Antibody production against a T cell-dependent antigen (goat red blood cell) and a T cell-independent antigen (killed Brucella abortus) was examined in chicks treated with estrogen in which eggs were dipped into ethyl alcohol solution containing β-estradiol. Relative weights (organ weights/body weight) of the primary lymphoid organs of chicks were also determined. Secondary antibody production against goat red blood cells (GRBC) was significantly increased by treating chick embryos with high doses of estrogen (1.0% solution) on the 4th day of embryogenesis. Primary and secondary antibody responses against killed Brucella abortus (BA) were dose-dependently increased with estrogen treatment on the 4th day of embryogenesis. In contrast, primary and secondary responses against BA of chicks treated with estrogen on the 14th day of embryogenesis were significantly suppressed. Thymus weight significantly increased in chicks treated with estrogen on the 4th day of embryogenesis. The rate of CD4-positive cells in the chick thymocytes significantly increased with estrogen treatment on the 4th day of embryogenesis. On the other hand, the weight of the bursa of Fabricius significantly decreased when treating chick embryos with high doses of estrogen (1.0%) on the 14th day of embryogenesis. Results from the present study indicated that estrogen treated at different stages of embryogenesis exerts discrete effects on B cell differentiation in the bursa and helper T cell differentiation in the thymus of chick embryos.

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We investigated genetic relationships of nine Japanese native chicken breeds (Oh-Shamo, Ko-Shamo, Yakido, Kinpa, Koeyoshi, Minohiki, Satsuma-dori, Hinai-dori, and Shoukoku) coupled with one foreign breed (White Leghorn) by means of microsatellite profiling technique. Excepting the Shoukoku breed, the other Japanese breeds are classified as Shamo or Shamo-related breeds. Genetic variabilities of 20 microsatellites examined varied depending on the breeds, as the number of alleles per locus, proportion of polymorphic loci, and mean expected heterozygosity ranged from 1.65 to 4.70, 0.50 to 1.00, and 0.206 to 0.670, respectively. Microsatellite alleles being unique to a particular breed were detected in all breeds. Attempted phylogenetic tree reconstruction based on the genetic distance estimated for all possible population combinations revealed that the genetic divergence was evident between the Japanese breeds and the foreign breed. Within Japanese native breeds, three groups could be differentiated : (1) Oh-Shamo and Ko-Shamo, (2) Yakido, Kinpa, and Koeyoshi, and (3) Minohiki and Shoukoku. The Satsuma-dori and Hinai-dori were located far from these 3 groups.

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The effect of ultraviolet (UV) irradiation on the ability of primordial germ cells (PGCs) to migrate toward the gonadal ridge was investigated in the domestic chicken.
When PGCs were irradiated with UV (254nm, 0.9±0.1μW/cm²) the extent of nuclear damage, as determined by the comet assay, was positively correlated with the duration of UV irradiation in the range from 0 to 60 seconds. However, no further increase in nuclear damage was detected when the duration of UV irradiation was extended from 60 to 120 seconds.
To evaluate the migratory ability of PGCs after UV irradiation, 15 fluorescent-labeled PGCs were transferred into the vascular system of 2-day-old embryos and the fluorescent-labeled PGCs present in the gonads of recipient embryos were counted 5 days later. When the duration of UV irradiation was less than 60 seconds, the number of fluorescent-labeled PGCs found in the gonads of the recipient embryos exceeded the number of transferred PGCs.
In conclusion, the ability of PGCs to migrate toward the developing gonad is retained after exposure to UV irradiation that causes apparent damage to the nucleus.

