Nutritional Values of Amphibian Foods
by Jennifer Macke
What are the most nutritious foods for carnivorous amphibians in captivity? The following are considered important factors:
- Protein. A good staple diet should be relatively high in protein.
- Fat. Some fat is needed in the diet. As in human diets, some fats are better than others.
- Calcium. When considering the calcium content of a food, pay particular attention to the calcium-to-phosphorous ratio; the availability of the calcium is affected by phosphorous. Ideally, the Ca:Phos ratio should be >1. Foods that have a lower ratio should be gutloaded, supplemented, or balanced with other foods.
- Vitamin D3. Vitamin D3 is required for the absorption of calcium. Live foods generally contain some vitamin D3, and it is included in most calcium supplements. There have been reports that some commercial supplements may contain an excessive amount of vitamin D3, so do your homework about the brand you are buying. Vitamin D3 can be obtained through exposure to UV light, but most amphibians do not require UV.
- Vitamin A. Like mammals, amphibians are unable synthesize vitamin A and must obtain it from their diet. It is present in most live foods. It is required for proper development and physiology, but excessive amounts are very toxic.
- Carotenoids. Carotenoids are forms of vitamin A, but amphibians are not necessarily able to interconvert among the chemical forms. Carotenoids are necessary for the formation of some orange and red skin pigments.
- Energy (calories). All foods listed below have a caloric content in the range of 4 - 7 kcal/g of dry weight. The exact amount is not generally critical. Foods higher in fat generally contain more calories per gram.
The table below shows the nutritional values of foods that are commonly used.
| Food | Protein (% dry wt) | Fat (% dry wt) | Calcium (% dry wt) | Phos. (% dry wt) | Ca:Phos Ratio | Ref. |
|---|---|---|---|---|---|---|
| Blackworms | 47.8 | 20.1 | 0.11 | 0.85 | 0.12 | 1 |
| Bloodworms | 52.8 | 9.7 | 0.38 | 0.90 | 0.42 | 1 |
| Crickets, adult | 64.9 | 13.8 | 0.14 | 0.99 | 0.14 | 1 |
| Crickets, pinheada | NA | NA | 1.29 | 0.79 | 1.63 | 2 |
| Cockroach, American | 53.9 | 28.4 | 0.20 | 0.50 | 0.40 | 1 |
| Earthworms | 62.2 | 17.7 | 1.72 | 0.90 | 1.91 | 1 |
| Nightcrawlers | 60.7 | 4.4 | 1.52 | 0.96 | 1.58 | 1 |
| Fruit flies | 63.9 | 19.5 | 0.10 | 1.05 | 0.09 | 1 |
| Fruit fly larvae | 40.3 | 29.4 | 0.59 | 2.30 | 0.25 | 1 |
| Maggots | 56.8 | 20.0 | 0.41 | 1.13 | 0.36 | 1 |
| Mealworms | 52.7 | 32.8 | 0.11 | 0.77 | 0.14 | 1 |
| Mosquito larvae | 42.2 | 16.1 | 0.79 | 1.07 | 0.73 | 1 |
| Tubifex worms | 46.1 | 15.1 | 0.19 | 0.73 | 0.26 | 1 |
| Daphnia | 55.2 | 6.6 | 0.10 | 1.17 | 0.08 | 1 |
| Waxworms | 42.4 | 46.4 | 0.11 | 0.62 | 0.17 | 1 |
| Phoenix wormsb | 45.3 | 32.4 | 2.33 | 1.53 | 1.52 | 5 |
| Leeches | 85.3 | 4.3 | 0.16 | 0.94 | 0.17 | 7 |
| Rangen soft moist salmon pellets | 44 | 18 | NA | NA | NA | 3 |
| Shrimp, raw | 83.3 | 8.3 | 0.22 | 0.85 | 0.26 | 4 |
| Squid, raw | 84.2 | 5.3 | 0.47 | 2.03 | 0.23 | 4 |
| Salmon, raw | 63.5 | 34.2 | 0.039 | 0.75 | 0.05 | 4 |
| Codfish, raw | 93.4 | 4.56 | 0.084 | 1.07 | 0.08 | 4 |
| Anchovy, raw, wholec | 74.0 | 18.5 | 0.544 | 0.644 | 0.84 | 4 |
| Beef heart, raw | 76.9 | 20.0 | 0.030 | 0.92 | 0.03 | 4 |
