Stated % of protein in typical analysis

[angieh]

OK - here is a very specific question about the percentage of protein that is stated on cat food packaging in their analysis.

I have checked on all the different packets that I currently have in the cupboard and find the following:

Iams Senior 8%
P&H supermeat 8%
Felix jelly and supermeat varieties 8.5%
Sainsbury's Perfectly Meaty 10%
Nature's Menu 11%
Almo nature 11.5%

I do understand that there is still debate as to whether a low protein diet is best for CRF cats, but on Tanya's CRF website, it is stated "Aim for 20-25% protein - never go below 20%." I think you can see my problem - and I suspect that it has to do with how the percentages have been calculated.

Can anyone help me understand this?

[Leesy]

Sorry I can`t help with that one, I keep wondering myself about Maxi`s food for his urinary problem at the moment as it seems low in certain things and higher in other things I find it all abit confusing because as I kitten I am thinking well he needs various things to grow etc. that this special prescription food hasn`t got in but the vet has said to continue with it, don`t know wether I am doing right from wrong at times. .

[dinahsmum]

No sorry, I can't help at all on that subject.
I agree that it is all hideously complicated - maybe over-complicated?

[Elaine]

Hiya Angie, the reason that the protein content in food for crf cats is a controversial one is because the tests were all ran on dogs and rats, cats being obligate carnivours they need a higher protein content.
http://www.felinecrf.org/tinned_food.htm
http://www.peteducation.com/article....1+1770&aid=667
Reading and understanding what it says on the tin can become a complicated issue but i hope the above links can help.

[Tink]

If it is wet food there is a calculation to find out actual protein percentage. I believe you have to convert it into dry matter first. The equation escapes me now but I'll try to find it.

[angieh]

Thanks, but my problem really is (I'm not explaining this well) - on Tanya's CRF website, she says that the % of protein in the food should not fall below 20% BUT all the foods that I have looked at have a range of between 8 - 11/5%

I am assuming therefore that there is a difference in assessing the % between what is stated on the website and the actual % in the analysis quoted on the food packages themselves.

Here is the website - the bit that is confusing me is under the heading Protein, towards the end of that section.

Page load error again on the link: http://www.felinecrf.org/nutritional_requirements.htm

[Elaine]

If a dry cat food has 10% moisture we know that it has 90% dry matter. So we look at the label and check the protein level that reads 20%. Next, we divide the 20 percent protein by the 90% dry matter and we get 22%, which is the amount of protein on a dry matter basis. Does this make sense so far? Good. Now let us compare this to canned food that has 80% moisture. We know that with 80% moisture we have 20% dry matter. The label shows 5% protein. So we take the 5% and divide it by 20% and we get 25% protein on a dry matter basis. So the canned food has more protein per pound on a dry matter basis after all the water is taken out. We can do the same for fat, fiber, etc.

[angieh]

That's amazing Elaine. And us mere mortals are meant to know how to do that????? (Maths were never my strong point you know.)

I'm going to copy that and see if I can do the sums!

[Elaine]

Easy when you know how

[Tink]

Originally Posted by Elaine

If a dry cat food has 10% moisture we know that it has 90% dry matter. So we look at the label and check the protein level that reads 20%. Next, we divide the 20 percent protein by the 90% dry matter and we get 22%, which is the amount of protein on a dry matter basis. Does this make sense so far? Good. Now let us compare this to canned food that has 80% moisture. We know that with 80% moisture we have 20% dry matter. The label shows 5% protein. So we take the 5% and divide it by 20% and we get 25% protein on a dry matter basis. So the canned food has more protein per pound on a dry matter basis after all the water is taken out. We can do the same for fat, fiber, etc.

That's what I was looking for..thank you!