Group Title: Animal science mimeograph report - Florida Agricultural Experiment Station ; no. AN64-9
Title: Nutritional experiments for science projects and demonstrations
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Permanent Link: http://ufdc.ufl.edu/UF00072944/00001
 Material Information
Title: Nutritional experiments for science projects and demonstrations
Series Title: Animal science mimeograph report
Physical Description: 6 leaves : ; 28 cm.
Language: English
Creator: Arrington, Lewis Robert, 1919-
University of Florida -- Agricultural Experiment Station
Publisher: Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1964
 Subjects
Subject: Nutrition -- Research -- Florida   ( lcsh )
Diseases -- Animal models   ( lcsh )
Animal experimentation   ( lcsh )
Laboratory animals   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: L.R. Arrington.
General Note: Caption title.
General Note: "January, 1964."
Funding: Animal Science Department mimeograph report ;
 Record Information
Bibliographic ID: UF00072944
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 77522090

Full Text


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Animal Science Florida Agri 1 U
Mimeograph Report No. AN64-9 Experiment n
Gainesvill, 1 'da
January, f6

NUTRITIONAL EXPERIMENTS FOR SCIENCE PROJECTS \
AND DEMONSTRATIONS ...

L. R. Arrington-/ s


Certain nutrition experiments can be easily designed and carried
out within a reasonable length of time using small laboratory animals.
There are, however, problems and limitations which should be considered.
The more suitable experiments probably are those designed to produce a
nutrient deficiency or demonstrate different rates of growth on adequate
and inadequate diets.

There are various methods of measuring the effect of different
diets upon animals, but most require equipment and laboratory facilities
which may not be available. Growth (change in body weight) is one of
the simplest, most widely used and useful measures. Certain symptoms of
deficiency will appear in some experiments and are useful in evaluating
the diet. Unthriftiness, rough and dirty hair coat, rough, scaly skin
and sometimes bleaching or depigmentation of the hair will appear.

The procedures and experiments recommended below represent very
simple types requiring the least equipment and materials. The outline
is brief but should provide basic information for direct use or modifi-
cation.

Experimental Animals: Laboratory rats are probably the most useful.
Mice, rabbits, guinea pigs, and hamsters are used in some nutritional
studies, but they are not as extensively used as are rats. Strains of
rats with colored hair coats are desirable if bleaching or depigmenta-
tion might result from the dietary treatment. For growth experiments
it is desirable that the rats be started on experiment at or soon after
weaning 3 to 4 weeks of age. If older and larger, the effect of diet
upon growth is obviously more difficult to demonstrate.

Sources of Experimental Animals:

Local breeders
Research laboratories occasionally have surplus
Rockland Farms, New City (Rockland County), New York
Carworth Farms, New City (Rockland County), New York
Sprague-Dawley, Madison, Wisconsin

Housing and Equipment: Wire (hardware cloth) cages with raised floors
are best. These may be constructed easily, usually circular, using 1/4
inch or 1/2 inch mesh hardware cloth. For young rats and for mice, the


i/ Associate Animal Nutritionist







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floor should be 1/4 inch mesh and for mature rats the floor should be
1/2 inch mesh. The raised floor permits feces and urine to pass through
to pan or paper below and affords better sanitation and easier cleaning.

Experimental rats should be caged individually when possible, but
animals of the same sex and receiving the same diet may be housed to-
gether when necessary. Temperature of the room in which animals are
kept should be approximately 75-800 F.

A laboratory scale, weighing in grams, is useful for weighing rats
and diet ingredients.

Feeding: Specific diets for experiments will be listed below. Rats not
on experiment may be fed a wide variety of feeds, but the most convenient
is a laboratory chow (pellets) or dry dog feed. Rats on growth experi-
ments may be fed ad libitum or pair fed. In pair feeding each member of
the pair is fed the same weighed amount daily, the amount provided being
equal to that consumed by the rat consuming the least. Pair feeding
provides a somewhat more critical measure of the diet effect, but it is
more time consuming and not necessary in all experiments. Pair feeding
experiments with rats should not continue more than about four weeks.

All diets should be thoroughly mixed and stored in a cool, dry
place. Rats will normally consume 8 to 15 grams of dry feed daily de-
pending upon size. Frequently young rats will waste excessive amounts
of meal type feeds and the use of deep feeders will help prevent this
wastage.

Procedures: Growth experiments should be started when rats are 3 to 4
weeks of age or shortly thereafter. Identification may be accomplished
by ear notches, cage number, color markings of individual animals or
other methods. Body weight of each rat should be taken at the beginning
and at weekly intervals thereafter if possible. Weekly weights provide
data for plotting growth curves. Length of the experimental period may
vary, but probably should not be less than 4 weeks and need not be more
than 10 weeks for most experiments.

Rats respond to careful and frequent handling and seldom bite after
they become accustomed to being handled properly. New or unhandled rats
may become excited and at times may bite. Any deep or painful bite
should be reported to a doctor. The best methods of holding are to
place the hand around the whole body with thumbs and forefinger around
the neck or lift the rat with the loose skin over the shoulders.

After several weeks on the experiment when definite symptoms or
differences in growth are apparent, it may be desirable to switch diets
and observe the effects. When the experiment is terminated, the rats
may be sacrificed and dissected if desirable. It is not likely, how-
ever, that any effects of the diets recommended will be observed except
differences in the amount of stored fat. Rats may be easily and pain-
lessly killed by placing them in a small closed container with 20-30 cc.






