STUDIES OF THE BIOLOGICAL VALUES OF THE PROTEINS
OF CERTAIN POULTRY FEEDS
By R. MUKHERJEE, and D. PARTHASARATHY, Poultry Research Section, Indian Veterinary Research
Institute, Izatnagar
(Received for publication on 26 August 1947)
T HERE is a little information on the nutritive vaue of the proteins of certain cereal grains fed either
singly or in combination to poultry in India. The biological value of some of these grains for
rats is known ; but the value of a protein for poultry must be assessed by conducting experiments
on the birds themselves since their amino acid requirements are different from those of rats [Almquist,
1941]. The lack of information on the nutritive value of proteins for poultry is due mainly to the
fact that urine and faeces are excreted through a common opening and their separate collection
is impossible unless artificial means are adopted. The following review indicates the methods used
to tide over this difficulty.
Fields and Ford [1900] and Brown [1904] assumed that the sum of uric acid and ammonia
nitrogen represented the urinary nitrogen and they subtracted this sum from the total nitrogen to
get the faecal nitrogen. This method is not sound since uric acid and ammonia nitrogen form only
a part of the urinary nitrogen. Coulson and Hughes [1930]. and St John, Johnson, Carver and Moore
[1932] calculated the urinary nitrogen by taking the sum of uric acid and ammonia nitrogen as 80
per cent of the total urinary nitrogen. The flaw in this method is , the arbitrary assumption of the
factor 80 per cent. Paraschtshuk [1902], Lehmann [1904] and others produced an aritficial anus
by operation and collected the faeces and urine separately. This method has been criticized because
the bird is under a strain. Katayama [1924] used a correction factor based on analysis of mixed
excreta of normal birds and of urine and faeces of the same birds after operation but this cannot
be regarded as accurate since the experiment was conducted on only two birds. The method of* Heller
Morris and Shirley [1930] based on the mechanical separation and analysis of the 'white caps' cannot
be expected to yield accurate results. The urine residue found in the front of a normal excretion is
commonly known as ' white cap '. Mitchell [1924] proposed a method, later elaborated by Ackerson,
Blish and Mussehl [1926] to determine the efficiency of dietary protein. The nitrogen excretion
of birds on a diet practically free from nitrogen was first determined for calculating the biological
value of the protein. Ackerson, Blish and Mussehl [1929] thus obtained the comparative efficiency
of various proteins of cereals when fed to poultry at varying levels of nitrogen in-take. Macdonald
and Bose [1944] also employed this method in principle and we have used it with slight modifications
in these investigations where the efficiency of proteins of five cereals, viz. cheena, jowar, bajra, ragi
and barley, commonly used as poultry feeds in India has been determined.
EXPERIMENTAL
The nitrogen balance trials were carried out on adult desi (indigenous) cockerels. The feeding,
management and other experimental technique was the same as in our previous study [Mukherjee
and Parthasarathy (in press)]. The experimental rations consisted of a single kind of grain with
daily supplements of about 1 g. of common salt and 2 g. of limestone grit per bird. The metabolism
periods were of 10 days and were preceded by adjustment periods of five to seven days. Throughout
each metabolism experiment, the birds were fed a constant amount of food sufficient to meet the
energy requirement and maintain body weight. The endogenous and metabolic nitrogen
of the birds was determined by feeding them on a nitrogen-free diet composed of sago, common
salt, limestone-grit, potassium phosphate and supplements of 'Adexolin ' and ' Berin'. (These are
patents of Glaxo Laboratories which were fed orally. ] drop of ' Adexolin ' daily and J c.c. of a sus-
pension of 1 tablet of ' Berin ' in 5 c.c. of distilled water, per bird.) The metabolism and adjustment
periods of the nitrogen-free experiment were seven and five days respectively. This diet was well
relished by the birds, and they maintained weight during the experiment Seven birds were fed the
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