• TABLE OF CONTENTS
HIDE
 Copyright
 Front Cover
 Board of control and staff
 Introduction
 Review of literature
 Table of Contents
 Materials and methods
 Experimental data
 Discussion
 Conclusions
 Acknowledgement
 Literature cited






Group Title: Bulletin - University of Florida. Agricultural Experiment Station - no. 483
Title: The nutritive value of various breads and supplements in experiments with white rats
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027298/00001
 Material Information
Title: The nutritive value of various breads and supplements in experiments with white rats
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 22 p. : charts ; 23 cm.
Language: English
Creator: Abbott, O. D ( Ouida Davis ), b. 1892
French, R. B ( Rowland Barnes )
Townsend, Ruth O
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1951
 Subjects
Subject: Bread   ( lcsh )
Enriched foods   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 22.
Statement of Responsibility: O.D. Abbott, R.B. French and Ruth O. Townsend.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
 Record Information
Bibliographic ID: UF00027298
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 000925741
oclc - 18266147
notis - AEN6397

Table of Contents
    Copyright
        Copyright
    Front Cover
        Page 1
    Board of control and staff
        Page 2
        Page 3
    Introduction
        Page 5
    Review of literature
        Page 5
        Page 6
        Page 7
    Table of Contents
        Page 4
    Materials and methods
        Page 8
        Bread
            Page 8
        Experimental animals
            Page 9
            Page 10
    Experimental data
        Page 11
        Nutritive value of the five types of bread
            Page 11
            Page 12
        Effectiveness of protein supplements in improving the nutritive value of enriched and unenriched water bread
            Page 13
            Page 14
            Page 15
            Page 16
        Realimentation
            Page 17
            Weight
                Page 17
                Page 18
            Skeletal development
                Page 19
            Reproduction
                Page 19
    Discussion
        Page 19
        Page 20
    Conclusions
        Page 21
    Acknowledgement
        Page 22
    Literature cited
        Page 22
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida







September 1951


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
WILLARD M. FIFIELD, Director
GAINESVILLE, FLORIDA








The Nutritive Value of Various Breads

and Supplements in Experiments

with White Rats

By O. D. ABBOTT, R. B. FRENCH and RUTH O. TOWNSEND








TECHNICAL BULLETIN











Single copies free to Florida residents on request to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA


Bulletin 483









BOARD OF CONTROL

Frank M. Harris, Chairman, St. Petersburg
N. B. Jordan, Quincy
Hollis Rinehart, Miami
Eli H. Fink, Jacksonville
George J. White, Sr., Mount Dora
W. F. Powers, Secretary, Tallahassee

EXECUTIVE STAFF
J. Hillis Miller, Ph.D., President
J. Wayne Reitz, Ph.D., Provost for Agr.3
Willard M. Fifield, M.S., Director
J. R. Beckenbach, Ph.D., Asso. Director
L. O. Gratz, Ph.D., Asst. Dir., Research
Geo. F. Baughman, M.S., Business Mgr.3
Rogers L. Bartley, B.S., Admin. Mgr.3
Claranelle Alderman, Accountant3

MAIN STATION, GAINESVILLE

AGRICULTURAL ECONOMICS
H. G. Hamilton, Ph.D., Agr. Economist 13
R. E. L. Greene, Ph.D., Agr. Economist
M. A. Brooker, Ph.D., Agr. Economist
Zach Savage. M.S.A., Associate
A. H. Spurlock, M.S.A., Associate
D. E. Alleger, M.S., Associate
U. L. Brooke, M.S.A., Associate4
M. R. Godwin, Ph.D., Associate
H. W. Little, M.S., Assistant4
Tallmadge Bergen, B.S., Assistant
D. C. Kimmel, Ph.D., Assistant
A. L. Larson, Ph.D., Agr. Economist
Orlando, Florida (Cooperative USDA)
G. Norman Rose, B.S., Asso. Agr. Economist
J. C. Townsend, Jr., B.S.A., Agr.
Statistician 2
J. B. Owens, B.S.A., Agr. Statistician

AGRICULTURAL ENGINEERING
Frazier Rogers, M.S.A., Agr. Engineer '
J. M. Johnson, B.S.A.E., Agr. Eng.3
J. M. Myers, B.S., Asso. Agr. Engineer
R. E. Choate, B.S.A.E., Asso. Agr. Eng."
A. M. Pettis, B.S.A.E., Asst. Agr. Eng.2 3

AGRONOMY
Fred H. Hull, Ph.D., Agronomist1
G. B. Killinger, Ph.D., Agronomist 3
H. C. Harris, Ph.D., Agronomist
R. W. Bledsoe, Ph.D., Agronomist
W. A. Carver, Ph.D., Associate
Darrel D. Morey, Ph.D., Associate
Fred A. Clark, B.S., Assistant
Myron C. Grennell, B.S.A.E., Assistant
E. S. Horner, Ph.D., Assistant
A. T. Wallace, Ph.D., Assistant
D. E. McCloud, Ph.D., Assistant

ANIMAL HUSBANDRY AND NUTRITION
T. J. Cunha, Ph.D., An. Husb.1 3
R. S. Glasscock, Ph.D., An. Husb.3
G. K. Davis, Ph.D., Animal Nutritionist 3
R. L. Shirley, Ph.D., Biochemists
J. E. Pace, M.S., Asst. An. Husb.3
S. John Folks, M.S., Asst. An. Husb.4
Katherine Boney, B.S., Asst. Chem.
A. M. Pearson, Ph.D., Asso. An. Hush.'
John D. Feaster, Ph.D., Asst. An. Nutri.
H. D. Wallace, Ph.D., Asst. An. Husb.3
M. Koger, Ph.D., An. Husbandman 3

DAIRY SCIENCE
E. L. Fouts, Ph.D., Dairy Tech.'1
R. B. Becker, Ph.D., Dairy Hush.3
S. P. Marshall, Ph.D., Asso. Dairy Husb.'
W. A. Krienke, M.S., Asso. in Dairy Mfs.s
P. T. Dix Arnold, M.S.A., Asst. Dairy Husb.2
Leon Mull, Ph.D., Asso. Dairy Tech.
H. Wilkowske, Ph.D., Asst. Dairy Tech.
James M. Wing, M.S., Asst. Dairy Husb.


EDITORIAL


J. Francis Cooper, M.S.A., Editor
Clyde Beale, A.B.J., Associate Editor
L. Odell Griffith, B.A.J., Asst. Editor3
J. N. Joiner, B.S.A., Assistant Editor 4

ENTOMOLOGY
A. N. Tissot, Ph.D., Entomologist
L. C. Kuitert, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
F. A. Robinson, M.S., Asst. Apiculturist

HOME ECONOMICS
Ouida D. Abbott, Ph.D., Home Econ.1
R. B. French, Ph.D., Biochemist

HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist 1
F. S. Jamison, Ph.D., Horticulturist 3
Albert P. Lorz, Ph.D., Horticulturist
R. K. Showalter, M.S., Asso. Hort.
R. A. Dennison, Ph.D., Asso. Hort.
R. H. Sharpe, M.S., Asso. Horticulturist
V. F. Nettles, Ph.D., Asso. Horticulturist
F. S. Lagasse, Ph.D., Asso. Hort.2
R. D. Dickey, M.S.A., Asso. Hort.
L. H. Halsey, M.S.A., Asst. Hort.
C. D. Hall, Ph.D., Asst. Horticulturist
Austin Griffiths, Jr., B.S., Asst. Hort.
S. E. McFadden, Jr., Ph.D., Asst. Hort.

