ATAM SINGH 169
TABLE I
Feed
Sunflower . .
Oat hay . .
Dub grass . .
Wheat bhusa . .
Jowar . .
Per 100 part of dry
Crude
fibre
31.8
38.5
26.2
44.2
33.3
Lignin
Cellu-
lose
Column I
8.6
9.6
9.9
13.2
9.9
27.0
35.6
24.3
40.4
29.5
Per 100 parts
of crude fibro
Lignin
Cellu-
lose
Column II.
18.9
9.2
10.3
8.5
8.0
74.8
88.1
84.5
89.1
86.5
Lig/
cellu-
lose in
c. fibre
0.253
0.104
0.122
0.095
0.093
Av. dig.
cooff. of
c. fb.
N. F. E.
Column III
20.2
66.2
53.8
61.2
57.5
70.9
64.9
46.4
52.5
61.9
Partition of
lignin in
c. c. ub. N. F. E.
Column IV
6.0
3.6
2.7
3.8
2.6
2.6
6.0
7.2
9.4
7.3
It will be seen from the figures given in Table I
that the amount of lignin expressed as percentage
of dry material in sunflower is the lowest of all
these feeds. But when we turn to column II
of this table we find that the crude fibre of sun-
flower contains the highest amount of lignin.
Another point which needs emphasis is the high
lignin: cellulose ratio present in the crude fibre
of sunflower (0.253) as compared with that of the
other feeds (0.093—0.122).
The low digestibility of the crude fibre of sun-
flower can be explained by its very high lignin
content which is the least digestible portion of
the crude fibre. However, this in itself cannot
be regarded as an adequate explanation for such
wide difference met with in the figures of diges-
tibility coefficient of crude fibre of sunflower and
other feeds.
As has been indicated already, the ratio of
lignin to cellulose in sunflower is the highest
of all the above feeding stuffs. This means that
the amount of lignin present per unit of cellulose
is more in this case. The work of Woodman
and Stewart [ 1932 ] shows that the presence of
lignin plays a very significant part in the bacterial
digestion of cellulose. In all crude fibres lignin
and cellulose are intimately associated with each
other, and whenever the proportion of lignin
in crude fibre increases, the digestibility of cellulose
in the crude fibre is affected adversely. This
may be due to lignin forming a sort of protective
cover over cellulose and thus preventing its
digestion by the action of bacteria. This is
obvious from the results given in Tables.
In the third column of the table are given the
average digestibility coefficient of crude fibre
and nitrogen-free-extract of these fodders. It will
be seen that, with the exception of sunflower and
Jowar, the digestibility coefficient of N. F. E. are
lower than that of crude fibre. This observation
is contrary to
the normal expectation, for
nitrogen-free-extract, being a more soluble and
therefore readily assimilable fraction of the feed
should give higher figures for digestible coefficient.
The case of Jowar is an exception, very likely be-
cause this feed contains a fair amount of soluble
sugars. Higher digestibility coefficient of the
nitrogen-free-extract of sunflower may be ex-
plained by taking into consideration the figures
of the distribution of lignin in crude fibre and
N. F. E. (the portion of the lignin which is dis-
solved by the alkaline treatment in crude fibre
estimation is included in N. F. E.). It will be
apparent that the amount of lignin which is in-
cluded in nitrogen-free-extract is much less in the
case of sunflower as compared with others and
therefore the digestibility coefficient of nitrogen-
free-extract of sunflower is higher than that of
others, as larger amounts of lignin are included
in the nitrogen-free-extract in these cases.
It will be seen from the above discussion that
the method of partitioning the carbohydrates of
foodstuffs into crude fibre and nitrogen-free-
extract followed at present is both unscientific
and misleading. Crampton and Maynard [ 1938 ],
while criticising the method for the estimation
of crude fibre, have suggested that the empirical
division of carbohydrates into crude fibre and
nitrogen-free-extract should be given up in favour
of the partitioning of carbohydrates into (A)
Lignin representing the indigestible portion of the
feed, (B) Cellulose hydrolysable only by bacteria
and (C) Other carbohydrates including hemicellu-
loses, starch and sugars which are easily digested
by enzymes and bacteria.
The results given above show that it will give
a much better picture of the chemical analysis of
a feeding stuff if a further step be taken and
liguin also partitioned into two fractions, viz.
(1) that closely infiltrated into cellulose represent-
ed by the amount which remains attached to
cellulose in crude fibre and (2) that portion which is
not so associated with cellulose. The analysis of
these feeding stuffs in the suggested form along