Two-way selection for the survival time of allografts in chickens was carried out over eight generations. The foundation stocks used for selection were composed of only B11 B11 genotype at the major histocompatibility B locus. The graft from the long survival line was used for testing the survival time of allografts for both long (L) and short (S) survival lines.
The selection was effective in the L line, but not necessarily effective in the S line. The differences between the L and S lines increased with each successive generation of selection except with the second generation. The realized herita-bility was comparatively high, with a mean value of 0.334. At the seventh generation of selection, the proportion of survival allografts in the L line was 48.5% at 90 days after transplantation and that in the S line was zero. However, when another line (GVHR line) was used as donor line, the proportions of survival grafts in the L and S lines were only 12.5 and 4.0%, respectively.
In comparison of graft-versus-host competence at the seventh generation of selection, the mean splenomegaly index of the L line was significantly larger than that of the S line. The immune response to sheep red blood cells was also compared in the L and S lines at the fifth generation of selection. No line difference was found.(Jpn. Poult. Sci., 27: 337-345, 1990)

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Arginine vasotocin (AVT) levels in plasma shortly after premature oviposition induced by intrauterine injection of prostaglandins (PGs) (PGE₁, PGE₂ and PGF_2α) and arachidonic acid were measured in the laying hen. The injection of PGs and arachidonic acid evidently led to premature oviposition when injected 15-17 h and 2-3 h before the expected time of oviposition, being coincided with a significant (P<0.01) increase in plasma AVT level. PGF_2α was most effective in eliciting premature oviposition, resulting in higher level of plasma AVT. A significant (P<0.01) increase in plasma AVT was also observed even when oviposition was not caused by PGF_2α injection, though the level of AVT was slightly lower than that in the case of induced oviposition. The arachidonic acidinduced oviposition was blocked by pretreatment with indomethacin, and plasma AVT level of treated hens 5 min after the injection of drug increased slightly but not significantly. The results obtained from this experiment suggest that the increase in plasma AVT level may be associated with the production of the uterine PGs, causing an enhancement of uterine contractility.

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Calcium is required for steroidogenesis and contraction of follicular wall at ovulation. The aim of this study was to determine the localization of calmodulin in the ovary of laying hens by immunohistochemistry. It is expected that calmodulin would be found in the tissues that contain calcium. Dense immunoreactive products showing the presence of calmodulin were observed in the granulosa cells and thecal interstitial cells of yellow large follicles and in the interstitial cells of small follicles and stroma. Dense reaction products were also observed in the smooth muscle bundles and in the thecal fibroblasts of yellow large follicles. The presence of calmodulin in steroidogenic and contractile tissues suggests that calcium and calmodulin system is involved in steroidogenesis and contraction of the follicular wall.

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Debeaking treatments were conducted at 1 (1WD) and 5 (5WD) weeks of ages, respectively. The tips of upper and lower beaks were removed at 3mm (1WD) or 5mm (5WD) by electrically heated debeaker. Regeneration of the upper beak was observed morphologically and histologically on subsequent weeks of age.
There were two chicken groups namelly depressed and non-depressed groups in regeneration of the beak in each treatment. The length of the beaks regenerated of the both groups of 1WD was significantly shorter (p<0.01) than that of the non-debeaked control chicks at 11 and 16 weeks of ages. At 11 weeks of age, the length of the depressed group of 5WD was shorter (p<0.01) than that of the control chicks and no difference was observed in the length of beak between the non-depressed group of 5WD and the control chicks. No significant difference was observed in the length between the depressed group of 5WD and the control chicks at 16 weeks of age. But the length of the non-depressed groups of 5WD at the same weeks of age was significantly longer (p<0.01) than that of control chicks. A few number of beaks (2 out of 19 chicks) of 1WD and all beaks (21 chicks) of 5WD were required to debeak again on subsequent weeks of age.
The tip of incisive bone including ossification zone of the chicks of 1WD was removed by debeaking. After debeaking, ossification was observed in the bone remained. However, the order of ossification was disturbed by debeaking. It is evident that the disorder of ossification in the incisive bone artribute to depress regeneration of the beak after debeaking. While debeaking at 5 weeks of age (5WD), a part of ossification zone in the bone was not removed or no injury was observed in the tip of the bone. Then, the ossification was occurred normally in the bone after debeaking.

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Annual changes in the reproductive ability of female guinea fowls under natural photoperiod were investigated. Six female guinea fowls were reared from May, 1986 to May, 1987 (from age 207 to age 603 days old) in individual cages and supplied with food and water ad libitum. Egg laying was recorded every day. The body weight and plasma concentrations of progesterone (P), testosterone (T) and estradiol (E2) were measured every two weeks.
The following results were obtained.
1. The mean body weight was maintained at more than 2.4kg from early May to late September, and decreased to minimum (2.27±0.103kg; mean±S.E.M.) in October. Thereafter it increased gradually until the following April.
2. Egg laying was concentrated in the period between April and September (Hen-day egg production rate: 49.3%). Molting was observed from late September to early November. After the molting, only one bird laid again from December through January.
3. The mean plasma concentrations of P, T and E2 maintained high levels during the egg-laying period (P: 666±40.7pg/ml, T: 390±16.2pg/ml, E2: 175±14.4pg/ml). Although the plasma concentrations of P, T and E2 increased temporarily (P: 392±80.7pg/ml, T: 894±56.7pg/ml, E2: 244±34.2pg/ml) in the latter period of the molting, the mean concentrations of these sex steroids showed the lowest levels (P: 84 ±7.5pg/ml, T: 177±40.2pg/ml, E2: 37±6.4pg/ml) during the molting period. The mean plasma concentrations of P, T and E2 during the non-laying period were 195±30.3pg/ml, 293±28.2pg/ml and 84±9.9pg/ml, respectively.

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The W chromosome specific repetitive DNA units were detected easily by the XhoI digestion of genomic DNA, purified from a female whole blood sample, but could not be detected in male. Since the red blood cells of the chicken are nucleated, it is possible to obtain enough amounts of DNA preparation from a small volume of whole blood without sacrificing the animal. The detection of the female-specific repetitive DNA units is simple, reliable and efficient. By applying this technique, the identification of the sex in chickens was easily achived.

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The study reported here was undertaken to evaluate the effect of disinfection on the slats placed in a specific pathogen free (SPF) chicken house.After washing, 10^3.3/cm² of bacteria were detected from the slats. Two kinds of disinfectant solution, invert soap and iodophor were used. Each disinfectant was diluted 1: 500 and sprayed 2l per slat. The bacterial counts reduced to 10^2.8 and 10^2.6 per 1cm² after spraying invert soap and iodophor solutions, respectively. When spraying was carried out repeatedly, the invert soap first and next the iodophor solutions, the counts reduced 10^1.4/cm².After 48 hours fumigation by formaldehyde liberated from 40ml of folmalin mixed with 20g of potassium permanganate per 1m³ of capacity, no bacteria were detected from the slats which had been sprayed two kinds of the disinfectant solution mentioned above.

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