LIBRARY
Ida Keeling Cresap, Librarian

PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist'3
Phares Decker, Ph.D., Plant Pathologist
Erdman West, M.S., Mycologist and Botanist
Robert W. Earhart, Ph.D., Plant Path.2
Howard N. Miller, Ph.D., Asso. Plant Path.
Lillian E. Arnold, M.S., Asst. Botanist
C. W. Anderson, Ph.D., Asst. Plant Path.

POULTRY HUSBANDRY
N. R. Mehrhof, M.Agr., Poultry Husb.1 3
J. C. Driggers, Ph.D., Asso. Poultry Husb.

SOILS
F. B. Smith, Ph.D., Microbiologist'
Gaylord M. Volk, Ph.D., Soils Chemist
J. R. Henderson, M.S.A., Soil Technologist
J. R. Neller, Ph.D., Soils Chemist
Nathan Gammon, Jr., Ph.D., Soils Chemist
R. A. Carrigan, Ph.D., Biochemists
Ralph G. Leighty. B.S., Asst. Soil Surveyor'
G. D. Thornton, Ph.D., Asso. Microbiologist 3
Charles F. Eno, Ph.D., Asst. Soils Micro-
biologist
H. W. Winsor, B.S.A., Assistant Chemist
R. E. Caldwell, M.S.A., Asst. Chemist 3
V. W. Carlisle, B.S., Asst. Soil Surveyor
James H. Walker, M.S.A., Asst. Soil
Surveyor
S. N. Edson, M.S., Asst. Microbiologists
William K. Robertson, Ph.D., Asst. Chemist
0. E. Cruz, B.S.A., Asst. Soil Surveyor
W. G. Blue, Ph.D., Asst. Biochemist

VETERINARY SCIENCE
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M., Veterinarian 3
C. F. Simpson, D.V.M., Asso. Veterinarian
L. E. Swanson, D.V.M., Parasitologist
Glenn Van Ness, D.V.M., Asso. Poultry
Pathologist
G. E. Batte, D.V.M., Asso. Parasitologist










BRANCH STATIONS


NORTH FLORIDA STATION, QUINCY

J. D. Warner, M.S., Vice-Director in Charge
R. R. Kincaid, Ph.D., Plant Pathologist
L. G. Thompson, Ph.D., Soils Chemist
W. C. Rhoads, M.S., Entomologist
W. H. Chapman, M.S., Asso. Agronomist
Frank S. Baker, Jr., B.S., Asst. An. Hush.


Mobile Unit, Monticello
R. W. Wallace, B.S., Associate Agronomist

Mobile Unit, Marianna
R. W. Lipscomb, M.S., Associate Agronomist

Mobile Unit, Pensacola
R. L. Smith, M.S., Associate Agronomist

Mobile Unit, Chipley
J. B. White, B.S.A., Associate Agronomist

CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Vice-Director in Charge
W. L. Thompson, B.S., Entomologist
R. F. Suit, Ph.D., Plant Pathologist
E. P. Ducharme, Ph.D., Asso. Plant Path.
C. R. Stearns, Jr., B.S.A., Asso. Chemist
J. W. Sites, Ph.D., Horticulturist
H. O. Sterling, B.S., Asst. Horticulturist
H. J. Reitz, Ph.D., Horticulturist
Francine Fisher, M.S., Asst. Plant Path.
I. W. Wander, Ph.D., Soils Chemist
J. W. Kesterson, M.S., Asso. Chemist
R. Hendrickson, B.S., Asst. Chemist
Ivan Stewart, Ph.D., Asst. Biochemist
D. S. Prosser, Jr., B.S., Asst. Horticulturist
R. W. Olsen, B.S., Biochemist
F. W. Wenzel, Jr., Ph.D., Chemist
Alvin H. Rouse, M.S., Asso. Chemist
H. W. Ford, Ph.D., Asst. Horticulturist
L. W. Faville, Ph.D., Asst. Bacteriologist
L. C. Knorr, Ph.D., Asso. Histologist 4
R. M. Pratt, Ph.D., Asso. Ent.-Pathologist
W. A. Simanton, Ph.D., Entomologist
E. J. Deszyck, Ph.D., Asso. Horticulturist
C. D. Leonard, Ph.D., Asso. Horticulturist
I. Stewart, M.S., Asst. Biochemist
W. T. Long, M.S., Asst. Horticulturist

EVERGLADES STATION, BELLE GLADE
R. V. Allison, Ph.D., Vice-Director in Charge
Thomas Bregger, Ph.D., Sugar Physiologist
J. W. Randolph, M.S., Agricultural Engr.
W. T. Forsee, Jr., Ph.D., Chemist
R. W. Kidder, M.S., Asso. Animal Husb.
T. C. Erwin, Assistant Chemist
C. C. Seale, Asso. Agronomist
N. C. Hayslip, B.S.A., Asso. Entomologist
E. A. Wolf, M.S., Asst. Horticulturist
W. H. Thames, M.S., Asst. Entomologist
W. N. Stoner, Ph.D., Asst. Plant Path.
W. A. Hills, M.S., Asso. Horticulturist
W. G. Genung, B.S.A., Asst. Entomologist
Frank V. Stevenson, M.S., Asso. Plant Path.
R. H. Webster, Ph.D., Asst. Agronomist
Robert J. Allen, Ph.D., Asst. Agronomist
V. E. Green, Ph.D., Asst. Agronomist
J. F. Darby, Ph.D., Asst. Plant Path.
H. L. Chapman. M.S.A., Asst. An. Husb.
Thos. G. Bowery, Ph.D., Asst. Entomologist


SUB-TROPICAL STATION, HOMESTEAD
Geo. D. Ruehle, Ph.D., Vice-Dir. in Charge
D. O. Wolfenbarger, Ph.D., Entomologist
Francis B. Lincoln, Ph.D., Horticulturist
Robert A. Conover, Ph.D., Plant Path.
John L. Malcolm, Ph.D., Asso. Soils Chemist
R. W. Harkness, Ph.D., Asst. Chemist
R. Bruce Ledin, Ph.D., Asst. Hort.

WEST CENTRAL FLORIDA STATION,
BROOKSVILLE
William Jackson, B.S.A., Animal Husband-
man in Charge 2

RANGE CATTLE STATION, ONA
W. G. Kirk, Ph.D., Vice-Director in Charge
E. M. Hodges, Ph.D., Agronomist
D. W. Jones, M.S., Asst. Soil Technologist

CENTRAL FLORIDA STATION, SANFORD
R. W. Ruprecht, Ph.D., Vice-Dir. in Charge
J. W. Wilson, Sc.D., Entomologist
P. J. Westgate, Ph.D., Asso. Hort.
Ben. F. Whitner, Jr., B.S.A., Asst. Hort.
Geo. Swank, Jr., Ph.D., Asst. Plant Path.

WEST FLORIDA STATION, JAY
C. E. Hutton, Ph.D., Vice-Director in Charge
H. W. Lundy, B.S.A., Associate Agronomist

SUWANNEE VALLEY STATION,
LIVE OAK
G. E. Ritchey, M.S., Agronomist in Charge

GULF COAST STATION, BRADENTON
E. L. Spencer, Ph.D., Soils Chemist in Charge
E. G. Kelsheimer, Ph.D., Entomologist
David G. Kelbert, Asso. Horticulturist
Robert O. Magie, Ph.D., Plant Pathologist
J. M. Walter, Ph.D., Plant Pathologist
Donald S. Burgis, M.S.A., Asst. Hort.
C. M. Geraldson, Ph.D., Asst. Hort.
W. G. Cowperthwaite, Ph.D., Asst. Hort.



