The present studies were performed to investigate whether the removal of the previously infected site of caeca would influence the subsequent maintenance of immunity to Eimeria tenella in chickens. The chickens used in the studies were White Leghorn males of 2 to 2.5 weeks of age fed an all-mash ration containing no antibiotics or coccidiostats. The results are summarized as follows.
1. Chickens were initially infected by asingle injection of sporozoite suspensions into the lumina of the left caeca isolated from the intestinal tracts, by means of ligation. Approximately two weeks later, the opposite right caeca of these chickens were challenged per os with sporulated oocysts, and thereafter the number of daily discharged oocysts was counted for seven days after the infection.
Chickens in which the ligated left caeca were previously infected with sporozoites showed remarkable resistance to the challenge with oocysts, in comparison with the controls not previously infected withthem. This confirmed the previous works (BURNS and CHALLEY, 1959; HORTON-SMITH et al., 1961) that the resistance to Eimeria tenella in chickens was not limited at the site of the initial infection.
2. Chickens were previously immunized by a single injection of sporozoite suspensions into the lumina of the ligated left caeca. The left caeca of these chickens were surgically removed approximately two weeks after the sporozoite infection. Thesubsequent maintenance of immunity inchickens was determined by daily measurements of discharged oocysts after the oral infection of oocysts.
From the measurements of discharged oocysts, it was found that there is little difference in the resistance to the challenge infection between the chickens with a single caecum and the controls. This suggests that the presence of the actually exposed site to the parasites is not essential for the subsequent maintenance of immunity to Eimeria tenella.

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Preventive effects of dipping with tylosin against egg transmission of avian mycoplasmosis and the antibiotic levels in eggs and chicks after dipping were studied by the pressure differential method.
The results were as follows:
1. There were significant differences in weight gain of eggs after dipping between the ages of embryonated eggs, applied reduced pressures or individual farms, but not between the duration of dipping or antibiotic concentration applied. The antibiotic levels in egg increased with the duration of egg storage and antibiotic concentration.
2. Anti-mycoplasmal effect of tylosin at 2, 500ppm in the experimentally inoculated eggs was apparently noted. The effect was not influenced by the age of embryonated eggs, applied reduced pressure and duration under atmospheric pressure. However, Mycoplasma gallisepticum was isolated in one of the 15 eggs which had been treated with tylosin at 156.8 to 1, 250ppm.
3. Though hatchability at 2, 500ppm tylosin was not affected at all by a negative pressure over than 300mmHg and did not hatch lower 30mmHg.
4. Tylosin appeared in albumin in a few minutes and in yolk 2 days after dipping. It remained in 3-day-old chicks from dipped eggs. However, the 4-day-old chicks were infected by the inoculation of Mycoplasma gallisepticum.
From these results, it is considered that dipping with tylosin by the pressure differential method was very effective for the prevention of egg etansmission of avian respiratory mycoplasmosis. However, the effect may be variable according to the eggs used.

