• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.187-195
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• 2013

This study was investigated the effects of dietary supplementation of Yacon by-products and pine needle powder on growth performance, carcass characteristics, pH, TBARS (thiobarbituric acid reactive substance), WHC (water holding capacity), shear force, and meat color of chicken thigh meat. Broiler chicks were fed diets for five weeks containing 0% Yacon by-products and pine needle powder (Control), 0.5% Yacon by-products powder (T1), 1.0% Yacon by-products powder (T2), 0.5% pine needle powder (T3), and 1.0% pine needle powder (T4). There was no significant difference in growth performance among treatments, but mortality was decreased in diets by the supplementation of Yacon by-products and pine needle powder than that of control. The chicken fed control diet had higher cholesterol. LDL-cholesterol. triglyceride compared to those chicken fed Yacon by-products and pine needle powder regardless of concentrations, and HDL-cholesterol of control was lower than treatment. The pH and TBARS were significantly decreased by the supplementation of Yacon by-products and pine needle powder compared to the control (P<0.05), especially, pine needle powder group was significantly more effective in improving freshness compared to other test groups (P<0.05). The WHC and shear force were not significantly different. CIE $L^*$ and $a^*$ value of test groups showed significantly higher value compare to the control, however, no difference in the CIE $b^*$ values was observed among test groups. In conclusion, a supplementation of Yacon by-products and pine needle powder were effective in decreasing pH, TBARS, total cholesterol and LDL-cholesterol and increasing HDL-cholesterol concentration. Pine needle powder supplementation was most effective (T3 and T4).

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.179-185
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• 2013

This study was conducted to investigate the effect of curing additives on color property of smoked duck meat. Curing process of samples was performed one of the following treatments: C, non-curing: T1, 2.43% salt: T2, 2.43% salt + 0.49% tripolyphosphate (TPP): T3, 2.43% salt + 0.49% TPP + 0.002% nitrite: T4, 4.76% duck seasoning: and T5, 1.47% salt + 0.24% TPP + 0.2% L-ascorbic acid. Instrumental meat color of both breast and thigh of smoked duck showed that the CIE $a^*$ value of the T4 was significantly (p<0.05) higher than that of the other treatments, whereas T5 had a significantly (p<0.05) higher CIE $b^*$ value than the other treatments. In results of nitroso pigment, T5 of smoked duck breast was significantly (p<0.05) higher value compared to other treatments, whereas T3 and T5 of smoked duck thigh had a significantly (p<0.05) higher value than other treatments. Heme pigment contents of control and T5 was significantly (p<0.05) higher value compared to other treatments in smoked duck breast. Meat color of T3 by sensory evaluation showed redder (p<0.05) than other treatments. These results suggested that using L-ascorbic acid is revealed to be pink color without nitrite or pigment when manufacturing of smoked duck meat.

• Korean Journal of Poultry Science
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• v.43 no.4
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• pp.219-228
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• 2016

A total of 720 slow-growing Korean meat-type (Hanhyop 3) chicken were used to evaluate the effect of stocking densities and dietary protein levels on growth performance, meat quality, bone mineral composition, and serum corticosterone. Three (6.3, 9.5, and $12.6birds/m^2$) stocking densities and two dietary protein levels (19% and 18%) were factorially ($3{\times}2$) arranged for six treatments. Overall body weight gain (BWG) was highest (p<0.001) at the lowest stocking density ($6.3birds/m^2$). The feed intake (FI) of birds at the highest density ($12.6birds/m^2$) was lower than that of birds at the other densities, but resulted in better feed/gain (F/G). Among 18% protein groups, the overall FI of birds at $9.5birds/m^2$ was higher than that at the lowest density; therefore, birds at $9.5birds/m^2$ had poorer F/G than birds at the lowest density during days 61~75. Difference in F/G among densities was only significant (p<0.05) during days 61~75 but not significant (p>0.05) during days 41~60. Although there were no significant differences (p>0.05) in BWG and F/G between 19% and 18% dietary protein levels, FI of the 18% protein diet was less (p<0.05) than that of the 19% diet. Although there was no difference (p>0.05) in meat TBARS values, meat color differed (p<0.05) with stocking density and dietary protein levels. There was no effect (p>0.05) of stocking density and dietary protein levels on bone mineral composition. Serum corticosterone concentration increased (p<0.05) with increasing stock density but was not affected (p>0.05) by dietary protein levels. This study indicated that a density of $12.6birds/m^2$ is not recommended for slow-growing chickens. Between 19% and 18% dietary protein levels, 18% would be recommended for the Korean Hanhyop 3 chicken in the finishing stage.