FIELD LABORATORIES
Watermelon, Grape, Pasture-Leesburg
C. C. Helms, Jr., B.S., Asst. Agronomist

Strawberry-Plant City
A. N. Brooks, Ph.D., Plant Pathologist

Vegetables-Hastings
A. H. Eddins, Ph.D., Plant Path. in Charge
E. N. McCubbin, Ph.D., Horticulturist

Pecans-Monticello
A. M. Phillips, B.S., Asso. Entomologist
John R. Large, M.S., Asso. Plant Path.

Frost Forecasting-Lakeland
Warren O. Johnson, B.S., Meteorologist 2

1 Head of Department
2 In cooperation with U. S.
3 Cooperative, other divisions, U. of F.
I On leave.









The Nutritive Value of Various Breads
and Supplements in Experiments
with White Rats

By O. D. ABBOTT, R. B. FRENCH and RUTH 0. TOWNSEND 1

A preliminary quantitative study (by the authors) of food
consumption of 106 rural school children in one county in Florida
showed that as income decreased the carbohydrate content of
the diet increased. Average consumption of bread and biscuit
by children in the highest income level was 127 grams per child
per day, in the lowest 189 grams. Consumption of rice and
grits followed the same pattern, 91 grams daily for children
in the highest income group and 155 grams for those in the
lowest. It is generally conceded that the higher the proportion
of carbohydrate in the diet the greater the possibilities for
dietary deficiencies.
Due to higher incomes and more extensive dissemination of
information on nutritive requirements, the diets of a large seg-
ment of the population in the United States have become better
and more varied. But while it is generally agreed that it is
only under stress of war that the composition of bread becomes
critical, it also should be recognized that bread still forms a
large part of the diet and therefore its composition is of im-
portance at all times.

Review of Literature
In 1939 it was announced in England that white flour was
to be enriched with thiamine. This program was challenged
immediately by the Medical Research Council (7).2 Chick (2)
then showed by experiments on rats the decided advantages of
whole wheat flour over flour enriched with thiamine. After much
controversy the British Government decided "to increase to 85
percent the ratio of flour from milled wheat" and to stop pro-
duction of white bread.
In America the question of fortification was first discussed
at a symposium in Toronto in 1939. Canadian medical men and
nutritionists, among them McHenry (6), opposed the fortifica-
tion of white flour on the grounds that B complex vitamins could
SProfessional Assistant.
SItalic figures in parentheses refer to Literature Cited.









The Nutritive Value of Various Breads
and Supplements in Experiments
with White Rats

By O. D. ABBOTT, R. B. FRENCH and RUTH 0. TOWNSEND 1

A preliminary quantitative study (by the authors) of food
consumption of 106 rural school children in one county in Florida
showed that as income decreased the carbohydrate content of
the diet increased. Average consumption of bread and biscuit
by children in the highest income level was 127 grams per child
per day, in the lowest 189 grams. Consumption of rice and
grits followed the same pattern, 91 grams daily for children
in the highest income group and 155 grams for those in the
lowest. It is generally conceded that the higher the proportion
of carbohydrate in the diet the greater the possibilities for
dietary deficiencies.
Due to higher incomes and more extensive dissemination of
information on nutritive requirements, the diets of a large seg-
ment of the population in the United States have become better
and more varied. But while it is generally agreed that it is
only under stress of war that the composition of bread becomes
critical, it also should be recognized that bread still forms a
large part of the diet and therefore its composition is of im-
portance at all times.

Review of Literature
In 1939 it was announced in England that white flour was
to be enriched with thiamine. This program was challenged
immediately by the Medical Research Council (7).2 Chick (2)
then showed by experiments on rats the decided advantages of
whole wheat flour over flour enriched with thiamine. After much
controversy the British Government decided "to increase to 85
percent the ratio of flour from milled wheat" and to stop pro-
duction of white bread.
In America the question of fortification was first discussed
at a symposium in Toronto in 1939. Canadian medical men and
nutritionists, among them McHenry (6), opposed the fortifica-
tion of white flour on the grounds that B complex vitamins could
SProfessional Assistant.
SItalic figures in parentheses refer to Literature Cited.







Florida, Agricultural Experiment Stations


best be obtained by milling wheat so that these vitamins would
be retained. Through cooperation of nutritionists and millers
a white flour of 75 percent extraction was produced which con-
tained 363 I.U. of thiamine per pound, instead of 252 I.U. as
found in the flour produced by the usual procedures.
According to Lepkovsky (5), however, the United States, un-
like Great Britain and Canada, did not discuss "with any degree
of thoroughness the relative merits of whole wheat, white bread
and 'enriched' white bread."
At the Toronto meeting Morgan (11) advised proceeding with
caution and Roberts (12) considered fortification merely "first
aid measures." "However in spite of this conservative and un-
certain attitude towards fortification of foods, including refine-
ment of cereals," (5), in 1941 the Food and Nutrition Board
of the National Research Council recommended the enrichment
of white bread and flour as a. safeguard against deficiencies of
certain B vitamins and of iron. In 1943 War Food Order No. 1
required. enrichment of all white bread and flour, and so "en-
riched" bread was accepted without discussion.
Since the passage of this act considerable work has been done
in evaluating the program. In 1943 Mitchell, Hamilton and
Shields (10) found that growth-promoting properties of bread
containing 6 percent milk solids were not increased by addition
of the enriching factors.
In the same year Williams, Mason and Wilder (13) studied
the nutritive contribution of diets containing 30 percent of bread
components made of enriched, unenriched and whole wheat flour,
while the remainder of the diet consisted of the commonly used
foods. These diets were fed to seven women with reference to
satisfying requirements for thiamine and riboflavin. On a diet
containing plain unenriched white flour, signs suggestive of
thiamine deficiency developed within 100 days, but in subjects
receiving enriched white flour to which had been added 6 per-
cent skimmilk solids, based on the weight of the flour, "signs,
symptoms and metabolic defects suggestive of thiamine de-
ficiency of an exceedingly mild degree were observed." Two
subjects received whole wheat flour and one showed symptoms
of a thiamine deficiency while "the nutritional status of the
second subject continued better than that of subjects receiving
enriched flour." According to the authors, "the conclusion seems
to be fully justified that a flour which contains, as a minimum,
2.0 mg. of thiamine and 15.0 mg. of niacin per pound with 6 parts







The Nutritive Value of Various Breads


per hundred of non-fat milk solids is nutritionally a satisfactory
food."
In 1944 a nutritional survey (8) was made of 868 unselected
people, part of whom lived in St. Johns, Newfoundland, while
the remainder lived in several Eastern and Southern outports.
No pellagra was found and peripheral neuritis was seldom seen.
There were, however, signs interpreted as evidence of chronic
niacin deficiency of mild degree and of less severe thiamine
deficiency.
A resurvey (9) was made in 1948 of 868 persons, of whom
227 individuals examined in 1944 were reexamined in 1948.
Results of this examination of the 227 subjects were interpreted
as showing that "those signs and symptoms of malnutrition
which could have been expected to decrease as a result of en-
richment of flour with riboflavin, niacin and thiamine were less
frequently encountered in 1948 than in 1944." However, the
data show that in 1948 the percentage of subjects with neuro-
logical signs indicative of a thiamine deficiency showed no sig-
nificant change from that found in 1944. And while in 1948
there had been considerable improvement in certain signs and
symptoms indicative of niacin and riboflavin deficiencies, no
significant improvement was noted in other signs and symptoms
of these deficiencies.
It would seem, therefore, that the current program of enrich-
ment played only a part in the shifting picture, since during
the years between these examinations there had been improve-
ment in sanitation and medical care, in economic status, in
family living, and in quantity and quality of available foods,
such as dry and evaporated milk, canned fruits and vegetables.
These factors would undoubtedly contribute greatly to the im-
proved nutritional status of these people.
At the close of the war enrichment was no longer required
but at present 26 states have passed laws making mandatory
the enrichment of white flour and bread. Moreover, in states
where enrichment laws have not been passed practically all white
flour for home use is enriched, as is practically all commercially
baked bread.
This review of the literature shows that while the current
enrichment program is widely accepted the justification for
mandatory enrichment and also for its continuation is still con-
troversial. For this reason experiments were designed for the
purpose of making a comparative study of the nutritive value











