LEAFLET 253, U. S. DEPARTMENT OF AGRICULTURE 
FEEDING 
The rat is capable of thriving on natural foods of considerable variety. Its 
natural diet is similar to that of human beings, and is derived principally 
from human-food sources. ‘Table scraps probably were the first diets used for 
raising these animals. This source of food is variable and undependable for 
more than a few animals, and is not satisfactory for feeding a rat colony 
where uniform animals are desired. Nutrition of the rat has been studied 
probably more thoroughly than that of any other animal; however, doubt 
exists that it is possible to formulate diets that will produce maximum growth 
and reproduction in these animals. Numerous combinations of natural foods, 
however, will produce good results. The purpose for which animals are to 
be used is generally the chief factor in determining a suitable diet. For 
example, a standardized animal for use in vitamin aSsays must be produced 
on a diet with restricted vitamin content. The vitamins to be assayed must 
be present in the diet in sufficient quantities for growth, reproduction, and 
lactation, but must be limited in amount so as not to allow storage of the 
vitamins in the bodies of the young animals. 
A stock ration of this type is generally composed of a mixture of cereal 
grains such as corn, wheat, and oats, usually in about equal parts, or only one 
or two of these grains may be used. This grain mixture usually composes 
from 60 to 80 percent of the diet. The remainder is made up of various 
vegetable and animal products intended to supplement the protein, mineral, 
and vitamin content of the diet. Among the ingredients often used are mill 
concentrates such as wheat germ, alfalfa meal, linseed meal, fish meal, milk 
powder, liver meal, calcium carbonate, and trace minerals. Table 1 gives 
examples of diets which, with slight modifications from time to time, have 
been used successfully for raising albino rats for many generations. 
Diet No. 1 is a type that may be fed to produce animals which will be Satis- 
factory for vitamin A and B complex assays. Diet No. 2 probably approaches 
optimum nutrition more nearly but results in faster growing animals which 
are unsuitable for vitamin assays. 
A less complicated procedure recommended, especially when only a few 
animals are to be raised, is feeding only the amount the animals will eat 
of one of the prepared dog feeds produced by commercial feed manufacturers. 
This may be supplemented with such vegetables as lettuce and carrots. 
TaBLE 1.—Suggested diets for laboratory rats 
Diet No.— 
Ingredient ; 
fle 2 
Percent Percent 
Grounds yellow, Corns ane eae oe We ae a 36. 00 25. 63 
GrounGiwheats. jewel ewes Cea Waren: tee os learns 36. 00 25.68 
Afaliarlea tim calle wyatt Saree ee ee eas ip eine eae ae 3: 00 ce ee ie 
IMSeSC meal es NE en es MR EN a io ce ee 1000) 23288 eae ee 
sine ime a beatles ante a a ae Ca eee, ROR ett i eeaetias weap Ouea tee 3; 00 ese 
pies eh oa Ces 9 ere a Pan ae, Oe Da set mS PS ei ND Bie Sec: nif OO hain eer ne OC 
Commercial’ Casein =e oe tk ae eae gs ete: meaner ever 4.00 |e Se 
ed eee Se Sa 8 en ne ata: EBs iO tee NR Ie eas Ae. ean ea ee BNL oO 1. 00 
Calcium carb Oma te eet et Sy ieee he a eee pres pel ee fo) 1. 00 
Skim ymil ko wl ers. ae So ye a A ee ere aie 4.00 Se 
East i (TE WETS). se ee Sees ae Eo cee 8 2. 00 3. 00 
EY) Us TG Levoyz i= ee a ee a I Pn eels trea une eee a eae eo er 25: 63 
Irradiated yeast so) Sie Ta See Bae ae ape Sea a |g 2. 00 
Soditrma phosphate ss sk ce Se se ie a ae ee hg pee eee 1. 00 
Potassium iodide. eS ee ise as peed | alg ec SOx 
Manganese sulfates 25752 ck Se eS ah Tra in Sea . 10 
Dried* peeks ss hye 0S ee EE EO Ae Pe Eh ee | aera 10. 00 
Driedehoe livers... 8 ae ee aes Ces |S ee eee 5. 00 
1 With diet 1, fresh whole milk is fed separately 3 times a week. 
