In this study a selection experiment was carried out in order to investigate the effectiveness of index selection including oviposition time as a selection trait for persistency of laying strain building in laying hens. The selection was applied by using an index consisting of age at first egg (SM), egg weight at 270 days of age (EW) and the rate of lay from 151 to 270 days of age between 06.00 and 11.00 h (6-11EP) under 14 hour light-10 hour dark cycle (photo period; 06.00 to 20.00 h).
After six generations of index selection, 6-11EP showed significant change, therefore short-term rate of lay from 151 to 270 days of age (SEP) and long-term rate of lay from 151 to 400 days of age (LEP) both improved significantly. Realized genetic gains per generation (P<0.01) were : 6-11 EP, 3.0%; SEP, 0.9%; LEP, 1.3%; rate of lay from 151 to 270 days of age between 11.00 and 20.00 h (11-20EP), −2.1%; residual-term rate of lay from 271 to 400 days of age (REP), 1.6%. Realized genetic gains were higher in 6-11EP than in SEP and LEP. However, improvement was not obtained in SM and there was not a marked genetic change in EW. The pooled heritability estimates for LEP and SEP were similar, 0.19 and 0.15 respectively, however the heritability estimate for 6-11EP was higher at 0.41. The genetic correlations pooled over 6 generations between LEP and egg production traits were all high and positive except 11-20EP: 6-11EP, 0.51; SEP, 0.71; REP, 0.94; 11-20EP, −0.25.
These results indicated that rate of lay including oviposition time are useful as selection traits. Therefore, the index selection consisted of 6-11EP was successful in persistency of laying strain building.

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The present experiment was designed to investigate a possibility of the in vitro cultured somatic cells to produce the germ line interspecific chimera in bird. The frozen-thawed fibroblast-like cells derived from a male 9-day embryo of Indian peafowl were cultured and treated with polyethylene glycol(PEG, mw8000). The treated cells were injected into the blastoderm of unincubated fertile White Leghorn eggs(at stage X). The manipulated eggs were incubated until hatching. A total of 108 White Leghorn eggs were manipulated with the injection of about 800-1600 peafowl cells for each egg. The chimerism was assesed by observation of the plumage and DNA analysis. To do DNA assay, peafowl mitochondrial cytochrome b (cyt b) gene carrying species-specific DNA loci with 418 bp fragments was adopted as a genetic marker. Of 108 manipulated eggs, only four hatched and two of them revealed partially pigmented feather mosaicism, denoting the existence of peafowl-specific cyt b gene in the feather pulp. In addition, the peafowl-contributed mosaic tissues were also found in the muscle, testis and ovary of dead embryos and one chick. The present results demonstrate that the cultured peafowl fibroblast-like cells, which were treated with PEG before the injection into the blastoderm of White Leghorn eggs, differentiated and integrated into the recipient tissues during embryonic development. This experiment also suggests that intersepcific chimera birds may be produced by using this method in the future.

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Six Single Comb White Leghorn laying hens (Shaver, Star cross 288) were used to estimate heat production (HP) for physical activities under different lighting regimes (LR) of 12L : 12D, 14L : 10D and 16L : 8D, respectively, fed ad libitum at 25°C. HP of each hen was measured by an open circuit indirect calorimeter for 48 h in each LR. Activity count (ACT), standing time (STN) and eating time (ETN) were also measured for the same 48 h. ACT was measured by the Actigraph, while STN and ETN were detected by the infra-red beam switches. The daily food intake (FI) did not vary significantly with the increase of LR. The daily ACT and STN increased significantly (P<0.05) during 16L : 8D in comparison with that of 12L : 12D, and HP had an increasing tendency with the increase of LR. LR may have no clear effect on the increase of HP. Physical activities increased with the increase of LR. Consequently, HP was also increased with the increasing ACT and STN. But the increase of daily HP for ACT and STN was 7 and 8 kJ/kg^0.75, respectively, which is very little. ACT-related energy expenditure was approximately 22% of the daily HP. Similarly, the estimated energy expenditure for STN was approximately 27% of the daily HP.