Contents


Page
INTRODUCTION .........- ...... ...........- .. ....... ....................... 5


REVIEW OF LITERATURE ...-.. .............. .... --...... ........................ 5


MATERIALS AND METHODS --- -------.................. ......... ..................... 8


Bread .............-..-.......--.............. ---- 8


Experimental Animals .......-----.. --..-- ......-- -....--- -- ..... .............. 9


EXPERIMENTAL DATA ......- ..------ ........-- .............. .. ...... .......... 11


Nutritive Value of the Five Types of Bread ......----.........-.....-........... 11


Effectiveness of Protein Supplements in Improving the Nutritive
Value of Enriched and Unenriched Water Bread ............-............--- 13


Realimentation ........-....-...-...-.................. --.............-.------ ............. .... 17


W eight ......... ... ...- ------.............. ........ .. -.................. 17


Skeletal Development ...---...-----...-- -----..... ........... .... 19


R production .... ....... ...... .................-.......-................... 19


D ISCUSSION .............. .- ------................... .......................... 19


CONCLUSIONS ..................----- ---.............. .... ......... ......................... ...... 21


ACKNOW LEDGMENTS ...... ....... ................... .......... .... -................ 22


LITERATURE CITED ...................... .... ................. .... .... .............. 22








Florida Agricultural Experiment Stations


of the five types of bread in general use and to test other nutri-
tive supplements with these breads. It was felt that a positive
research program in this field was of importance.

Materials and Methods
Bread.-The breads used in these experiments were as follows:
Water bread-white bread made without enrichment; enriched
water bread-white bread enriched according to present official
standards; milk bread-white bread containing 6 percent non-fat
milk solids based upon the weight of the flour; enriched milk
bread-white bread enriched according to present official stand-
ards and containing 6 percent non-fat milk solids, based upon
the weight of the flour; whole wheat bread-made from 100
percent whole wheat flour, no milk.
These breads were made in the laboratories of the American
Baking Institute. Enough bread was baked at one time to last
through each experiment. All bread was made by the straight
dough method from a blend of wheat flours typical of commer-
cial bread flours. The general formula based on the weight of the
flour was as follows: Yeast 2 percent; malt 1 percent; salt 2
percent; sugar 5 percent; fat 4 percent; yeast food 1/2 percent.
Bread was enriched according to federal standards for enrich-
ment.
The fermentation time was approximately 2 hours, with 25
minutes to pan proof. The dough was baked in 1-pound pans
at 375 to 4000 F. for 45 minutes. After storage for 24 hours in
a proofing cabinet the top, bottom and side crusts were shaved
off and the remaining loaf was cut into thin slices, which were
then dried at a temperature of 40 to 500 C. The dry breads were

TABLE 1.-ANALYSES* OF WHOLE WHEAT BREAD AND ENRICHED AND UN-
ENRICHED WHITE BREADS CALCULATED ON THE COMPOSITION OF THE DRY
CRUMBS (8.2 PERCENT MOISTURE).
I Ribo-
Type of Bread ICrude Ash Thiamine flavin Niacin
S Protein mgs mgs mgs

Water bread ........ 13.05 1.83 .29 1.55 6.01
Enriched water
bread .................. 13.16 1.84 1.36 2.35 17.64
Milk bread ........... 14.00 2.94 .29 1.74 5.13
Enriched milk
bread ................. 14.00 2.94 1.36 2.54 17.17
Wheat bread ....... 15.14 3.34 1.75 .80 17.80

American Dry Milk Institute.








Florida Agricultural Experiment Stations


of the five types of bread in general use and to test other nutri-
tive supplements with these breads. It was felt that a positive
research program in this field was of importance.

Materials and Methods
Bread.-The breads used in these experiments were as follows:
Water bread-white bread made without enrichment; enriched
water bread-white bread enriched according to present official
standards; milk bread-white bread containing 6 percent non-fat
milk solids based upon the weight of the flour; enriched milk
bread-white bread enriched according to present official stand-
ards and containing 6 percent non-fat milk solids, based upon
the weight of the flour; whole wheat bread-made from 100
percent whole wheat flour, no milk.
These breads were made in the laboratories of the American
Baking Institute. Enough bread was baked at one time to last
through each experiment. All bread was made by the straight
dough method from a blend of wheat flours typical of commer-
cial bread flours. The general formula based on the weight of the
flour was as follows: Yeast 2 percent; malt 1 percent; salt 2
percent; sugar 5 percent; fat 4 percent; yeast food 1/2 percent.
Bread was enriched according to federal standards for enrich-
ment.
The fermentation time was approximately 2 hours, with 25
minutes to pan proof. The dough was baked in 1-pound pans
at 375 to 4000 F. for 45 minutes. After storage for 24 hours in
a proofing cabinet the top, bottom and side crusts were shaved
off and the remaining loaf was cut into thin slices, which were
then dried at a temperature of 40 to 500 C. The dry breads were

TABLE 1.-ANALYSES* OF WHOLE WHEAT BREAD AND ENRICHED AND UN-
ENRICHED WHITE BREADS CALCULATED ON THE COMPOSITION OF THE DRY
CRUMBS (8.2 PERCENT MOISTURE).
I Ribo-
Type of Bread ICrude Ash Thiamine flavin Niacin
S Protein mgs mgs mgs

Water bread ........ 13.05 1.83 .29 1.55 6.01
Enriched water
bread .................. 13.16 1.84 1.36 2.35 17.64
Milk bread ........... 14.00 2.94 .29 1.74 5.13
Enriched milk
bread ................. 14.00 2.94 1.36 2.54 17.17
Wheat bread ....... 15.14 3.34 1.75 .80 17.80

American Dry Milk Institute.







The Nutritive Value of Various Breads


rolled, put into gallon buckets and shipped via express to the
Florida Agricultural Experiment Station. Upon receipt the
bread was stored in a refrigeration plant at 370 F. and taken
out as needed. Analyses of these breads are given in Table 1.

