• Korean Journal of Environment and Ecology
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• v.24 no.4
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• pp.345-350
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• 2010

In the Vinous-throated Parrotbill Paradoxornis webbianus, potential intraspecific nest parasitism was observed in four nests (0.38%, n=1,062) during twelve breeding seasons between 1988 and 2007. At first, a nest involved 9 white eggs was found in Puyong-ri, Yangpyong-gun, Kyonggi Province in 1995. This nest would be parasitized by the same species, given that this is out of range of normal clutch size (5 eggs) in Vinous-throated Parrotbills. The second and third cases were recorded in 2001 and 2005 in Sa-dong, Ansan City, Kyonggi Province, respectively. In these nests, two eggs were added to the clutch in a single day. The final observation was made in Puyong-ri in 2007, in which one white egg was laid in the nest at the pre-laying stage. The color of the egg was different from that of the original clutch (blue). The above four things suggest that intraspecific nest parasitism can occur in Vinous-throated Parrotbills although it is an uncommon phenomenon in their life history.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2002.11a
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• pp.113-115
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• 2002

Two experiments were conducted to compare the effects of the natural and the synthetic commercial pigments on the laying performance, pigmentation and fatty acid contents in egg Yolk of laying hens. Feed intake, egg production, egg weight and feed efficiency did not have significant difference(p〈0.05) in experiments I and II. White height and haugh unit did not have significant difference(p〈0.05) in two experiments. In order to approach the yolk pigmentation to 12∼13 of Roche color fan, addition level of natural red pigment was 25∼30 ppm. In the case of synthetic red pigment, the level was 15∼20 ppm. In this experimental condition, the pigmenting effect of the synthetic pigment had better than that of the natural pigment. In the experiment 2, the Pigmenting effect of mixing Pigments were inveatigated between TM2 mixed with natural red pigment, and TM6 mixed with synthesis red pigment. The fatty acid content in yolk was not affected by pigment addition.

• Korean Journal of Poultry Science
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• v.15 no.4
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• pp.281-286
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• 1988

This experiment was conducted to determine the optimum level of Red Pepper (including seeds) for laying-hen'diet in summer. A total 240 birds of 37 week-old Manina Brown Hen was alloted to 4 treatments, 3 replications per treatment, according to complecately randomized design to find out the effects of adding levels (0, 0.03, 0.05, 0.08%) of Red Pepper on laying Performance and e99 Quality of experimental birds for 10 weeks. The results obtained from this study were summaried as follows : 1) I班 shell thickness was different significantly among treatments, (P＜0.05). Especially, Ta was highest one. 2) Egg shell breaking strength was highly significant difference between C and $T_1$, $T_2$, $T_3$ (p＜0.01). 3) Yolk color of $T_1$, $T_2$, $T_3$ was higher than C (p＜0.01), but there was no significant difference between treatments. 4) Egg Production was slightly higher with adding Red Pepper, but the differences were no significant. 5) No significant differences were found in average egg weight among treatments.

• Korean Journal of Poultry Science
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• v.26 no.4
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• pp.261-265
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• 1999

The objective of this experiment was to investigate the effect of feeding Angelica gigas Nakai by-products on performance and meat quality of Korean native chicks(KNC). Five hundred forty KNC were placed into 0, 0.2, and 0.4% Angelica gigas supplements with four replications between males and females. Weight gain, feed conversion ratio(FCR), breast meat lipid, fatty acid and protein contents were measured from 17 to 20 weeks old. Egg production, feed intake and FCR were examined from 22 to 29 weeks at four weeks at four weeks intervals. Basal diets based on corn and soybean meal contained 15% crude protein and 2,850㎉/kg ME for the growing period, 16.5% and 2,800㎉/kg for the laying period. Experiments were designed in a one way analysis. Weight gain of female chicks fed 0.2% Angelica gigas by-products increased significantly compared to that of other treatments for the growing period, but was not consistency in male groups. Moisture, protein, fat content were not statistically different among all treatments. Fatty acid composition(C16:0, C18:0) of chicks fed 0.2% Angelica gigas by-products was higher than other treatments. In laying period, hens fed 0.2 or 0.4% Angelica gigas Nakai by-products seemed to increase the egg production and significantly improved FCR compared to that of control(P〈0.05). Birds fed 0.4% treatment showed significantly the lowest feed intake and FCR of all treatments(P〈0.05). The results of these studies indicated that dietary supplemental Angelica gigas by-products may have a role to improve the performance of KNC.

