Читать книгу Blackwell's Five-Minute Veterinary Consult: Reptile and Amphibian - Javier G. Nevarez - Страница 43

All animals need a source of calcium and a calcium to phosphorus ratio of 1.5 : 2. Carnivorous animals eating adult whole prey items have the advantage of obtaining calcium form the prey’s bones. However herbivorous and omnivorous reptiles often lack an appropriate source of calcium. Young carnivores being fed immature prey items or carnivores not being offered whole prey items should also be supplemented with calcium. Most plant materials and invertebrates have a negative calcium to phosphorus ratio, so animals must find other sources of calcium. In their natural environment, these animals will travel to clay and mineral deposits or select particular feedstuffs to supplement their calcium intake. In captivity, reptiles do not have the opportunity to seek calcium sources but rather rely on it being supplemented in their diet. All herbivorous, omnivorous, and insectivorous reptiles require calcium supplementation.

Various commercial sources of calcium are available, but some are better than others. First off, it is recommended that calcium supplements be purely calcium with no phosphorus or vitamin D3. While many see a benefit of adding a D3 supplement, there are serious and real concerns about over supplementation of vitamin D3. Adding a calcium supplement that also contains phosphorus does not make sense because the reptiles are already in a negative calcium to phosphorus imbalance. Adding more phosphorus would not help solve this imbalance in an effective manner. The author prefers calcium only supplements including calcium powders sold for reptiles, cuttle bones, and crushed oyster shells. Another alternative is the use of fruit‐flavored calcium carbonate antacid tablets. These tables are more palatable than other products. They can be pulverized or fed in small pieces.

Regardless of the type of supplement, calcium is best offered daily to account for variations in intake. The supplement is mixed with the vegetables or by coating prey items. However, it must be noted that when insects are coated with a powdered supplement, the powder will fall off within 10–20 minutes. Insects should therefore be dusted immediately before feeding. There are some products that advertise calcium in a spray or gel cubes. These have not been proven to be effective and should be avoided until research to support their effectiveness is available. There are also some multivitamin products advertised for reptiles, and many of these include calcium as well as D3. Given that we do not know the nutritional requirement of most reptile species, the use of multivitamins is questionable. While it may be beneficial in some species it could be detrimental in others that may be over supplemented by certain minerals or vitamins. Finally, earthworms and hornworms (Manduca sp.) are two excellent sources of nutrition for carnivores and invertebrates because they tend to have a positive calcium to phosphorus ratio. However, this ratio can also vary with the conditions in which they are reared and maintained.