Experimental Animals.-In planning this experiment the au-
thors were of the opinion that experimental time would be
shortened and results made more conclusive if the young rats
making up the experimental groups were not allowed access
to stock diet during the nursing period. Accordingly, when the
young were 12 to 15 days old the mothers were fed only the
water bread diet. On this diet the quantity or quality of the
milk was evidently affected, as the young at 21 days of age had
an average weight of 32 to 33 grams instead of the usual aver-
age for this age of 38 to 40 grams. Therefore, when these rats
were put on the experimental bread diets they were somewhat
underweight and it was assumed that their reserves were low.
The experimental animals consisted of six groups of Albino
rats with 13 animals to the group equated on the basis of initial
weight, sex and breeding as determined by litter. These several
groups were fed as follows: 1, stock food (controls); 2, water
bread; 3, enriched water bread; 4, milk bread; 5, enriched milk
bread; and 6, whole wheat bread. Fat was added to bring the
bread diets up to a 10 percent level and vitamin A so that each
rat received 200 IU of vitamin A daily.
In all subsequent feeding tests the mothers were kept on stock
food throughout the entire lactating period. When the young
were put on experimental diets at 21 days of age their weights
were average for the colony, 38 to 40 grams. In these experi-
ments there were 23 groups of rats with six to the group. The
basal diet was one of the five types of bread with vitamin A and
fat to which various supplements were added.
During the experimental period of 12 to 13 weeks the ad
libitum feeding method was used. Scattering of food was re-
duced by special food containers.
The rats were weighed weekly and the weight curves were
considered indicative of the relative nutritive value of the five
types of bread. Other indices of the adequacy of the diets were
general appearance, which included size, condition of the hair,
eyes and skin, and skeletal structure as shown by roentgeno-
grams, gestation and lactation.





WEIGHT
IN GMS.
220 ---
1946 -47 1948-49
200

180

160

140




Soo /

80 4 _6

60 2

40

TIME
IN WKS. 2 4 6 8 10 12 2 4 6 8 10 12
Fig. 1.-Weight curves of rats fed bread diets; (2) unenriched water bread; (3) enriched water bread; (4) un-
enriched milk bread; (5) enriched milk bread; (6) wheat bread; and (1) controls fed stock food.








The Nutritive Value of Various Breads


Experimental Data

Experiment I.-Nutritive Value of the Five Types of Bread
At the close of the feeding period of 13 weeks all animals
showed signs of varying degrees of malnutrition which came
as a result of the bread diets. Rats fed whole wheat bread or
either type of milk bread, while not comparable in appearance
to the controls, were superior in size and general condition to
the extremely malnourished animals fed the two types of water
bread.
The effect of this feeding regimen on weight is shown in
Figure 1 (1946-47), where average weights are plotted against
weeks on the diet. Regardless of the type of bread, only slight
differences occurred in the weights of the five groups of rats
during the first 28 days. At the end of the feeding period the
average weights of the rats fed whole wheat bread or either
type of milk bread were from 32 to 39 grams heavier than those
fed either type of water bread. No appreciable differences in
weight were found between rats fed enriched or unenriched
water bread, nor between those fed either type of milk bread.
The small weight gains made by all groups suggested the
possibility that growth may have been inhibited by the quantity
or quality of the milk produced by the mothers when bread diets
were substituted for stock food before the young were weaned.
There was also the possibility that, because of the small growth
increment, requirements for the enriching factors, thiamine,
riboflavin, niacin and iron, were low and perhaps were ade-
quately supplied by unenriched breads. Under these conditions
the benefits of enrichment could not be demonstrated.
For these reasons the experiment was repeated with rats
whose mothers had had access to stock food until the young
were put on the bread diets at the age of 21 days. These rats
were then of average weight for this age. The data in Figure
1 (1948-49) show that while the initial weights were slightly
higher than those of rats in the above experiment, the final
weights were only slightly higher. In fact, in all respects the
results of the two experiments were in close agreement.
Since all animals in both experiments were grossly under-
weight and under the setup of the experiment no advantages.
due to enrichment could be demonstrated, there was the sugges-
tion that if the bread diets were supplemented so that the an-








The Nutritive Value of Various Breads


Experimental Data

Experiment I.-Nutritive Value of the Five Types of Bread
At the close of the feeding period of 13 weeks all animals
showed signs of varying degrees of malnutrition which came
as a result of the bread diets. Rats fed whole wheat bread or
either type of milk bread, while not comparable in appearance
to the controls, were superior in size and general condition to
the extremely malnourished animals fed the two types of water
bread.
The effect of this feeding regimen on weight is shown in
Figure 1 (1946-47), where average weights are plotted against
weeks on the diet. Regardless of the type of bread, only slight
differences occurred in the weights of the five groups of rats
during the first 28 days. At the end of the feeding period the
average weights of the rats fed whole wheat bread or either
type of milk bread were from 32 to 39 grams heavier than those
fed either type of water bread. No appreciable differences in
weight were found between rats fed enriched or unenriched
water bread, nor between those fed either type of milk bread.
The small weight gains made by all groups suggested the
possibility that growth may have been inhibited by the quantity
or quality of the milk produced by the mothers when bread diets
were substituted for stock food before the young were weaned.
There was also the possibility that, because of the small growth
increment, requirements for the enriching factors, thiamine,
riboflavin, niacin and iron, were low and perhaps were ade-
quately supplied by unenriched breads. Under these conditions
the benefits of enrichment could not be demonstrated.
For these reasons the experiment was repeated with rats
whose mothers had had access to stock food until the young
were put on the bread diets at the age of 21 days. These rats
were then of average weight for this age. The data in Figure
1 (1948-49) show that while the initial weights were slightly
higher than those of rats in the above experiment, the final
weights were only slightly higher. In fact, in all respects the
results of the two experiments were in close agreement.
Since all animals in both experiments were grossly under-
weight and under the setup of the experiment no advantages.
due to enrichment could be demonstrated, there was the sugges-
tion that if the bread diets were supplemented so that the an-







Florida Agricultural Experiment Stations


mals could grow at a more nearly normal rate the advantages
of enrichment might be shown. In a preliminary study two
types of supplements administered orally and manually were
evaluated-one, B complex concentrates; the other, protein and
WEIGHT
IN GMS.

220

200

180

160

140 /

120







60
4 / /3







40



TIME
IN WKS. 2 4 6 8 10 12
Fig. 2.-Comparison of weights of rats fed basal water bread diets
supplemented with (3) casein, (5) B complex and (7) essential amino acids
with those of rats fed (4) milk bread and (2) milk bread with yeast. Lines
1 and 6 represent weights of controls fed stock food and those of rats fed
the basal water bread diet, respectively.







The Nutritive Value of Various Breads


essential amino acids. The average weights of the rats on
bread diets constituted the base lines which were used in evaluat-
ing the effective results of the supplements. These supplements
were added when the animals had been on bread diets for four
weeks.
The results of this supplementation show (Fig. 2) that B com-
plex concentrates, one containing synthetic vitamins plus desic-
cated fractions of liver-stomach concentrate with yeast and the
other, derived entirely from yeast, were both ineffective in in-
creasing weights of rats fed a basal diet of unenriched water
bread, as were also all essential amino acids fed singly and in
combination. On the other hand when the total protein of the
diet of either unenriched water or milk breads was increased
to 24 percent by supplements of crude casein or of dried yeast
there were significant increases in weights over those of rats
fed the unsupplemented diets containing 14.2 or 15.3 percent
protein.

Experiment II.-Effectiveness of Protein Supplements in Im-
proving the Nutritive Value of Enriched and Unenriched
Water Bread

When it was found that protein induced a more nearly normal
growth of rats the level of protein in basal diets of both en-
riched and unenriched water bread was increased from 14.2 to
15.3 and 18 percent (dry weight) by supplements of non-fat
milk solids. As shown in Figure 3, there was an appreciable
increase in weight of all animals. At the 18-percent level there
was a weight increase of approximately 64 percent over that of
rats fed the basal water bread diet. It will be noted that, when
based on weight, no advantages due to enrichment were found
at either the 15.3 or 18 percent protein level. At the 24 percent
level, weights of rats fed a basal diet of unenriched water bread
supplemented with non-fat milk solids exceeded those of the con-
trols fed stock food containing 21 percent protein.
While supplements of non-fat milk solids were effective in
increasing weights of rats fed either type of water bread, milk
also furnished other food factors, especially vitamins used in
enrichment. For this reason a study was made of the supple-
mentary value of casein. Three casein products were used,
technical or crude, the hydrolysate produced by enzymatic
hydrolysis, and purified or acid washed. The total dietary pro-









WEIGHT
IN GMS.


