Ancient Egyptians used pigeons not only as food in the form of squab but also as a messenger by virtue of their strong homing ability. Pigeons are bred for many purposes like meat in the form of squabs, exhibition as fancy and ornamental, flying and sports like racing competition, and finally for laboratory experiments of cognitive sciences. In this study, a total of 133 pigeon samples of six Egyptian breeds (n=110) and Japanese racing pigeons (n=23) were surveyed. One sample from each breed was sequenced for mitochondrial COI gene and all samples were genotyped across 11 microsatellites loci. From COI sequence, all the seven studied populations were found to belong to same the species (Columba livia). By the analysis of 11 microsatellite loci a total of 89 alleles were observed with an average of 8.1 alleles per locus. The expected heterozygosities of the six Egyptian breeds and Japanese racing pigeons were 0.580 and 0.630, respectively. F_ST showed a relatively high mean of 0.203 which indicated that there is a great differentiation among the seven pigeon populations. Zagel breed and Japanese racing pigeons showed the lowest values for both pairwise F_ST (0.108) and Nei's genetic distance (0.154). The information from this study would be useful for genetic characterization and provide a foundation for developing sustainable genetic improvement and conservation programs of this agriculturally and commercially important species.

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Global demand of corns for feed and fuel will be increasing at a rapid pace in the near future. Rice is one of the candidate cereals as a substitute of corn. However, the amino acid digestibility of rice in the gastrointestinal tract in chickens has not yet been investigated. The present study was conducted to investigate the amino acid digestibility of hulled rice using fistulized chickens. Chickens were fistulized to either the distal end of the jejunum, the middle part of the ileum, the distal end of the ileum or the distal end of the rectum. Intestinal digesta were collected from each site of the intestines, and the contents of amino acids were measured. Chickens were fed a rice diet, a rice-fish meal diet or a corn-based diet. There was no significant difference in the true digestibilities of all measured amino acids between the sites of chicken intestines. However, the true digestibilities of all measured amino acids without arginine of the rice diet were significantly higher than those of the corn-based diet. The true digestibilities of all measured amino acids without tyrosine of the rice-fish meal diet were significantly higher than those of the corn-based diet. These results suggest that rice might be used as a substitute of corn in chicken feed.

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A relationship between skeletal muscle proteolysis and mRNA expression of atrogin-1/MAFbx, a muscle-specific ubiquitin ligase, was examined in food-deprived broiler chickens. In response to food deprivation for 24 and 48h, body and muscle weights decreased in a time-dependent manner. Muscle free N^τ-methylhistidine content, an index of myofibrillar proteolysis, was 1.8-fold and 2.5-fold greater than that of fed controls following 24 and 48h of food deprivation, respectively. Gene expression of atrogin-1/MAFbx drastically increased in response to food deprivation in a time-dependent manner. At 48h of food deprivation, the induction of atrogin-1/MAFbx mRNA expression level elevated up to 20-fold greater than that of fed controls. By contrast, mRNA expression levels of 20S proteasome C1 and C2 subunits tended to decrease with time. No significant difference was seen in the change of ubiquitin mRNA expression. A highly significant linear negative relationship (r²=0.754, P<0.001) was found between atrogin-1/MAFbx expression and muscle mass, while a highly significant linear positive relationship (r²=0.784, P<0.001) was found between atrogin-1/MAFbx expression and muscle free N^τ-methylhistidine content. These results indicate that atrogin-1/MAFbx plays a critical role in the development of muscle proteolysis and its gene expression is a reliable index of muscle proteolysis in broiler chickens.

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Two incubation and two growing trials were carried out. A total of 1000 (Trial 1) and 1897 (Trial 2) eggs of the ROSS (308) strain were incubated from d 1 to 17 under normal conditions and from d 18 until hatch as follows: 37.2 to 37.4°C (control), 38.2 to 38.4°C for 24h daily (chronic warm incubated) and 38.2 to 38.4°C for 2h daily (short term warm stimulated). In incubation Trial 2, the chickens were sorted by sex. Chick quality was analysed by the Pasgar score. In the 35 day growing Trial 1, a total of 240 one day old chickens and in Trial 2 a total of 120 male and 120 female chickens from all incubation groups were kept at 34°C at d 1 and 2, and from d 3 up to the age of 35 days, at 32°C. The results of the two incubation trials showed that chronic or short-term increase in incubation temperature at the end of incubation did not diminish hatchability and chick quality. The data indicates different effects of chronic and short-term warm incubation as well as warm growing conditions on the performance of female and male broiler chickens. Female chickens seem to be better adapted to warm growing conditions and show a higher tendency in performance parameters (feed intake, body weight gain, and body weight) during the final growing period. In male chickens exclusively chronic warm-incubation leads to a lowered daily feed intake in the final growing period which results in the lowest fattening weight of 1332g per animal (control: 1476g, short term warm incubated: 1482g). A lower feed intake decreases the bodily heat production and can help to minimize heat stress. At slaughtering (Trial 2), the percentages of breast meat, liver, heart, stomach, spleen and fat showed no statistical difference between the groups or sexes.

