Why the phosphorus and protein are not good for tortoise

[Jessica Yue]

I read many articles which says tortoise needs low protein food. Also the calcium to phosphorus ratio should be high. But I am not able to find any explanation. Maybe this is some common knowledge to tortoise keeper so it doesn’t need to explain. But I am still curious what’s wrong with the protein and phosphorus

 

[Tom]

I read many articles which says tortoise needs low protein food. Also the calcium to phosphorus ratio should be high. But I am not able to find any explanation. Maybe this is some common knowledge to tortoise keeper so it doesn’t need to explain. But I am still curious what’s wrong with the protein and phosphorus

Which species are we talking about?

 

[Jessica Yue]

Which species are we talking about?

I feel this is some common knowledge for most of tortoises (not only specifically 1-2 kinds of tortoise cannot eat higher protein and high phosphorus food) other than Redfoot and yellow foot so I am interested in why

 

[jaizei]

The calcium to phosphorus is ideally around 2:1. The reason you want to stay around that ratio is that if it's lower, the body will take calcium from other sources (the bones) to make up for it.

Higher protein isn't a problem when the animal is well hydrated.

 

[Tom]

I feel this is some common knowledge for most of tortoises (not only specifically 1-2 kinds of tortoise cannot eat higher protein and high phosphorus food) other than Redfoot and yellow foot so I am interested in why

Many tortoise species eat higher amounts of protein in the wild. Elongata, forstens, Manouria, hingebacks...

Tortoises have a long digestive tract. It is designed to handle high fiber, low protein foods. Too much protein in a GI tract of this natures causes all sorts of problems. Protein digestion also creates waste products that require large amounts of water to flush, so this could create additional problems, like uric acid build up in times of drought.

In order for an animal to use calcium, or any other mineral or nutrient for that matter, it has to be in the correct balance with other minerals and nutrients. Many foods have an incorrect calcium to phosphorous ratio, and this makes the calcium biologically unavailable to the animal. We see this with insects fed to reptilian insectivores. This is why feeder insects are dusted with a calcium powder. This corrects the calcium to phosphorous ratio, so that the reptile can use the calcium coming in. Some people over supplement with calcium and this can cause other mineral deficiencies.