The objective of this study was to determine whether vitamin D directly stimulates the shell gland to induce calcium binding protein-D28K (CaBP-D28K) in vivo, which plays an essential role in calcium transport for shell formation. White Leghorn laying hens were injected with 1, 25-dihydroxyvitamin D₃ [1, 25 (OH)₂D₃] or saline (control) into the shell gland lumen at 3h (precalcification phase) or 8h (early calcification phase) after oviposition. The CaBP-D28K levels in the shell gland and intestine were examined by immunocytochemistry and Western blot analysis. Also, the changes in the serum calcium levels were examined. The immunoreaction products for CaBP-D28K were localized in the tubular glands of the shell gland at precalcification and calcification phases in both the 1, 25 (OH)₂D₃ treated and control hens. At the calcification phase the density of immunoreaction band for CaBP-D28K was greater in the 1, 25 (OH)₂D₃ treated hens than in the control hens, whereas difference in the densities of CaBP-D28K was not found between 1, 25 (OH)₂D₃ treated and control hens at the precalcification phase. No significant differences in the densities of immunoreaction products for the intestine CaBP-D28K and in the serum calcium concentrations were observed between the 1, 25 (OH)₂D₃ treated and control hens. These results suggest that 1, 25 (OH)₂D₃ directly stimulates the shell gland to induce CaBP-D28K.

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The effect of hypervitaminosis A on bone histomorphology was studied in the tibiae of young growing chicks. Male White Leghorn chicks were orally administered excessive vitamin A (300 or 600IU per g body weight per day) for 10 consecutive days. For histological examination, middle diaphyses were excised and cross sections were stained with toluidine blue. Morphological differences were examined by a computerlized histomorphometry. Radiographic and histological observations indicated the hypervitaminotic chicks to have short tibial length, narrow diaphyseal width and abnormal bone morphology characterized by flattened spindle-shaped osteoblasts. Histomorphometric analysis indicated excessive vitamin A intake to cause severe retardation of bone formation. Cortical bone thickness, measured at middle diaphysis, was less in hypervitaminotic than control chicks receiving the vehicle alone. Osteoblast area and number significantly decreased in the hypervitaminotic chicks. Changes in these osteoblast parameters are associated with marked decrease in bone volume, expressed as percentage of mineralized bone matrix area. Excessive vitamin A intake did not affect all histomorphometric indices of bone resorption. Hypervitaminosis A would thus appear to decrease osteoblastic activity and inhibit bone formation in chick tibia.

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The effects of intermittent lighting on the activity of male broiler chickens were studied in two experiments. In both, all chickens were grown under a condition of continuous light until 2 weeks old. Thereafter they were separated into the four lighting regimes, and reared from 3 to 8 weeks of age. In Experiment 1, lighting regimes were: the continuous light (CL); half hour light and one hour dark (0.5L 1D); one hour light and two hours dark (1L 2D); and two hours light and four hours dark (2L 4D). In Experiment 2, lighting regimes were: the continuous light (CL); half hour light and one and half hour dark (0.5L 1.5D); one hour light and three hours dark (1L 3D); and two hours light and six hours dark (2L 6D).
During the experiment, five birds were selected from each group; these chickens were marked and their behavior at 4, 6 and 8 weeks of age was observed, using video cameras and a time-lapse video recorder. The posture and the feeding behavior were recorded during light periods in intermittent light chickens and for 8 or 6 hours in continuous light chickens.
At 4 and 6 weeks of age, the intermittent light chickens spent more time on feeding than the continuous light chickens. However, in the intermittent light chickens, the frequency and total duration of feeding decrease with age, and at 8 weeks of age, no difference was observed in the frequency and total feeding duration among the light regimes. The total duration of standing posture of intermittent light chickens were significantly longer than those of the continuous light chickens at 4 and 6 weeks of age, but this declines with age, and consequently the intermittent lighting regimes had no effect on the total duration of standing posture at 8 weeks of age.
The intermittent lighting stimulates the activity of broiler chickens in an early stage of rearing, but does not in a latter stage.

