Safety and immune effect of TCND vaccine, which was established by BANKOWSKI and produced by Eli Lilly & Co., were studied on young chickens.
Results obtained were as follows:
1. TCND vaccine was moderately pathogenic against young chicks under 3 days of age.
2. The vaccine was effective on most chicks free from passive antibody. It was not so, however, on chicks having maternal antibody.
3. Rise of antibody titer of birds by using the vaccine was compared with that by a B1-strain vaccine and with that by a killed vaccine. Though HI antibody titer by TCND vaccine was lower than by the others, neutralization antibody titer of the TCND group was similar among chicken groups with respective vaccination.
4. Relatively high immune effect was obtained in chickens inoculated with the vaccine through intramusclar, intravenous and wing-web routs, but none by oral and eye-dropping administration.

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It has been reported that starting chicks or growing meat-type chicks become fatty or lean by simply changing dietary levels of protein, and the fat deposition may be controlled by certain hormones. This paper deals with the effects of diethylstilbestrol (DES), testosterone, thyroxine, thiouracil and prolactin in growing chicks.
One hundred and forty-four meat-type chicks of both sexes were placed in growing cages at 2 weeks of age, and fed with either one of the two isocaloric diets with a different protein level (CP: 20 and 26%) up to 6 weeks of age. Hormone treatments and thiouracil feedings were started at 3 weeks of age. DES (1mg/bird), testosterone (1mg/bird) and thyroxine (30μg/100g body wt.) were injected intramusculary into the birds once daily for three weeks, prolactin (25 I.U./bird) was injected intramusculary every other day. Thiouracil was fed at 0.2% level in the basal diet. The birds were sacrificed at 6 weeks of age and the abdominal fat was removed and weighed. Percentages of the weight of the abdominal fat to the body weight were used for the comparison of the fat deposition.
1) The injection of diethylstilbestrol resulted in an increase in the fat deposition in both groups of birds. However, the birds fed with the higher protein diet showed less fat deposition than the birds fed the lower protein diet, although the difference was statistically not significant at 5% level.
2) The injection of testosterone did not affect the fat deposition in both groups of birds, and the less fat deposition was observed in the birds fed with the higher protein diet.
3) The injection of thyroxine resulted in a decrease in the fat deposition, but the less fat deposition was still thiouracil observed in the birds with the higher protein diet.
4) Feeding thiouraci caused an increase in the fat deposition, but the difference between the two groups of different protein levels was not observed.
5) No appreciable effect of prolactin on the fat deposition was observed in the male birds. But, in the female birds, the depressing effect of the higher protein diet was diminished.

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Growing and laying perfermance of total 1, 290 hens and cocks of the fourth and the fifth generations fed either the control diet or the diet containing 15% of one of four kinds of yeast grown on n-paraffin in four domestic manufacturers, their reproducibility tested on total 6, 550 eggs, and growth rate of total 740 chicks of the sixth generation fed a conventional chick starter diet in the collaborative research in National Institute of Animal Industry and six Prefectural Experiment Stations for succesive generations were as follows:
1) Growth rate of the chicks of the fourth generation and feed intake of the chicks of the fifth generation on the yeast diet tended to be inferior to those on the control diet. Normal growth of the offspring of the hens of the fifth generation suggests that the delay in growth of the chicks on the yeast diet was mainly due to the unbalance of nutrients in the yeast diet, not due to the fault of yeast itself.
2) Little difference between the control and yeast groups was observed on laying performance, i.e. egg production, feed intake, feed conversion, egg weight and viability. Body weight of the hens of the fourth generation on the yeast diet at 36 weeks of age was significantly lighter than that on the control diet, but little difference was observed on body weight between the two groups of the hens of the fifth generation.
3) Fertility of the yeast group of the fourth and the fifth generations and hatchability of fertile eggs of the yeast group of the fourth generation were higher and that of the fifth generation was lower than those on the control diet, though the differences were not significant statistically.
4) Abnormally large variation in body weight and feed conversion were observed between two lots of the hens of the fifth generation fed the same diet in the same station. Abnormally low fertility was also observed in both of the two groups of the hens of the fifth generation fed either the control or yeast diet in two stations out of six. Adverse effect of inbreeding in a closed flock was suspected from these findings. However, normal growth of the offspring indicate that the hens of the fifth generation has normal ability to produce normal chicks.

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Total 711 hens of the third generation in the multi-generation experiment carried out in cooperation of National Institute of Animal Industry and six prefectural experiment stations, half of which were fed the diet containing 15% of yeast grown on n-paraffin continuously from the first generation, were reared until 108 weeks of age and hatchability test with total 3083 eggs of these old hens was conducted.
Hen-housed egg production of the hens on the yeast diet was higher than that on the control diet and the difference was significant statistically. The difference in egg production between the two groups became apparent after the seventh laying period when the hens were about one and a half years of age. Higher egg production reflected as better feed conversion (feed/egg) on the yeast diet, especially after the seventh period.
Daily feed intake was similar between the two groups, and seasonal variation was observed on feed intake. Little difference was also observed between the two groups on average body weight, egg weight and fertility and hatchability measured at age older than 104 weeks.
Viability during 20 to 108 weeks of age was excellent, being 91% in average. No single cause of death was attributable to the yeast feeding. In Gifu Station, 12 hens died of visceral lymphomatosis and mortality of the control group was significantly higher than that of the yeast group.

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Under specific conditions, it has been shown that some monogastric animals are able to utilize the nitrogen from non-protein nitrogen (NPN) sources to a limited extent.
FEATHERSTON et al.1) were able to show that chicks fed a diet containing all the essential amino acids and supplemented with several sources of nitrogen retained more nitrogen and higher plasma levels of non-essential amino acids. In their study, urea and diammonium citrate (DAC) were effective sources of nitrogen, thus indicating that nitrogen from non-protein sources could be utilized by the chick. YOUNG et al.2) reported that laying hens fed a low protein diet were able to utilize NPN to partially satisfy the total nitrogen requirement. Diammonium citrate and glutamic acid were proved to be effective in a diet adequately balanced.
The present experiments reported herein were designed to determine the relative effectiveness of NPN, such as L-glutamic acid, dibasic ammonium phosphate (DAP), DAC and urea in the cockerels by judging from the nitrogen balance index and urinary nitrogenous constituents.

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Yeast grown on n-paraffin, which will be called just the yeast hereafter, has specific flavor common to yeast. Although many preliminary trials just tasting the meat of broiler and hen fed a diet containing high level of the yeast and egg laid by hens fed the diet revealed no detectable change in flavor of the meat and egg, the flavor specific to the yeast in feed is suspected to be transferred to the meat and egg, making these products unfavorable for food. Accordingly, sensory test based on more reliable experimental design was carried out to find whether the meat and egg of hens fed the yeast has any specific and detectable flavor.

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[in Japanese]

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