• Korean Journal of Poultry Science
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• v.43 no.4
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• pp.235-242
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• 2016

This study was conducted to investigate the microbiological sanitation status of raw chicken meat distributed in Korea, and potential changes in chicken breast quality during storage. The microbiological sanitation status analysis of raw chicken involved studying the results of microbiological monitoring for a 5-year period (2010~2014) by the Korean Food and Drug Administration. Furthermore, the microbiological status of raw chicken meat in meat packing centers and shops in Seoul/Gyeonggi, Kangwon, and Chungcheong Provinces was investigated from July to August 2015. The total bacterial counts of chicken meat in the packaging centers and meat shop of these Provinces were below the level specified in the Korean Meat Microbiological Guideline ($1{\times}10^7$ colony forming units [CFU]/g) and showed a similar microbiological sanitation status with results of the microbiological monitoring for the analyzed 5-year period. To evaluate the relationship between quality change and microbiological level of the meat distributed in Korea, the pH and microbiological and sensory quality characteristics of the chicken breast samples during storage at $4{\pm}2^{\circ}C$were determined. On day 4, the total bacterial count of the chicken breast was 6.76 log CFU/g, which was close to the official $1{\times}10^7CFU/g$ standard, the pH was 5.96, and the overall acceptability was reduced significantly (p<0.05). In particular, the aroma score was <5, indicating that the consumer panel expressed a negative perception even though the chicken contained a lower microbial level than that specified in the Korean microbiological guideline. These results suggest that the current Korean microbiological guideline for raw chicken meat may require a stricter level of up to $1{\times}10^6CFU/g$ to satisfy both meat safety standards and organoleptic quality for consumers.

• Korean Journal of Poultry Science
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• v.43 no.4
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• pp.229-233
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• 2016

This study was conducted to compare three commercially available egg testing devices for measuring egg quality. The devices used were a Laser-type (automatic), a Ultrasonic-type (automatic), and a Probe-type (manual). Fresh eggs weighing 60~68 grams were obtained from a commercial hen farm. Three trials were conducted. In Trial 1, a total of 50 eggs were successively analyzed by the three egg testing devices. In Trial 2, fresh eggs were successively analyzed by a combination of two egg testing devices. In Trial 3, a total of 600 eggs (weighing 60~68 grams) laid by same flock were selected, further divided into three sub-groups with a total of 200 eggs, and analyzed by an egg testing device. In Trials 1 and 2, no apparent difference was observed in egg weight between egg testing devices. However, albumin height was scored highest in the Ultrasonic-type egg tester followed by the Probe-type and Laser-type (Trials 1 and 2). Consequently, the Haugh unit was similarly altered. Yolk color was highest in the Laser-type egg tester followed by the Ultrasonic-type and Probe-type (Trials 1 and 2). When fresh eggs laid by a single flock were independently analyzed by three devices, egg weight did not differ, but albumin height and Haugh unit were higher (p<0.05) in the Ultrasonic-type egg tester than in the Probe-type or Laser-type testers. However, Laser-type testers produced higher (p<0.05) yolk color values than the Ultrasonic-type or Probe-type egg testers. In conclusion, the commercially available egg testing devices exhibited performance differences in measuring egg qualities, which warrants further consideration as to whether the magnitude of bias and precision between the devices could be acceptable in the egg grading system, especially when assessing eggs stored for certain durations.

• Korean Journal of Poultry Science
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• v.43 no.4
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• pp.253-261
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• 2016

Egg quality is a very important factor for both consumers and producers. Factors affecting egg quality include strain and age of hens; egg storage temperature, time, and humidity; laying season; and feeding. This study aimed to determine the effect of hen age and egg storage time on egg quality. A total of 700 eggs obtained from Hyline Brown commercial layers were used for this experiment, and they were separated into two hen age groups (30 vs. 60 weeks) with eight treatments and four storage times (day 0, 10, 20, and 30). The egg weight; shell color, thickness, and density; albumen height; Haugh unit (HU); yolk color; and the yolk and albumen pH and viscosity were measured for the egg quality assessment. The results showed that the age of the hen and egg storage time significantly affected almost all parameters of the internal and external egg quality. The shell thickness, albumen height, HU, yolk color, pH of yolk and albumen, and yolk viscosity significantly decreased with increasing hen age. The egg shell color was significantly lighter in eggs from 60-week-old hens than in those from 30 weeks-old hens. The egg weight; shell weight, thickness, and density; albumen height, HU; and albumen viscosity significantly decreased, but the yolk color and pH of the yolk and albumen increased with increasing egg storage time. The interaction effects between the storage time and hen age were significant in shell thickness, albumen height, yolk color, and yolk and albumen pH and viscosity. The eggs obtained from 60-week-old hens showed significantly lower shell thickness, albumen height, and HU values, which are considered typical egg quality measurements, than values of eggs from 30-week-old hens. Therefore, increasing hen age and egg storage time caused the deterioration of egg quality. In conclusion, this study demonstrated that hen age is the major factor affecting the quality of fresh eggs, whereas the storage time is the determinant factor affecting the quality of stored eggs.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.169-180
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• 2020

