• Korean Journal of Poultry Science
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• v.37 no.2
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• pp.139-143
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• 2010

Quail is a very useful animal model for studying vertebrate development because of its small body size and unique reproductive traits. This species is also ideal model for producing germline chimeras via transferring exogenous primordial germ cells (PGCs) into the recipient embryo. To increase the contribution efficiency of donor PGCs into recipients' tissues, decreasing the population of endogenous PGCs has been rate-limiting factor. We therefore conducted this study to investigate if gamma ($\gamma$)-irradiation depletes endogenous PGCs in developing quail embryo. Firstly, freshly laid stage X quail embryos were irradiated with various output of $\gamma$-irradiation and its teratogenic effect on the embryo was evaluated. Although a dose-dependent increase in the number of embryo showing malformation was found as the output increased (0, 250, 500, 750, and 1,000 rads), only a maximum of 10.1% of embryos were abnormal in 1,000 rads. Immunocytochemical analysis using the QCR1 antibody, which is specific marker for quail PGCs, was conducted to analyze the effect of sterilization. As results, $\gamma$-rays at a dose-rate of 500 rads/73 sec onto undeveloped stage X embryo significantly reduced the number of germ cells to an average of 75.55 % and 82.03 % in male and female embryos, respectively. We conclude that $\gamma$-ray selectively targets PGCs while affects minimally to the somatic development in quail embryo. Our results will not only provide important data for germline chimera production but can be used for analyzing the effect of ionized rays on the differentiating germ cells in various stages during animal development.

• Korean Journal of Poultry Science
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• v.37 no.2
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• pp.145-150
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• 2010

This study was conducted to evaluate effects of dietary Agariemycetes on egg quality and fecal noxious gas concentration in laying hens. A total of two hundred forty laying hens were randomly allocated to four treatments with five replicates of twelve chicks per pen. The experiment lasted 42 days with a 7-day adjustment period. Dietary treatments were as follows: 1) CON (basal diet), 2) A1 (basal diet + Agariemycetes 0.1%), 3) A3 (basal diet + Agariemycetes 0.3%) and 4) A5 (basal diet + Agariemycetes 0.5%). There was no significant difference in egg production and egg weight between CON and Agariemycetes treatments. During the second week of the experiment, eggshell breaking strength was higher in A3 and A5 treatments than that in CON treatment (P<0.05). Besides, eggshell breaking strength in P5 treatment was higher when compared with that in CON treatment (P<0.05) in the sixth week. During the second week of the experiment, eggshell thickness was higher in Agariemycetes treatments than CON treatment (P<0.05). Also, A5 treatment was higher than other treatments in the fourth week of the experiment (P<0.05). At the end of the second week, yolk color unit in A5 treatment was lower compared with CON treatment (P<0.05). During the fourth week of the experiment, CON treatment was higher than A3 treatment (P<0.05). During the second week of the experiment, Haugh unit in A3 treatment was greater than that in CON treatment (P<0.05). At the end of six weeks, Haugh unit in CON treatment was lower than other treatments (P<0.05). Fecal ammonia and hydrogen sulfide were increased in Agariemycetes treatments when compared with CON treatment (P<0.05). Compared with CON and A5 treatments, fecal mercaptans was higher than in other treatments in first of the experiment (P<0.05). In conclusion, this study indicated that the addition of Agariemycetes in the diet improved the egg quality and decreased the feacal noxious gas concentration in laying hens.

• Korean Journal of Poultry Science
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• v.34 no.2
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• pp.151-156
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• 2007

The Function of the calcium sensing receptor (CaSR) is to control calcium levels by altering PTH (parathyroid hormone) secretion and renal calcium resorption. The influence of calcium on the basal and stimulated release of several hormones from chicken pituitary glands has been determined in vitro. The objective of this study was to identify SNP in chicken CaSR gene and to investigate the effect of the SNP on economic traits. The sequencing analysis method was used to identify nucleotide polymorphisms within chicken CaSR gene. This study identified SNP at position 1949 bp(Genebank accession No : XM_416491) in the exon 1. The SNP changed the amino acid to alanine(GCC) from serine(TCC). This SNP showed three genotypes, AA, AS and SS by digestion with the restriction enzyme NcoⅠ using the PCR-RFLP method. The A963S showed significant effect only on the first lay day (P<0.05) in Leghorn population. Leghorn with the genotype AA had significantly faster the first lay day(137.6) than the genotype AS(143.0, P<0.05). Also, the A963S showed significant effect only on the first lay day(P<0.05) and mean of egg weight(P<0.05) in KNC population. KNC with the genotypes AA ans AS had significantly faster the first lay day (151.0 and 152.6, respectively) than the genotype SS(159.4, P<0.05). And the genotypes SS had significantly heavier the mean of egg weight(50.4 kg, P<0.05) than the genotype AA ans AS (47.5 and 47.8 kg, respectively). According to result of this study, an a allele of the A963S was found to have a significant effect on the first lay day. It will be possible to use this SNP marker on selecting chicken to improve the first lay day.

