Is there a particular cage or feeding tray that will help me get a more accurate measure of food intake? I have very limited resources. Can you suggest a cheaper alternative to electronic-monitoring devices for measuring rat food intake?
In most cases one measures disappearance from the feed trough, sometimes corrects for spillage and calls that feed intake. The real intake can never be measured. So try to minimize spillage or playing with food, to get as close as possible to the actual consumption.
Should rats be placed in individual cages, or can we put the rats one group in one cage?
Preferably rats being social animals, are kept in groups. But be aware that than the group is the experimental unit and not the animal.
Dear Dianne
The simplest method is to keep in plastic cages having space to keep feed and water separately. These are cheap boxes avaiable in tarson site.
Regarding feed intake you can easily monitor the feed intake by measuring the difference between feed offered and feef residue aftet 24 h of feed offering. For an instance suppose you are keeping 30 g of feed in the feesing tray at 9 am and next day 9am we can weigh the feed refusal. Keeping the change in moisture level minimum we can tell the absolute amount of feed taken by the rats.
Plz send me your suggestins if some better alternatives areavailable.
Regards
Partha
So, I will keep the rats from the same group in same cage, and measure the leftover as a group?
This also works for the feces collection? the 6 animals in one group will be kept in one cage and their feces collected together and analyzed as data for the whole group? I am thinking of a more complicated method that is keeping them in individual cages to measure their individual food intake and collect their individual fecal samples, just like what we do in humans.
We have also limited facilities for the feeding trial to rabbit, therefore we keep animals in a group usually 5 each and not in individual cage. another reason for keeping in group because rabbit is easily getting stress therefore is better to keep in group.
to measure feed intake, We offer feed in the morning and after 24 hours we weigh the refusal. The feed intake is the difference between offered and refusal for a group and we divide by number of animal for each group to get an average of feed intake.
The animal no depends on the size and duration of trial. The cages can accomodate 3 adult rats for a long duration and we sld not separate them during the trial.
Regarding collection of faeces we hv to collect them manually by hand picking. If you can specify the study then we can find out something more precise
Redards
Partha
Thank you for your answers. I will be testing the effect of a plant extract on food intake of rats and also measure the fecal caloric content. Thus, I would like to refine my method to accurately measure their daily food intake and collection of their feces for analysis in bomb calorimeter.
As this is a feeding trial you can keep 3 rats in a cage and note the intake and refusal. And thus daily intake can be calculated. And after diving the no of rats we can get avg intake. In my notion this will give a better representitive data as individual varitions will be huge.
Regarding collecton of fecal matter you can hand pick them and you can get the energy out go
Dianne the methods described above are simple to execute even if using groups. However, even with ensuring the size of the rats is initially the same, each animal will have a different intake. There lies the problem, variable intake will impact on all other parameters you measure. Digestibility, nutrient flows, faecal components will vary and individual growth rates will be affected. You might have to clarify what you are trying to achieve with this project beyond measuring feed intake.
Dear, I think the real intake can never be measured , because the consumption food affect by many factors which can differ immediately , so you can measure that by limit introduced food and weighting the residual in cages \ day for about 5 days , then take average
As mentioned above the feed intake is usually measured by giving a weighted amount of food and measurement of the left over / refusals.
You should be aware that the food may loose water (relevant for fruits and vegetables) or dry food may "gain weight" due to water spoilage or ambient humidity - therefore best way is to dry the refusals after collection and calculate everything on basis of dry matter.
Normally lab animals has higher individual variation in all possible measures. To minimise the error and to get a true representative data the replicate size should be more. Normally 3 rats are taken as one replicate and minimum 4 such reolicates are taken in feeding trials. So each group sld hv atleat 12 rats or lab animals.
Dear Dianne Faye Manabat,
My suggestions are as follows:
Option 1: Use metabolic cages if available.....it houses rat individually and helps measuring the feed intake of individual rat precisely and also facilitates the collection of feces without contamination.
Option 2:
1. If metabolic cages are not available, use polypropylene or polycarbonate cages (which are of low-cost and serves the purpose)
2. If feed intake is a critical parameter, then house the rat individually to get an accurate feed intake measurements
3. To collect the feces, i would suggest you to use a perforated cage mesh that can be placed inside the cage and feces will be collected underneath
Regards
Selvam...
feed intake calculation has already been provided by Dr Partha Sarathi....
for small animals I would recommend group feeding and take averages for any measurements
After 24 h, rats will be briefly removed from their cages and weigh, and the amount of food remaining, including any on the bottom of the cages or any that had spilled onto plastic sheets place under each cage, will be recorded. Intake will be calculated as the weight (in grams) of food provided less that recovered.
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