This study examined the effects of a probiotic complex (PC) containing Lactobacillus plantarum, Bacillus subtilis, and Saccharomyces cerevisiae on growth performance, organ weight, immune parameters, fecal microbial count, and noxious odor in broiler chicks. A total of 216 birds (4-day-old) were fed a basal diet (CON) and a diet supplemented with 0.25% (PC1) and 0.5% (PC2) of PC until 35 days of age. No difference in body weight, feed intake, and FCR was observed among the groups. The intestinal mucosal weight of the PC1 group was greater than that of the CON group without affecting weights of the other organs. Intestinal secretory immunoglobulin A (sIgA) levels in the PC2 group increased significantly (P<0.05) compared with that in the CON group. The PC2 group also had a strong tendency for elevated blood sIgA levels. Dietary PC did not affect the level of interleukin-1β in the blood and mucosal tissues or alter maltase, sucrase, and leucine aminopeptidase activities in the intestinal mucosa. The PC2 group had higher colony-forming units (cfu) for L. plantarum and S. cerevisiae, but lower cfu for E. coli than those in the CON group. Compared to the CON diet, the PC2 diet resulted in a decreased H₂S concentration and a tendency toward decreased CH₃SH concentration. In conclusion, a 0.5% PC diet showed increased sIgA and desirable microbial population, and decreased noxious odor in the feces, suggesting that PC could be applied as an environmentally friendly feed additive in broiler chicks.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.189-197
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• 2020

This study was conducted to compare the production performance and stress response of chickens kept in the conventional cages and floor pens. 491 female White Leghorns were used in this study, and their production characteristics and stress response indicators were analyzed from 34 to 43 weeks of age. The results showed that there was no significant difference in survival rate, hen-day egg production, and body weight between the chickens kept in the conventional cages and those kept in the floor pens. The chickens kept in the conventional cages had a significantly higher egg weight and egg quality compared with those kept in the floor pens (P<0.01). The amount of telomeric DNA in lymphocytes was significantly higher in the chickens kept in floor pens than in those kept in conventional cages (P<0.05). The heterophil-lymphocyte ratio, HSP-90β gene expression level, and DNA damage rate significantly increased in chickens kept in the conventional cages, as compared to the chickens kept in floor pens (P<0.01). In conclusion, there seems to be no difference in the production performance between chickens kept in conventional cages and those kept in floor pens. Furthermore, chickens kept in conventional cages had higher stress response values than those kept in floor pens for all stress response indicators. Therefore, conventional cage types are considered to be a more stressful environment for chickens than floor pens, regardless of the production performance of the chickens.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.143-151
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• 2020

This study investigated the effects of the addition of commercial enzyme products to broiler feed with reduced levels of metabolizable energy and crude protein on the growth performance, blood profiles, and cecal microflora. A total of 750 seven-day-old male Ross 308 broiler chicks were randomly allotted to five treatment groups with six replicates (25 birds/replicate) for 28 days. A corn-wheat-soybean meal-based diet was formulated to meet or exceed the nutrient recommendations and used as the control diet. Experimental diets with metabolizable energy reduced by 100 kcal/kg and crude protein by 1% were formulated containing four different commercial enzyme products. Feed intake and weight gain were not affected by the dietary treatments; however, feed conversion ratios were significantly lower (P<0.01) in the control group than in the other treatment groups during the entire experimental period. There were no significant differences in the blood profiles and cecal microflora between the dietary treatments. However, the viscosity of jejunal contents in chicks fed a diet with enzyme B was significantly lower than that in the other groups. The tentative marketing age was unaffected by any of the dietary treatments, and ranged from 26.39 d to 26.84 d. Collectively, the use of commercial enzymes contributed to a similar weight gain as that in chicks fed diets with reduced energy and crude protein levels; however, it failed to maintain the feed conversion ratio.

