NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
BALANCED DIETS, NET ENERGY VALUES AND SPECIFIC
DYNAMIC EFFECTS
BY
H. H. MITCHEL,
Division of Animal Nutrition, University of Illinois, U. S. A.
[Reprinted from Science, Vol. 80, December 14, 1934, pp. 558—561.]
A fact that is not infrequently lost sight of in contemporary nutritional
research 1 is that the utilization of any food nutrient for any purpose in the animal
body requires the simultaneous presence of all other nutrients required for that
purpose. And for the most complete sustained utilization of any food nutrient, the
proportions in the diet of it and all other required nutrients must attain or exceed
certain minimum values. For example, an adult man may require forty grms. of
protein daily, although, consuming only this, he will not be able to establish
nitrogen equilibrium. If his energy requirements are simultaneously covered,
he may be able to establish nitrogen equilibrium, but there is no reason to expect
that he could prevent losses of nitrogen from his body indefinitely unless his daily
diet contains also at least certain minimum proportions of each nutrient, inorganic
as well as organic, that is required for all the animal functions essential to the
maintenance of life. He is then receiving what may be called a " balanced diet "
for adult maintenance. It is of course well known that diets may be unbalanced
by including in them excessive proportions of some nutrients, such as protein or
vitamin D, but this is a phase of the problem about which little definitely can be
said.
For the growing animal we have a similar conception of a balanced diet, and
in this case there is available much more information concerning nutrient require-
ments, for in the science of nutrition, as in the medical sciences, the adolescent
animal has received much more attention than has the adult.
It is reasonable to assume that the balanced or unbalanced character of a diet
for growth will be reflected in the efficiency with which that diet promotes growth.
The completely balanced diet will promote growth the most efficiently, in the sense
that, when compared with any less completely balanced diet in properly controlled
feeding experiments, a greater rate of growth will be secured on the same amount
of food. This is the principle underlying the Armsby " paired feeding " method,
the most precise method that has yet been proposed for effecting ration compari-
sons. In this method, animals are paired on the basis of sex, parentage, weight and
1 For example, vitamin units are commonly defined as amounts that will produce
certain more or less well defined physiological effects. In these definitions no. reference
is made to the simultaneous necessity of other nutritive factors, and in the methods
used for vitamin assay no provision is made to assure adequate, or even constant,
intakes of other nutrients.
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BALANCED DIETS
201
possible mixtures of foods. The recent developments in the net energy conception,
initiated and defended by the Pennsylvania group have tended to complicate the
problem of net energy determinations and perhaps even to discourage those who
have hoped to put the conception to practical use in the rationing of farm animals.
But if all perfectly balanced rations exhibit the same net energy value (except for
differences in digestibility) under the same conditions of feeding, then the problem
is greatly simplified and the plan of its solution is clear ; furthermore, the proba-
bility that the solution will be sufficiently simple to possess great practical value
is enhanced.
A second important implication from the conception of a balanced diet
developed above is that the specific dynamic effects of the various nutrients are
not characteristic values except when they are fed to animals singly. When the
nutrients are fed in combinations, the specific dynamic effects of the mixtures will
be less than the weighted mean of the individual effects, and this decrease will
continue as the combinations approach a perfectly balanced combination for the
animal under experiment, of which the heating effect will be minimal. In this
discussion, the term " specific dynamic effect " will be applied to the total excess
heat developed by a given food or nutrient, and not the so-called "peak"
effect, which possesses an extremely limited significance.
This is a decidedly heretical deduction. It is, however, a direct corollary of the
preceding implication, since if the net availabilities of the metabolizable energy
of all perfectly balanced rations are maximal and identical, then their specific
dynamic effects must be minimal and identical.
