Pinkie mice taboo? (semi-long post)

[Greasy3489]

I was just wondering why many people advise against feeding Beardies pinky mice. Not that I am thinking about doing it right now, but I don't see the harm for dragons.

As a Biochemistry Premed PrePhD student I have studied, in my Biology 310(Cell Biology) class, the chemical build up of young mammals. Pinkies were discussed and comparing them to traditional analyses of crickets they are close to if not healthier than crickets in nutritional value.

Many of us feed sub adult crickets to our beardies so % base the crickets are 81% moisture, 16% protein, 3.5 crude fat.
Adult crickets on the other hand will be about 73% moisture, 21% protein and 6% crude fat.
Without dusting and a low calcium diet crickets have a 1:5.5 Cah ratio.
With a high calcium fortified diet crickets will have a 1:1.1 Cah ratio.

So now down to the topic of this post. Neonatal mice(pinkies)
Just born pinkies(best examples are <=3 days old have pretty high calcium levels as bones are not fully developed(the undeveloped bones are more like cartilage and in these neonatal mice have small chance of impaction if your dragon is the right size to eat them)

Neonatal mice are also ~84% moisture, ~13% protein and ~3-4% crude fat(tested amount is 3.4% so less than the young crickets and almost half adult crickets) Also naturally these mice have a 1:1.1 Cah ratio so are great to be dusted lightly for the perfect ratio of 1.43:1
Pinkies have vitamin A as well which contains beta-Carotene. The amount is less than the dose limit which is 10,000IU/kg.

Lastly based on difficulty of metabolizing pinkies have more kcal/g then silkworms and those that argue that pinkies are high in fat are thinking of pinkie rats or fuzzy mice. Fuzzy mice(by Biological definition 5+days old) can be up to 17% crude fat which is worse than any feeder invertebrate except for waxworms.

Obviously pinkies are eaten by Beardies in the wild when possible, so I just wanted to know why some owners are so adamant against them. I am not suggesting that pinkie mice may be an acceptable staple even if the numbers show them to be, but being a possible feeder as more than a rare treat is certainly a possibility(remember this is based off numbers I would love to have educated input). This is purely for gathering facts please keep the flaming out and share experience, sources or advice.

 

[tempusfugit]

Great post. I'm on the fence, its not that I think that they are that bad, I just don't see enough of a benefit to risk it in case I'm wrong.. I know a number of members have been looking for good fat and protein numbers on pinkies and fuzzies, so I thank you for posting those.

 

[Greasy3489]

I was reading through articles in my school's biological library trying to find the enzymatic break down of Bearded Dragons and came across this:

TABLE 1. A summary of the nutritional composition of diets fed to bearded dragons (Pogona
vitteceps) at Philadelphia Zoo prior to their whole body analysis
Dietary nutrient (DM basis) Pinhead crickets(fasted)
Crude protein (%) 55.17
Neutral detergent fiber (%) 16.47
Fat (%) 9.87
Vitamin E (IU/kg) 71
Vitamin A (IU/kg) 4717
Ca (%) 1.297
P (%) 0.79

Moisture (%)/Crude protein (%)/Crude fat (%)/Fiber (%)/Ash (%)
Acheta domesticus (adult) Whole raw, fasted 69.2/66.6/22.1/10.2/3.6
Acheta domesticus (nymph) Whole raw, fasted 77.1/67.2/14.4/9.6/4.8
Mus Domesticus(neonatal) Whole raw, thawed 82.3/64.3/15.9/NA/5.2

Not exactly sure how the researcher did his %s because they were over 100 lol, but the pinky tested in the middle of crude fat, same tests put 3.1g-5g pinkies at 29% crude fat and 5.1-15g fuzzies at 31% crude fat. Adults were at 22%; but if the pinky is below 3g, the younger the better, they seem to be within acceptable dietary ranges for our dragons. I would prefer to use a local breeder(reptile store) or breed myself so I can be sure of how old the pinkies are getting if I would use them more often than a treat. More food for thought, no pun intended.

Unsupplemented crickets are fed to both the young bearded dragons and the
adult anoles. Although crickets are high in protein, a portion of the N is bound in
chitin [Barker et al., 1998] and may not be digested or incorporated into the body
proteins of the lizard. Enzymes that hydrolyze chitin and may make the N available
for absorption have been documented in anoles [Jeuniaux, 1963], but not in bearded
dragons.
__________________________________________________________________________
Now possibility of feeding non-live prey also analyzed:

Most iguanian lizards are insectivores that do not use chemical cues sampled by tongue-flicking to identify prey before attacking, but the sole iguanian herbivore previously studied did so. To investigate the effects of a partially herbivorous diet on responses to food chemicals, I conducted an experiment to determine whether the omnivorous bearded dragon (Pogona vitticeps) has a similar ability. Chemical stimuli from crickets and carrots, both preferred foods, and alfalfa sprouts, and deionized water (a nonpreferred food and odorless control, respectively) were presented on cotton-tipped applicators. The lizards responded more strongly to both preferred foods than to the controls, performing more tongue flicks and biting the cotton in a greater number of trials. It is hypothesized that lingually mediated food-chemical discrimination is useful to herbivorous and omnivorous lizards for identifying plant and animal foods and for evaluating the quality of plant foods. The insectivorous ambush foragers ancestral to P. vitticeps could not locate prey by tongue-flicking repeatedly at an ambush post and do not exhibit prey-chemical discrimination. Adding plants to the diet altered the selective milieu because plants approached using visual cues can be evaluated using chemical cues, allowing the evolution of the ability to discriminate between plant-food chemicals. The ability to identify animal prey by tongue-flicking may have evolved through correlated evolution with chemosensory identification of plants or specifically for locating or identifying immobile prey.