220


200


180


160


140


120


100


80


60


40

TIME


Florida Agricultural Experiment Stations


IN W K ; 6 8 10 I2
Fig. 3.-Comparison of growth curves of rats fed a basal diet of water
bread supplemented with non-fat milk solids with protein levels of (2) 24%,
(3) 18%, (4) 18%, bread enriched, (5) 15.3%, (6) 15.3%, bread enriched,
with those of rats fed (1) stock food, 21%, and (7) and (8) enriched and
unenriched water bread, 14.2% protein.

tein in the bread diets was increased from 14.2 to 18 percent by
the addition of casein.
Data on the nutritional value of these supplements in increas-
ing weight of rats are presented in Figure 4. Largest gains
were made by rats fed crude casein or the hydrolysate and
least by those fed the purified. Differences in these weight gains


3
4









-5
6







The Nutritive Value of Various Breads


suggested that during extraction and purification some growth
factor or factors had been denatured or destroyed. Accordingly,
there was set up an experiment consisting of four groups of
weanling rats with six animals to the group. These rats were
fed a basal diet of unenriched water bread, vitamin A and fat
with supplements as follows: 5, Purified casein (total protein

WEIGHT
IN GMS.

200


180


160


140


120


100 -


80


60 5


40

TIME
IN WKS. 2 4 6 8 10 12
Fig. 4.-Comparison of weights of rats fed a basal diet of unenriched
water bread supplemented with (2) casein hydrolysate, (3) technical casein,
(4) vitamin-free casein, at 18% protein levels, with those of rats fed (1)
stock food, 21% protein, and (5) unenriched water bread, 14.2% protein.






Florida Agricultural Experiment Stations


18 percent) ; 2, purified casein (total protein 18 percent) plus 4
percent aureomycin-B12 feed supplement; 4, purified casein (total
protein 24 percent) ; 3, purified casein (total protein 24 percent)
plus 4 percent aureomycin-B12 feed supplement; 1, controls.
Data presented in Figure 5 show that from the first week
there was a variation in weights of rats in Groups 5 and 2.
WEIGHT
IN GMS.


200


180 -2


160 3


1404


120


100 5


80


60


40

TIME
IN WKS. 2 4 6 8 10 12
Fig. 5.-Weight curves of rats fed unenriched water bread-casin diets
containing (5) 18% protein, (2) 18% protein plus 4% aureomycin-B. feed
supplement with those of rats fed the bread-casein diet containing (4) 24%
protein and (3) 24% protein plus 4% aureomycin-B. feed supplement.
Line 1 represents controls fed stock food.







The Nutritive Value of Various Breads


Both groups were on diets containing 18 percent protein, but
at the end of the 12th week rats fed the supplement weighed
183 grams, while those without this factor weighed 112 grams.
At the 24 percent protein level the differences in weight were
not so large, 158 grams and 138 grams, respectively.
During the course of the experiment rats fed diets containing
24 percent protein without aureomycin-B12 feed supplement de-
veloped a marked degree of hyper-irritability, as shown by
squealing when touched, fighting with cage mates and spastic
muscular tremors when picked up. These symptoms were not
so marked in rats on 18 percent protein without the supplement.
However, with the supplement at both protein levels nervous
symptoms were not present.
As the experimental feeding continued rats on the higher
protein level without the supplement became more irritable and
tense and had to be handled with gloves. The eyes protruded
and changed in color from pink to scarlet. When these nervous
disorders became critical each rat was given an injection of
thiamine, riboflavin, niacin or pyridoxin for 14 days at 10 times
the minimum daily requirement. At the end of this treatment
no changes were noted in either nervous or eye symptoms. In
order to determine whether nervous symptoms found in both
groups without the supplement were due to a deficiency in the
B complex, Becotin (Lilly), a B complex concentrate, was given
orally at 5 times the minimum daily requirement for seven
weeks. Again no measurable improvement was noted.

Experiment III.-Realimentation
There is considerable support to the theory that animals fed
deficient diets in early life may have sustained tissue damage
that is not apparent during the relatively short period of experi-
mental feeding. Therefore, after the nutritive values of the
five types of bread were evaluated by the rat growth method,
the after-effects were evaluated by realimenting the rats from
three to four months on stock feed and noting not only weight
gains and skeletal development but also gestation and lactation
performance.
Weight.-Since the females were being bred at this time, data
presented are on males only. In Figure 6 it is shown that upon
realimentation the weights of males in the 1946-47 series rose
rapidly for about five weeks and thereafter began to plateau.







The Nutritive Value of Various Breads


Both groups were on diets containing 18 percent protein, but
at the end of the 12th week rats fed the supplement weighed
183 grams, while those without this factor weighed 112 grams.
At the 24 percent protein level the differences in weight were
not so large, 158 grams and 138 grams, respectively.
During the course of the experiment rats fed diets containing
24 percent protein without aureomycin-B12 feed supplement de-
veloped a marked degree of hyper-irritability, as shown by
squealing when touched, fighting with cage mates and spastic
muscular tremors when picked up. These symptoms were not
so marked in rats on 18 percent protein without the supplement.
However, with the supplement at both protein levels nervous
symptoms were not present.
As the experimental feeding continued rats on the higher
protein level without the supplement became more irritable and
tense and had to be handled with gloves. The eyes protruded
and changed in color from pink to scarlet. When these nervous
disorders became critical each rat was given an injection of
thiamine, riboflavin, niacin or pyridoxin for 14 days at 10 times
the minimum daily requirement. At the end of this treatment
no changes were noted in either nervous or eye symptoms. In
order to determine whether nervous symptoms found in both
groups without the supplement were due to a deficiency in the
B complex, Becotin (Lilly), a B complex concentrate, was given
orally at 5 times the minimum daily requirement for seven
weeks. Again no measurable improvement was noted.

Experiment III.-Realimentation
There is considerable support to the theory that animals fed
deficient diets in early life may have sustained tissue damage
that is not apparent during the relatively short period of experi-
mental feeding. Therefore, after the nutritive values of the
five types of bread were evaluated by the rat growth method,
the after-effects were evaluated by realimenting the rats from
three to four months on stock feed and noting not only weight
gains and skeletal development but also gestation and lactation
performance.
Weight.-Since the females were being bred at this time, data
presented are on males only. In Figure 6 it is shown that upon
realimentation the weights of males in the 1946-47 series rose
rapidly for about five weeks and thereafter began to plateau.





WEIGHT
IN GMS.


300


280


260


240


220


200


180


160


140


120


100


80


60

TIME
IN WKS.


-3

/-2 4
_3 __



5
















1 9 4- 45 19 4 6- 4












17 19 21 23 25 27 29 31 13 15 17 19 21 23 25 27_ 29


Fig. 6.-Effect of previous bread feeding upon weight of rats realimented on stock food: (5) unenriched water bread;
(4) enriched water bread; (3) unenriched milk bread; (2) enriched milk bread; and (1) stock food.


00


1
3.




