• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.4
• /
• pp.532-537
• /
• 2005

Increasing of body weight has been one of the important economic factors in the poultry industry. Insulin-like growth factor (IGF)-I is a polypeptide that serves to regulate muscle development and body growth. Moreover, IGF-I is related to feed efficiency. However, there are few studies regarding the regulatory roles of chicken IGF-I/-II compared with that of mammals. Especially, the Korean Native Ogol Chicken (KNOC) has a lean body growth and its body weight is generally lighter than the broiler chicken. Therefore, this study was conducted to investigate associations among serum IGF-I/-II concentration, feed efficiency, and body growth in KNOC. The body weight and feed intake of KNOC were recorded from 20 to 36 weeks at 2 weeks intervals, and blood was taken every 2 weeks. Serum IGF-I/-II were measured by RIA. Chickens were divided into two groups, high and low serum IGF-I concentration. Generally, feed efficiency and growth performance (body weight and weight gain) in the high serum IGF-I group were higher than those of the low group during the experimental period. In particular, the body weight of the IGF-I high group were significantly different from those of the IGF-I low group at 34 and 36 weeks, respectively (p<0.05). Moreover, body weight, weight gain, and feed efficiency had a significant correlation with serum IGF-I at several weeks (p<0.05 and p<0.01). These results show that IGF-I plays an important role in body growth and suggests a possibility that serum IGF-I could be used as a selection marker for body growth in KNOC.

• Proceedings of the KSAR Conference
• /
• 2002.06a
• /
• pp.17-17
• /
• 2002

There are considerable reports that the expression of insulin-like growth factor-Ⅰ (IGF-Ⅰ) is related to ovarian regulation and oviductal development in poultry. Korean Native Ogol Chicken (KNOC) have been inbred to keep a pure line so that there has been limitation in the improvement of egg productivity by genetic studies. Therefore, this study was conducted to investigate the early egg productivity of KNOC pre-selected by IGF-Ⅰ expression. (omitted)

• Korean Journal of Poultry Science
• /
• v.41 no.3
• /
• pp.191-196
• /
• 2014

The identification and utilization of potential candidate genes with significant effects on economically important traits have become increasingly important in poultry breeding programs. The ovocalyxin-32 (OCX-32) gene is located chromosome 9 in chicken, plays an important role in eggshell formation. This study was performed to assess the association between single nucleotide polymorphisms (SNPs) of OCX-32 gene and egg production traits in the Korean native chicken. Four Korean native chicken population (n = 181; including 46 females of Ogol, 46 females of white, 43 females of gray and 46 females of black) were used to analyze two SNPs (c.494A>C and c.267T>G) in the OCX-32 gene by PCR-RFLP (Polymerase Chain Reaction-Restricted Fragment Length Polymorphism). We measured egg production traits of age at first egg, first egg weight, egg production ratio and egg weight. The SNP c.494A>C was significantly associated with egg production ratio in Korean Ogol chickens (p<0.001) and egg weight in Korean white chickens (p<0.05). SNP c.267T>C was significantly associated with egg weight in Korean Ogol chickens (p<0.05). But there was no significant association in Korean gray and black chickens. Results suggest the possibility of using molecular markers in OCX-32 gene as a tool for performance and egg production traits in Korean native chicken breeding program.

• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.11
• /
• pp.1546-1550
• /
• 2006

The purpose of this study was to assess the genetic variation and establish the relationship amongst breeds and strains using 15 chicken specific microsatellite markers. A total of 285 unrelated DNA samples from four Korean native chicken strains (Black strain of Korean native chicken; KL, Red Brown strain of Korean native chicken; KR, Ogol strain of Korean native chicken; KS and Yellow Brown strain of Korean native chicken; KY) and three introduced chicken breeds (F strain of White Leghorn; LF, K strain of White Leghorn; LK, Rhode Island Red; RC and Cornish; CN) were genotyped to estimate within and between breed genetic diversity indices. All the loci analyzed in 15 microsatellite markers showed a polymorphic pattern and the number of alleles ranged from 5 to 14. The polymorphism information content (PIC) of UMA1019 was the highest (0.872) and that of ADL0234 was the lowest (0.562). The expected total heterozygosity (He) within breed and mean number of observed alleles ranged from 0.540 (LF) to 0.689 (KY), and from 3.47 (LK) to 6.07 (KR), respectively. The genetic variation of KR and KY were the highest and the lowest within Korean native strains, respectively. The genetic distance results showed that Korean native chicken strains were separated with the three introduced chicken breeds clustered into another group. The lowest distance (0.149) was observed between the KR and KL breeds and the highest distance (0.855) between the KR and LK breeds. The microsatellite polymorphism data were shown to be useful for assessing the genetic relationship between Korean native strains and other foreign breeds.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.11
• /
• pp.1546-1552
• /
• 2002

