Two experiments were conducted with 1-day-old chicks to determine the effect of dietary crude chitin processed industrially from marine crab shell waste on thyroid function in chicks fed a low iodine diet. In Experiment 1, chicks were assigned to four different dietary treatment-groups and fed on each diet for 3 weeks. All diets were formulated by supplementing 5% crude chitin and/or 0.5mg/kg KI to the low iodine basal diet. Dietary treatments in Experiment 2 were similar to those in Experiment 1 except that the low iodine basal diet was supplemented with 0.03% thiouracil (TU). In Experiment 1, the dietary crude chitin or KI ameliorated the decrease in plasma thyroxine concentration, the enlargement of the thyroid gland and the excessive abdominal fat deposition induced by the low iodine basal diet, but crude chitin had no additional effect on these parameters in chicks fed the KI-added diet. In Experiment 2, the dietary crude chitin or KI improved the growth retardation and excessive abdominal fat deposition induced by the low iodine basal diet containing 0.03% TU, but there were no significant differences in the growth and abdominal fat weight among dietary crude chitin, KI and crude chitin+KI treatments. These results suggested that dietary crude chitin improved a low thyroid function induced by the low iodine diet with or without TU in chicks.

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The present study was conducted to clarify the changes of calpain and calpastatin activities in skeletal muscle as a function of growth rate at advancing age of commercial chickens, using male broiler and layer chickens of 2, 4, 6, and 8 weeks of age. The body weight of broilers were significantly greater than those of layers (P<0.01). The fractional growth rates during the period of 0∼2, 2∼4, 4∼6 and 6∼8 weeks of age were also significantly greater for broilers than for layers (P<0.01). Calpain and calpastatin activities were decreased with advancing age in both broiler and layer. Statistically significant differences (P<0.01) in calpain and calpastatin activities (units/g muscle and units/mg extractable muscle protein) between broiler and layer chickens were observed. The broiler has lower calpain activity than the layer, but higher calpastatin activity than layer during the entire period of the investigation. The rates of change with age in calpain activity and calpastatin activity showed the same trends in both breeds. The differences of the activities observed between broiler and layer chickens might be due to the different breeding methods. The differences in calpain and calpastatin activities at different age of broiler and layer chickens in the present study suggest that the regulations of proteolytic enzyme activity in muscle are related to the aging and genetic factor of breed.

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Crowing of Red, Grey, Green and Ceylon Jungle Fowls, 16 breeds of Japanese native chickens and White Leghorn breed was recorded on tape and analyzed by a sound spectrography for the level of pitch, the length of duration and the number of syllable. The pitch was the highest in Grey and Ceylon Jungle Fowls and the lowest in Koeyoshi. Red and Green Jungle Fowls and Chabo had a relatively hight pitch. Duration was the longest in Totenko and longer in Tomaru and Koeyoshi. The number of syllable was 3 to 5 in the Jungle Fowls, 2 to 4 in the breeds of the Japanese native chickens, and 4 in White Leghorn breed.

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The first experiment was conducted to show that shochu distillery by-product (SDBP) and its ether soluble fraction contains growth promoting factor of broiler chickens. The second experiment was conducted to separate the growth promoting factor of SDBP from the ether soluble fraction by column chromatography. And the third experiment was conducted to endorse the second experiment. In the first experiment, 10-day-old Cobb strain chicks were given diets containing the ether extract and its residue of SDBP. In the second experiment, 16-day-old Cobb strain chicks were given diets containing chromatographically separated fractions. The unidentified growth factor (UGF) of SDBP was separated using Sephadex LH-20 with the solvent system; water: methanol: 1, 2-dichloroethane (10:90:20). And in the third experiment, 16-day-old Cobb strain chicks were given diets containing fraction I. Its concentrations were equivalent to 0.025, 0.05 and 0.1% ether extract of SDBP. In the first experiment, it was observed that body weight gain was significantly (P<0.05) higher, and feed intake and feed conversion ratio were significantly (P<0.05) lower than the control when the diet containing 0.05% ether extract was given. However, body weight gain, feed intake and feed conversion ratio were not significantly different from the control when the diet containing 0.05% ether extract residue was given. In the second experiment, body weight gain tended to increase and feed intake and feed conversion ratio decreased when the diet containing fraction I was given. Whatever, when the diets containing fractions II, III, and IV were given, body weight gain and feed intake were significantly (P<0.05) inferior to those of the control. On the other hand, feed conversion ratio was significantly (P<0.05) higher than the control. In the third experiment, body weight gain was significantly (P<0.05) higher when the diet containing 0.1% fraction I was given. Whatever, there were not significant effects when the diets containing 0.025 and 0.05% of fraction I were given. Body weight gain and thigh muscle weight were significantly (P<0.05) higher in all the treatment groups compared with the control. Feed conversion ratios were significantly (P<0.05) lower in all the treatment groups compared with the control. These results show that the UGF occurs in ether soluble fraction, and it can be separated by column chromatography using Sephadex LH-20.