3.
0









re


" -- --


--







The Nutritive Value of Various Breads


At the close of the realimentation period the average maximum
weight for males previously fed either type of water bread was
approximately two-thirds, and for those fed either type of milk
bread it was three-fourths of that of the controls.
In the 1948-49 series (Fig. 6) realimentation was carried only
through the 15th week, but at the end of that period the weight
curves, while not yet stabilized, were considerably above those
of males in the earlier series. However, average weight of rats
in Group 5 was about the same as that for the controls.
Skeletal Development.-Effects of previous bread feeding upon
skeletal development will be discussed in a separate report.
Reproduction.-At the end of 13 weeks of experimental feed-
ing the rats fed the unsupplemented bread diets were all poorly
nourished and no litters had been produced. After realimenta-
tion healthy litters were produced by all groups in the first series,
except those fed basal diets of either enriched or unenriched
water bread. In the second series litters were produced by all
groups. Litters varied in size from 2 to 15, but only in the
groups previously fed supplements of non-fat milk solids did
the young reach the average weight for the colony of 38 to 42
grams in 21 days.

Discussion
The plan adopted for the study of the nutritive value of the
five types of bread in general use was the feeding of diets con-
sisting primarily of bread, fat and vitamin A, and measuring
the nutritive value of these diets by effect upon weight, general
appearance, skeletal development and reproduction of rats.
Under this plan and as judged by standards and criteria used
in these experiments no signs associated with a deficiency in
thiamine, riboflavin or niacin appeared. Accordingly, supple-
mentation of these bread diets was initiated which made possible
a normal or near-normal growth. Again, animals fed enriched
bread were in no way superior to those fed unenriched bread.
Results of supplementation indicated that protein or factors con-
tained in protein was the limiting factor and further experi-
mentation showed that the most practical and effective means
of improving the nutritive value of bread was the inclusion of
non-fat milk solids. A milk supplement which increased the
protein from 14.2 to 18 percent greatly improved weight gains
of rats, while a protein level of 24 percent permitted weight gain







The Nutritive Value of Various Breads


At the close of the realimentation period the average maximum
weight for males previously fed either type of water bread was
approximately two-thirds, and for those fed either type of milk
bread it was three-fourths of that of the controls.
In the 1948-49 series (Fig. 6) realimentation was carried only
through the 15th week, but at the end of that period the weight
curves, while not yet stabilized, were considerably above those
of males in the earlier series. However, average weight of rats
in Group 5 was about the same as that for the controls.
Skeletal Development.-Effects of previous bread feeding upon
skeletal development will be discussed in a separate report.
Reproduction.-At the end of 13 weeks of experimental feed-
ing the rats fed the unsupplemented bread diets were all poorly
nourished and no litters had been produced. After realimenta-
tion healthy litters were produced by all groups in the first series,
except those fed basal diets of either enriched or unenriched
water bread. In the second series litters were produced by all
groups. Litters varied in size from 2 to 15, but only in the
groups previously fed supplements of non-fat milk solids did
the young reach the average weight for the colony of 38 to 42
grams in 21 days.

Discussion
The plan adopted for the study of the nutritive value of the
five types of bread in general use was the feeding of diets con-
sisting primarily of bread, fat and vitamin A, and measuring
the nutritive value of these diets by effect upon weight, general
appearance, skeletal development and reproduction of rats.
Under this plan and as judged by standards and criteria used
in these experiments no signs associated with a deficiency in
thiamine, riboflavin or niacin appeared. Accordingly, supple-
mentation of these bread diets was initiated which made possible
a normal or near-normal growth. Again, animals fed enriched
bread were in no way superior to those fed unenriched bread.
Results of supplementation indicated that protein or factors con-
tained in protein was the limiting factor and further experi-
mentation showed that the most practical and effective means
of improving the nutritive value of bread was the inclusion of
non-fat milk solids. A milk supplement which increased the
protein from 14.2 to 18 percent greatly improved weight gains
of rats, while a protein level of 24 percent permitted weight gain







The Nutritive Value of Various Breads


At the close of the realimentation period the average maximum
weight for males previously fed either type of water bread was
approximately two-thirds, and for those fed either type of milk
bread it was three-fourths of that of the controls.
In the 1948-49 series (Fig. 6) realimentation was carried only
through the 15th week, but at the end of that period the weight
curves, while not yet stabilized, were considerably above those
of males in the earlier series. However, average weight of rats
in Group 5 was about the same as that for the controls.
Skeletal Development.-Effects of previous bread feeding upon
skeletal development will be discussed in a separate report.
Reproduction.-At the end of 13 weeks of experimental feed-
ing the rats fed the unsupplemented bread diets were all poorly
nourished and no litters had been produced. After realimenta-
tion healthy litters were produced by all groups in the first series,
except those fed basal diets of either enriched or unenriched
water bread. In the second series litters were produced by all
groups. Litters varied in size from 2 to 15, but only in the
groups previously fed supplements of non-fat milk solids did
the young reach the average weight for the colony of 38 to 42
grams in 21 days.

Discussion
The plan adopted for the study of the nutritive value of the
five types of bread in general use was the feeding of diets con-
sisting primarily of bread, fat and vitamin A, and measuring
the nutritive value of these diets by effect upon weight, general
appearance, skeletal development and reproduction of rats.
Under this plan and as judged by standards and criteria used
in these experiments no signs associated with a deficiency in
thiamine, riboflavin or niacin appeared. Accordingly, supple-
mentation of these bread diets was initiated which made possible
a normal or near-normal growth. Again, animals fed enriched
bread were in no way superior to those fed unenriched bread.
Results of supplementation indicated that protein or factors con-
tained in protein was the limiting factor and further experi-
mentation showed that the most practical and effective means
of improving the nutritive value of bread was the inclusion of
non-fat milk solids. A milk supplement which increased the
protein from 14.2 to 18 percent greatly improved weight gains
of rats, while a protein level of 24 percent permitted weight gain







Florida Agricultural Experiment Stations


beyond that of the controls. At the same time milk provided an
adequate intake of other food essentials so that further supple-
mentation was without effect.
On the other hand, when a supplement of casein was used to
increase the protein content of the basal diet from 14.2 to 18
percent, weight gains of rats fed this diet were much below
those of rats fed the bread-milk diet at the same protein level.
In addition to the low weight gains, the rats became unkempt
and hyper-irritable, as manifested by squealing when touched.
It therefore seems reasonable to assume that during purification
of the casein some factor or factors necessary for growth had
been removed or denatured.
Cary et al (1) found that the exhaustive extraction of casein
with hot alcohol made it inadequate for growth of rats unless
a concentrate prepared from liver was added. Apparently, the
growth factor or factors in casein had been removed in some
process, for with the addition of 4 percent of an aureomycin-B12
feed supplement to the bread-casein diet the weight gains at
the 18 percent protein level were approximately 38 percent
higher than those of rats on the same diet without the supple-
ment and slightly above those of rats fed the bread diets supple-
mented with non-fat mild solids at the same protein level. How-
ever, with an increase in protein level from 18 to 24 percent there
was no significant difference in weight of rats fed the bread-
casein diet with and without the supplement. Moreover, average
weights of both groups were lower than those of rats with the
supplement at the lower protein level. The cause of these varia-
tions was not evident. There is the possibility that as the
higher protein level was reached an additional amount of the
supplement would be necessary. This view appears to be sub-
stantiated by the fact that the nervous and eye symptoms in
rats fed the high protein diet without the supplement were
critical, while with the supplement they were of a minor nature.
This view is further strengthened by the work of Hartman et al
(4), who found that rats fed a basal diet adequate in respect to
all chemically identified nutrients and containing 25 percent
casein had a weight increase of 86 grams at the end of 28 days
when a daily dose of 0.01 gamma of B12 was given, but when the
daily dose was increased to 0.05 gamma the average weight gain
was 130 grams for the same length of time.
On the other hand, Edwards et al (3) have shown that the
aureomycin-B12 feed supplement contains growth factors separ-






