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Working out nutrient balance in a custom gluten free rat mix

Posted: Wed Jan 24, 2018 11:59 am
by chaos_amoeba
Hello everyone!

Newbie here looking for advice from experienced ratters :)

My husband is a coeliac and we have recently taken on three fab little bucks. They've been on Supreme Science Selective with a bit of Mix7 from RatRations thrown in once in a while to keep life interesting, but it is looking increasingly likely that I'm going to have to formulate a custom rat food that is both perfect for ratties and also gluten free, because my coeliac is starting to show symptoms of low dose, repeated gluten exposure and the rats' food is the only gluten source allowed in the house, so...

I'm looking at recreating RR Mix7 for them without the gluten-containing ingredients - I've been in touch with RatRations, who advise this approach, too. I've so far looked into the Protein, Fat and Fibre content of each of the (30+!!!) ingredients in Mix7 and worked out the ratio to mix them all to match the supreme science food on protein % and fat % (will be slightly higher fibre but I guess that's ok). [Note: will share spreadsheet if anyone *asks* but is a bit dull! I guess someone might find my list of nutrient compositions of rat food ingredients useful one day].

I'm also looking at adding a bit of gf dog kibble to the blend, because it contains loads of added vitamins and minerals (inc copper, calcium and D3), but can't use too much as it contributes a lot of protein and fat (I think it's suitable at about 5-10% of their food, but not more). Similarly, I'm thinking of including RatRations insectivorous feast at about 3% and a little kelp and spirulina powder.

I'm obviously concerned about making sure they get enough calcium and D3, but also copper since barley is good for copper and they will have to go without barley. I'm going to go through nutritional data for all the gf ingredients in Mix7 and replacements I'm planning to use, to check they will also be getting enough Vitamin A, zinc, manganese and selenium, as the SupremeScience packet tells me how much of each of these are in their current food.

- Are there any other nutrients that you know of, that I should worry about?
- If I use things like kelp and spirulina powders that are rich in many different trace nutrients, do I need to be careful that they don't have too much of any nutrient? Any particular risks?
- A vet friend suggests nutrobal as a supplement, but it's marketed for reptiles - anyone use it?

Thanks - sorry for the long and involved post!

Re: Working out nutrient balance in a custom gluten free rat

Posted: Thu Jan 25, 2018 9:42 pm
by tabirat
Sorry for the delay in responding... I am feeling very ill with a virus at the moment, but will respond properly as soon as I can make my achy head work. I'll copy the mix that's in The Scuttling Gourmet, for exactly thus situation, but you do sound like you've got it sussed! I'd love a look at your database, being a rat diet geek!

Re: Working out nutrient balance in a custom gluten free rat

Posted: Sat Jan 27, 2018 12:08 pm
by tabirat
Okay, just realised that I don't have access to the book files as they back up storage is on a hard drive in my motorhome, and I am working on borrowed laptop as my own laptop died completely a few days ago. So for now I'll just answer your queries. A good working protein level for your rats depends to a degree on their age and I'm assuming from your language that they are still young and growing. If over about 10 to 12 weeks they can be on adult levels and this should be around 10 to 12% for bucks. Bear in min with your calculations that if you use whole grains as the bulk of a feed, with less processed grains/biscuits etc, the protein is not all as bioavailable, and to achieve say 10% you will need more like 12 to 13% in the actual mix. Fibre is one of the components of diet which can affect how much of the nutrients in food is actually absorbed. This is just something to be aware of. The pelleted is food is more highly processed and will have greater bio-availibility of nutrients.

Regarding the likely deficiencies - copper, calcium and d3 are all potentially under-available in most mixed grain rat diets, hence needing supplementation. In the pelleted food this is added at source during manufacture. With grain mixes you usually need to supplement at least to a degree. Rat Rations Daily3 or Dr squiggles daily essentials and Calcivet are both possible supplements that may people use.

Selenium can be quite low in UK grown grains, but can be easily topped up by feeding chunks of brazil nut as a treat, once or twice a week.

I agree that dog food is a useful addition in your situation, and would especially recommend something like fish for dogs small bite kibble and hand feeding a couple of pieces for each rat, each day, so that they was no possibility of them not getting their share of this.

Re: Working out nutrient balance in a custom gluten free rat

Posted: Mon Jan 29, 2018 11:30 am
by chaos_amoeba
Hi Alison!

First off, I do hope you are feeling fully recovered now :) If not, get well soon!

Second, sorry for the slow response - I realised by spreadsheet wasn't necessarily user friendly to people who are not me, so I've been improving it -but it's a mad time at work!

Now that it's ready to share I realise I can't post it as an attachment, so here is a link to it in my dropbox: ... .xlsx?dl=0

Do let me know if it doesn't work!

I'd like to buy the relavant scuttling gourmet books; the only reason I haven't is that I lost my e-reader when we moved house >:(

I think I've covered Cu, Ca, VitD3, & Se.
My protein levels are a bit higher than you recommend at 14 % (I matched selective) - but taking into account your comments on bioavailability and fibre, this is likely about right. Our three boys are around 12 weeks now.

My only concerns are that Selective has an incredibly high calcium content - 2.6% by mass, being 5% limestone flour. Whereas the academic literature on optimal rat bone growth seems to conclude that 2-5 g of Calcium per kilo of food is best (with Ca:P ratio around 1.2-1.5) and higher Ca bad for Mg absorption. Overall, the amount of Ca I've settled on is less than Selective but more than the amount that would be provided by the amount of Calcivet recommended on RatRations for maintenance. I'm planning to shake the powdered supplements over their rough food (things like puffed rice and millet, that it will stick on) and hopefully they'll eat the majority of it that way.

Notes on spreadsheet: all the ingredients in RR Mix #7 are listed on the first tab, with column for their protein, fat, fibre, iron, calcium, and phosphorous content. Then, columns showing how much of each nutrient each ingredient will contribute to my mix per 150g (I found this easier to manipulate the final values for than 100 g). Some are in g, some in mg and some in %; depending on the nutrient values given on the Selective bag, which I was aiming to match. The Selective values are shown at the bottom of each column. I've also calculated the Ca:P ratio underneath there.

In the other tabs are data on the supplement I'm using and on the dog food, and then calculations for each nutrient of interest. These show only the main sources (I've not bothered to calculate, eg, the contribution of every trace nutrient from every ingredient as some will be giving microgram quantities and just not worth considering).

Anyway: thanks a lot for your help!!!