• Korean Journal of Poultry Science
• /
• v.37 no.4
• /
• pp.347-354
• /
• 2010

The current work was carried out to investigate the effect of crossbred Korean native chickens (KNC) on performance and carcass ratio. Seven hundred twenty 1-d-old chicks were divided into groups by strain (A, B, C and D) and sex (male and female). Strains were A) (KNC egg-meat type C strains $\times$ KNC meat type S strains) $\times$ KNC meat type H strains, B) (KNC egg-meat type C strains $\times$ KNC meat type H strains) $\times$ KNC meat type S strains, C) (KNC native R strains $\times$ KNC meat type S strains) $\times$ KNC meat type H strains and D) (KNC native L strains $\times$ KNC meat type H strains $\times$ Ross broiler. Experimental diets consisted of 3 phases such as starter(0~5 weeks; CP 20.0%, ME 3,050 kcal/kg), earlier (5~8 weeks; CP 18.0%, ME 3,100 kcal/kg) and finisher (8~12 weeks; CP 16.0%, ME 3,150 kcal/kg). Body weight (BW) and feed intake (FI) was measured every week and carcass ratio(CR) was calculated at 5 and 10 week after starting experiment. There was no difference in BW among strains until 5 weeks (P>0.05), however D strain resulted in a higher BW after 5 weeks (P<0.05). Body weight gain (BWG) and FI in D strain were also significant higher compared to the other strains for all periods. However, D strains showed the lowest (P<0.05) fee conversion ratio (FCR). The other strains except D showed a similar BW, BWG, FI and FCR among strains. In addition, there were no differences in carcass weight (CW) and carcass ratio (CR) among strains at 5 weeks, however D strain showed higher CW and CR at 10 weeks. These results suggested the basic data that needed to develope the new strains.

• Korean Journal of Poultry Science
• /
• v.37 no.3
• /
• pp.229-235
• /
• 2010

This work was carried out to improve the performance and the carcass yield of Korea native duck (KND) according to crossbreeding KND and broiler duck (BD). Two hundred forty out of crossbred ducks were divided into 4 strains and selected as 120 ducks separated by sex, respectively. Crossbred ducks were native ducks (female)${\times}$native ducks (male), native ducks (female)${\times}$broiler ducks (male), broiler ducks (female)${\times}$native ducks (male), and broiler ducks (female)${\times}$broiler ducks(male) as A, B, C and D, respectively. Broiler duck diet was fed as experimental diet for 0~3 weeks (CP 22.0%, ME 2,900 kcal/kg) and 3~8 weeks (CP 18.0%, ME 3,000 kcal/kg). Body weight of male was high compared to female, and that of B and C was high compared to A and low compared to D at 3 and 8 week (P<0.05). Body weight gain of male was high compared to female at 3~8 weeks and 0~8 weeks, and it was shown as D>C>B>A on body weight gain (P<0.05). In case of feed intake, there was no difference between male and female, and B and C were high compared to A and low compared to D (P<0.05). Male feed requirement was high at 3~8 weeks, and there was significant difference between A and B, C and between B and D. Carcass yield of 4 strains was shown as 70.1%, 70.8%, 73.1% and 71.2%, respectively. Finally, Crossbreeding of KND and BD may improve the performance and the carcass yield of KND.

• Korean Journal of Poultry Science
• /
• v.37 no.4
• /
• pp.383-388
• /
• 2010

The chicken eye can discriminate light color, and different light wavelengths may affect reproduction ability. This study was carried out to identify effect of monochromatic light using light emitting diode (LED) in laying hens. Chickens were exposed to white light (WL), blue light (BL), yellow light (YL), green light (GL) and red light (RL) made by using LED as well as incandescent light (IL) (control). All light sources were equalized to a light intensity of 20 lux. The results indicated that the age of first egg laying and 50 % egg laying in laying hens treated under RL is significantly younger than under other lights (P<0.05). And the ovary weight of laying hens reared under RL is significantly heavier than under other at from 16 to 20 wks (P<0.05). The largest number of eggs production was produced in a group with treated with RL by 59 wks of age compared with any other group. The egg weight of YL was greater than other treatment groups from 26 to 45 wks (P<0.05). The egg shell from hens treated with RL was the strongest and thickest at 20 wk (P<0.05). These results suggest that the egg quality of laying hens reared in different spectrum of LED can be different and RL may enhance the laying performance.