• Journal of Veterinary Science
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• v.25 no.3
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• pp.43.1-43.13
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• 2024

Importance: Haemaphysalis longicornis is an obligate blood-sucking ectoparasite that has gained attention due its role of transmitting medically and veterinary significant pathogens and it is the most common tick species in Republic of Korea. The preferred strategy for controlling ticks is a multi-antigenic vaccination. Testing the efficiency of a combination antigen is a promising method for creating a tick vaccine. Objective: The aim of the current research was to analyze the role of subolesin and enolase in feeding and reproduction of H. longicornis by gene silencing. Methods: In this study, we used RNA interference to silence salivary enolase and subolesin in H. longicornis. Unfed female ticks injected with double-stranded RNA targeting subolesin and enolase were attached and fed normally on the rabbit's ear. Real-time polymerase chain reaction was used to confirm the extent of knockdown. Results: Ticks in the subolesin or enolase dsRNA groups showed knockdown rates of 80% and 60% respectively. Ticks in the combination dsRNA (subolesin and enolase) group showed an 80% knockdown. Knockdown of subolesin and enolase resulted in significant depletion in feeding, blood engorgement weight, attachment rate, and egg laying. Silencing of both resulted in a significant (p < 0.05) reduction in tick engorgement, egg laying, egg hatching (15%), and reproduction. Conclusions and Relevance: Our results suggest that subolesin and enolase are an exciting target for future tick control strategies.

• Korean Journal of Poultry Science
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• v.34 no.3
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• pp.197-205
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• 2007

This study was conducted to compare the effect of feeding molting and fasting molting on the performance, egg quality, and visceral organs in laying hens for animal welfare. Eighty one 62-wk-old White Leghorn hens that egg production was over 80% and average weight was $1.6{\pm}0.3\;kg$ were used in this study. Treatments were control (non-molt treatment), feeding molt treatment, and fasting molt treatment. The three treatments were administered to three replicate group of nine hens wherein each group. All treatment groups were fed the basal diet (CP 15%, ME 2,700 kal/kg) for two weeks as the adaptation period. Induced molt diets contains low CP (6.7%) and low energy (2,200 kal/kg). Test periods were 14 days for feeding molting and 10 days for fasting molting. Egg production decreased to be 0% at 10 days of feeding molting treatment, but at 2 or 3 days of fasting molting treatment. Egg production restarted after 19 days ending molt at feeding molting treatment, while after 24 days at fasting molting treatment. On the egg quality was improved at molting treatments (p<0.05) except egg yolk. Egg shell tissue was crowded at molting treatment to compare to control. Liver weights, heart weight, and oviduct weight of laying hens decreased at molting treatments (p<0.05). Finally, feeding molting might could be replaced fasting molting on the welfare and further studies were needed about molting program.

• Korean Journal of Poultry Science
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• v.30 no.4
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• pp.275-280
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• 2003

This study conducted to investigate the effect of dietary germanium biotite by protein level in laying hen diets. One hundred forty four, 51 weeks old ISA brown commercial layer, were used in experiment. Dietary treatments were 1) low protein diet(LPD), 2) high protein diet(HPD), 3) LPD-GB(LPD + 1.0% germanium biotite) and 4) HPD-GB(HPD + 1.0% germanium biotite). Henday egg production tended to be increased as the concentration of protein in diets increased with significant difference(P<0.01). Egg weight tended to decrease by increasing of supplementation germanium biotite in the diets(P<0.01). Egg shell breaking strength was not influenced by germanium biotite supplementation(P>0.05). Large band of egg decrease as increasing of supplementation germanium biotite in the diets(P<0.02). Sharp and middle band of egg were not influenced by germanium biotite supplementation. Egg yolk index tended to decrease as increasing of supplementation germanium biotite in the diets(p<0.01). Fecal propionic acid(P<0.01) and butyric acid(P<0.03) were decrease as the concentration of germanium biotite in the diet was increased. Also, butyric acid increased as the concentration of protein in diets increased with significant difference(P<0.02). Supplementation germanium biotite in the diet reduced the fecal acetic acid(P<0.01). Fecal $NH_3$-N of hens fed HPD-GB diet was decreased(P<0.05) compared to that LPD-GB diet. In conclusion, germanium biotite supplementation to layer diets can reduce fecal volatile fatty acid compabebts.

