From The Crab Street Journal- Scientists evaluate that crabs use a natural selection imprint to prevent themselves from eating only one type of food source and thus harm themselves with not getting all food resources needed. They are also imprinted to ignore foods that have been smelled or eaten within a 9 -14 hour period of time, and one of the reasons relying on commercial foods is so dismally inadequate. They are not of the type of animal that relies only on one type ofr food like protein, or vegetation or calcium, etc. They must have a robust combination of all of them! Many of the foods must support their ability to metabolize to their environment (heat, humidity, light, growth) and they require a balance of ALL these types of food resources (some more at specific times like pre-molt, or PPS) in order to thrive. These groups are classed in the following way and I will include why:
Protein and lipids: this is for energy to grow, forage, reduce competition or minimize cannibalism which more frequently occurs in captivity. Foods in this class are:
meats, fish like silver sides, gold fish, clams, oyster; bone marrow (all meats including poultry), nut meats (many also fall in the omega fats group) salmon skin(including fat). Some vegetation like avocado meat (only) and bamboo stalks. (which also provide Cellulose, high energy)
Carotenoids, zeaxanthin and cellulose: these foods are necessary to assist the crabs metabolic functions of calcium absorption, processing of minerals, and coloring an individual crab has (darkens pigments). It also improves the crab's immune system and nervous system functionality.Foods in this class are:
tannin rich leaves, bark, cambium (inner branch skins) of plants like oak, maple, mangrove root, some perennial leaves; fresh fruits and vegetables that are orange, yellow, red or dark green (i.e. squash, sweet potatoes, carrots, natural corn, mango, blue berries, etc); many flower petals (dry), spinach, foliage, bean sprouts, seaweed: spirulina in particular, reptile moss (from pet store) etc.
Carbohydrates: these foods are quick energy foods that will help your crab by immediately fueling them but saving their "stored" reserves necessary for metabolic function. Foods in this group include:
grapes, apple, honey, wheat germ, oatmeal, dried fruit (raisins mostly due to Copper sulfate use in others), banana, pineapple, citrus pulp (inner membrane of skin considered cellulose).
Omega fats: this food group is very important and is totally missed in commercial food formulations unless they are frozen foods! These are necessary for nervous system, exo-skeletal health and processing of carotenoids and other minerals. If there are deficiencies in this group it is typically exhibited by molt death (where you are uncertain), a mildewy appearance to the exoskeleton (they look dehydrated), and they are not active! Foods in this group overlap proteinous groups. They include:
Coconut, walnut, whole fish (like a dead gold fish), fish skin, animal fat, olive oil, some grass seeds, seeds, peanut butter, etc. There is a mirade of these suitable, some found in fresh flower petals like roses, sunflower, crab apple blossom, etc. Take a look at the edible plants list at Epicurean Hermit!
Calcium: it is considered superior to provide more than one natural form of calcium! Calcium of course is used mainly for growth of the exoskeleton. Calcium without the support of light and carotenoids will not be properly absorbed by the crab! The acceptable form for supplementation outside of natural forms is Calcium carbonate powder ONLY! Foods containing calcium, will also provide some proteins as well; here are the main foods ideally used:
freeze dried brine shrimp, meal worms, blood worms, krill (fresh, frozen or freeze dried), shrimp tails, sand dollars, powdered oyster shell, cuttle bone, broccoli heads, milk.
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