Current theories attach definite heating effects to proteins, sugars, starches,
fats, and even the various naturally occurring amino-acids, and teach that com-
bination of these nutrients does not modify appreciably their characteristic effects
as metabolic stimulants, but these theories fail to account for many facts in the
science of nutrition. Eight years ago Carman and the author 3 showed that the
mere inclusion of 1 per cent of sodium chloride in a ration predominantly made up
of corn increased its growth-promoting value by from 40 to 50 per cent in paired-
feeding experiments with rats and chicks, without appreciably affecting its digesti-
bility. Assuming reasonably that this effect could not have been the result of a
depression of the basal metabolism or of the muscular activity of the experimental
animals, it must have been an expression of a great increase in the net energy value
of the ration and as great a depression in its specific dynamic effect. As we said at
the time : "The growth data of this experiment afford a striking illustration of the
fact that the utilization of food energy by growing animals may be greatly impaired
by an improper balance among indispensable dietary factors ". None of the
current theories of the cause of the specific dynamic effect of food would seemingly
account for this phenomenon.
3 Jour. Biol. Chem., 68 : 165, 1926.
M
202 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY
[VI, II
Protein ingested alone by animals causes a marked specific dynamic effect,
much greater than any other nutrient, but when incorporated into a protein-free
diet, otherwise complete, it must decrease the specific dynamic effect of such a
diet rather than increase it, because the combination will be more efficient in
maintaining the energy balance of an adult animal or in increasing the energy
balance of a growing animal. Weiss and Rapport 4 were greatly mystified when they
found that calorigenic amino-acids, administered to dogs along with proteins,
failed to increase the calorigenic action of the latter. But equally mystifying
from the standpoint of the current theories of the specific dynamic effects of food
is the action of amino-acids in improving greatly the efficiency for growth of rations
containing protein complexes deficient in those amino-acids 5 . In all probability
this increase in efficiency means a decrease in the specific dynamic effect, assuming
again that the basal metabolic rate and the activity of the experimental animals
was not depressed by the amino-acid supplements.
Apparently the specific dynamic effects of isolated nutrients fed as such have
very little if anything to do with the specific dynamic effects of mixtures of
nutrients, particularly balanced mixtures. Without being able to specify the
exact causes of the metabolic stimulation induced by the consumption of food,
we may nevertheless conclude reasonably that its intensity is dependent
primarily upon the degree of accumulation of the end-products of digestion within
the tissues, which is in turn dependent for any given intake of food upon the rate
of utilization of these products by the tissues. Their rate of utilization will be
determined by the proportions existing among them, such that the better the
balance with reference to the requirements of the animal the more rapid the rate of
utilization and withdrawal from the cellular fluids. The metabolic stimulation
thus occurs only when there is an excess of nutritive material in the tissues, and is
to a considerable extent proportional to this excess. It is possibly a mechanism
operating merely for the removal of excess food material from the body cells in the
interests of physiological efficiency.
These speculations are now being investigated experimentally in the Division
of Animal Nutrition of the University of Illinois.
4 Jour. Biol. Chem., 60 : 513, 1924.
5 H. H. Mitchell and D. B. Smuts, Jour. Biol. Chem., 95 : 263, 1932.
BALANCED DIETS, NET ENERGY VALUES AND SPECIFIC
DYNAMIC EFFECTS
BY
E. B. FORBES,
Institute of Animal Nutrition, Pennsylvania State College, U. S. A.
[Reprinted from Science, Vol. 81, No. 2099, March 22, 1935, pp. 291—292.]
In a recent number of science 1 , H. H. Mitchell presents a theoretical dis-
cussion of the subject of this communication, involving certain of the writer's
published conclusions.
After developing a line of argument similar to and in harmony with that of
the writer in the publication of the so-designated " law of maximum, normal nut-
ritive value ", Mitchell discusses the significance of this principle in relation to
net energy values, saying, in part:
With these definitions in mind, the first implication of the above defined conception
of nutritive balance in a ration or diet is that except for differences in digestibility the
net energy of all perfectly balanced rations is the same under the same conditions of
feeding, or somewhat more precisely, the net availability of the metabolizable energy
of all perfectly balanced rations is maximal for any imposed conditions of feeding.
Further he says :
However, Forbes' recently announced " law of maximum normal nutritive value ",
although it advocates the use of completely balanced rations in determinations of net
energy values, does not state nor imply that the net availability of the metabolizable
energy of such rations will be maximal and identical.
