March, 1956]
ABSTRACTS
45
Eggs laid from January to March were considered as winter eggs and those laid
from May to July as summer eggs. Winter eggs were superior to summer eggs as
regards albumen index, yolk index and albumen score. Even though eggs laid
by New Hampshire were slightly superior to those of White Leghorn, this can be
attributed to strain difference rather than to breed difference. The internal quality
of eggs deteriorated from one to five weeks but the changes observed by pH measure-
ments and yolk colour were not statistically significant, in storage or between seasons.
But diet plays a definite role in yolk colour.
Volume, flavour and texture of cakes decreased in summer as compared to winter
season. Cakes made from stored eggs were poorer than those from fresh eggs.
As summer advanced, albumen index and yolk index decreased with increase in
albumen score. pH also increased slightly perhaps due to poor shell quality and
concomitant loss of CO 2 . Flavour also was affected by storage.
No significant differences were observed in functional or flavour properties of
fresh eggs, produced during the months January to July, but season did have an
effect on the physical qualities of eggs. The winter eggs were significantly superior
to summer eggs in their keeping quality for one to five weeks at 72°F, with respect to
physical quality, functional properties and flavour. (T. S. K.)
Disappearance of the growth response of chicks to dietary antibiotics in an
"old" environment. PAUL E. WAIBEL, O. J. ABBOT, C. A. BAUMANN and H. R.
BIRD (1954). Poult. Sci. 33, (6) 1141-1146
THE authors describe experiments conducted in one environment over a three
year period. They found consistent growth responses to antibiotics for nearly
two years, but during the third year, responses became inconsistent and negligible.
Many variations in composition were introduced in the diets, in an attempt to produce
maximum growth in the absence of antibiotic. During the first 20 months, 66
positive responses were recorded in 69 observations by the addition of penicillin or
aureomycin and none of the various nutritional supplements fed during this period
eliminated the response to antibiotics. The quantitative responses to the antibio-
tics tended to vary inversely with the growth of control groups. When the growth
in the control group was relatively poor, the percentage increase due to the antibiotic
was large and when growth in the control group was good, the improvement due to
the antibiotic diminished. The dietary variations, therefore, played some part in
the variability of response to antibiotics. The percentage increase in growth due
to aureomycin ranged from 6 per cent to 39 per cent on different diets and a com-
parable variability was noted in the presence of penicillin between certain diets.
During the third year, the antibiotics failed to stimulate growth consistently.
This lack of response might have been due to the change in the microbial balance with
the decrease in the moisture in the room brought about by a change in cleaning practi-
ces. Another possibility is that the harmful bacteria had been eliminated through
continued use of antibiotics. But, whatever may be the explanation, it is apparent
that a decrease in the growth promoting effect of the antibiotic occurred in an en-
vironment continuously occupied by chicks. (S. B.)