• KOREAN POULTRY JOURNAL
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• v.13 s.146
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• pp.108-116
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• 1981

제15회 산란계 경제능력검정에는 총 13개 계군이 출품되었으며 능력검정 결과를 요약하면 다음과 같다. 1. 육추율, 육성율, 성계생존율 이번회 검정계의 육추율은 13개 계군 평균 97.72$\%$로서 14회 99.7$\%$와 비슷하다. 특히 이번 검정에서 육추기간 중 한마리의 폐사도 없는 구는 3구였으며 9구 만이 79.64$\%$로 육추율이 가장 낮았는데 그 원인은 1개 검정소에서 육추기간 중 백혈병으로 인한 폐사수가 많았기 때문으로 보인다. 육성율 평균은 99.07$\%$로서 14회 99.0$\%$와 같았고 한마리의 폐사도 없는 구는 11구로서 최고 육성율을 보였다. 성계 생존율은 평균이 90.14$\%$로서 14회의 92.6$\%$에 비슷 하였으며 13구는 97.98$\%$로서 상당히 좋은 성적을 보였으며 6구, 7구 9구, 10구 및 11구는 90$\%$이하로 성계생존율은 5회 점검 이후 점차 높아 졌는데 이유는 MD백신이 개발되어 이의 접종으로 인한 마렉병의 발생을 예방 할 수 있었던 것으로 생각된다. 2. 성 성숙일령 15회 검정에서 13개 계군의 평균 성 성숙 일령은 163일에서 14회 161일과는 비슷하였는데 성 성숙 일령은 육성기의 사료 급여와 사양관리에 따라서 영향을 많이 받는 형질이므로 더 이상의 고찰이 필요하지 않다. 성 성숙이 제일 빠른구는 5구의 154일이었고 늦은 구는 9구의 168일 이었는데 그 차는 14일이였다. 3. 산란율 및 산란지수 이번 검정계군의 평균 산란율은 70.14$\%$로서 14회에 73.8$\%$와 약 3.6$\%$가 낮았다. 한편 최고 산란율을 나타낸 구는 5구의 73.86$\%$였으며 산란율이 제일 낮은 구는 11구의 65.95$\%$였다. 산란지수의 평균은 232.02로서 14회의 246.5보다는 14.5개가 적었는데 이는 산란율에서와 같은 경향치 였다. 최고 산란 지수를 보인 구는 5구의 250.69였고 2구와 3구, 8구, 13구도 240이상으로서 상당이 좋은 성적을 보였으며 9구는 204.82로서 산란지수가 최하위 였고 최상위와 최하위와의 산란지수의 차이는 무려 45.87이었다. 4. 사료 요구율 13개 계군의 평균사료 요구율은 2.67로서 14회 2.68과 비슷하였다. 사료 요구율이 제일 낮았던구는 3구의 2.56이였고 사료 요구율이 제일 높았던 구는 9구의 2.78이였다. 5. 난중 13개 계군의 평균난중은 60.72g으로서 14회 59.08g보다는 약간 무거웠는데 난중은 다른 형질에 비하여 유전력이 높은 형질인 것을 감안할 때 사양관리 면에서의 영향이 아니고 출품계군의 구성에 의한 영향인 것으로 생각된다. 8회 검정 성적 중 난중이 제일 무거운 구는 4구의 63.32g이었고 제일 가벼운 구는 5구의 58.08g이었다. 6. 체중 300일령 평균체중은 1,966.33.g으로 14회 1,986.7g보다는 가벼웠는데 체중 역시 유전력이 높은 형질로서 이 차이는 검정계군의 구성에 따른 차이로 생각 된다. 500일령 체중의 평균은 1,985.68g으로 14회의 1,994.9g보다는 약간 가벼웠으나 500일령 체중에 있어서와 같이 검정계군의 구성에 따른 차이로 생각 된다. 7. 사료 섭취량 육추기간 중의 1일 1수당 평균사료 섭취량은 32.97g으로 14회 34.82g보다 적었는데 이것 역시 출품계군의 구성에 있어 겸용종 내지 유색종의 비율이 낮았던 데에 기인한 것으로 생각된다. 육성기의 1일 1수당 사료섭취량은 70.06g으로서 14회의 70.91g과 같았고 산란기간 중의 1일 1수당 사료섭취량은 평균이 113,54g으로서 14회 115.81g과 비교할 때 큰 차가 없었으며 특히 11구는 118.61g으로 가장 사료를 많이 섭취 했는데 산란기 수당 사료 섭취량은 해가 거듭될수록 적어지는 경향이었다. 8. 경제성 13개 검정계군이 총 수입은 45,405원으로 계란 판매 수입은 86.4$\%$였고 폐계 판매수입은 13.59$\%$였으며 총 지출은 33,657원으로 사료비의 지출비율이 95.5$\%$였고 초생추대가 4.5$\%$였다.