Supplements
If offered a complete and varied diet, an iguana will need supplements only occasionally, if at all. Some owners claim a properly fed iguana does not need supplements; they have kept iguanas healthy for years without using them. Research on iguana diets does not provide a clear picture as to the necessity of supplements. Reptile veterinarians see iguanas in their offices suffering from both dietary deficiencies and toxically high levels of vitamins and minerals. However, most iguanas that have nutritional problems have deficiencies, not excessive vitamin levels. It seems more prudent to provide some supplementation, but be careful not to overdo it.
For an adult, I recommend giving a high-quality vitamin/mineral/calcium supplement once every two weeks. Increase to once weekly for an actively breeding female. Hatchlings also should be given supplements in their diets once a week, with perhaps a pinch of extra calcium given another time weekly. This regimen has worked well for my iguanas for the past 12 years. When using a powdered supplement (which is the type I recommend), only lightIy dust the food with it. You should only be using about enough supplement to cover a fingernail (about equivalent to one-eighth of a teaspoon).
There are many different supplements on the market, making it difficult to choose a good one. There are several things to look for in a supplement, as well as a few things to avoid. First, avoid any supplement not made specifically for reptiles. Supplements for birds, fish, or other animals will do no good and may harm iguanas and other reptiles.
Among the various reptile supplements, I would recommend a powdered vitamin. Liquid vitamins tend to spoil quickly and often are not accepted by iguanas. Vitamins that are meant to be added to drinking water are not a good choice either. Iguanas don't drink al! that often, and putting vitamins in drinking water just encourages bacterial growth. A powdered vitarnin that is made to be added to the food is the best way to go.
So, we've now narrowed down the search several levels. Next you need to look at the ingredients and the analysis on the label. Avoid any vitamins with conspicuous animal ingredients; remember that these are vegetarian animals. If possible, find a vitamin supplement that does not contain minerals, because when combined, the minerals speed the breakdown of the vitamins. Admittedly, these are hard to find in many pet stores. If you buy a vitamin supplement that does contain minerals, look for vitamins with at least twice the amount of calcium as phosphorus. Also, look for one that contains most of its vitamin A in the form ofbeta carotene. This negates any chance of giving your iguana too much vitamin A. Beta carotene is transformed into vitamin A by the body. If your iguana has enough vitamin A, its body just excretes the beta carotene. Once you've screened down the selection of vitamins this far, pick the one that has the most complete list of vitamins and minerals.
You should also get a calcium supplement. Again, pick one that is made for reptiles. Some calcium supplements have rather high levels of phosphorus; these should be avoided. Vitamin D is added to many of the calcium supplements on the market. This is of no consequence to iguana owners because iguanas do not appear to be able to absorb vitamin D through their digestive tract. So, while a supplement that contains vitamin D will do no harm, it is not necessary. Just buy a calcium supplement that has no or low levels of phosphorus.