The Nutritive Value of Various Breads


ate and apart from B12. They found that the treatment of this
supplement with NaOH destroys B12 and 97 percent of the in-
hibitory factors against Staphlococcus aureus, but still the
material contained a growth factor or factors for the pig.
It appears to be generally accepted that the aureomycin-B12
feed supplement provides factors for more efficient utilization
of feed, but which one or ones were operating in this study were
not determined. Therefore, all that can be stated at this time
is that when judged by standards and criteria used in this
laboratory, a bread-casein diet containing 18 percent protein
plus 4 percent aureomycin-B12 feed supplement is of comparable
nutritive value to that of bread-non-fat milk solids diet of the
same protein level. In this connection it should be mentioned
that the bread used in this test was unenriched water bread, and
while the supplement was a good source of B12 and perhaps other
factors, it contained only traces of the B vitamins commonly
used in enriching bread.

Conclusions
A series of experiments were planned to test the value of
various supplements to all-bread diets when fed to white rats.
Under the adopted plan and judged by the standards and criteria
used, no advantages due to enrichment of bread with thiamine,
riboflavin, niacin and iron were demonstrated. No signs or
symptoms associated with deficiencies in these factors appeared.
With an increase in protein which permitted more nearly nor-
mal growth, still no beneficial results were secured from the
standard enrichment at any protein level. Supplementation of
water bread with non-fat milk solids provided the best and most
practicable means of improving the nutritive value of bread.
At the 24 percent protein level non-fat milk solids furnished an
adequate intake of other food essentials so that further supple-
mentation was without effect.
The limiting factor in bread appeared to be protein but with
a purified protein such as casein the factor or factors which
make possible the more effective utilization of protein and per-
haps other dietary essentials was necessary. Aureomycin-Ba1
feed supplement provided these constituents.
Although all this work was done with rats, the lack of re-
sponse to the standard enrichment of water bread diets makes
this program seem of questionable value. Enrichment of bread







Florida Agricultural Experiment Stations


with non-fat milk solids deserves further evaluation and trials
in nutrition.

Acknowledgments
The authors wish to express their appreciation to the American Dry
Milk Institute for the bread used in these experiments; to Dr. T. H. Jukes
of the Lederle Laboratories for aureomycin-B. feed supplement and to
Dr. T. J. Cunha for assistance in evaluating the data.


Literature Cited
1. GARY, C. A., A. M. HARTMAN, L. P. DRYDEN and G. D. LIKELY. An
unidentified factor essential for rat growth. Federation Proc. 5:
128. 1946.
2. CHICK, HARRIETTE. Nutritive value of white flour with B1 added and
of whole-meal flour. Lancet 239: 511-512. 1940.
3. EDWARD, H. M., T. J. CUNHA, G. B. MEADOWS, C. B. SHAWVER and A.
M. PEARSON. Effect of APF in supplying multiple factors for the
pig. Proc. Soc. Exp. Biol. and Med. 76: 173-175. 1951.
4. HARTMAN, ARTHUR M., LESLIE P. DRYDEN and CHARLES A. CARY. The
role of vitamin B1 in the normal mammal. Arch. Biochem. 23:
165-168. 1949.
5. LEPKOVSKY, SAMUEL, The bread problem in war and in peace. Physiol.
Rev. 24: 239-276. 1940.
6. MCHENRY, E. W. Observations on the nutritive value of bread.
Canadian Public Health Journ. 31: 428-432. 1940.
7. Medical Research Council memorandum on bread. Lancet 239: 143.
1940.
8. Medical survey of nutrition in Newfoundland. Canadian Med. Assn.
Jour. 52: 227-250. 1945.
9. Medical resurvey of nutrition in Newfoundland, 1948. Canadian Med.
Assn. Jour. 60: 3-30. 1949.
10. MITCHELL, H. H., T. S. HAMILTON and J. B. SHIELDS. The contribution
of non-fat milk solids to the nutritive value of wheat breads. Jour.
Nutrition 25: 585-603. 1943.
11. MORGAN, AGNES FAY. Fortification of foods with vitamins and min-
erals. Milbank Mem. Fund Quart. 17: 221-229. 1939.
12. ROBERTS, LYDIA J. Fortification in a general program for better nu-
trition. Milbank Mem. Fund Quart. 17: 230-240. 1939.
13. WILLIAMS, RAY D., HAROLD L. MASON and RUSSELL M. WILDER. Evalu-
ation of nutritive contribution of enriched white flour. Jour. Amer.
Med. Asso. 121: 943-945. 1943.







Florida Agricultural Experiment Stations


with non-fat milk solids deserves further evaluation and trials
in nutrition.

Acknowledgments
The authors wish to express their appreciation to the American Dry
Milk Institute for the bread used in these experiments; to Dr. T. H. Jukes
of the Lederle Laboratories for aureomycin-B. feed supplement and to
Dr. T. J. Cunha for assistance in evaluating the data.


Literature Cited
1. GARY, C. A., A. M. HARTMAN, L. P. DRYDEN and G. D. LIKELY. An
unidentified factor essential for rat growth. Federation Proc. 5:
128. 1946.
2. CHICK, HARRIETTE. Nutritive value of white flour with B1 added and
of whole-meal flour. Lancet 239: 511-512. 1940.
3. EDWARD, H. M., T. J. CUNHA, G. B. MEADOWS, C. B. SHAWVER and A.
M. PEARSON. Effect of APF in supplying multiple factors for the
pig. Proc. Soc. Exp. Biol. and Med. 76: 173-175. 1951.
4. HARTMAN, ARTHUR M., LESLIE P. DRYDEN and CHARLES A. CARY. The
role of vitamin B1 in the normal mammal. Arch. Biochem. 23:
165-168. 1949.
5. LEPKOVSKY, SAMUEL, The bread problem in war and in peace. Physiol.
Rev. 24: 239-276. 1940.
6. MCHENRY, E. W. Observations on the nutritive value of bread.
Canadian Public Health Journ. 31: 428-432. 1940.
7. Medical Research Council memorandum on bread. Lancet 239: 143.
1940.
8. Medical survey of nutrition in Newfoundland. Canadian Med. Assn.
Jour. 52: 227-250. 1945.
9. Medical resurvey of nutrition in Newfoundland, 1948. Canadian Med.
Assn. Jour. 60: 3-30. 1949.
10. MITCHELL, H. H., T. S. HAMILTON and J. B. SHIELDS. The contribution
of non-fat milk solids to the nutritive value of wheat breads. Jour.
Nutrition 25: 585-603. 1943.
11. MORGAN, AGNES FAY. Fortification of foods with vitamins and min-
erals. Milbank Mem. Fund Quart. 17: 221-229. 1939.
12. ROBERTS, LYDIA J. Fortification in a general program for better nu-
trition. Milbank Mem. Fund Quart. 17: 230-240. 1939.
13. WILLIAMS, RAY D., HAROLD L. MASON and RUSSELL M. WILDER. Evalu-
ation of nutritive contribution of enriched white flour. Jour. Amer.
Med. Asso. 121: 943-945. 1943.




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