It is true that, in my " law of maximum, normal nutritive value " 2 , I avoided
making any statement or implication to the effect that the net availability of the
metabolizable energy of completely balanced rations is maximal and identical
(though we had discussed the idea), becasue I cannot conceive of balanced rations
—as practicable entities—being so perfectly balanced that there would be no
individuality of dynamic effect of the nutrients serving the same purposes in
different rations, and that there would be no differences in either the excess nutri-
ents, or in substances present without nutritive value, which would affect the
economy of utilization of metabolizable energy.
One must remember, in theorising, that in feeding practice we deal not with
pure nutrients, of known identity and character, but—in each feeding stuff—with
a vast complication of little-known substances.
1 Science, 80 : 558—561.
2 Science, 77 : 306—307.
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BALANCED DIETS
205
literature—have been so unsatisfactory, in fact, so largely fallacious, in the light of
findings of this institute during the past six years, especially as set forth in a very
recent paper by Kriss, Forbes and Miller, 4 which places the problem of determining
specific dynamic effects of nutrients in a new and vastly improved position.
The new point of view and procedure depend upon Rubner's idea, 5' 6 of a
specific dynamic effect of body substance katabolized, from which follows the
hypothesis (Forbes, Braman and Kriss, 6 ) of a status of minimum heat production
of life in which the energy requirement of the animal would be rendered available
without waste of heat—that is, without energy expense of utilization ; heat incre-
ments (dynamic effects) as usually determined at planes of nutrition below energy
equilibrium being less than the true energy expense of utilization by the amount
of the dynamic effect of body nutrients katabolized (Forbes, Braman and Kriss 7 );
heat increments determined above maintenance, with the heat production of main-
tenance as the base value, therefore, representing the true energy expense of
nutrient utilization.
We are free to admit, however, that if—as we have concluded—net energy
values of individual foodstuffs are not constants, because of the supplementing
effects of food combination, in rations and other conditions affecting the economy
of food utilization then it is conceivable that, for similar reasons specific dynamic
effects of individual nutrients likewise are not constants. We have unpublished
results on conditions affecting specific dynamic action, and a second year's experi-
ments on the subject are in progress.
The recent studies of this institute on specific dynamic effects and their deter-
mination afford an improved basis of understanding and procedure from which to
investigate this question. In this connection I would propose that it would save
confusion to limit the term " specific dynamic effect " to signify the dynamic effect
of specific kinds of nutriment, and to use the equivalent term " heat increment "
to signify other dynamic effects—that is, those which are not specific of particular
kinds of nutriment.
4
Jour. Nutrition, 8 : 509—534.
5 " Die Gesetze des Energieverbrauchs bei der Ernahrung ", Leipzig und Wien,
1902, S. 370.
6
Jour. Agr. Research, 37 : 285, 1928.
7
—
40 : 77, 1930.
210 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [VI, II
gland may occur and in rachitic birds the thyroid becomes extremely hyperplastic.
It is realised that adequate attention has not yet been paid to the relation of vitamins
and minerals to the incidence of diseases and the hope is expressed that further research
in these lines may have a valuable practical application in reducing the high mortality
which frequently occurs in poultry flocks. [K. C. S.]
Protecting the natural flavour of Milk. J. L. HENDERSON and C. L. ROADHOUSE
Hoard's Dairyman, Vol. 80, No. 19, October 10th, 1935.
For the consumption of fluid milk to be maintained and increased, the product
must be kept uniformly palatable from day to day.
The authors summarise the results of recent investigations carried out by the
United States Department of Agriculture on the sources of certain unpalatable
flavours in milk.
The unpalatable flavours maybe brought about by feed by auto-oxidation of milk
fat hastened by certain metals, by high temperature, by sunlight, by absorption of odours
of some fruits, vegetables, chemicals or by rancidity caused by the enzyme lipase which
splits fats into fatty acids having characteristic odours.
The natural flavour of milk may be protected by adjustment of the feed programme,
so that animals do not have an access to feeds like, clover, corn silage, turnips, legume
silage, etc., five hours before milking—such roughages should be fed immediately
after milking. All types of dairy equipment should be obtained n non-corrcdable
metals [galvanised utensils so often seen in India are particularly bad—C. E. M.] and milk
should be protected from exposure to direct sunlight through all stages of handling.
