74
ABSTRACTS
The interrelationship of manganese, phosphatase
and vitamin D in bone development (1942).
G. F. COMBS, L. C. NORRIS and G. F. HEUSER.
J. Nutr. 23, 131.
THE authors demonstrated the role of manganese in
bone formation by observing the effect of manganese
deficiency upon bone phosphatase activity and calcifica-
tion in chicks fed on rachitogenic and non-rachitogenic
qiets. Two series of experiments were conducted,
using Rhode Island Red chicks as the experimental
animals. The results showed that the bone phosphatase
activity of the chicks fed on an adequate diet, except
for a lack of manganese, was markedly reduced
as
compared to that of chicks fed on the same diet
supplemented with manganese. In rachitic chicks, it
was found that the bone phosphatase activity was in-
creased to almost twice the amount found in normal
chicks. By omitting manganese from the rachitogenic
diet, the bone phosphatase was decreased to approxi-
mately the normal amount. The lowering of the bone
phosphatase level in manganese deficiency shows that
there is an intimate relationship between the phos-
phatase activity of the bones and the manganese con-
tent of the diet.
The ash content of the bones of chicks fed on an
adequate diet, except for a deficiency of manganese,
was slightly lower than that of the bones of normal
chicks. The examination of the longitudinal sections
of the tibiae, after staining with silver nitrate, showed
that the metaphyses of the tibiae of the chicks fed
on the manganese-deficient diet were approximately
one-half as wide as the metaphyses of the tibiae of the
normal
chicks.
The
epiphyses
of
the
tibiae
of the chicks
fed on
the
manganese-deficient
diet were very weakly united to the diaphyses. The
results suggest that in manganese deficiency the lower-
ing of the phosphatase level retards bone development
with the result that the bones are shortened, the ash
content of the bones is reduced and the strength of
the union between the epiphysis and the diaphysis is
greatly reduced. [S. B.]
A filterable virus, the cause of a respiratory
nervous disorder of chickens. D. E. STOVER
(1942). Amer. J. Vety. Res., 3, 207.
RESPIRATORY nervous disorder is a serious disease
affecting young growing chickens in North California,
and is caused by a filterable virus. The disease affects
fowls in the age range of three to ten weeks. Some
outbreaks have been observed in younger chickens and
in mature hens also.
The incubation period in artificially infected chicken
is found to vary between two and six days, with an
average of four days. The disease runs a protracted
course both in the flock and in the individual bird.
The respiratory and general symptoms consist of
droopiness, sneezing, shaking of the head, a husky
voice, gasping for breath, breathing becomes laboured
as the disease progresses and the body temperature
may be between subnormal and 111°F. These are
followed by nervous symptoms which are of three
general types. They are in co-ordination of the muscles
of the neck and leg, constant tremor of the body and
paralysis of the legs.
The post-mortem examination reveals a cloudiness of
the air-sacs in the early stages, followed by oedema.
The contents of the air-sacs become purulent;
and
adherent to the membrane are found particles of yellow
caseous material. A frothy
colourless serous fluid
occurs in the body-cavity and the froth-covered
mesentery has a cloudy or turbid appearance. A good
many cases show oedema or congestion of the lungs
and the presence of frothy mucus in the bronchiae
and lower portion of the trachea. In a few cases
bronchitis and tracheitis and the presence of a caseous
material in the sinuses is noticed.
Histological and macroscopical examination of the
brain and nervous system failed to detect any specific
lesions.
The virus is found to be present in the air sacs,
lungs and trachea of affected birds. The disease can
be transmitted experimentally by inoculation with in-
fected material intranasally, intratracheally, subcutane-
ously and by injecting directly into the crop. The
disease can also be transmitted by pen contact. In
nature, the usual method of transmission is by the in-
gestion of food and water contaminated
with the
excreta of sick fowls. A rapid passage of the infec-
tive agent through several lots of chickens resulted in
a shortening of the incubation period from an average
of five days to an average of three days.
Macerated saline emulsion of infective material from
the air sacs, lungs and trachea were filtered through
Berkefeld V, N and W filters and the filtrates inocu-
lated in chickens developed the disease which demons-
trated that the disease is caused by a filterable virus.
Cross-immunity tests which were carried out indicat-
ed that the virus of Respiratory nervous disorder is
distinct from the virus of infectious bronchitis and
from that of infectious laryngo-tracheitis. [P. R. K.]
GIPD—SI—471 ICofAR—30-11-44—520