• Korean Journal of Poultry Science
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• v.22 no.3
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• pp.167-178
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• 1995

The purpose of this research was to get basic information for the development of Korean native chicken industry by reviewing the current native chicken farm management and marketing situation of native chicken products(meat and eggs). The research was carried on the basis of the farm field survey covering 210 native chicken feeders out of 9 different local areas, and the results were as follows ; 1. Average raising size of native chicken flocks of sample farms was 1,787 heads and about 50% of those farms raised less than 500 heads chickens for self-sufficiency or on the side. 2. Most farmers made the decision to start on feeding native chickens in small scale with small amount of capital without sound feeding program, and their decision was mainly influenced by recommendation of mass-media( 19.5%) and neighbors (17.2%). 3. The average income per farm earned by raising the native chickens was 13,719 Won, and income per head of chicken was 8,800 Won. 4. About 40% of feeders expressed that the poor marketing management and lack of capital were the bottleneck to native chicken farm management. 5. About 70% of feeders evaluated the prospect of native chicken industry positively and so, about 60% of feeders hoped to expand the raising size in the future. 6. Most farmers directry made a bargain with marketer including middleman and enduser in selling the chicken products because there was not established special marketing system for native chicken products. 7. The sales age of native broiler was about 16~20 weeks and average body weight of broiler was 1.5~2.0 kg. And farm recieved price was not decided on the basis of each body weight or meat quality but only number of heads. 8. The average first egg-laying age of chickens was about 165 days and average annual laying rate was only about 56%. 9. In order to develop the successful Korean native chicken industry, followings are recommended ; 1) Reducing the production costs and increasing the productivity of native chickens should be carried out through technological research and development for sound feeding program of native chickens and sufficient fund supply. 2) Orderly native chicken marketing and pricing system should be established to give good vision about native chickens to farmers and to delight the consumers. 3) The measures for product differentiation including meat quality and nutritional value of native chicken products against other improved chickens should be actively taken by feeders and government.

• Korean Journal of Poultry Science
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• v.37 no.1
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• pp.51-62
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• 2010

This study was conducted to investigate the effects of dietary supplementation of multiple probiotics on the performance, small intestinal microflora and immune response in laying hens and broilers. In Exp.1, a total of 800, 82 wk old Hy-line Brown$^{(R)}$ laying hens were assigned to one of the following five dietary treatment; Control, Antibiotics (avilamycin 6 ppm), Probiotics; PB-M (Micro-ferm$^{(R)}$ 0.2%), PB-L (Lacto-sacc$^{(R)}$ 0.1%), PB-Y (Y University probiotics 0.2%). Each treatment was replicated eight times with 20 birds in each replicate and two birds were housed in each cage. Twenty birds units were arranged according to completely randomized block design. Feeding trial lasted 6 wk under 16 h lighting regimen. The Exp. 2, was conducted with a total of 1,000 broilers chicks (Ross$^{(R)}$). They were divided into five treatments, same as those of Exp. 1. Birds were fed starter (0~3 wk) and grower (4~5 wk) diets. Each treatment was replicated four times with 50 birds per pen comprising of deep litter. In Exp. 1, egg production parameters, such as hen-day and hen-house egg production, egg weight, broken and soft shell egg production, feed intake and feed conversion were not significantly different among treatments. However, strength and thickness of eggshell were significantly (P<0.05) different. Among the probiotics, PB-Y showed the highest strength and thickness of eggshell. Eggshell color, egg yolk color and Haugh unit were not significantly influenced. In Exp. 2, overall weight gain (0~5 wk) and mortality were not significantly different among treatments. However, weight gain of birds from PB-Y treatment during starter (0~3 wk) was significantly lower than the birds from Control and Antibiotic treatment. During the whole period (0~5 wk), birds from Antibiotics treatment had higher feed intake and Production Index (PI) and lower feed conversion than birds from Control treatment. Probiotics treatments were not significantly different from the Control on feed intake and feed conversion. In Exp.1, there were significant (P<0.05) differences in leukocytes parameters, such as white blood cell (WBC), hetrophil (HE), lymphocytes (LY), monocyte (MO), eosinophil (EO) and stress index (SI; HE/LY) in the blood of layers. Birds from Antibiotics and probiotics treatments tended to increase these parameters. In Exp. 2, however, only SI was significantly (P<0.05) decreased in Antibiotics treatments. Concentration of serum immunoglobulin (IgG) were higher (P<0.05) in PB-M and PB-Y treatments when compared with Control treatment in Exp. 1. The population of E. coli significantly (P<0.05) decreased in birds from Antibiotics, PB-L and PB-Y treatments when compared with birds from Control treatment in Exp. 1. Metalbolizability of crude fat decreased significantly (P<0.05) in birds from probiotic treatments in Exp. 2. It was concluded that the response of probiotics on the productivity of layers and broilers were different. Probiotics increased strength and thickness of eggshell in layers, and decreased feed conversion and increased PI in broilers. Leukocytes and IgG tended to increase by supplementation of antibiotics and probiotics in layers. Intestinal E. coli tended to decrease in layers. Digestibility of crude fat of diet decreased in probiotics treatments broilers. Parameters of blood and microbial were more sensitive in layers than broilers.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.3
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• pp.401-412
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• 2000