[C. E. M.]
211
CORRESPONDENCE
THE EDITORIAL COMMITTEE,
The Indian Journal of Veterinary Science and Animal Husbandry,
DEAR SIRS,
Since the publication of my article on Pyosepticaemia of Calves in the Sep-
tember (1935) issue of The Indian Journal of Veterinary Science and Animal
Husbandry, the organism which I described as a common cause of this disease
has been serologically typed as Salmonella enterditis, var.dublin.
This is an interesting finding, as it appears the first record in India of the
existence of this organism as the cause of disease in calves. A similar disease of
calves has been encountered within recent years in a number of countries. One
may quote from a recently published article by Lovell and Hughes, from the
Research Institute of Animal Pathology, Royal Veterinary College :—
" Both S. typhi-murium (Bact. aertrycke) and S. enteriditis var. dublin have
been incriminated in diseases of calves. The disease described by Thomassen
[1897], was probably of this nature and as previously mentioned, the " para-colon "
bacillus of Jensen which causes the well-known calf dysentery of Denmark is identi-
cal with the Dublin variety of S. enteriditis. S. enteriditis, or one of its varieties,
has also been connected with calf disease in America [Meyer, Traum and Road-
house, 1916], Kenya [Daubney, 1927], Germany [Proscholdt, 1931] and in Great
Britain [Bosworth and Lovll, 1931]. Henning (private communication) has re-
cently examined a number of strains of salmonella isolated from calves in South
Africa and all but one were S. enteriditis, var. dublin. Judging from the litera-
ture, this is the common salmonella infection of calves and, incidentally, the same
organism causes gastro-enteritis and continued fever in human beings ".
In the light of the foregoing observations, the finding of this organism in cattle
in India, will most probably be of interest, not only to the veterinary, but also to
the medical profession, on account of the implications involved in the presence of
such an organism in mature milch cattle as well as in calves.
The part played by this organism in typhoid-like fevers of man, where attempt-
ed cultural examinations fail to reveal the presence of a true typhoid infection,
may warrant serious consideration.
Yours faithfully,
J. F. SHIRLAW, M.R.C.V.S.,
Professor of Pathology, Punjab Veterinary College, Lahore.
18th March 1936.
212
BIHAR VETERINARY COLLEGE, PATNA.
The following notice has been received from the Principal, Bihar Veterinary
College, Patna :—
A Post-Graduate class will be held at the Bihar Veterinary College from 1st July,
1936, for the advanced training of Veterinary Graduates in (1) Pathology and Bacte-
riology including Parasitology and Postmortem technique, (2) Histology, (3) Veteri-
nary Hygiene, Dietetics and Genetics, (4) Meat and Milk Inspection and (5) Veterinary
Medicine including parasitic, contagious and inanition diseases. The course will be
for three months only for which a sum of Rs. 30 will be charged as tuition fee and
Rs. 10 as admission fee. Seat rent for the hostel will be at the rate of Rs. 5
per month.
Private candidates desiring admission should apply to the Principal, Bihar
Veterinary College, on or before the 15th June, 1936.
Further particulars, if required, may be obtained on application from the
Principal.