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To determine the effects of yeast phytase addition to low non-phytate phosphorus (NPP) diet on performaoce, phosphorus retention and excretion of chicks, three experiments were done with corn soybean meal diets. The low NPP diet was formulated to contain 0.30% NPP without any addition of inorganic phoshporus. The yeast phytase was added to the low NPP diet at levels ranging from 438 to 3, 285 unit per kg of diet. One unit of these activities was equal to one micromol of ortho-phosphate liberated from sodium phytate per minute at 37°C and pH4.4.
Addition of the yeast phytase to the low NPP diet produced an increase in body weight gain, feed efficiency, phosphorus retention and toe ash content indicating hydrolysis of phytate by the yeast phytase. The effect of the yeast phytase addition at the level of 1, 920 unit (860 unit at pH5.5) was equivalent to 0.1% inorganic phosphorus addition. These result indicate that phytase can serve to reduce the total and NPP levels resulting the reduction of phosphorus in excreta of chicks.
The activities of added yeast phytase in digestive tract were slightly recognized in the content of gizzard, duodenum and jejunum and ileum. This indicates that the hydrolysis of phytate by supplemental phytase may occure mainly in the crop of chicks.

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This study was designed to investigate the influence of day length on sexual maturity in female Japanese quail (Coturnix coturnix japonica). At 10 days of age, chicks were divided into four groups; 21H (14L:7D), 24H (16L:8D), 27H (18L:9D) and 30H (20L:10D). At 20, 30, 40 and 50 days of age, 9-10 birds from each group were selected randomly, weighed, and slaughtered to determine ovary weight and the number of ovarian follicles. The age at the first egg and the egg production rate were recorded until 70 days of age. Overy weights in 21H, 27H and 30H at 40 days of age were significantly less than that of birds in 24H (P<.01). At 50 days of age, however, no significant differences were found among groups in ovary weight. The egg production rate was also highest in 24H and the difference between 24H and 30H was statistically significant (P<.01). It was suggested that the female quail exposed to ahemeral light/dark cycle might be influenced only in the early stage of ovary growth, but thereafter, compensatory growth might occur and restore the delay of growth.

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Laying guinea fowls were sacrificed at various times after oviposition, and the presence of ovulated ovum in each portion of the oviduct was checked. Ovulation occurred at a time less than 15min. after oviposition, and the ovulated ovum stayed for 15-30min. in the infundibulum, 2 hours 15-45min. in the magnum, and 1 hour in the isthmus. Subtracting these times from the interval between ovipositions (24 hours 22min.), the time spent in the uterus and vagina was estimated to be 19 hours 52min.-20 hours 52min.

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A comparison was made of the effects of layer and corn with 2% fish meal diets as molt diets on egg production performance of laying hens. Four lines of commercial White Leghorn laying hens hatched at summer or autumn were induced to molt at 73 and 118 weeks of age by fasting. Feed consumption, body weight, laying performance and egg quality after fasting were studied.
Hens fed a layer diet as a molting diet consumed more feed, recovered body weight and began to lay sooner, and egg production rate in the first molting was higher, compared to corn with fish meal diet hens. In the second molting, hens fed the corn with fish meal diet laid more eggs, although hen day egg production was less than 60% in both treatments. Egg weight was the same for both diets. Hen fed the corn with fish meal diet had stronger egg shells, lower cracked egg production and a higher Haugh unit value.
The layer diet was thus shown satisfactory as a molt diet for egg production after molting in the case of the first induced molt at 73 weeks of age. The corn with fish meal diet led to superior results in high egg shell quality. This diet was also superior as a molt diet when hens were induced to the second molting at 118 weeks of age, although no economical advantage could be expected.

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