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ABSTRACTS
The role of carbohydrates in urea utilisation, cellulose digestion and fatty acid
formation. I. J. BLESCO. (1956). J. Anim. Sci., 15, 426-508
I NVESTIGATIONS were carried out to explore the role of various carbo-
hydrates on urea utilisation and the differences in production and distribution
of the fatty acids produced from the fermentation of these energy sources. The
usual artificial rumen technique was employed and the systems were maintained
in an inert atmosphere at a constant temperature of 39°C and at a fermentation
pH of 6.2 to 6.9 for a specified period. The samples were then analysed for their
urea, ammonia and fatty acid contents after suitable intervals. It has been reported
that utilisation of urea by micro-organisms in vitro was dependent on the amount
and type of carbohydrates used as the energy source. Urea utilisation was slightly
more with starch as compared to cellulose, xylan and pectin. It has been further
reported that the formation of volatile fatty acids and. their distribution was also
dependent on the amount and the type of carbohydrate employed. Starch gave the
highest amount of fatty acid produced and was followed by dextrose and then by
cellulose. Digestion of cellulose was markedly retarded when higher doses of
dextrose were used. On the other hand, addition of starch up to 1 per cent of the
medium in combination with 1 per cent cellulose enhanced the rate of digestion
of cellulose and fatty acid formation. Starch, however, when used alone as carbo-
hydrate source, resulted in marked increase in valeric acid concentration with a
corresponding decrease in propionic acid formation. [P.C.S.].
Fluctuation within a day in the liver-fluke egg-count of the rectal contents of cattle.
W. DORSMAN. (1956). Vet. Rec. Vol. 68, No. 34, 571-574
F AECAL egg-count is the usual criterion employed for the diagnosis of disease
caused by helminths, the estimation of the degree of subclinical worm
infestations and the determination of the efficacy of anthelmintics. However,
the interpretation of the results of such counts is often found difficult owing to
variations in the faecal egg-contents of the same animal at different times. The
faecal egg-count of cattle suffering from severe trichestrongylidosis was found by
Messerli to vary from several hundreds to zero within a few days. Spedding observed
highly significant variations in the nematode egg-content of sheep faeces collected
at two, three, or four-hourly intervals and also in those collected from day to day.
The author studied during April and September, 1955, the variations from hour
to hour in the number of eggs of Fasciola hepatica in the rectal contents of housed
and grazing cattle at Rotterdam, Holland. The faecal samples were collected by
manually induced defaecation. Whenever possible only the last few hundred grammes
of the dung which passed out of the rectum were used for determining the eggs
per gramme of faeces. The results obtained were highly remarkable and unexpected.
There was a gradual rise in the egg-count during the morning which reached the
peak near 1.30 p.m. and was followed by a gradual descent during the afternoon.
During the night the egg-count was found to remain constant at the minimum value
of 5 e.p.g. from 8-30 p.m. to 7-30 a.m. It is not yet understood whether the
variations are the result of some physiological process of the host or a fluctuation
in the egg-laying capacity of the flukes. (H.D.S.)