• Korean Journal of Poultry Science
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• v.34 no.2
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• pp.111-117
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• 2007

This experiment was conducted to research the effects of Yellow Clay(YC) on the sensory evaluation of cooked meat in broiler chicks. A total of 216 one day old broiler chicks were divided into 6 groups at random. The six groups are consisted of one control group, to which no YC was added, and 5 groups to which an amount of YC was differently added. Diets contained 0.5, 1.0, 2.0, 4.0 and 8.0% of YC and fed to the 5 group broilers for 6 weeks. The lightness of meat in the broilers treated with YC was significantly higher than that of the control group in after-cooking(P<0.05). Besides, the lightness of meat was higher after-cooking than before-cooking. The properties of hardness, gumminess and chewiness were significantly lowered in the groups treated with Yellow Clay, as the amount of Yellow Clay increased at before-cooking and after-cooking(P<0.05). The turbidity of stock was higher in the groups treated with Yellow Clay as the percentage level of Yellow Clay increased, compared with the control group(P<0.05). The acceptability of color, flavor, and texture of meat and stock was higher in the groups treated with Yellow Clay, when compared with that of the control group(P<0.05). In total, the group treated with the 4 percentage of Yellow Clay was the highest in the overall preference(P<0.05).

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.261-270
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• 2014

This study was conducted to establish the method for preserving chicken primordial germ cells (PGCs) that enables long-term storage in liquid nitrogen ($LN_2$) for developmental engineering or preservation of species. The purpose of this study is to clarify the effects of simple freeze-thaw treatment on viability of PGCs in chickens and to the optimal protocol for PGCs freezing. PGCs obtained from the germinal gonade of an early embryos of 5.5~6 day (stage 28) of Isa Brown, Korean Ogye (KO), White Leghorn and Commercial breeds, using the MACS method were suspended in a freezing medium containing a freezing and protecting agents (e.g. dimethyl sulfoxide (DMSO), ethylene glycol (EG) and propylene glycol (PG)). The gonadal cells, including PGCs, were then frozen in 1 of the following cryoprotectant treatments : 2.5%, 5%, 10%, 15%, and 0% cryoprotectant (DMSO, EG, PG) as a control. Effects of exposure to simple freezing, with different concentrations of the cryoprotectant solution, were examined. After simple freezing, the viability of PGCs after freeze-thawing was significantly higher for Commercial breeds ($88.7{\pm}2.4%$) than KO ($85.1{\pm}0.4%$), Isa Brown ($84.6{\pm}0.2%$) and White Leghorn ($85.9{\pm}0.1%$) (p<0.05) using 10% EG cryoprotectant. Therefore, these systems may contribute in the improvement of cryopreservation for a scarce species in birds preservation. This study established a method for preserving chicken PGCs that enables systematic storage and labeling of cryopreserved PGCs in liquid ($LN_2$) at a germplasm repository and ease of entry into a database.

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.287-296
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• 2014

Chicken eggs undergo various physiological changes during egg maturation. To study genes associated with the egg maturation in pre-ovulation (immature) and post-ovulation (mature), we compared gene expression patterns between in the immature egg and mature egg using RNA sequencing data. Mature and immature eggs were obtained from a Heuksaek Jaerae-jong of Korean native chicken. Total RNAs obtained from the eggs were sequenced by Illumina HiSeq 2000 platform, and the generated sequence reads were mapped to Galgal4 reference sequence assembly using Tuxedo Protocol. From the comparison of the RNA sequencing data, 315 genes were differentially expressed between mature and immature eggs, and 46 genes were only detected in immature egg. Further gene ontology (GO) analysis was performed for the differentially expressed genes using DAVID, showing that 29 and 28 GO terms were independently clustered from mature and immature, respectively. From those clustered GO terms, genes related to germ cell development, sex differentiation and defense response to bacterium were mainly expressed in the immature egg, while genes related to regulation of apoptosis, steroid metabolic process and lipid homeostasis were mainly detected in the mature egg. Our results could contribute to understand egg maturation before and after ovulation, and develop genetic markers for improving egg quality and productivity.

• Korean Journal of Poultry Science
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• v.41 no.2
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• pp.93-98
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• 2014

This study was conducted to analysis the reason for implementing HACCP system, advantage and disadvantage of HACCP system implemented laying hen farm. The study was carried out by randomly selected fifteen laying hen farms located in all around Korea. All data were collected from fifteen laying hen farms before and after the implementation of HACCP system. The results were as follows: The egg production rate, livability rate and monthly used animal medicine fee did not changed after HACCP system implementation. However, monthly used disinfectant fee tended to be higher in HACCP farm compared to non-HACCP farm. 26.92% of the laying hen farmer responded enhancement of their farm competitiveness as the major propose for implementing HACCP system. The advantages of HACCP implemented laying hen farms were methodical farm management (22.39%), improvement of awareness (21.18%), improvement of the farm sanitation management level (15.30%), safety egg production (15.05%), productivity enhancement (7.29%), reduction of mortality rate (6.82%), and improvement of labor's welfare (5.89%). The disadvantages of HACCP implemented laying hen farms were HACCP recording (43.30%), alteration of consciousness (22.60%), HACCP monitoring (11.11%), HACCP education (9.97%), HACCP verification (6.90%), and A high turnover of labor (6.13%). In conclusion, implementation of HACCP system to laying hen farm did not affect on the productivity or the use of animal medicine. However, the HACCP system may enhance safety and sanitation of egg production for consumer.

