In order to elucidate whether endogenous phosphorus (P) was a factor in the fluctuation of the phosphorus excretion along with the egg shell formation cycle, effects of low calcium (Ca) and/or P diets on the fluctuation in P excretion during egg formation were studied.
Laying hens were fed a control diet containing 3.38% Ca and 0.43% total P and then divided into 3 groups and fed one of 3 diets containing Ca 3.41% and P 0.12% (NCa-LP) ; Ca 0.32% and P 0.39% (LCa-NP) or Ca 0.03% and P 0.12% (LCa-LP) for 2 days. The excreta were collected individually every 3 hrs on the 5th day of the control diet and on the next 2 days on experimental diets.
On the LCa-NP and LCa-LP diets, the eggshell weights decreased, P excretion increased and the apparent P absorption turned into negative. But there was no significant effect of feeding the NCa-LP diet on the eggshell weight and apparent P absorption. Ca intake was highly correlated with Ca excretion and apparent Ca absorption. The apparent P absorption had a high correlation with apparent absorption or intake of Ca rather than P intake. On the LCa-NP and LCa-LP diets, apparent P absorption markedly decreased each time compared to on the control diet. While, not only the fluctuation in apparent Ca absorption, but also apparent P absorption during egg formation on the NCa-LP diet was similar to those on the control diet.
In conclusion, these results demonstrate that : 1) the increase in P excretion is due to the increase in the endogenous P excretion during shell formation. : 2) the apparent P absorption is not significantly affected by dietary P intake and reflects the fluctuation in the endogenous excretion of P.

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Primary monolayer culture cells prepared from the anterior pituitary of 1-day-old male chicks were used to examine the effect of estrogen on GnRH-induced LH release. The half-maximal response (ED₅₀) values of several kinds of GnRH determined by dose-response incubations with day-4 culture cells were in the following ascending order (in nM) : (D-Lys⁶)GnRH (a synthetic analogue; 0.07), chicken GnRH-II (0.24), chicken GnRH-I (0.51), and mammalian GnRH (0.82). By the use of the most potent and stable GnRH, (D-Lys⁶) GnRH, at a dose (1 nM) less than that inducing a maximal LH release, the GnRH-induced LH release was found to decrease in day-4 culture cells which had been pre-incubated with estradiol-17β (E₂) for 12, 24 or 48 h. Whereas basal LH secretion was not changed by pre-incubation with E₂. Following pre-incubation with E₂ or diethylstilbestrol for 24 h the dose-response curves for the GnRH-induced LH release were shifted to a higher concentration with the ED50 enhanced. The results suggest that estrogen reduces the sensitivity of the chicken anterior pituitary cells to GnRH in vitro.

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Five-day-old broiler chicks of both sexes were fed the conventional diets containing 0, 1, 2, or 3% propionic acid (PA) and water ad libitum until 54 days of age, then the tarsometatarsal bone (TMT) was removed after the feeding experiment. The size, fracture and crash strength, crude ash and calcium contents of TMT were measured.
1. In male chicks, no effects of dietary PA on the size of TMT were obtained but the dry weight/fresh weight of TMT was increased. In females, the diameter, dry weight and dry weight/fresh weight of TMT were increased.
2. In both sexes, the elasticity, and fracture and crash strength of TMT were significantly improved by the dietary PA, in which 3% PA-fed birds showed the highest improvement in TMT strength.
3. Crude ash and calcium contents of TMT also showed a positive correlation with increasing dietary PA level in both sexes.
These results suggest that the dietary PA in broilers increased the breaking strength of the bone due to the elevated calcium content in the bone by activated absorption of mineral such as calcium.

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The objective of the present study was to compare the behavior and production performance of laying hens housed in cages with and without perches. Thirty-six commercial laying hens were divided into 3 groups of 12 each. They were subjected to the following types of cage with 2 birds per cage (474 cm²/bird), according to the Latin square methods : C, conventional cages without perches ; PN, conventional cages with perches from 20 : 00 to 08 : 00 h ; PD, conventional cages with perches in whole days. Each experimental period consisted of 2 weeks. The proportion of birds resting (not eating, drinking, preening, aggression and walking) in C, PN and PD was 74.3%, 76.6% and 81.3%, respectively. More than 90% of birds resting in PN and PD used the perches during the dark period. In PD, more than 70% of birds resting used the perches in the daytime. The production performance was not affected by the existence of perches. However, as the significant positive transitions from pacing to eating and drinking, and from aggression to eating and vice versa were observed in only PD cages, the perches in the center of cages might prevent hens moving.

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The specificities of lymphocytes from peripheral blood, thymus, bursa of Fabricius and spleen were investigated according to the results in FACS analysis (fluorescence activated cell sorter) and rosette forming reaction for fed blood cells from rabbit and sheep.
Anti-chicken IgG antibody labeled by FITC (fluorescein isothiocyanate; Ab-ChIgG) was employed in the present experiments.
Lymphocytes from peripheral blood, bursa of Fabricius and spleen were composed of two populations, a population reacted positively with Ab-ChIgG and the other reacted negatively, but thymoctes were reacted negatively with this antibody.
A part of peripheral lymphocytes from normal quail reacted positively in rosette forming reaction for rabbit red cells (RaRBC), nevertheless the lymphocytes reacted negatively in rosette forming reaction for sheep red blood cells (SRBC). However, some population of lymphocytes from quail immunized with SRBC were considered to be B cells, because they reacted positively in cell sorting by employed Ab-ChIgG and in rosette forming reaction for SRBC using as immunogen.
Rosette forming cells (Ra-RFC) and non rosette forming cells (Ra-NRFC) for rabbit red cells were analysed by FACS.
It was observed in results in cell sorting by FACS that the rosette forming cells for rabbit cells (Ra-RFC) showed the negative reaction for FITC labeled Ab-ChIgG, but non rosette forming cells for rabbit red cells (Ra-NRFC) the positive reaction for this antibody.
Tiherf ore, it was recognized that the negative cells in cell sorting by FACS are able to be classified into two sub-populations, Ra-RFC and Ra-NRFC, or Tα sub-population and Tβ.

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A hemagglutination (HA) factor which reacted with non-self chicken red blood cells (RBC) but not with self RBC was detected in a solubilized solution of normal chicken kidney (NCK) cells treated with a mild detergent. The HA activity was characterized as follows; 1) restricted to allogenic RBC but not xenozenic RBC of sheep or horse, and had no aggregation capacity for dayold chicken RBC and any spleen lymphocytes; 2) a detergent-dependent reaction; 3) absorbed by f ormalin-fixed chicken RBC, 4) heat-labile (completely inactivated within 5 min by heating to 37°C); 5) not inhibited by the presence of N-acetyle-D-glucosamine, L-fucose, D-mannose or D-galactose at a concentration of 1, 2, 5, 10 and 20mM; and 6) small molecularly size; less than 10, 000 Da. Although the HA factor is speculated to be one of the lectins, its characteristics exhibit a different nature from chicken lectins reported previously.

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Surgical thyroidectomy tended to increase circulating concentrations of growth hormone (GH) in normal Rhode Island Red chickens (Gifu 15 line) but not in dwarf ones (Gifu 20 line). The operation significantly reduced serum IGF-1 concentrations in normals but resulted in an increasing tendency in dwarfs. Serum IGF-binding activity decreased following thyroidectomy in dwarfs. Basal levels of IGF-binding activity were 3-times higher in dwarfs than in normals, presumably reflecting low basal concentrations of IGF-1 in dwarfs. The results suggest that circulating concentrations of IGF-1 as well as those of GH are influenced by thyroid status and dwarfing gene dw.

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