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A novel and simple method for isolating viable gonadal germ cells (GGCs) was developed in the domestic chicken, Gallus domesticus. Developing gonads were isolated from 7-day-old chick embryos and cultured for up to 24 hours at 37.8°C in phosphate buffered saline without Ca²⁺ and Mg²⁺ (PBS[−]). A discharge of GGCs from the gonad was observed within 30 minutes after introducing the embryonic gonad into PBS[−], and the number of discharged GGCs increased until 12 hours of incubation. The purity of the GGCs (number of discharged GGCs/total number of discharged cells) was approximately 50% for the initial 1.5 hours of incubation and decreased thereafter. The number of discharged GGCs from the left gonad was significantly higher than that from the right gonads in females. Fifty discharged GGCs in PBS[−] were injected into the blood stream of 2-day-old chick embryos after staining with PHK26 fluorescent dye. GGCs exhibiting a fluorescent signal were detected after incubating recipient embryos for 5 days.
These results indicate that high-purity, viable GGCs can be collected by simply introducing isolated developing gonads into PBS[−].

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Testicular gonocytes differentiate into spermatogonia and spermatogonial stem cells could be established by culturing spermatogonia in vitro. Spermatogonial stem cells differentiate exclusively into spermatozoa and thus they are very useful for genetic manipulation in chickens. The present study was carried out to examine the possibility of in vitro proliferation of testicular and ovarian gonocytes in chickens. Gonads were obtained from 19-day incubated chicken embryos and the dissociated gonadal cells were cultured in vitro. Then, non-adherent cells containing gonocytes were collected and cultured further. It was confirmed that a part of the testicular gonocytes proliferated in vitro, when analyzed by anti-CVH antibody. The proliferated testicular gonocytes occasionally formed cell colonies. The cultured testicular gonocytes were successfully implanted in the gonads by transferring them into the coelomic epithelium that corresponds to the future gonadal region of recipient embryos. However, no apparent proliferation was observed in the ovarian gonocytes in vitro. These results suggest that testicular goncytes can be cultured in vitro and are one of the candidate cells for genetic manipulation in chickens.

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The structure and mineral composition of eggshell cuticles were studied in 5 species of birds. The approximate thickness of the cuticle layer at the top of shell columns was about 1μm in the Red Junglefowl (Gallus gallus), about 130μm in the White Pelican (Pelecanus onocrotalus), about 10μm in the Japanese quail (Coturnix japonica), about 110μm in the Greater Flamingo (Phoenicopterus ruber roseus) and about 45μm in the Humboldt Penguin (Spheniscus humboldti). The matrix of the cuticle layer decalcified with EDTA was composed of vesicles in a variety of sizes in all birds. Major elements in cuticle materials detected by X-ray microanalysis were O, C, Ca and P, and their percentage numbers of atoms decreased in this order. The concentration of P was significantly higher in the cuticles of the quail, flamingo, and penguin than in those of the junglefowl and pelican. Ca mapping on electron-microscopic images showed strong signals in the shell layer and weaker ones in the cuticle layer, whereas P mapping showed that signals were mostly confined in the cuticle layer. X-ray diffraction analyses on the inside of the shell layer showed a profile of calcite crystals of calcium carbonates in all birds. In the cuticle materials, the profile was of calcite in the junglefowl, and a mixture of calcite and vaterite in the pelican. The profiles in cuticle materials of the quail, flamingo and penguin showed no specific signals, indicating that mineral compounds are amorphous in these forms. It was suggested that the diversity of mineral structures in the cuticle layer is caused by the presence of phosphorous, in addition to the structure of the cuticle matrix.