| Beef liver, rawd | 69.0 | 13.8 | 0.017 | 1.33 | 0.01 | 4 |
| Beef sirloin, raw | 79.4 | 16.1 | 0.081 | 0.756 | 0.11 | 4 |
| Chicken breast, raw | 92.0 | 4.0 | 0.044 | 0.784 | 0.06 | 4 |
| Chicken, whole 1-day-old | 64.9 | 22.4 | 1.69 | 1.22 | 1.39 | 4 |
| Mouse, pinkiee | 64.2 | 17.0 | 1.17 | NA | NA | 6 |
| Mouse, whole adulte | 55.8 | 23.6 | 2.98 | 1.72 | 1.73 | 6 |
| Frog, Green | 71.2 | 10.2 | 4.80 | 1.87 | 2.29 | 6 |
| Toad, Southern | 61.0 | 14.0 | 2.94 | 1.79 | 1.64 | 6 |
| Quail, whole | 71.5 | 31.9 | 3.43 | NA | NA | 6 |
Footnotes
NA: Data not available.
aFor pinhead crickets, the calcium and phosphorous values shown are from Reference 2. Note that Reference 1 reported values for pinheads being similar to those of adult crickets. We know of no explanation for the large discrepancy in the Ca:Phos ratio reported by the two different studies.
bPhoenix worms are larvae of the soldier fly, Hemetia illucens.
cAnchovies are not a commonly-used food for amphibians, but are used in some commercial fish foods. Anchovies are included in this table as an example of a fish that has been analyzed whole (bones included). Note that calcium content is much higher for whole fish than for fish filets. Other whole fish are likely to be similar.
dLiver is no longer recommended as a food for amphibians, as it contains excessively high levels of vitamin A, which can interfere with absorption of vitamin D and, hence, calcium. Other varieties of liver, such as chicken liver, have nearly identical levels of nutrients, vitamins, and minerals to those given for beef liver.
eValues for rat are very similar to values for mouse.
References
- Bernard, JB and Allen, ME. 1997. Nutritional Advisory Group Handbook, Fact Sheet 003. Nutritional Aspects of Insects as Food (PDF).
- Barker, D, Fitzpatrick, MP, Dierenfeld, ES. 1998. Nutrient composition of selected whole invertebrates. Zoo Biology 17:123-134.
- Information from the manufacturer's website, Rangen Salmon Feeds.
- United States Department of Agriculture website, Nutrient Data Laboratory.
- Sheppard, D. Craig, personal communication of data from an independent analysis performed for Phoenix Worms.
- Dierenfeld, ES, Alcorn, HL, Jacobsen, KL. 2002. Nutrient Composition of Whole Vertebrate Prey (Excluding Fish) Fed in Zoos.
- Ellward, Trace, personal communication. Data from an independent analysis of Nephelopis obscura, a commercially-available bait leech species in the U.S.A. Data available on request.
Additional information on amphibian foods and nutrition
CC article: Foods for Captive Caudates
CC article: Microfoods for Caudate Larvae
CC article: Worms: The Ideal Food for Caudates
Amphibian Ark: Husbandry Documents
Caudata.org article: Daphnia: An Aquarist's Guide
Melissa Kaplan: Nutrients of Foods Commonly Fed to Carnivorous and Omnivorous Reptiles
Browne RK. 2009. AArk Science and Research. Amphibian diet and nutrition (PDF)
Browne RK, et al. 2009. AArk Science and Research. UV-B, Vitamin D3, and amphibian health and behaviour (PDF)
McWilliams, 2008. Nutrition Recommendations for some Captive Amphibian Species (Anura and Caudata) (PDF)
Oonincx, DGAB and Dierenfeld, ES. 2011. An Investigation Into the Chemical Composition of Alternative Invertebrate Prey (PDF)
IACUC Learning Module Xenopus Nutrition
© 2007 Caudata Culture
Updated July 2013, Jennifer Macke.