would think the dominant microbial presence would be yeast in the same way that cheeses can safely age for long periods of time above refrigeration temperature because lactobacillus simply outcompetes other bacteria. What are the risks inherent to culturing bacteria in an enriched medium that could include animal matter (from something like powdered fish food) or other non-starches?

Any thoughts would be appreciated. This is all in consideration of whether or not I should explore gut loading more.

Thanks!

[Eric R]

Interesting question. I can't answer it, but I can say that I culture microworms on potatoes (actual peeled and boiled potatoes, not the mix in a box kind). The culture seems to last a long time without smelling bad, sometimes 3-4 months. Recently, I've started sprinkling yeast on the top of the culture about once a week, which greatly increases culture production for a couple days.

[Lowells Fish Lab]

Now that is interesting! I have only used potato flake and I think the cultures last about a month tops. I'm going to give that a try.

[MJV Aquatics]

For microworms, I culture using mashed potato flakes. Yeast processes the media and the microworms consume the yeast. For white worms, I feed yogurt and a blend of whole wheat flour, powdered chick feed, and corn meal. Worms process organic matter but derive their nutrition from bacteria and protozoa that process the feed. Gut loading is really unlikely.

[Lowells Fish Lab]

21 minutes ago, MJV Aquatics said:

Worms process organic matter but derive their nutrition from bacteria and protozoa that process the feed. Gut loading is really unlikely.

That's exactly the distinction I was getting at, thanks!