SOYA BEAN MEAL SUPPLEMENTS FOR CHICKENS
By A. J. MACDONALD AND S. BOSE, Poultry Research Section, Imperial Veterinary Research
Institute, Izatnagar
(Received for publication on 21 August 1942)
PREVIOUS experiments by Macdonald [1941]
demonstrated that separated milk in the ration
of chickens gave better results than equivalent
amounts of protein from soya bean meal. It
was suggested, however, that better results might
have been obtained with extracted soya bean
meal. As separated milk is normally a somewhat
expensive ingredient, it was decided to investigate
the possibility of improving the value of soya
bean meal by processing it prior to its use as a
supplement in the ration of chickens.
LITERATURE
From experiments with rats, Hayward, Steen-
bock and Bohstedt [1936] concluded that ordinary
soya bean meal had a fairly low nutritive value.
Commercial soya bean oil meal, manufactured by
the expeller process at a temperature of 105°C.
for 2 minutes, and hydraulic meal, cooked at a
temperature of 82°C. for 90 minutes, proved of
a value similar to raw soya bean meal. On the
other hand, commercial soya bean meal which
had been prepared by the expeller process at
medium temperatures (112-130°C.) and at high
temperatures (140-150°C.) for 2½ minutes or hy¬
draulic meals cooked at 105°C. and 121°C. for 90
minutes contained proteins which had about
twice the nutritive value of the raw soya bean
meal or the low temperature processed meals. As
the food intake of all the rats during the early
stages of the experiment were similar, it was
concluded that the poor growth results with the
raw soya bean meal and the low temperature
processed meals were due to some deficiency and
not to lack of palatability.. The addition of
casein supplements to the deficient diets resulted
in normal growth, suggesting that the deficiency
existed in the protein fraction. The authors
concluded that the processing of the soya bean
meal at medium or high temperatures resulted in
the release of some factor which was essential for
normal growth. In later experiments [1936]
the isame authors found that the addition of
cystine to unheated soya bean oil meal was bene¬
ficia. Cystine supplements to soya bean oil
meals processed under controlled conditions proved
of no value. Workers at Purdue University [1928]
found that raw soya bean meal plus minerals for
chickens was inferior to soya bean oil meal and
minerals.
Hayward, Halpin, Holmes, Bohstedt and Hart
[1937] found that high temperature soya bean oil
meal (processed at 140-150°C. for 2½ minutes),
medium and high temperature hydraulic soya
bean oil meal (cooked at 105° and 121°C. for 90
minutes) and solvent extracted soya bean meal
(cooked at 98°C. for 15 minutes) all gave much
superior growth with chicks over a period of eight
weeks than raw soya bean meal and low tempera-
ture soya bean meal (processed at 105°C. for 2
minutes).
In experiments with chicks and rats, Hayward
and Hafner [1941] found that supplements of 0.3
per cent cystine or 0.3 per cent methionine to raw
soya beans improved the biological value of the
proteins. The nutritive value of the protein
fraction of the soya beans was also increased by
autoclaving.
METHODS
Two experiments with chicks, one over a period
of 24 weeks and the other over a period of eight
weeks, were conducted to test out the relative
values of separated milk, soya bean meal, ex-
tracted soya bean meal and heated extracted soya
bean meal. Both experiments were carried out
on week-old, White Leghorn × Rhode Island
Red chicks. Week-old chicks were chosen in pre-
ference to day-old chicks as former experience
had shown that day-old chicks usually contained
a number of weaklings which, if used for ex-
periment, somewhat interfered with the results,
whereas with week-old chickens it is possible to
eliminate most of those showing undesirable
characters. All the chicks prior to the commence-
ment of the experiment were fed on a standard
diet of cereals and separated milk, supplemented
with green food and calcium.
FEEDING
In both experiments all the birds were fed on
mash and grain rations. The mash was fed ad
libitum in suitable containers and the grain was
fed in the morning and evening according to
appetite. Supplementary calcium as broken lime-
stone was fed ad libitum and succulent chopped
berseem in adequate amounts was fed once daily
throughout the experiments.
A basal mash consisting of wheat bran 50 parts,
yellow maize meal 30 parts and ground oats 20
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