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Two experiments were conducted to ascertain the histological features in pituicytes and hepatocytes and the enzyme activities of liver and blood plasma at 8 weeks of age in Japanese quail (Coturnix japonica) exposed to high environmental temperature. The birds were divided into two groups. The control group was kept under a constant temperature of 26°C, and the heat stress group was kept at 40°C, with the same 60% relative humidity, for 2 weeks. The birds under heat stress became weary, showed higher panting and water consumption, and had lower body weight gain and feed intake than the control birds. The body temperature of the birds in both conditions was in the same range from 40.8 to 41.4°C.
The paraffin sections of the pituitary and liver, stained by HE and PAS, and the frozen sections, stained by Oil Red O, were used for ascertaining histological changes in the organs of two male and two female birds. Under heat stress, the testis, the ovary, and the liver of birds shrank. The pituicyte and hepatocyte changed in conformation, shape, size and amount of lipid droplets. The nucleus conformation shrank. The cytoplasm surrounding the nucleus showed a peripheral pallor and signs of necrosis, and the composition became acidic. The liver and pituitary showed a decrease in the size and amount of small and large of lipid droplets. Enzyme activities were obtained from four male and four female birds. The glutamic pyruvic transaminase (GPT), glutamic oxaloacetic transaminase (GOT), and lactic dehydrogenase (LDH) enzymes in the blood plasma of the birds exposed to high temperature in both sexes increased significantly (P<0.01). However these enzymes decreased significantly (P<0.01) in the liver due to heat stress. This study showed that there were the histological features of the hepatocyte changes resulting from prolonged heat stress. It is reasonable to assume that the functional reserves of the liver which are needed to serve the physiologically demanding reproductive processes in the birds are sufficiently depleted under heat stress to cause a shortage of materials needed to fully support these processes.
This study suggests that heat stress has an effect on the pituicytes and hepatocytes, bringing about necrosis, and that the GPT, GOT, and LDH decrease in the liver, but increase in blood plasma in Japanese quail.

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Effect of L-ascorbic acid phosphate magnesium (APM) on chicks injected radical initiator, 2, 2′-azobis(2-amidinopropane) dihydrochloride (AAPH), was examined. Chicks were fed APM as ascorbate resource for 7 days. Birds were administrated AAPH by intraperitoneal injection after APM feeding. The changes of ascorbate and thiobarbituric acid reactive substances (TBARS) in plasma and liver were determined before, and 3 and 6 hours after AAPH injection. Both plasma and liver ascorbate increased by APM feeding. After AAPH injection, liver ascorbate decreased, but plasma ascorbate increased in both control and APM-fed birds. AAPH administration raised liver TBARS, but decreased plasma TBARS. Both plasma and liver TBARS were lower in APM group than control group before and after AAPH administration. Peroxyl radical trapping activity in plasma was elevated by APM feeding as compared to control group. APM was utilized as ascorbate, and was effective for prevention of oxidative stresses derived from AAPH by increasing plasma and liver ascorbate and plasma radical trapping activity.

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This study examined whether chicken seminal fluid was a useful diluent for quail sperm. Both sperm motility and progressive motility, when diluted with chicken seminal fluid (90.4% and 54.6%), were significantly higher than those of Lake solution supplemented with 0.005% caffeine and 10% quail cloaca fluid (80.1 and 41.6%), respectively. This result suggested that chicken seminal fluid colud be used as an effective diluent for the analysis of quail sperm motility.

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Intracerebroventricular (i.c.v.) injection of corticotropin-releasing factor (CRF) on monoamine contents of the paraventricular nucleus of the hypothalamus (PVN) was investigated in neonatal chicks. The PVN was isolated from the brains of neonatal chicks 15 minutes after the i.c.v. administration of 0, 0.01, 0.1 or 1μg of CRF. The concentrations of noradrenaline, adrenaline, dihydroxyphenylacetic acid, dopamine, 5-hydroxyindole-3-acetic, homovanillic acid and 5-hydroxytryptamine were determined. The monoamines and their metabolites showed some alterations, but the differences were not significant among all treatments. The results suggested that CRF did not affect the monoamine contents of the PVN in the neonatal chick.

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The objective of this study was to determine if the bore diameter of needles used for in ovo injection of amino acids (AA) would affect subsequent chick hatchability. In Experiment 1, needles of different bore diameter were inserted into the egg. In Experiment 2, needles of different bore diameter were used to administer an AA solution that is identical to the AA pattern of the whole egg protein. In both experiments, 27, 24, 22, 20, and 18 gauge needles were tested. Needles were inserted to a depth of 13 mm in both experiments. Non-injected eggs were served as control in each experiment. Needle bore diameter did not affect (P<0.05) hatchability or body weight (BW) of hatched chicks in either experiment.

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