Dear Dr Guillermo Jiménez,

There is always an official method to make a high fat diet, so it does not need trial and error because at the end of the day when you publish your article the reviewer will ask you to cite a reference for making  a high fat diet, sometimes  a paper is rejected because the reference you cited is not known!! So I have attached a document has several models to make a high fat diet, take your time and do not rush.

Best regards

Dear Dr Guillermo Jiménez,

There is always an official method to make a high fat diet, so it does not need trial and error because at the end of the day when you publish your article the reviewer will ask you to cite a reference for making  a high fat diet, sometimes  a paper is rejected because the reference you cited is not known!! So I have attached a document has several models to make a high fat diet, take your time and do not rush.

Best regards

The numbers for leptin looked fairly low in the publication cited by Aly so I did a quick search and found that indeed, others have reported much higher value (as is the case of human numbers). For example, here is a study published 2006:

Leptin secretion after a high-fat meal in normal-weight rats: strong predictor of long-term body fat accrual on a high-fat diet

Am J Physiol Endocrinol Metab 290: E258 –E267, 2006;  

The above study finds levels of leptin in normal rats at 6.9±0.3ng/ml (as opposed to ~200pg/ml in the previously quoted publication).

The following publication has some relevant information from humans:

http://www.ncbi.nlm.nih.gov/pubmed/20484473

It may be important to dig a little deeper before relying on absolute values - compare the methodology used for quantitation etc.

Best,

[PS: My apologies for inadvertently posting the above in response to another question regarding levels of leptin in experimental rodents.]

Dear Dr Guillermo Jiménez,

I am surprised that the animals do not consume the lard diet, as we commonly use 20% lard in our rodent diets and the rats find it highly palatable. Were the rats eating the diet prior to strep administration? I echo the comments made by Dr Aly R Abdel-Moemin and I would also recommend using a semi-purified diet that is based on AIN-93 formulation. For details http://www.ncbi.nlm.nih.gov/pubmed/8229312

Kind regards,

Dr Belobrajdic.

Dear Guillermo,

I have the same experience namely that mice enjoy lard and even select it....

It is hard to tell from the distance but I have a few suggestions for you:

-check if the diet has got any particular smell and/or if any of the containing fatty acids became rancid

- how is the shape of the pellet and the consistency (they don't like it if it is too soft)

- when you expose them to the new diet also stil provide the old one to have a smooth transition.

I hope this helps, otherwise be in touch. best wishes, teresa

This study characterizes the high-fat diet–fed mouse as a model for impaired glucose tolerance (IGT) and type 2 diabetes. Female C57BL/6J mice were fed a high-fat diet (58% energy by fat) or a normal diet (11% fat). Body weight was higher in mice fed the high-fat diet already after the first week, due to higher dietary intake in combination with lower metabolic efficiency. Circulating glucose increased after 1 week on high-fat diet and remained elevated at a level of 1 mmol/l throughout the 12-month study period. In contrast, circulating insulin increased progressively by time. Intravenous glucose challenge revealed a severely compromised insulin response in association with marked glucose intolerance already after 1 week. To illustrate the usefulness of this model for the development of new treatment, mice were fed an orally active inhibitor of dipeptidyl peptidase-IV (LAF237) in the drinking water (0.3 mg/ ml) for 4 weeks. This normalized glucose tolerance, as judged by an oral glucose tolerance test, in association with augmented insulin secretion. We conclude that the high-fat diet–fed C57BL/6J mouse model is a robust model for IGT and early type 2 diabetes, which may be used for studies on pathophysiology and development of new treatment.

Article The High-Fat Diet-Fed Mouse: A Model for Studying Mechanisms...

Thanks you for your answers

Dr. Aly Abdel-Moemin

Thank you for the paper, I will talk with mi tutor about the different diets.

Dr. Demien Belobrajdic

Yes, the rats were eating the standard diet before I mixed it with lard. I just wet the pellets (100gr) with lard (50ml), the pellets absorb the lard but had bad smell.

Dr. Teresa Valencak

Thanks for the suggestions, as I told Dr. Demien, the “new diet“ had bad smell. The shape of the pellet and the consistency didn’t change and finally I didn´t made a smooth transition.

Dr. Ali A R Aldallal

Thank you for the paper, as I told you I had problems importing the commercial diet and we lost it in the custom.

Last week I mixed lard with standard rodent chow (dust) and some vanilla, the result was a soft pellet with good smell, the rats fed with the new diet ate almost as the control group (standard rodent chow).

Success, congrats!   :)

Good luck

...sounds like all problems are solved. well done and good luck!

Dear Dear Dr Guillermo Jiménez,

I do apologize to start the thread again, could you check the level of vitamin E in your diet? from my food chemistry background I know that lard is low in vitamin E. If you you happy and sure that vitamin E is enough in the diet and meet the requirement for rats so ignore my message. Good luck

Dear Guillermo. You can add the lard pellet, avoiding odor and even taste, on the higher position of the the pellet, so the rats eate the first part of the pellet before the  lower position containing normal diet.. We have  this experience  when we add  n-3 Fatty acids  to normal diet , without problems.  and  post prandially ,we found enrichmment in n- 3 fatty acids in rat plasma  with previously high triglyceridemia and then,  even lower content of triglycerides ,  which was the desired effect.

As Dr. Wikinski mentioned the must applicable way is using odorless fat. In case of not finding odorless fat, you can put your fat in vacuum chamber until its odor gone.

you can combine some nuts and oilseeds with lard that will help to mask the objectionable odour of the lard and rodents love the crunchiness of nuts and oilseeds. Starts with taking different proportions of nuts and oil seeds once you find the exact proportion of nuts & oilseeds to lard that the rodent accepted , you can go for that.

seems to be too interesting topic you are dealing with. All the best for your experiment

Rat models including outbred SpragueDawley and Wistar rats are popular strains to study obesity as they readily gain weight on high-fat diets. In particular, Sprague-Dawley rats have been studied for their ability to show a a variable response to a high-fat diet (32 or 45 kcal% fat).

Hi all, 

I am trying to make a ketogenic diet with 90% calorie from fat. I need to make a solidify mix at the end. I am using lard as my high fat source with sucrose and yeast. My question is that how you dissolve lard? 

The article titled appropriate insulin level in selecting fortified diet fed streptozotocin treated rat model of type 2 Diabetes published by PLoS One may be of valuable help to your queries

Agree with@ Ali A R Aldallal