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Body weight, oviduct weight and plasma estradiol-17β(E₂) concentration were measured at every week from hatch to 10 weeks of age in guinea fowl (GF) and White Leghorn chickens (WL). The body weight was greater in GF than in WL from 3 weeks of age, and the oviduct weight was also greater in GF from 4 weeks of age. The oviduct weight per 100g body weight did not show any appreciable change from 2 weeks of age in both GF and WL, and no difference was observed between them. Plasma E2 concentration did not change up to 8 weeks of age in GF, but increased after 4 weeks of age in WL. When diethylstilbestrol was injected once daily for 5 consecutive days into GF and WL at 5 weeks of age, the oviduct weight on 6th day was found to be increased linearly with the increase in the daily dose injected (62.5-1, 000μg/bird). The response (fold-increase over the control) of GF was less than that of WL. Similar injections were also made into GF at 4 weeks of age, and the response was also less than that of WL at 5 weeks of age. The results suggest that the greater oviduct weight in GF than in WL during an early growth period may be due neither to the estrogen secretion nor to the responsiveness to estrogen.

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This study demonstrates that Shochu distillery by-product (SDBP) has an increasing effect on blood concentration of α-tocopherol as well as a growth promoting activity in broiler chicks. Five-days-old broiler chicks (Arbor Acres strain) were fed diets containing different levels (0.00, 0.05, 0.10, 0.20, 0.40 and 1.60%) of dried supernatant (DSN) of SDBP for 6 days. DSN was prepared from SDBP by centrifugation and freeze-drying. Body weight gain, muscle weight, and feed intake were all increased by feeding the diets containing DSN and were significantly different from those of control in 1.6% group. Feed conversion ratio (gram of feed intake/gram of body weight gain) was not changed by DSN. Plasma α-tocopherol concentration was significantly increased in a dose dependent manner by feeding the diets containing DSN except 0.05% group. Muscle α-tocopherol content was tended to be increased by DSN. These results indicate that SDBP has a factor increasing plasma concentration of α-tocopherol.

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This study was conducted to examine the effect of dietary cellulose on growth and nitrogen utilization in chicks fed 65% CP and 80% ME of Japanese Feeding Standard. Body weight gain, feed efficiency, apparent N digestibility, N retention and N retention rate were not influenced by dietary cellulose if the levels were from 0.0% to 3.5%, but started to decrease when dietary cellulose level exceeded 5%. Feed efficiency, apparent N digestibility, N retention and N retention rate were significantly higher in chicks fed 1.5% and 3.5% cellulose diets than in those fed 10% and 20% cellulose diets (P<0.05). Body weight gain in chicks fed 1.5% and 3.5% cellulose diets were significantly larger than that of 20% cellulose group (P<0.05). Retention rate of absorbed N was significantly increased by 1.5% dietary cellulose and the level was maintained in 3.5% cellulose group, then started to decrease when dietary cellulose exceeded 5% level. Retention rates in chicks fed 1.5% and 3.5% cellulose diets were significantly higher than those of 10% and 20% cellulose groups(P<0.05). It is concluded that the highest retention rate of absorbed N is obtained when dietary cellulose levels range from 1.5% to 3.5% in chicks fed 65% CP and 80% ME of requirements, and the same tendency was observed in growth and N utilization.

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The effects of onset age of intermittent lighting with cycles of 0.5-hr light and 1.5-hr dark on fat accumulation were studied in male broiler. After being grown under a condition of continuous light to 2 weeks of age, chickens were placed on litter floors of light-controlled chambers. Four chambers were assigned to each of four lighting regimes: 1) continuous light from 3 to 8 weeks of age (CL); 2) continuous light from 3 to 6 weeks of age and intermittent light from 7 to 8 weeks of age (IL 7); 3) continuous light from 3 to 4 weeks of age and intermittent light from 5 to 8 weeks of age (IL 5); and 4) intermittent light from 3 to 8 weeks of age (IL 3).
The body weight gains and feed intakes of IL5 and IL3 chickens were lower than the other chickens just after the shift from the continuous light to the intermittent light. However, there was no marked difference in body weight gains and feed intakes within the lighting regimes at 7 weeks of age. It also discovered that the fat accumulation was not affected by onset age of intermittent lighting with 0.5-hr light and 1.5-hr dark. The present data suggested that the intermittent lighting in the finisher period was not effective means of reducing the fat accumulation in male broilers.

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