Like other livestock, monogastric animals are essential components of the farming systems in the tropical countries. Pigs, chicken and ducks are by far the most important animals in the culture of the peoples of developing countries in the tropics. Traditionally these animals are raised in small farms and they are also the bulk producers of meat, eggs etc. in the tropics. In many countries the farmers of these small farms are unable to meet the requirement set by financial institution and other loan giving agencies for agricultural loan. Thus, the small farmers can get neither the opportunity to generate sufficient income to support the family nor to extend the livestock activities. The production systems are characterized by small number of animals with no or minimal inputs, low outputs and periodic destruction of animals by disease. Typically the litter size or flocks are small in number with each household containing 5-6 pigs and 7-10 poultry. Animals are owned by individual households and mostly maintained under a scavenging systems with little or no inputs for housing, feeding or health care. Because of the nature of this production system, productivity of these animals is rather low. The low level of inputs is due to a lack of capital and a low risk oriented outlook. The feed resource base for monogastric is scavenging and consists of household waste, roots and tuber, grain by-products and anything edible found in the immediate environment. Usually farmers select breeding gilts from their own female piglets or to a lesser extent, buy them from neighbors for natural mating. As regards poultry attempts have been made to increase egg and meat production by improving local poultry birds by upgrading and crossbreeding with exotic germ plasma in the tropics. Animal disease present a major constraint to animal production in the tropical region and the extent of the losses due to disease is very high.

• Animal Bioscience
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• v.36 no.11
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• pp.1727-1737
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• 2023

Objective: The poultry industry is a primary source of animal protein worldwide. The gut microbiota of poultry birds, such as chickens and ducks, is critical in maintaining their health, growth, and productivity. This study aimed to identify longitudinal changes in the gut microbiota of laying hens from birth to the pre-laying stage. Methods: From a total of 80 Hy-Line Brown laying hens, birds were selected based on weight at equal intervals to collect feces (n = 20 per growth) and ileal contents (n = 10 per growth) for each growth stage (days 10, 21, 58, and 101). The V4 regions of the 16S rRNA gene were amplified after extracting DNA from feces and ileal contents. Amplicon sequencing was performed using Illumina, followed by analysis. Results: Microbial diversity increased with growth stages, regardless of sampling sites. Microbial community analysis indicated that Firmicutes, Proteobacteria, and Bacteroidetes were the dominant phyla in the feces and ileal. The abundance of Lactobacillus was highest on day 10, and that of Escherichia-shigella was higher on day 21 than those at the other stages at the genus level (for the feces and ileal contents; p<0.05). Furthermore, Turicibacter was the most abundant genus after changing feed (for the feces and ileal contents; p<0.05). The fecal Ruminococcus torques and ileal Lysinibacillus were negatively correlated with the body weights of chickens (p<0.05). Conclusion: The gut microbiota of laying hens changes during the four growth stages, and interactions between microbiota and feed may be present. Our findings provide valuable data for understanding the gut microbiota of laying hens at various growth stages and future applied studies.

• Korean Journal of Agricultural Science
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• v.14 no.1
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• pp.26-37
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• 1987

This studies were conducted to investigate pathgenicity and host range of Colletotrichum dematium isolated from anthracnose of pepper, and phytoxicity of its culture filtrate and the partially purified toxin. The results obtained were as follows. 1. Investigation on the host range of C. dematium has revealed that pepper as well as soybean, tomato, spinach, and beet were highly susceptible, egg plant and water melon were moderately susceptible and stone leek was slightly suceptible, but no symptoms were produced on carrot, tabacco, cucumber and melon. 2. The culture filtrates of C. dematium in Czapeck dox liquid media were toxic to leaves of pepper and caused necrosis and wilting of the plant. The toxicity of culture filtrates was most active at 15 days after fungal growth in Czapeck dox liquid media and the toxin productivity in still culture was higher than that in shaking culture. 3. The partially purified toxic substance was isolated from the culture filtrates by the acetone precipitation method. When cuttings of various pepper cultivars were placed in the toxin solutions, suceptible cultivars and resistant cultivars were equally toxic and showed necrosis and wilting of the leaves. 4. Several other plants such as soybean, tomato and carrot were also affected with the toxin solution by shoot cutting bioassay and showed veinal necrosis, leaf spots and wilting of the shoots. 5. The acetone precipitation toxin affected seed germination of pepper, cucumber, sesame and egg plant and inhibited the growth of root and hypocotyl of the seedlings.