Proliferation and differentiation of ovarian cells are regulated by gonadotrophins and various intraovarian factors, with many of their actions dependent on growth factors. Transforming growth factor-$\beta$ (TGF-$\beta$) has been reportedly involved in the regulation of ovarian follicular development. The overall objectives of the present study were to examine the influence of TGF-$\beta$1 expression in ovarian follicular development or yolk formation and to investigate the association of egg weight with ovarian TGF-$\beta$1 expression at 60 wk. Egg weights of 70 Korean Native Ogol Chicken (KNOC) were recorded from 20 to 60 wk. Ovaries were taken at 60 wk, and TGF-$\beta$1 was measured with ELISA, respectively. Based on egg weight up to 60 wk and TGF-$\beta$1 expression in ovary, the chickens were divided into high and low groups. Egg weights and follicle weight in the high TGF-$\beta$1 group were higher than those in the low groups. Also, TGF-$\beta$1 expression and follicle weight in high egg weight group were higher than those in the low groups. Taken together, the results indicate that TGF-$\beta$1 is associated with egg weight in KNOC. This association of TGF-$\beta$1 with egg weight in KNOC supports the report that TGF-$\beta$ is mainly involved in the development and differentiation of follicles in the poultry. Further studies about other endocrine factors related to yolk formation are required to fully understand the endocrine mechanism of egg weight in Korean Native Ogol Chickens.

• Proceedings of the KSAR Conference
• /
• 2003.06a
• /
• pp.20-20
• /
• 2003

Phenotypic characteristics and genetic markers in livestock have been utilized for improvement of the economic traits including egg productivity. Korean Native Ogol Chicken (KNOC) has low egg productivity compared to White Leghorn. Therefore, in this study, serum IGF-I concentration and number of egg production were used as selection markers to improve egg productivity. KNOCs were divided into three groups showing high IGF-I concentration (IGF-I high), high egg production (EP high), and IGF-I/EP high groups. Blood was collected every 10 weeks, and serum concentrations of IGF-I, estradiol (E2), and progesterone (P4) were measured by radioimmunoassay. In comparison of three groups in each generation, the highest increment of egg production was detected in the IGF-I/EP high group from 20 weeks till 40 weeks, and the IGF-I high group also showed the significant increment of egg production after 50 weeks. Interestingly, there were the increase of egg production and decrease of periods in sexual maturity in the second and third generation selected by serum IGF-I concentration, while egg weight and body weight decreased during experimental period. In conclusion, the present study suggest the possibility of IGF-I as a selection marker to improve the egg productivity of KNOC.

• Proceedings of the KSAR Conference
• /
• 2003.06a
• /
• pp.95-95
• /
• 2003

Endocrine factors, such as steroid hormones and growth factors, regulate egg productivity including the number of egg production, egg weight, sexual maturity, and the number of small yellow follicles. Especially, insulin-like growth factor-I (IGF-I) is involved in the regulation of ovulation rate and ovarian follicular development in chickens, and the relationship between IGF-I genotype and egg weight was reported. However, the effect of grwoth factors on egg productivity in Korean Native Ogol Chicken (KNOC) has not been studied. Therefore this study was conducted to identify the relationship among endocrine factors, IGF-I genotypes, and egg productivity. IGF-I genotypes (AA, AB, BB) were represented to 12.6%, 34%, and 53.4%, respectively. AB genotype stimulates the secretion of estradiol and progesterone in serum (30 and 40 week), regulates growth and proliferation of follicles at 60 weeks, and is positively associated with the number of small yellow follicles. Therefore, these results suggest that there are possibility to IGF-I genotypes for a genetic marker in egg productivity of KNOC.