• Korean Journal of Poultry Science
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• v.34 no.4
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• pp.279-286
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• 2007

This study was conducted to induce molting with DDGS and non-salt diet and compare the effect of feeding molting and fasting molting on the performance, egg quality, and visceral organs in laying hens for animal welfare. One-hundredeight 62-wk-old White Leghorn hens that egg production was over 80% and average weight was $1.8{\pm}0.1kg$ were used in this study. Treatments were control(non-molt treatment), feeding molt treatment(DDGS, non-salt diet), and fasting molt treatment. The four treatments were administered to three replicate group of nine hens wherein each group. All treatment groups were fed the basal diet(CP 15%, ME 2,700 kal/kg) for two weeks as the adaptation period. Test Periods were 28 days at all treatments. Egg production decreased for 18 days to be 0% at feeding molting treatment, and for 17 days to be 0% at non-salt feeding molting treatment. Egg production stopped for 6 days at fasting molting treatment. Egg production restarted after 12 days molt at feeding molting treatment, while after 16 days at fasting molting treatment. On the egg quality was improved at molting treatments (p<0.05) except egg yolk. Egg shell tissue was crowded at molting treatment to compare to control. Liver weights, heart weight, and oviduct weight of laying hens decreased at molting treatments(p<0.05). Finally, feeding molting might could be replaced fasting molting on the welfare and further studies were needed about molting program.

• Korean Journal of Poultry Science
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• v.25 no.4
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• pp.169-175
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• 1998

A feeding trial was carried out to evaluate optimum feeding system to Korean Native Chicken (KNC) with various feeding programs for 64 weeks. Eight hundreds and ten KNC＇one day birds were assigned to three feeding systems, NRC(T1), Japanese Feeding Standard(T2), Korean Feeding Standard(T3). Each treatment had three replicates of 90 birds a replicate. Data were obtained growing performance to 20 week of age and laying performance from twenty one to sixty four week. Viability to 20 week of age was similar to treatments. Growth characteristics by feeding systems were not significantly difference on body weight, feed intake and 50％ egg production days. However, body weight was less about 100g in T2. There were no different on egg production, egg weight, and egg mass during laying period. Feed intake of T1 was 104g daily and showed lower than other treatments, but was not different significantly. Feed conversion was significantly improved in T2(P <0.05) compared to other treatments(P<0.05). Egg production of all treatments was the highest between 27 to 30 week of age. ME intake of T1 was significantly maximized, whereas CP intake was the lowest of all treatments(P < 0.05). Nutrient requirements for egg mass tended to depend on nutrients intake. Interior egg and eggshell characteristics were not different among treatments except yolk color. Fertility and hatchability were similar to treatments, and the results at 39 week of age were higher than at 62 week in all treatments. In conclusion, treatments fed three or four phase feeding would be superior to other treatments during the growing period and suggest 2,800 ㎉/kg ME, 15％ CP for Korean native laying hen.

• Korean Journal of Poultry Science
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• v.46 no.3
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• pp.193-204
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• 2019

This study aimed to investigate the changes in production performance of five strains of Korean native chickens (KNCs), which have been collected and established at the National Institute of Animal Science, Korea, since 1992. A total of 38,026 KNCs were tested and survival rate, body weight, age at first egg-laying, hen-housed egg production, and egg weight was analyzed. The mean survival rates of KNCs were $87.9{\pm}0.8%$, but no significant difference in survival rate between strains and in the annual survival rates of KNCs was observed. The average body weight of KNCs was $1,609.7{\pm}21.3g$ at 150 d. The average body weight of KNC-Black was the highest, whereas KNC-White had the lowest weight. A gradual increase in the annual weight change has been observed in almost all strains after 2004. The average age at first egg-laying was $146.9{\pm}1.1d$ in KNCs where KNC-White was the earliest and KNC-Black was the latest. The age at first egg-laying has increased after 2003, but has gradually decreased after 2008. The average hen-housed egg production at 270 d was $77.3{\pm}1.7$ in KNCs, wherein KNC-Yellowish brown was the highest and KNC-Black was the lowest. The average egg weight at 270 d was $51.2{\pm}0.3g$ in KNCs, indicating that KNC-Black was the heaviest, whereas KNC-White was the lightest. A significant increase in annual egg weight has been observed since 2008. To conclude, the appearance and feather colors of KNCs have improved uniformly, and the body weight has also improved slightly since 2002.