Question about protein levels in rat diets

[Dogstar]

I have a question I'm hoping someone can help me answer!

I have noticed most people feed dog food with 18% protein or less. I posted in another thread and some people said that 18% is the highest protein they would use in a dog food...

However I am a little confused here about protein levels in the diet... Many of the lab blocks available are 18% protein and are meant to be fed as the sole or main diet.
If instead of a lab block you are feeding a mixture including dog food and other ingredients-- for example like Suebee's diet mix where half the diet is dog food and half is mostly grains/fruit/veggies-- and you're using a dog food with 18% protein, then isn't the actual percent of protein in your rat's diet much lower because only half their diet is dog food and the other half is low or no protein foods? 
So since the protein level of the rat's diet in this case would be much lower than 18% wouldn't it be ok to feed a dog food with protein levels which are higher than that? I am not sure if I am figuring this correctly so please correct me if I have the wrong idea here!

[Addicted2Rats]

From what I have been told, you should feed an 18% protein diet to young and adult rats that don't have any problems with obesity.  The geriatric and obese rats need to have a lower protein content (probably about 14%).  I have also been told that the high quality lab blocks (Harlan Teklad) can be fed as the sole diet.  I'm sure that is done in laboratories to help prevent any problems with test results being screwed up because of random food being fed.  However, for pet rats, I think that giving them lab blocks along with something like Suebee's diet helps to provide variety.  I also give them vegetables and fruits to provide other sources of nutrients.  So I guess what I'm trying to say is that the lab blocks should be fed as their *main* source of nutrients while giving Suebee diet, veggies, fruits, occasional nuts etc as an added (not constituting more than 10% of their daily diet).

Does this answer your question? 

Deb

[hairless_love]

You could ONLY feed your rats lab blocks or dog food. That is the STAPLE of their diet. But it's better to feed that and also suppliment with grains, fruits, veggies, ect. You can use either lab block or dog food as the staple, and in the different mixtures you were talking about people use both. Since most of their diet is made up of the dog food/block, then it is important that it doesn't have too high of protein.

Rats are very sensitive to diets that are too high in protein, so that's why you need to be choosy about how much protein they are getting. Every rat is different of course, and if you have a young or high energy rat that doesn't seem to be keeping weight on, then you can up the protein. Or, if you have a lazy rat who is a big fatty, cut down on the protein.

I'm not a nutritionist...so I'm not sure how well I'm explaining this.  We do have a few nutritionists ((human and pet)) floating around on the board though...so hopefully they'll chime in and give you a more intelligent explanation. 

[WS]

Remember that dietary protein is considered for the total diet. So if you're feeding a mix with 18% crude protein, you are not feeding this much as total diet if you also add in other fresh foods like veggies and other complex carbohydrate sources.

Protein isn't the bugaboo of rat diets, IMHO, I feel that fats and foods that are high on the glycemic index (simple carbohydrates) are even worse.   It's not easy to overdose a ratty on protein with a typical diet.  (No rat-style Atkins, please  )

Science has actually struggled somewhat with the protein requirement for people and for rats... most of the protein information was garnered based on growing (young) animals looking for amounts that promoted growth.  Different types of protein, the quality of the protein as well as which amino acid profiles  (and digestibility) are supported ALSO relate to how protein is used by the body. In animal studies which estimate protein usage based on nitrogen gain, the types of protein used have produced different "requirements" (ie. eggs versus casein versus animal protein)  and values that represent requirement for "growth" do not always relate to what is needed for maintenance.   Dietary protein requirements also change with age (lessen).
Some current thinking is that we (and possibly our omnivorous friends) don't need as much protein as was once thought.     Kidney failiure or other serious problems are unlikely unless you're feeding a PURE protein.

In my experience too much protein or too little can cause some itching but too much protein isn't what causes a rat to be FAT  (depending on the source -- cheeseburgers for example, are loaded with other things -LOL)  high protein foods also tend to be highly caloric foods. Obesity results from dietary fats, caloric intake as a whole and the storage of energy (again the short-chain carbohydrates)

Feeding a good rat diet and then supplementing with fresh foods and keeping carbs on the complex non-processed side really helps balance things out.    AND it provides the amino acides, enzymatic exchanges and other chemistry needed to use protein and glucose properly.

[hope4peace]

I read a post on here a few days back that had a letter/email (not sure, but some correspondence) from a scientist/nutritionist (PhD) at Harland Tekland. They said that for non breeding adult rats, you should be feeding no more than 14% protein.

I will try and find the post again and link to it here.

http://www.goosemoose.com/component/option,com_smf/Itemid,118/forum,rat/topic,4022050.msg4219027/,#msg4219027

[WS]

The previous ideal was approximately 16-18% protein for a male and up to 24% for a female but published data has this more around 12-14% for adults. (16-18 for females) --  for a lactating or growing rat and as low as 4.5% for maintenance per some studies.  Thanks for the link -- it mentions that back in the day, they really didn't know what constituted a healthy diet other than short-term sustainablity of a lab animal.

  I shoot for formulas at around 14% total crude protein.  And of course this value is actually lower (see above) taking all the foods eaten into account.

[Ratlovingkippy06]

 I give all my animals Mazuri pellets, gerbils, rabbit and all 18 rats. But with my rats i do  add dired oatmeal to the mix along with some fruit here and there to add in a healthy diet. I have Reggie rat food which is a seed formula ( i take the corn out) that i give my rats as a treat every once in a while. I had given them dog food at one point but i don't use it very much. I have large rats some are large because they are just big others are large because they eat a lot more than they  should so i have started to restirct the diet more. 3-5 pellets per a animal in the cage.

[Kendra]

My rats have been on the Harlan with 16% protein for a while and I'm switching to 14% protein soon.  My rats are fat and this is part of an overall weight-loss attempt. 

Ratlovingkippy - That Reggie rat food is not very good.  I suggest when you finish the current bag, you make up some grain mix like Suebee's without the dog food.  That way, you know for sure what's in it and that it is all human quality.  The kicker to me was that Reggie rat contains alfalfa, which is indigestible to rats.  Some people even use it as litter material.