Nutritional value of hatched baby brine shrimp

[JoJosReef]

I've read that brine shrimp are like potato chips for fish, nutritionally low value. Thus, you need to get gut-loaded brine shrimp for any nutritional value.

And I've also read that hatched baby brine shrimp (BBS) are very nutritious, and somewhere that it has to do with their yolk sacs. And then I've read that it depends on how long after you hatch them whether or not they are nutritious. Presumably, if you wait too long after they hatch, then they've exhausted their yolk sacs and need to be gut loaded.

The topic of this thread is hatched BBS. Does anyone have knowledge on how long after hatching they maintain their nutritional value? At what point should you be gut loading them? In my case, I have powdered spirulina to add to the tube I collect them in before dosing them into the DT.

Also, it seems like the eggs don't all hatch at once. I can add a scoop of BRS Artemia eggs to the bowl hatchery on Monday, and they steadily move to the center ring until Friday. Are those Thursday/Friday BBS newly hatched? Or did they hatch on Tuesday and just hang out in the dark part of the bowl for a few days?

Thanks!

 

[ISpeakForTheSeas]

I've read that brine shrimp are like potato chips for fish, nutritionally low value. Thus, you need to get gut-loaded brine shrimp for any nutritional value.

Gut-loading them once they're developed enough to eat (i.e. once the yolk sac is absorbed) is always a good idea, but whether they're nutritious or not really depends on the species eating them; for some species, brine shrimp are incredibly nutritious, and for others, they could be force fed a bunch of brine shrimp and still die from malnutrition.

And I've also read that hatched baby brine shrimp (BBS) are very nutritious, and somewhere that it has to do with their yolk sacs. And then I've read that it depends on how long after you hatch them whether or not they are nutritious. Presumably, if you wait too long after they hatch, then they've exhausted their yolk sacs and need to be gut loaded.

Again, dependent on species, but - generally speaking - newly hatched brine shrimp are pretty nutritious, and they do rapidly lose nutritional value as their yolk sacs are depleted (see the first link at the bottom, which says they lose 30-50% of their nutrition between 24 and 48 hours post hatching). So, the earlier you can feed them, the better.

Does anyone have knowledge on how long after hatching they maintain their nutritional value? At what point should you be gut loading them?

Peak nutritional value would be retained for about 24 hours after hatching; as mentioned above, they can lose approximately half of their nutritional value within 48 hours, and it likely goes down further from there (ignoring the nutritional value of any food they may be fed).

They can begin feeding after ~12 hours post hatching, so offering them food then is probably the best idea; without food, they can reportedly feed off of just the yolk sacs for anywhere from 3-5 days (likely dependent on various conditions like broodstock health, water quality and temperature, specific species and strain, etc.), but - again - their nutritional value does go down fast for many species that might eat them.

Also, it seems like the eggs don't all hatch at once. I can add a scoop of BRS Artemia eggs to the bowl hatchery on Monday, and they steadily move to the center ring until Friday. Are those Thursday/Friday BBS newly hatched? Or did they hatch on Tuesday and just hang out in the dark part of the bowl for a few days?

I'm not entirely sure on this one. The longest I've heard for these to hatch is 48 hours, with 18-36 being more typical. So, if you add them Monday night, some could theoretically hatch Wednesday night and be "newly hatched" still for at least part of Thursday, but they'd be more than 24 hours old come Friday (and rapidly losing nutrition).

https://digitalcommons.uri.edu/cgi/viewcontent.cgi?article=1085&context=srhonorsprog