• Korean Journal of Poultry Science
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• v.11 no.1
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• pp.49-64
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• 1984

During the 1978-79 Newcastle disease (ND) epizootic period, a detailed survey was conducted on the five representative farms which had been following one of the recommended vaccination programs. When the disease broke out during laying period, clinical symptoms were mild to moderate respiratory distress and greenish diarrhea. Affected flocks experienced weekly mortality from less than 1% to 17%. Egg production returned to normal 18 to 36 days after the initial signs appeared although some flocks never returned to normal. On postmortem examination,, most affected chickens showed severe hemorrhagic lesions in the duodenum, hematoma on ova, and heavy fat accmulation on various visceral organs. Most of the NO affected flocks had geometric mean hemagglutination inhibition antibody(HIA) titers of 7 log$_2$ or higher two to three weeks after the appearance of clinical signs. These HIA titers were at least 16-fold higher than those before infection. Flock mean HIA titers before infection were usually lower than 3 log$_2$. Severity of clinical signs and anamnestic antibody response were maximum in the flocks whose vaccination immunity was insufficient or waned considerably. Observations showed that even young birds, if properly vaccinated, could get effective protection from field ND exposure.

• Korean Journal of Poultry Science
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• v.42 no.3
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• pp.205-214
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• 2015

This study aimed to investigate the effects of reducing feed intake on performance and meat quality in old laying hens. A total of 200 Hy-Line Brown laying hens (100 weeks old) were randomly allotted to five dietary treatments: control (100% daily feed intake), 90%, 60%, 50%, and 20% daily feed intake. Each treatment was replicated four times with 10 birds per replication and two birds per cage. Ten-bird units were arranged according to a randomized block design. The feeding trial lasted for 4 weeks under a 16L:8D lighting regimen. The results indicated that the daily feed intake correlated with hen-day egg production and feed conversion ratios (P<0.05). The carcass yields and partial ratios were also correlated with daily feed intake (P<0.05). The levels of leukocytes (without basophils) were higher in the 50% and 20% daily feed intake groups than in the other groups. The concentrations of dry matter, crude ash, crude fat, and crude protein, water holding capacity, cooking loss, and fatty acids in the breast meat did not decrease as the daily feed intake decreased. In conclusion, reducing daily feed intake decreased laying performance and carcass yield but had no effect on breast meat quality.

• Korean journal of applied entomology
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• v.58 no.3
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• pp.175-182
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• 2019

The citrus leafminer, Phyllocnistis citrella (Lepidoptera: Gracillaridae), is an important pest that decreases the productivity of citrus trees by attacking citrus leaves, and especially it causes a severe damage during the young growth stage. In this study, we investigated the distribution of eggs on the leaves of shoots according to the position and the survival rate of this pest in the field condition. The occurrence patterns of P. citrella eggs in citrus orchards were largely affected by the occurrence of shoots. Even if the adults were still being attracted in the pheromone traps, the eggs were not observed on leaves when the growth of shoots was stopped. The density of P. citrella eggs in the citrus shoots peaked at the fifth or sixth leaf from the terminal leaf, and over 90% of the eggs were found in the first to eighth leaves as a whole. In 2015 and 2016, the average survival rate of larvae surviving to pupa was 1.4%, and the rate of survival to adults was 0.2%, indicating that most of them died. Furthermore, we have discussed the management strategy of P. citrella considering the distribution of eggs and the larval survival rate in the citrus shoots.

• Korean Journal of Poultry Science
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• v.16 no.2
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• pp.105-127
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• 1989

Although poultry industry in Japan has been much developed in recent years, it still needs to be developed , compared with developed countries. Since the poultry market in Korea is expected to be opened in the near future it is necessary to maximize the Productivity to reduce the production costs and to develop the scientific, technologies and management organization systems for the improvement of the quality in poultry production. Followings ale the summary of poultry industry in Japan. 1. Poultry industry in Japan is almost specized and commercialized and its management system is ： integrated, cooperative and developed to industrialized intensive style. Therefore, they have competitive power in the international poultry markets. 2. Average egg weight is 48-50g per day (Max. 54g) and feed requirement is 2. 1-2. 3. 3. The management organization system is specialized and farmers in small scale form complex and farmers in large scale are integrated.

• Korean journal of applied entomology
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• v.53 no.3
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• pp.199-207
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• 2014

It is true that the proper environmental risk assessments for many GM (Genetically Modified) insects almost have not been executed in Korea. Therefore, we tested the environmental risk assessment about GM silkworms if there is any difference between GM silkworms and non-GM silkworms by the following three measurements. First, we measured their mobility in the breeding environment conditions with food and without food. Secondly, we measured their viability at the artificial extreme environmental conditions (low and high temperature and humidity, absent/present of foods,) after escaping from their breeding environments. Thirdly, we observed the number of laying eggs and their hatchability between GM silkworms and non-GM silkworms with four different pair experiments. The mobility of GM silkworms and non-GM silkworms statistically did not differ, and the egg productivity and hatchability were not also different. The hatchability by couple of GM female silkworms and non-GM male silkworms was lower than by non-GM male and female couple between the GM silkworms and non-GM silkworms, and there was statistically different. Relatively, the viability of GM silkworms was lower than non-GM silkworms. We could not exactly test for viability of silkworms in low temperature conditions because of their hibernating. Although there was any difference in viability and hatchability between GM silkworms and non-GM silkworms, all ability of GM silkworms was lower than non-GM silkworms. Conclusively, the environmental risk of GM silkworm was relatively lower than non-GM silkworm in this study.