The effects of diets on the excretion of cecal feces and their nitrogen contents were studied using 80-day-old Single Comb White Leghorn male chicks. The diets used here were whole grain wheat and stock diets added with or without 10% fibrous part of Italian ryegrass, 10% fish meal and 15% feather meal (Group 1), semi-purified diets containing 15% feather meal or 13% casein as a sole protein source (iso-nitrogenous) (Group 2), and semi-purified diets containing graded levels of casein (0 to 30%) (Group 3). The results obtained were as follows:
1. Among the birds in Group 1, the chicks given whole grain wheat excreted the largest amount of cecal feces, and the chicks fed the fibrous part of Italian ryegrass and feather meal excreted the smallest amount of cecal feces. The amounts of nitrogen components in rectal feces were largest in the chicks fed the feather meal diet and smallest in those fed the whole grain wheat. The reverse result was obtained in the cecal feces.
2. Although the chicks were given the same amount of protein in Group 2, the chicks receiving the feather meal diet excreted twice as much rectal feces and half as much cecal feces as those receiveng the casein diet. Compared to the casein diet-fed chicks, the feather meal diet-fed chicks excreted a larger amount of rectal nitrogen and a smaller amount of cecal one. Frequency of excretion was not affected by the diets in Groups 1 and 2.
3. As the casein level of the diet was increased, the amount of nitrogen was increased in both rectal and cecal feces. Nitrogen contents of blood was also increased in the chicks fed the diet containg 30% casein in Group 3.

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By the use of the intestinal perfusion technique, the secretion of nitrogen into the cecal lumen and small intestine was investigated for single comb White Leghorn cockerels of various growth stages and those fasted or fed on different diets. Nitrogen concentration in blood of those chikens was also estimated. The results are summarized as follows:
1. The cecal and intestinal secretions of total nitrogen, uric acid and ammonia were large at the early stage of growth of chickens and decreased as the growth stage proceeded.
2. The secretion of nitrogen into cecal lumen was larger in the fasting than that in the feeding on the conventional diet. When the chickens were fed on fish meal diet, the secretion of nitrogen into the cecal lumen was larger than that in the fasting. On the other hand, the secretion of nitrogen into small intestinal lumen was not affected by the change of feeding condition.
3. When the chickens were fed on the semi-purified diet containing various levels of casein, the nitrogen secretion into the cecal lumen was larger after feeding on the casein-free diet than that after feeding on 10% casein diet. The secretion of nitrogen into the cecal lumen was increased with an increase of dietary casein level.
4. The nitrogen secreted into the cecal lumen was mainly composed of non-protein nitrogen, exceeding 96% of total nitrogen, but that secreted into the small intestinal lumen contained 20-30% protein nitrogen.
5. When the large amount of nitrogen was secreted into the cecal lumen, there was high concentration of nitrogen constituents in the blood.

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Experiments were conducted to investigate the counteracting effect of the irradiation treatment with gamma rays on the goitrogenic effect of rapeseed meal. Rapeseed meals were exposed to gamma rays of 20-70 Mrad and the diets containing 10 or 20% of these irradiated meals were fed to day-old White Leghorn male chicks for 3 or 4 weeks. These diets were formulated to be isonitrogenous and isocaloric, respectively. In addition, the influences of irradiation treatment on the contents of oxazolidinethione (OZT), which plays a significant role in the goitrogenic effect of meal, and several other constituents of meal were also examined.
When rapeseed meals were irradiated at a level of 60Mrad, their OZT, isothiocyanates and crude fiber contents decreased markedly and such a irradiation dosage also resulted in a little loss of the available lysine of meals. The extent of the above changes in the content of OZT was similar to that in rapeseed meal which was autoclaved under the reasonable condition (moisture content 20%, 120°C, 30min).
The irradiation treatment at any dosage had no adverse effects on growth rate, feed consumption and feed efficiency in chicks fed diets containing the treated meals. When the level of dosage was increased from 20 to 70 Mrad, thyroid weight of chicks tended to be lighter and an increase in thyroid weight of those receiving meals, which were irradiated at a level of about 60 Mrad, was very slight as was to be expected accordin to the chemical assay of OZT in the these meals. The rate of counteracting effect of treatment with above dosage was comparable to that of the treatment by autoclaving under the reasonable condition.
From these results, it may be concluded that the gamma irradiation at dosage of about 60 Mrad is effective in counteracting the goitrogenic effect of rapeseed meal and does not cause any adverse effect on growth performance in birds.

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[in Japanese]

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The averaged electroretinogram (ERG) and visual evoked potential (VEP) from the superficial Wulst were recorded in 3 adult cormorants under anesthetized conditions. Furthermore, some anatomical characteristics of the cormorant's brain were briefly described.
1) The outline of the cormorant's telencephalon in shape was very similar to that of the crow which has the conspicuously developed Wulst.
2) The a-wave of the ERG in the adult cormorant showed maximum amplitude at 20 to 80 joule stimulation. While the amplitude of the c-wave increased with increasing flash intensities, the amplitude of the b-wave was maximum at 2 joule.
3) The averaged VEP from both the scalp and the surface of the Wulst were reliably obtained by 0.3 to 80 joule flash stimulation. At 20 joule stimulation, the VEP consisted of a few positive-negative notches with very small amplitide which was followed by two major negative deflections. The peak latencies of the two negative deflections were 40-50msec and 96-140msec, respectively. The amplitude of the VEP of the Wulst region was higher from the skull (150-250μV) than from the scalp (ca. 50μV).

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[in Japanese]

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