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It is important to quantify and estimate stressful stimulation because stress appears to limit productivity and welfare in poultry. The purpose of this study is to investigate the effect of acute isolation stress (5, 10 or 30min) on the levels of blood parameters (glucose, free fatty acid (FFA) and corticosterone (CORT)) and diencephalic stress related peptide gene expressions (corticotrophin-releasing hormone (CRH) and arginine vasotocin (AVT)) in neonatal chicks. Although the isolation treatment did not affect concentration of plasma glucose (P>0.05), plasma FFA at 30min after treatment was higher than control (P<0.01). The level of CORT increased significantly after 5 and 10min of treatment (P<0.01), but that significant increase had disappeared in the chicks isolated for 30min. The expression level of CRH in the chicks treated for 10min, but not in the chicks treated for 5 and 30min, was higher than in control (P<0.01), whereas there was no change in AVT mRNA for any of the isolation treatments (P>0.05). These findings demonstrate that high levels of CORT, through negative feedback, decrease CRH synthesis until 30min after isolation, and further suggest that AVT expression in the diencephalons may not be applicable as an indicator of acute isolation stress in neonatal chicks.

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Ghrelin is a prolactin (PRL)-releasing factor in animal species. The aim of this study was to investigate the effects of in ovo ghrelin administration on plasma PRL levels in hatched chicks. We divided 350 fertilized eggs into 7 groups: group T1 as the control (without injection), group T2 (in ovo injected with solvent: 1% acetic acid, without ghrelin on day 5), group T3 (in ovo injected with solvent without ghrelin on day 10), group T4 (in ovo injected with 50ng/egg ghrelin on day 5), group T5 (in ovo injected with 100ng/egg ghrelin on day 5), group T6 (in ovo injected with 50ng/egg ghrelin at day 10) and group T7 (in ovo injected with 100ng/egg ghrelin at day 10). After the eggs hatched, we determined serum PRL concentrations. Group T6 and T7 showed significantly higher serum PRL levels (1.18 and 1.19ng/ml, respectively) compared with groups T1, T2, T3, T4 or T5 (0.87, 0.86, 0.89, 0.90 and 0.90ng/ml, respectively). This result suggested that in ovo administration of ghrelin on day 10 affects PRL release in newly hatched chicks, while ghrelin administration during the early embryonic period (day 5) could not.

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A study was conducted to investigate how ammonia (NH₃) emission of laying hen manure is affected by manure accumulation time (MAT). Three trials were conducted. For each trial, 108 W36 laying hens in their prime laying stage were housed in two calorimeter chambers (54 birds per chamber) that were maintained at a temperature of 24±1°C and a concomitant relative humidity of 45 to 65%. Measurements were done continuously over a 5-week period. The environmental variables measured continuously in each chamber included NH₃ gas concentration, ambient temperature, dew-point temperature and air flow rate. On a daily basis, the eggs were collected, counted and weighed. The feed supplied to the birds was also weighed daily. Once a week, 18 hens per chamber were weighed. Ammonia emission rate was then calculated from the differences in NH₃ concentrations between the exhaust and inlet air and the corresponding airflow rate; and it was expressed as mg·d⁻¹·hen^-1, g·d^-1·AU^-1 (AU=animal unit, 500kg live body weight), g·d⁻¹·kg egg^-1, and g·d^-1·kg feed N intake^-1. The results showed that NH₃ emission progressively increased from 101±10 to 605±10mg·d⁻¹·hen^-1 when MAT increased from 1 to 5d. There was a linear relationship between NH₃ emission rate and MAT and the empirical relationship has been developed for the various emission units. The NH₃ emission rates measured in this study contributes to the U.S. national inventory on NH₃ emissions from laying hen operations.

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This study was conducted to evaluate the effects of adding ferrous sulfate, aluminum sulfate (alum) and aluminum chloride to poultry litter on pH and volatile fatty acids (VFAs) in a laboratory study. The treatments utilized in this study included an untreated control, 8g of FeSO₄, 8g of alum, and 8g of AlCl₃/100g of litter. All three chemicals reduced total VFAs, as well as individual VFA concentrations for most times. However, no significant differences were observed (P>0.05) among all treatments in acetic acid at 1 week and n-butyric acid content at 2 weeks. The reduction in total VFAs and acetic acid concentrations obtained from litter over time was in following order: 8g of AlCl₃/100g of litter>8g of alum/100g of litter>8g of FeSO₄/100g of litter>Control. When compared to the controls at 3 weeks, total VFA production was reduced by 14, 33, and 42%, respectively, with 8g of FeSO₄, alum, and AlCl₃/100g of litter. Likewise, application of 8g FeSO₄, alum, and AlCl₃/100g of litter decreased acetic acid by 9, 25, and 39%, respectively. These results would help to fill a need for a technical method suitable for decreasing the negative environmental impact of poultry litter.

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