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of chloroform or ether and leaving the container closed for 5 to 10
minutes. Extreme caution must be exercised in handling ether since it
is highly inflammable.

Sources of Dietary Ingredients: Certain diets may be prepared from
common foods or feeds, but many experiments designed to produce a
specific deficiency and some growth studies require the use of purified
ingredients. Following is a list of some of the more common ingredi-
ents used and sources. A problem may occur in the purchase of small
quantities of ingredients from feed stores, but the stores should be
able to recommend other sources.

Sugar and starch for carbohydrate Grocery store grades usually
satisfactory
Soybean meal Feed stores
Vegetable oil or corn oil Groceries
Bone meal Feed stores
Salt Groceries
Limestone Feed stores or CaC03 from Pharmacy
Salt-trace mineral mixture Feed stores
Purified ingredients (Casein, Egg albumin, for protein; amino
acids, vitamins and vitamin mixes, dried brewers yeast, mineral
mixtures) Nutritional Biochemicals Corp.
21010 Miles Avenue
Cleveland 28, Ohio

General Biochemicals Corp.
Chagrin Falls, Ohio

The Florida Agricultural Experiment Station does not recommend any
particular supplier of materials or of experimental animals. Many other
companies supply these materials and those listed are for reference if
needed.

Companies supplying purified diet ingredients may also have or can
prepare specific diets which are deficient in a certain nutrient. Feed
manufacturing companies will usually have vitamin mixtures and may be
interested in the experiments so that they might supply vitamins to
students. Concentration of the vitamins in the mixture will vary, so
the amount needed in the feed should be determined from the supplier.

Some Nutritional Experiments for Demonstration and Projects Using Rats
or Mice:

1. Inadequate vs. adequate diet
Diet A White bread, crackers etc. plus water. No meat, milk
or protein.
Diet B Normal diet such as small portions of a complete meal
from the cafeteria, including milk and meat.

This experiment is useful for young students. Differences in growth
should be evident in 3 to 4 weeks even without body weight measurement.





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2. Single vs. combination of foods
Diet A Enriched white bread only and water
Diet B Fresh whole milk only
Diet C Enriched bread and whole milk and water

Diet A should produce poorest growth. Diet B intermediate and Diet C
best growth.

3. Effect of protein intake

Ingredient Diet A Diet B Diet C

Corn meal 20% 20% 20%
Starch 32 23 20
Sugar 30 24 12
Soybean meal 10 25 40
Vegetable or corn oil 3 3 3
Salt-trace mineral mixture 1 1 1
Bone meal 3 3 3
Vitamin mixture* 1 1 1

100 100 100

4. Amino acid deficiency

Ingredient Diet A Diet B

Corn meal 40% 40%
Zein (purified corn
protein) 20 10
Casein 0 10
Sugar 35 35
Salt-trace mineral mixture 1 1
Bone meal or mineral
mixture 3 3
Vitamin mix* (if possible)
or brewers yeast 1 1

100 100


The amount of vitamin mixture needed must be determined from supplier,
depending upon concentration of vitamins in the mixture. The protein
in corn meal and in Zein is deficient in the amino acids lysine and
tryptophan. Casein supplies these amino acids so Diet B should pro-
mote normal growth while rats on Diet A should grow very little or
none. One percent lysine and 0.2 percent tryptophan added to Diet A
should also correct the deficiency and promote growth.






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5. Vitamin B complex deficiency

Ingredient Diet A Diet B

Corn meal 20% 20%
Starch 26 21
Sugar 25 25
Vitamin free casein 20 20
Vegetable or corn oil 4 4
Salt 1 1
Complete mineral mix (preferred)
or Bone meal 4 4
Dried brewers yeast or
Vitamin mixture* 0 1-5

100 100

Rats should be given 1 or 2 drops of cod liver oil weekly as a source
of vitamins A and D. This may be placed on the feed or dropped
directly on the mouth. This experiment does not produce a single
vitamin deficiency, but should illustrate the poor growth when the B
complex vitamins are lacking. (Diets for producing a single vitamin
deficiency are rather difficult to prepare. Vitamin mixtures, using
milligram quantities of each of 15 or more vitamins would have to be
prepared or purchased from a biochemical company and purified ingredi-
ents for the diet, free of vitamins, would have to be purchased).

6. Phosphorus deficiency

Ingredient Diet A Diet B

Corn starch 40% 40%
Sugar 37 37
Egg albumin 14 14
Vegetable or corn oil 5 5
CaC03 or limestone 3 0
Bone meal 0 3
Salt-trace mineral mix 1 1
Vitamin mixture* -

100 100

One percent CaHP04 may be used in place of bone meal as a source of
phosphorus in Diet B. Definite symptoms of deficiency may require 6
to 8 weeks. Poor growth should be noted earlier, but rear leg
"paralysis" or inability to stand on rear legs should be noted in 10-
12 weeks.

* The amount or concentration of vitamins in different mixtures may
vary. Some mixtures are prepared so that one percent added to the
diet supplies the vitamins in adequate amount. The amount of
vitamin mixture needed in the diet should be determined from the
supplier.








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Other diets or modifications of those recommended may be prepared
depending upon availability of ingredients and facilities for prepara-
tion. Careful attention should be given to weighing of the ingredi-
ents, especially those added in small amounts. Thorough mixing of the
diets is also important.




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