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This study was carried out to investigate the behavior and physiological conditions of hens housed in cages with or without perches. The physiological parameters investigated were heart rate (HR), body temperature (BT) and locomotor activity (LA) using a radiotelemetry system. Six White Leghorn hens (90-weeks-old) were used after transmitters implantation. Following the preconditioning period for at least 10 days, the behavioral and physiological data were recorded for 2 consecutive days, which were the data in the control cages without perches (C). After that, the same hens were exposed to the following types of cages : conventional cages with perches available all day (P24), followed by conventional cages with perches from 19.00 to 08.00 hours (P13), and finally housed in conventional cages with perches from 19.00 to 04.00 hours (P9). The interval between each trial was a 10 days to habituate the hens with their new environment. Immediately following this, the behavioral and physiological data were recorded for 2 consecutive days for each trial. The only significant behavioral difference was found in the time consumed in resting, which increased significantly in P24 cages than in C and P9 cages (P<0.05). Our physiological data during the light period indicate that the hens in P24, P13 and P9 cages had a significantly higher heart rate than in C cages (P<0.01). On the other hand, hens in P24 cages had a significantly lower BT than in C, P13, and P9 cages (P<0.01), however, hens in P24 cages had a significantly higher LA than in C, P13 and P9 cages (P<0.01). Moreover, during the dark period, hens in P24 cages had a significantly lower HR, BT and LA than all the other treatment (P<0.01). These results suggest that the use of cages with perches might be important for the hens’ welfare than those without perches.

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Changes in plasma constituents in the crossbred (aigamo) duck (female Japanese mallard duck × male mallard) were successively investigated at two-week intervals during winter from December to March. The pattern of changes in plasma triacylglycerol and glucose were similar over this period. A good correlation between plasma total protein and albumin was detected, but the trend in plasma uric acid correlated better with triacylglycerol and glucose than with total protein and albumin. These five plasma constituents were more closely correlated with the average ambient temperature at 2-4 days before blood sampling than on the day of sampling itself, implying that the metabolic response of aigamo ducks to a change in temperature occurs slowly. The concentrations of plasma constituents recorded in aigamo ducks were similar to the mean values for wild and domestic ducks reported in previous studies.

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The goal of this study was to determine whether TGFβ receptors mRNA were expressed in the chicken anterior pituitary, and their expressions were changed during induced molting by the regulation of feeding. White Leghorn laying hens were subjected to induced molting. The anterior pituitary tissues were collected from hens of pretreatment (PT), 3d after withdrawal of feeding (3DWF), 1d and 5d after the resumption of feeding (1DRF and 5DRF, respectively), and on the day of resumption of egg-laying (RL). They were processed for semi-quantification of TGFβ receptors type II (TβRII) and type III (TβRIII) mRNA expressions by reverse transcription-polymerase chain reaction (RT-PCR). The TβRII and TβRIII mRNA expressions were observed in the anterior pituitaries in all groups of hens. The expression of TβRII and TβRIII βmRNA significantly declined in the 1DRF hens and recovered by the resumption of laying. These results suggest that TGFβs may play role as a local regulator of the glandular cell population and/or differentiation during induced molting.

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We investigated the efficiency of DNA extraction and the accuracy of polymerase chain reaction- (PCR-) based sexing of DNA that was obtained from adult chickens and early chicken embryos. DNA samples were prepared using water-, ammonium-, and proteinase-mediated extraction. PCR-based sexing was performed by amplifying a 276-bp fragment of the 717-bp W-chromosome-specific XhoI repetitive sequence. In blood samples from adult chickens, the time required for DNA extraction using the three aforementioned methods was less than that required by the conventional method of using phenol/chloroform/isoamyl alcohol (PCI). Accurate PCR-based sexing was possible using DNA samples that were prepared using the ammonium and proteinase methods. PCR-based sexing was successful for DNA samples from a 2-day-old embryo and the small intestine, gonad, and kidney of a 7-day-old embryo that were extracted using the ammonium and proteinase methods. However, DNA from the gonads of the 7-day-old embryo could not be sexed reliably using the ammonium method. In summary, the ammonium and proteinase methods are simple and practical means of extracting DNA for PCR-based sexing, but the reliability of sexing after use of the ammonium method should be checked when DNA samples have not been used previously for sexing.

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