• Korean Journal of Poultry Science
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• v.41 no.2
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• pp.77-85
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• 2014

This study was conducted to investigate the effect of duck and pork meat mixing ratio on quality characteristics of emulsion type sausage at $4^{\circ}C$ during 5 weeks. Treatments on the basis of the meat content were subjected to 100% duck meat (T1), 100% pork meat (T2), 50% duck meat + 50% pork meat (T3), 40% duck meat + 60% pork meat (T4), and 30% duck meat + 70% pork meat (T5). The moisture content was significantly (p<0.05) higher in TI sample but significantly (p<0.05) lower in T2 sample than those in comparison to the other treatments. Crude protein and fat content were significantly (p<0.05) higher in T2 sample compared to the other treatments. CIE $L^*$value was significantly (p<0.05) lower in T1 sample than those of other treatments until 5 weeks of cold storage. CIE $a^*$value was significantly (p<0.05) higher in T1 sample but significantly (p<0.05) lower in T2 sample than those in comparison to the other treatments until 5 weeks of cold storage. Hardness was significantly (p<0.05) higher in T4 sample compared to the other treatments during all cold storage. Cohesiveness was significantly (p<0.05) higher in T5 sample compared to the other treatments until 2 weeks of cold storage. The results of sensory evaluation showed that the meat flavor, taste and texture were significantly (p<0.05) lower in T5 sample compared to the other treatments whereas no difference among treatments except T5 sample. Overall acceptability was significantly (p<0.05) lower in T5 sample compared to the other treatments. Therefore, these results suggested that the ratio of 40% duck meat and 60% pork meat is appropriate levels for hardness and palatability when manufacturing emulsion type sausage with duck meat.

• Korean Journal of Poultry Science
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• v.41 no.2
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• pp.143-149
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• 2014

This study was conducted to investigate the effects of dietary supplementation of the mixture of probiotics (MP) on growth performance, size of small intestine, cecal microflora and ammonia concentrations in broiler chicks. A total of 700, one-day-old male broiler chicks were randomly allotted to four treatments with seven replications having 25 birds per pen. The birds were fed one of the four experimental diets; containing no antibiotics nor MP (negative control, NC), containing antibiotics without MP(positive control, PC), negative control with MP 0.1% and negative control with MP 0.2% for 5 weeks. During overall experiment, birds in PC and MP treatments had higher final BW and daily BW gains than birds in NC treatments; however, the significance was not identified. The feed conversion ratio of the chicks fed the diet containing MP was significantly improved as compared to those fed the NC diets. The weights of jejunum were increased by the MP (p<0.05), but weights of duodenum, ileum and length of small intestine were similar among the groups. Birds in PC treatment showed lower populations of total microbes and lactic acid bacteria than other groups (p<0.05), cecal ammonia concentrations of the chicks fed the diet containing MP were significantly decreased as compared to those of NC and PC (p<0.01). In conclusion, MP added to the broiler diets improved the feed conversion rate and reduced cecal ammonia concentration.

• Korean Journal of Poultry Science
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• v.41 no.2
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• pp.135-142
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• 2014

This study was conducted to evaluate dietary effects of Marigold extract on laying performance, egg quality, oxidative stability of egg yolk and lutein transfer into chicken eggs. A total of one-hundred eighty nine 55-wk-old Hy-Line Brown layers were divided into seven groups and fed control diet or each experimental diet containing 0.1, 0.3, 0.5, 1.0, 1.5 or 2.0% Marigold extract. Egg production, egg weight and daily egg mass were not affected by dietary treatments. The yolk colors in groups fed diets containing Marigold extract were significantly higher than that of control. The Haugh unit were tended to be improved by feeding of diets containing Marigold extract although there were no significant difference in egg shell strength and thickness. The MDA (malondialdehyde) contents in groups fed diets containing Marigold extract above 0.5% were significantly reduced than that of control. After 14d of storage, the Haugh unit values in groups feed diets containing 0.3 and 1.0% Marigold extract were significantly higher than that of control (p<0.05). The concentration of lutein in egg yolk increased by feeding of Marigold extract. When 2% Marigold extract was supplemented to the diet, lutein content of egg was increased as much as 1.71 mg/60 g. These results indicated that the use of Marigold extract in layer diets was effective in egg quality and for the production of lutein fortified eggs.