The pros and cons
There is much debate as to whether to provide extra calcium for our chinchillas – for healthy teeth and bone development – or not.
Some owners do decide to supplement – in the form of cuttlefish, vitamin and mineral supplement, calcium block or mineral water etc etc. However, many people cannot understand why chinchillas can still get dental problems when they have always received adequate amounts of calcium in their diet – so hopefully this topic may go a little way to explain why (disregarding genetic or hereditary causes).
Chinchillas actually require either 2 parts calcium to 1 part phosphorus or equal amounts of calcium to phosphorus in their diet for healthy bones and teeth. Lots of extra calcium alone is not as beneficial as we think (may also predispose some chinchillas to calcium deposits in their urinary system). Hay, Readigrass and Supa Forage Excel (SFE) are all natural calcium to phosphorus balanced – and most quality chinchilla pellets are too.
So how is calcium absorbed? The body does not easily absorb calcium. It needs to be ingested in an ionic form and have vitamin D present for it to be fully absorbed. Some sources of calcium are more ionic (absorbable) than others.
Calcium is absorbed through the intestinal wall (duodenum) into the bloodstream. Vitamin D assists with this – and that is why adequate vitamin D is also needed in a chinchilla’s diet (generally included in the pellets).
When levels of calcium in the bloodstream become low, various hormones are released, and this triggers certain functions that remove and deposit calcium to and from the bones when needed. Parathyroid hormone (PTH) stimulates uptake of calcium into the bones – but the absorption of calcium also requires the activity of specialized cells: osteoblasts.
These osteoblasts also make the bone-structure, upon which the calcium can be deposited (stored).
Removal of calcium from the bones (to where needed) requires the activity of cells called osteoclasts. Obviously, the removed calcium has to be replaced again – via the process described above. If the diet is deficient in calcium then the stores in the bones become depleted.
Daily calcium supplementation confuses this process – and can actually cause similar symptoms to calcium deficiency.
Here is why..
- If more calcium is absorbed into the bones, from the bloodstream – the production and activity of both osteoblasts and osteoclasts is increased. If lots of calcium is absorbed, then lots of calcium is also removed (as excess is only stored in the bones temporarily). But 50 to 70% of the composing osteoblasts die during this exchange activity. The more their activity is stimulated, the more they die.
- Because the number of times any cell can reproduce is fixed, the reproduction capacity of that cell will be exhausted sooner if too much calcium is absorbed into the bloodstream and then skeletal structure, on a regular basis. If the reproduction capacity is exhausted, there will be a lack of new osteoblasts. And since only osteoblasts can make bone-structure, too little new structure will be made. Without this, the calcium cannot be deposited, and new bone cannot be composed, because there is a lack of structure upon which to build and replacement cannot occur.
- As with all minerals – the body normally only absorbs just as much calcium from the food and bloodstream as it needs regardless of how much calcium is given. But if calcium is given too regularly then the body has to do something to prevent the blood-calcium level from rising too high – so, to save a life, excessive dietary calcium is ONLY TEMPORARILY stored in the bones, before excretion.
- Since all this extra calcium is absorbed due to the action of osteoblasts, (as already explained) these osteoblasts die sooner, leaving you with too little new bone-structure!!!
- After the excess calcium has been absorbed into the bones, two hormones stimulate deportation of calcium from the bones, and the third one stimulates excretion of calcium into the urine.
So….. bones CANNOT hold on to extra calcium – so all that calcium eventually gets excreted anyway.
Therefore it is only recommended that calcium supplements are added to the diet once or twice a week (if needed) and NOT DAILY (unless there is a medical reason)!
So what is the best way to ensure chinchillas can make the best use of the calcium they get?
- Only give a calcium supplement once or twice a fortnight and not every day!!!
- Make sure the chinchilla’s diet contains adequate amounts of vitamin D by feeding fresh chinchilla pellets.
- Try to ensure that the chinchilla’s diet is calcium to phosphorus balanced.(by feeding a simple diet of pellets and hay – and ensuring any supplements are correctly balanced)
- Remember Calcium, phosphorus, magnesium and vitamins D, A and C – are the nutrients needed TOGETHER – in the RIGHT BALANCE that helps keep bones and teeth healthy!
I have deliberately not mentioned the calcium-phosphorus-D3-magnesium link in detail.
Phosphorus as Phytates
Cereal products have an inverted ratio of calcium to phosphorus (also present as phytates – which bind to calcium, preventing its absorption), so buffering any cereal mix with a little extra calcium is recommended.
However, just to confuse things – phosphorus in phytate form is also malabsorbed – so although it interferes with calcium metabolism (i.e., binds to calcium) – it may not upset the 2:1 balance too much due to the fact it is not being retained.