• Korean Journal of Poultry Science
• /
• v.35 no.4
• /
• pp.351-359
• /
• 2009

This study was carried out to investigate dietary effects of extracts of Skullcap (Scutellaria baicalensis) (SCE) grown in Korea on growth performance, immune and physiological responses in broiler chickens. Total of seven-hundred fifty 1-d-old Ross male broiler chicks were divided into five groups and fed control diets (antibiotics medicated or non-medicated commercial diets) or each experimental diet (non-medicated diets containing 0.1, 0.3 or 0.5% SCE) for 5 weeks. The body weight gain and feed conversion rate in the groups fed diets containing 0.1% or 0.3% SCE were significantly improved as compared with those of non-medicated control group (P<0.05). The levels of total cholesterol and HDL-cholesterol of blood were not influenced by feeding the SCE. The average antibody titers against NDV and IBV in the groups fed diets containing SCE were significantly increased compare to those of the control groups (P<0.05). The number of coli form bacteria was significantly reduced by feeding 0.3% or 0.5% SCE as compared to that of non-medication control (P<0.05). The results demonstrated that the SCE used in this study modulated humoral immunity and the profiles of cecal microflora and thus can be used as a potential alternative substance to replace antibiotics for feeding broiler chicks.

• Korean Journal of Poultry Science
• /
• v.37 no.4
• /
• pp.389-398
• /
• 2010

The present experiment was carried out to compare performance, carcass characteristics and meat quality among three major meat-type duck strains in Korea. Two commercial duck (CD) strains, produced from parent stocks (PS) (Cherry Valley and Grimaud), and $F_1$ strains, self-produced by farmers, were used in an 8-week feeding experiment. Both feed conversion ratio and production index were significantly higher in Cherry Valley strain compared with the other two at the ends of 6 and 8 weeks (p<0.05). However, no differences were found in carcass characteristics and meat quality, with the exception of abdominal fat weight where Grimaud were higher than the others. Overall, the results of the current study show that Cherry Valley CD strain had higher performance among three strains tested.

• Korean Journal of Poultry Science
• /
• v.36 no.2
• /
• pp.177-186
• /
• 2009

It is well-known that unregulated over-expression of foreign gene may have unwanted physiological or toxic effects in transgenic animals. To circumvent these problems, we constructed retrovirus vector designed to express the foreign gene under the control of the tetracycline-inducible promoter. However, gene expressions in the tetracycline-inducible expression system (Tet system) are not completely regulated but a little leaky due to the inherent defects in conventional Tet-based systems. A more tightly controllable regulatory system can be achieved when the advanced versions ($rtTA2^SM2$) of rtTA and a minimal promoter in responsive components (pTRE-tight) are used in combination therein. In this study, we tried to produce human thrombopoietin (hTPO) from various target cells and transgenic chickens using the retrovirus vector combined with Tet system. hTPO is the primary regulator of platelet production and has an important role in the survival and expansion of hematopoietic stem cells. In a preliminary experiment in vitro, higher hTPO expression and tighter expression control were observed in chicken embryonic fibroblast (CEF) cells. We also measured the biological activity of the hTPO using Mo7e cells whose proliferation is dependant on hTPO. The biological activity of the recombinant hTPO from CEF was higher than both its commercial counterpart and hTPO from other target cells. The recombinant retrovirus was injected beneath the blastoderm of non-incubated chicken embryos (stage X). Out of 138 injected eggs, 15 chicks hatched after 21 days of incubation. Among them, 8 hatched chicks were hTPO positive. When the Go transgenic chicken was fed doxycycline (0.5 mg per 1 gram of feed), a tetracycline derivative, hTPO concentration of the transgenic chicken blood was 200 ng/mL. Germline transmission of the transgene was confirmed in sperm of the Go transgenic roosters. These results are informative to establish transgenic chickens as bioreactors for the mass production of commercially valuable and biological active human cytokine proteins.

• Korean Journal of Poultry Science
• /
• v.37 no.3
• /
• pp.237-245
• /
• 2010

A survey of transovarially transmitted diseases, including salmonellosis [(pullorum disease; PD)/(fowl typhoid; FT)], mycoplasmosis, avian infectious anemia (CIA), and fowl adenovirus infection was conducted in the breeder chickens from August to December in 2009. The numbers of flocks sampled out were: Grand Parents Stock (GPS), 45; Parents Stock (PS) 1,018, Baeksemi breeder (BSB) 54. The seroprevalence of salmonellosis (PD/FT) were 0% (GPS), 3.2% (PS), and 3% (BSB), respectively. A total of 983 chicken farms were affected with FT outbreaks between 2000 and 2008. The incidence of FT in commercial broilers, Baeksemi, commercial layers, native chickens, and broiler breeders was 44.3%, 26.2%, 15.7%, 12.6% and 1.08%, respectively. Of the affected broilers, over 90% birds were under 2 weeks of age, indicating it was possible that they were infected with S. gallinarum via vertical transmission. The sero-positive flocks against Mycoplasma gallisepticum (MG) were 71.1% (GPS), 88.7% (PS), 88.7% (BSB), while the rates of positive flocks against Mycoplasma synoviae (MS) were 86.0% (GPS), 77.0% (PS), and 98.0% (BSB). In GP and parent farms, the detection rates on specific genes of CIA virus were 19/45 (42.2%), and 169/1039 (18.0%), respectively, whereas the seroprevalence of CIA were 86.0% in GPS and 93.7% in PS flocks. In addition, positive flocks of fowl adenoviruses were 4.4% (GPS), 2.7% (PS) and 9.35% (BSB), respectively. As the results, avian mycoplasmosis and CIA have been more prevailing in chicken breeder than avian salmonellosis and fowl adenovirus infection in Korea.

