48
INDIGENOUS GRASSES OP INDIA
[Vol. XXIII, Part I,
constituents like protein, soluble ash, phosphoric acid and to some extent ether
extract decreased with the maturity of the plants. The maximum fall took place
in the ripe stage. Crude fibre, on the other hand, increased steadily from young
to ripe stage. Both these facts point out the decrease in the nutritive quality of
the grass with age. (Fig. 1.)
Protein. Both crude protein and true protein contents of the grasses studied
decreased with the maturity of the plants. A comparison of the two types of
protein shows (Tables I, II and III) that changes in the two were closely correlated
with each other. The distinction between crude protein and true protein is based
on the fact that all the nitrogen in plants is not in the form of protein, but is partly
present as, non-proteinous compounds which are water soluble. Any protein,
which dissolves in water, is also precipitated by boiling and addition of copper
hydrate reagent. Hart and Bentley [1915] have shown that the non-proteinous
nitrogen in grasses and hays is largely composed of free amino acids. Further the
recognition of the fact that the value of feed for its protein nutrition is determined
by its amino acid content has caused the distinction between crude and true protein
to lose its significance. But opinion still differs as to the nutritive value of non-
proteinous nitrogen. In Britain 50 per cent value is generally given to non-pro-
teinous nitrogen when calculating rations. It is seen from Tables I, II and III that
difference between crude protein and true protein decreased with the approach of
maturity of the plants, the difference in the ripe stage being very small. In other
words, in old matured plants the quantity of non-protein nitrogenous compounds
decreases. Amphilophis odorata gives the least protein content in every stage of
growth as compared to other grasses. One noteworthy point is that the protein
content of Iseilema laxum slightly increases in the flowering stage and this value
is not much different from that reported in the young stage. This fact may be of
some practical interest in that this grass may be kept for late harvesting. In case
of Amphilophis glabra, the protein content does not change much upto the pre-
flowering stage, but it decreases appreciably in the flowering stage.
Ether extract. Ether extract, in addition to fats, also includes various phos-
phatides, sterols, plant pigments, some essential oils and carotene which are. removed
with the fats during extraction of a material with ether. Fats, however, constitute
the major portion and are sources of energy. Ether extract content did not show
regular variations in all the three species, though there was a fall in the percentage
of ether extract in the ripe stage for all the grasses. Highest percentage of ether
extract was obtained in different stage of growth in each case. Amphilophis glabra
gave the highest content of ether extract in the young stage. The corresponding
values for Amphilophis odorata and Iseilema laxum reached in the preflowering
and flowering stages respectively.
Crude fibre and nitrogen-free-extract. High crude fibre content is generally
associated with low digestibility and palatability of the feeds. It is seen from the
Tables I, II and III that the percentage of crude fibre increased progressively from
young to ripe. The highest percentage of crude fibre was obtained in the ripe
stage. Nitrogen-free-extract, on the other hand, did not show regular variations,
though tending to decrease with maturity.