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Effects of Extraction on Palatability
When boiled in a common kitchen pot for 7 days, the residual leaves of A4 still retained high palatability. However,
boiled in the steam-heated pot for 5 days, A4 lost its palatability to hares, although it retained high palatability after boiling
for up to 24 h. The percent dry matter of the fresh leaves used in these trials was 35-39%; after boiling, residual leaves were
22-25% of the original fresh weight. Thus, about one-third of the dry matter was extracted by boiling. However, when
boiled in the steam-heated pot for 5 days, the residue of A4 was reduced in weight to 18%of the original, whereas N4
remained at 24%.
When essential oils were removed by steam distillation, A4 retained its palatability, but further extraction with
methanol made it unpalatable (Fig. 3). Similarly, after extraction with n-hexane, A4 residue did not lose palatability but
further extraction with methanol rendered it unpalatable. In contrast, the unpalatability of U36 and N4 seemed to diminish
after each extraction.
Atetsu 4 Uda 36 Niimi 4
a: Fresh leaves b:Steam-distilled +MeOH-extracted c:Hexane-extracted+MeOH-extracted
0 t , , .. , ,
_ _ I I 1 I _'I_.l_l, .ll[1._ * __l.J
O I Z 3 0 I Z 3 0 I Z 3 0 I Z 3 0 I 2 3
Days of exposure
Figure 3.--Change of palatability of three clones after extraction. Vertical axis represents the weight of uneaten leaves
or extracted residue leaves. Upper and lower graphs each represent the results for one hare.
Effects of Methanol Extracts on Fresh and Residual Leaves
Application of methanol extracts from dried A4 leaves did not affect the palatability of fresh leaves of A4 and N4 but
made the residues after extraction palatable in both clones. In contrast, application of N4 extract made the fresh leaves of A4
unpalatable, but showed no effect on the fresh leaves of N4 nor the residual leaves after extraction in both clones.
Palatability Test of Fractions
The filter paper test was not valid for some hares, because they showed little interest in filter paper and ate it only
occasionally. One hare showed constant interest and gave suggestive results. Most of the fractions of A4 extracts showed
high palatability, whereas some of the fractions of N4 extracts showed only weak palatability (Fig. 4). Little of the untreated
filter paper was consumed.
Of A4 extracts, both water-soluble (W) and water-insoluble (M) fractions were highly favored. The Wh fraction was
less palatable than tile others. The Mh fraction also showed less palatability than did the Mm. For N4, although the MW
extract was moderately consumed, the separate water-soluble and water-insoluble fractions showed the least consumption.
The water-soluble fractions showed light (Wh) to fairly high palatability (Wb), whereas tile Mh was taken only in small
amounts.
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