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Several reports have been published on the restricted feeding of layers. It has been demonstrated that performances of layers such as egg production, egg weight and body weight were decreased and the feed conversion was improved by feed restriction. There is no report, however, concerning the effect of graded levels of feed restriction on the performance of layers. It is considered that the economical profit will be increased by the improvement of feed conversion owing to the feed restriction.
This report deals with the effect of graded levels of feed restriction on the performance of layers and the relationship between the graded levels of feed restriction and the economical profit was discussed.
Numbers of layers used in this experiment were 918 and 946 of the commercial strain S_A and S_B respectively, which were hatched in the two hatcheries at the same time. Experiments were conducted at five poultry experiment stations under the same experimental design.
Layers of each strain were divided into two groups and a control group. In one group, the restricted feeding was started at 24 weeks of age (T₂₄) and in the other group the restricted feeding was started at 52 weeks of age (T₅₂). Feed restriction was terminated at 72 weeks of age in the two groups. In the control group of each strain, no feed restriction was carried out. The layers of each restricted feeding group were divided into 4 sub-groups, in which feed restriction rate was 4, 8, 12 and 16% of the control layers, respectively. The feed supplied contained 16.4% of crude protein and 67.6% of total digestible nutrients. Natural and artificial light were supplied for 14 hours per day from 20 weeks of age until 72 weeks of age. During the restricted feeding period (24-72 or 52-72 weeks of age) egg production, egg weight, feed consumption, body weight and viability were recorded. Economical profit of each graded levels in the two groups were estimated based on the records of total egg weight and feed consumption from 24 weeks of age to 72 weeks of age.
Egg production rate during the restriction feeding period was lower in all sub-groups of feed restriction than in the control group. The lower egg production was recorded in sub-groups of higher feed restriction. In the spring season, however, egg production in the sub-group of 16% restricted feeding did not differ from that in the control group. On the contrary, egg production was reduced even in the sub-group of 4% restricted feeding in the summer. This tendency was observed in the two groups. A different effect of feed restriction was observed, however, between strain S_A and S_B. Decrease in the egg production in strain S_B was greater than that in strain S_A. Egg weight in all sub-groups of feed restriction was slightly less than that in the control and there was no significant difference among the restriction sub-groups. Difference in the feed conversion was observed between strain S_A and S_B. Feed conversion in restricted subgroups of strain S_A was better than that in the control. But in strain S_B, the feed conversion in all of the restricted sub-groups was not improved comparing with that in the control. Seasonal variation was observed in the feed conversion. Feed conversion in the restricted sub-groups was better than that in the control in the spring season and an adverse effect was observed in the summer. Body weight gain in higher restricted sub-groups was lower than that in lower restricted sub-groups of both strains.
In T₂₄ group, crude profit of feed restriction in strain S_A was much more than that in the control. It was considered that maximum crude profit would be obtained in 11-13% feed restriction. It was estimated that the higher feed restriction might result in the more profit when egg price was low (210 yen per kg weight).

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The hypothalami of thirty-four laying hens (W. L.) were electrolytically lesioned in order to observe changes of their feed intake and body weight. They were autopsied about twenty-eight days after the operation. Five experimental hens which were lesioned the ventral part of N. hypothalamic inferior to N. tuberalis, showed hypothalamic hyperphagia and obesity. In these hyperphagic hens the daily mean feed consumption was 178.7g, and at the peak from the fourth day to the eighteenth day they took more than 200g daily. The mean body weight gain during the experimental period was 460g. In the sham-operated control the feed consumption was 113.8g, and the body weight gain was 53g. The differences of the feed consumption and the body weight gain between two groups were highly significant (P<0.001). Two slightly hyperphagic hens whose satiety center were unilaterally lesioned showed intermediate results the feed consumption 157.5g, the body weight gain 395g.
The weights of abdominal fat and liver of the hyperphagics increased. Their ovaries were atretic, but the atresia of ovary seemed not to be connected to the obesity, since eight hens of the non-hyperphagics had atretic ovaries and moderate amounts of abdominal fat.
Diurnal variation of feed intake was observed for three days from the seventeenth day. Commercial mash feed was given at 9:00, and the feed consumption was estimated hourly by weighing the feeders. As results, the control took very much within one hour after feeding, and thereafter in the daytime they took invariably. Before feeding in the morning they took slightly, though feeds remained in their feeders. The hyperphagics took greatly much more than the control within a few hours after feeding, and also before feeding they took significantly much more. And in the other time they took more or so. Therefore the information for satiety from the crop and the digestive tracts was supposed not to be accepted, although there was not any evidence about the chemical informations.

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Effect of storage of quail eggs in an unairconditioned room (temperature 10-28°C, relative humidity 60-90%) or in an electric refrigerator (temperature 1.2-2.8°C, relative humidity 45-65%) for one year on the interior quality was studied. Furthermore, the effect of coating shell of the egg with liquid i-paraffin (mineral oil, Cristol 70 Esso) was studied.
Selected characteristics of fresh quail eggs were as follows: egg weight 9.74±0.12g (mean of 50 eggs±SE), yolk weight 2.91±0.08g, albumen weight 6.02±0.08g, shell and shell membrane weight 0.83±0.01g, albumen height 4.93±0.09mm (mean of 30 eggs± SE) and yolk height 11.41±0.11mm.
Maximal storage time for maintaining a good interior egg quality and obtaining a good quality of boiled egg was 2 months in an unairconditioned room and 3 months in a refrigerator.
Oiling of quail shell egg resulted in higher interior egg qualities such as a higher albumen height and a higher yolk height, but resulted in dificulty in removing shell when it was boiled.

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