substituting crab meal for fish meal

annagoodspeed

Songster
7 Years
Jan 24, 2017
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Central Idaho 3000 ft
Hi All, I feed a winter mix with a base of non gmo peas wheat 16%, and supplement it with Fertrell fish meal (and dried nettle and alfalfa) to get the protein up a little more and give them those essential enzymes. Can I substitute feed grade crab (crustacean) meal for the fish, in terms of essential nutrients? Thanks!
 
Doing this now, forgive thetypos, I'm pre-caffeine. :caf

Here is the guaranteed feed label for Fertrell's Crab Meal

and here is the Fish Meal from Fertrell's

Right off the bat, we see neither label offers guidance regarding the vitamin content of the feeds (almost), and none of "gardening" varieties of fish or crab meal offer even that much information, so if you choose to use them, you are taking a (barely) educated shot in the dark.

With what we know, Fertrell's Fish Meal is substantially higher in protein (60% min vs 42% minimum for Crab meal), high enough in fat (4%) that you may (depending on the other components of the feed) may want to consider using a "filler" to reduce it slightly, while Crab Meal's low (1.5%) fat is much more tolerant of a higher fat, greater seed or oil content feed. While Fish Meal does not disclose its salt content, I understand from other sources that it is not supposed to exceed 4% - high, but not critically so, since most of your other feed ingredients should be relatively low. That leaves fiber, and fish meal is VERY high (10%) - you will want to avoid other high fiber (seed hulls, rice hulls, etc) additions to your feed.

Now we make some educated guess, relying on Feedipedia.org, and the assumption that Fertrell's producst are similar to the "generic" Fish and Crab meals. Fertrell tells us that their fish meal meats minimum levels of calcuim, phosphorus and selenium - and being non-phytate phosphorus (that is, not plant based), we know its readily digestible by our chickens wihtout need for the addition of phytase. According to Feedipedia, crab meal has MUCH more Calcium per unit weight, and significantly less Phosphorus per unit than fish meal, and an unknown level of selenium. Because calcium and (digestible) phosphorus are used in a ratio for most biological processes by all animals (nature is "unfond" of reinventing the proverbial wheel), we can draw some additional inferences confidently.

The ratio for bone building and most other processes is 2:1. According to the label, that's what Fetrell's Fish Meal provides. Feedipedia gives a ration closer to 6:5, but critically, the amount of calcium does not far exceed the amount of phoshporus. Crab Meal? The ration is almost 12:1! Much less P per unit, many times more Ca per unit weight. Sources vary - a lot (and likely driven in part by the relatively recent discovery that phytate and non-phytate P are digested differently (if at all) by chickens, absent supplimental phytase, so some of the older study findings need a caveat - you know, the older studies on which "layer feed" is based!). But for most laying hens, since egg shells are around 40% calcium, ratios of 4:1 to 6:1, sometimes high as 8:1 fill the literature.

Related literature indicates that high levels of unused calcium both inhibits nutritive absorbtion in the gut, and contributes to a LARGE number of known and predictable health problems in hatchlings, juveniles, adolescents, infrequent layers of small- medium eggs, and male chickens of all ages. While some forms of Ca (Dicalcium Phosphate, Calcium DiPhosphate) are less likely to promote those conditions, they aren't present in quantity here.


tl;dr - the differences betwee the two feed sources are so great, in so many dimensions, that "substitution" is not recommended. If you intend to use crab meal routinely, your entire feed mix should be reconstituted and rebalanced around that ingredient. Feedipedia does not offer Amino Acid profiles for crab meal (in fact, the page is under construction), and I did not find any studies in a (VERY) rapid search of the internet, it appears SOME modern research is being conducted formally on crab meal as a poultry feed ingredient. LONG ago, it was investigated but not (seemingly) followed up on, likely for reasons of cost or availability - in favor of more common ingredients (like meat scraps). In theory, its quite useful - in practice, it seems somewhat less than scientific (though likely successful for some), which makes it harder for us to jump to the desired end goal without first "F'ing around and finding out for ourselves".

Hope that helps?
 
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Man, does it!! Thank you for your explanation. I hesitate to speculate what your mind is like post caffeine, but really looking forward to reading all your other posts. I’ll stick with the fish meal. Hoping some day some kind of affordable dried insect meal comes along. Anyone farming termites? Someplace far away from my wood house? 🤣🤣
 
Man, does it!! Thank you for your explanation. I hesitate to speculate what your mind is like post caffeine, but really looking forward to reading all your other posts. I’ll stick with the fish meal. Hoping some day some kind of affordable dried insect meal comes along. Anyone farming termites? Someplace far away from my wood house? 🤣🤣
That's what BYC is for - happy to have been in a position to assist.
 

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