• Korean Journal of Poultry Science
• /
• v.36 no.2
• /
• pp.125-131
• /
• 2009

This study was conducted to investigate the effects of dietary supplementation of mannan-oligosaccharides (MOS) and fructo-oligosaccharides (FOS) on the performance, immune response and small intestinal microflora in laying hens. A total of 960 Hy-Line $Brown^{(R)}$ laying hens of 27 wks old, housed in 2 bird cages, were assigned in a completely randomized block design into one of the following 6 dietary treatments: control, antibiotic (6 ppm avilamycine), 0.025% MOS, 0.05% MOS, 0.25% FOS, and 0.5% FOS. Each treatment had 4 replicates of 40 birds and was fed ad libitum for 6 wks under 16 h lighting regimen. There were significant differences among treatments in hen-day and hen-housed egg production. Hen-day egg production in 0.025% MOS was significantly higher than that of control. Hen-housed egg production in antibiotic-treated group was significantly higher compared with control. Egg weight, feed intake and feed conversion were not significantly different among treatments. Egg shell thickness was highest in 0.25% FOS, but was not significantly different among the rest of treatments. There were no significant differences among treatments in egg shell strength, egg shell color, egg yolk color and Haugh unit. IgG concentrations in serum were not significantly different among treatments. On the other hand, IgA concentrations of the treated birds tended to be increased compared with control. Dietary treatments tended to decrease Cl. perfringens and E. coli, and to increase Lactobacillus spp. The result of this experiment showed that dietary supplementation of MOS and FOS in laying hens tended to improve egg production comparable to the supplementation of antibiotics. The level of serum IgA and small intestinal microflora were also significantly affected by the treatments.

• Korean Journal of Poultry Science
• /
• v.37 no.4
• /
• pp.373-382
• /
• 2010

This study was carried out to investigate the effect of reverse osmosis (RO)-treated deep sea water (DSW) supplementation on the quality characteristics of chicken breast meat. For 28 days, one-day-old broiler chicks (Ross 308) were divided into two groups and supplemented with either water (control) or RO-treated DSW (diluted with deionized water at 1:20 [RO-treated DSW:deionized water] ratio). The control group was fed on a basal diet containing 0.21% salt. Five birds were slaughtered on each group and breast meat from carcasses was stored at $4^{\circ}C$ for 9 days. The proximate composition, fatty acid composition, cholesterol content, mineral content, pH value, water-holding capacity and Warner-Bratzler shear force value were not affected by RO-treated DSW supplementation. At 6 day of storage, lipid oxidation (2-thiobarbituric acid reactive substances) was significantly higher in RO-treated DSW group than in the control (P<0.05). With regard to meat color, CIE $L^*$ value was significantly lower in RO-treated DSW group than in the control after 6 day of storage (P<0.05), whereas CIE $a^*$ and $b^*$ values were not significantly different between two groups during storage. Consequently, RO-treated DSW supplementation led to a darker color and reduced the lipid oxidation stability in chicken meat during storage. Therefore, these results may indicate that RO-treated DSW can not be used as drinking water of chickens because it negatively affects the quality of chicken meat.

• Korean Journal of Poultry Science
• /
• v.35 no.4
• /
• pp.327-333
• /
• 2009

In Korea chicken meat price is not determined in the auction markets, but it is artificially calculated using the live chicken price of one day before, transporting cost, converting rate of live chicken into carcass, and slaughtering cost. This calculated price is published through the mass media and used as the base for chicken meat transaction. By the way, since 85% of the Korean broiler industry is composed by the integrated system, the live chicken price is nothing to do with ex-factory price of chicken meat produced by the integrators. Under this pricing system, when we estimate the margin of the chicken meat through the marketing process, the margin of the integrator is fluctuated by the live chicken price of one day before, which is nothing to do with integrators; When the live chicken price is low, the margin of the integrators is low, but the margin of the selling agencies' is relatively high. On the contrast, when the live chicken price is high, the margin of the integrators is high, but the selling agencies' margin will be relatively low, because consumer's price could not be increased in parallel with increase of the live chicken price. Accordingly, the ex-factory price of chicken meat determined using the production cost of live chicken and slaughtering cost of the integrator by adding resonable margin of the integrator should be determined and published, so that it could be used for chicken meat transaction. In Japan the Zen-Noh Chicken Foods Corporation announce the ideal piece of chicken every morning, and all the transactions of the chicken meat will be determined based on this price. In Korea, it will be desirable to make bench marking from Japanese case, in other words the NH could announce the ideal price of chicken meat every morning, so that it would be the base price of chicken meat transaction. Even though the market share of the NH is less than 5%, its publicity should be accepted, since it is a subsidiary of the National Agricultural Cooperative Federation of Korea.