• Asian-Australasian Journal of Animal Sciences
• /
• v.14 no.7
• /
• pp.915-921
• /
• 2001

IGF-I is involved in the regulation of growth and differentiation in mammals, but its role as a modulator of growth and metabolism in poultry is poorly understood. And, no studies have so far been reported for the comparison between serum IGF-I concentration and body growth in the egg type or the dual purposes (meat and egg type) chicken including the Korean Native Ogol Chicken (KNOC). Therefore, in order to improve the body growth and meat production of the KNOC, this study was conducted for the identification of the polymorphism of IGF-I gene and for its possible association with both body weight and IGF-I concentration. The RFLP patterns for IGF-I gene were identified by the PstI restriction enzyme. The frequencies of +/+, +/-, and -/- genotype were 16.9%, 51.7%, and 31.4%, respectively. Any statistical significance was not observed in all variations except for sex variation (p<0.01) by covariate quadratic model. The significant effect of the IGF-I genotype on body weight by sex indicates that there are different physiological characteristics in gender. Although the body weights of male KNOCs in most ages were not significant, there was a tendency of KNOCs with +/+ IGF-I genotype to be heavier than those with any other genotypes. But all IGF-I genotypes in female did not influence on body weight. The ANOYA revealed no significant effects of IGF-I genotypes on serum IGF-I concentration but sex effect was highly significant on the IGF-I concentration at 20 and 40 weeks (p<0.01). Although the +/+ genotype, in gender, tended to express a higher IGF-I concentration than the other genotypes at all ages in males, a statistical difference among the genotypes was not found except for 60 weeks (p<0.05). Furthermore, since body weight and IGF-I genotypes are associated, it is possible to improve KNOC to a meat type breed if a continuous selection can be made for the body weight and/or IGF-I traits.

• Asian-Australasian Journal of Animal Sciences
• /
• v.14 no.7
• /
• pp.922-928
• /
• 2001

There exists considerable evidence that steroid hormones are involved in the regulation of ovulation rate and oviductal development in poultry. However, the effect of steroid hormones on egg productivity of Korean Native Ogol Chicken (KNOC) has yet to be studied. Therefore, this study was performed to relate the expression of steroid hormones, especially progesterone ($P_4$) and estradiol ($E_2$), with egg productivity during the laying period. Egg production and egg weight of 70 KNOC were recorded from 20 to 60wk. Blood was taken every 10 wk and serum $P_4$ and $E_2$ were measured by radioimmunoassay. Based on egg productivity and steroid hormones levels up to 60 wk, chickens were divided into two groups, high and low. Compared to the low egg production group, a significantly higher expression of $P_4$ at 30 wk was detected in the high group. Moreover, egg production in the high $P_4$ group significantly differed from that in the low group at 30 wk. On the other hand, a Significant difference (p<0.05) in $E_2$ expression was found between high and low egg weight groups at 30 wk. Although a significant difference in egg weight between two groups by $E_2$ was not detected, the high $E_2$ group showed a higher level of egg weight than the low $E_2$ group except for 25 wk. In the comparison of ovary weight and small yellow follicle number, the group with high egg productivity and steroid concentration showed greater levels than the low group. Taken together, the results indicate that $P_4$ is related to egg productivity whereas expression of $E_2$ is associated with egg weight in KNOC.

• Food Science of Animal Resources
• /
• v.27 no.4
• /
• pp.401-408
• /
• 2007

This study examined the histochemical and physiological characteristics during Korean native Ogol chickens (KNOC) development. The body weight, Pectoralis major and soleus muscle weights, and muscle samples were taken at hatching as well as at 3, 5, and 15 weeks of age. The fiber characteristics of the Pectoralis major and soleus muscles from the KNOC at hatching to 15 weeks of age were determined, and the deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein concentrations were measured from the left Pectoralis major muscles. A greater increase in body and muscle weights was detected between hatching and 3 weeks of age than during any other period. Moreover, the cross sectional area (CSA) of the fibers, as well as the total concentration of DNA, RNA, and protein also showed a greater increase betweenhatching and 3 weeks of age than during any other period. The KNOC breed is a dual purpose breed, however, the it has lower body and muscle weights than commercial meat type chickens or layer type chickens. Moreover, the KNOC breed has a small muscle fiber CSA of and a low nucleic acid concentration.