ORIGINAL ARTICLES
THE CURATIVE TREATMENT OF SURRA IN BOVINES
BY
S.K. SEN, M.Sc., F.R.E.S.,
Imperial Institute of Veterinary Research, Muktesar
[Received for publication on 10th April 1936]
(With Plate VII and three text figures)
INTRODUCTION
The present investigation originated out of an inquiry made by the Animal
Health Division of the Council for Scientific and Industrial Research, Common-
wealth of Australia, concerning the possibility of importing into that country
certain types of Indian cattle under a guarantee to be given by the veterinary
authorities in India that they are free from surra. A very real responsibility was
involved in advising upon a matter of this kind, in view of the risk of veterinary
officers inadvertently tarnishing the fair name of India by certifying animals as
being entirely free from this disease, when such was not actually the case. At the
same time, the inquiry brought into prominence the almost entire lack of authen-
tic information concerning a dependable method of rendering affected cattle free
from surra. Bovine surra, both in India and other countries, has never appeared
to be deserving of the same degree of attention as most other diseases of cattle,
this being attributable to the fact that, except in the few instances where the
disease has been observed to progress to a fatal issue [Mahajan, 1934; Iyer and
Sarwar, 1935 ], its symptoms have, as a rule, been confined to a negligible and
erratic elevation of the body temperature. As remarked by Sheather [ 1934 ],
" Cattle and buffaloes very seldom come as subjects for treatment owing to the
fact that they may be infected without showing symptoms ". Similarly, writing
in 1921, Hornby went as far as to state : "I am aware of no literature which
records recent outbreaks of surra among bovines, and this in spite of the wide dis-
tribution of the disease among horses and camels in countries where cattle and
buffaloes are numerous. Consequently there has been no need for any work to be
done on the treatment." The remarkable resistance displayed by bovines to the
development of the clinical symptoms of surra is strikingly illustrated by the fact
that " specially selected cattle from India, in the best of condition, have been found
to be the carriers of trypanosomes in their blood after they have travelled to
America" [Hoare, 1913]. Similar instances are recorded by Joseph [ 1928 ],
according to whom the presence of surra trypanosomes in the circulating blood of
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CURATIVE TREATMENT OF SURRA IN BOVINES
217
that there is little evidence on record to show that any one of these can be utilized
with success in the diagnosis of cattle surra, it still remains to be unequivocally
established that the reactions obtained by these methods are not essentially group,
as opposed to specific, reactions. The diagnostic value of Adhesion Phenomenon
was repeatedly tested at Muktesar upon rats artificially infected with T. evansi,
but the results were found difficult to interpret. As to the Complement Fixa-
tion test, however, Randall [ 1934 ] records having employed this successfully in
detecting the infection in suspected horses in the Philippines, where T. evansi
is the only known pathogenic type of trypanosome—a fact which evidently largely
contributed to the deduction that the reaction obtained in these cases was not due
to a species of trypanosome other than T. evansi.
In view of the uncertainty of the results to be expected from these tests, it was
not considered worth while to employ them in the present trials, but to adhere to
the established methods of diagnosis, as will be described later in this paper.
THE CHEMOTHERAPY OF BOVINE SURRA : A RESUME OF THE LITERATURE
While, as would appear from what has been stated in the preceding section,
there is a concensus of opinion concerning the unreliability of the methods hitherto
used in the diagnosis of bovine surra, nevertheless, some workers would appear to
hold that a permanent recovery in this condition is possible, although their views
in this respect do not appear to be based on any extensive experimental data.
Thus, Doeve [1917] refers to complete recovery having occurred in bovines when
they were well fed and kept indoors, so that re-infection could not take place.
Again, Leger and Vienne [ 1919 ] quote Lingard as having stated that recovery is
the rule among cattle in India, infected with surra. Similarly, Broudin [ 1927 ]
mentions the occurrence of spontaneous recovery in bovines if conditions are
favourable.
Mesnil and Leger [ 1912 ] would appear to furnish somewhat more definite,
although indirect, information upon the possibility of rendering cattle permanently
free from surra. These authors quote Wryburg [ 1907 ] as having stated that
two zebus which had recovered from surra in Sumatra were immune for a period
which did not exceed two years, and Mesnil had previously [ 1910 ] recorded the
case of another bovine that retained its immunity against a Mauritius strain for a
period of more than two years. These observations would seem to imply that in
the case of a " cured " bovine, a relapse is not likely to occur within two years from
the date of its recovery, and one may assume that an animal that has not shown
signs of relapse during this period is not likely to do so during the rest of its
life.
Douwes [ 1923 ], in Java, claims to have effected complete cure with Naganol
in seven out of eleven buffaloes suffering from surra, the blood of all cured animals
remaining negative for surra trypanosomes " as long as they were under obser-
vation ". Each animal received a single intravenous injection of 3 or 5 grms. of