• Korean Journal of Veterinary Research
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• v.46 no.4
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• pp.371-379
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• 2006

Newcastle disease virus (NDV) is a single-stranded negative sense RNA virus, which has been classified as a member of the Avulavirus genus of the Paramyxoviridae family. It is also one of the most important pathogens in the poultry industry. The glycoproteins, fusion (F) and hemagglutinin-neuraminidase (HN), determine the virulence of NDV, and the relevant molecular structures have already been determined. NDV isolates differ in terms of virulence, and at least 2 of 9 genotypes (I-IX) have been shown to co-circulate. Therefore, it is clearly important to differentiate between vaccine strains and field isolates. In vivo pathogenicity tests have been the standard protocol for some time, but molecular methods appear preferable in terms of the rapidity of diagnosis, as well as animal welfare concerns. In this study, we have designed primer sets from HN gene for phylogenetic analysis and restriction enzyme analysis, and from F gene for pathotype-specific RT-PCR. Via the combination of 2 methods, 106 Korean NDV isolates obtained from 1980 to 2005 were differentiated into vaccine strains, and virulent genotypes VI and VII. The genotype VI viruses were only rarely isolated after 1999, and genotype VII, after it was initially isolated from poultry in 1995, recurred in 2000, and then became the main NDV constituting a threat to the Korean poultry industry.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.159-167
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• 2020

This study investigated the effect of different light sources in the poultry house on performance, meat quality, and blood composition of finishing broilers. Two hundred and forty male broilers (1-day-old, 42.2±0.1 g) were divided into three groups and subjected to different light source treatments (incandescent, LED, and fluorescent lamps) from 3 weeks of age (four replications/treatment, 20 birds/replication). After breeding for 6 weeks, the carcass yield and meat quality of broilers with similar body weight (BW; 3.4±0.07 kg) were investigated, and blood components were analyzed. Corn-soybean meal-based feed was provided as starter (CP 22.5%, ME 3,020 kcal/kg), early (CP 18.5%, ME 3,050 kcal/kg), and finishing (CP 18%, ME 3,100 kcal/kg). Performance, carcass yield, meat quality, and blood components were evaluated. BW, BW gain, feed intake, and feed conversion ratio did not show any significant differences among treatments. There was no significant difference on live weight and carcass yield among treatments. There was no significant difference on meat color, shear force, and water holding capacity; however, cooking loss at 17.2% was the highest in the LED treatment (P<0.05). There was no significant difference on blood components except for glucose (blood biochemistry component) among treatments. Glucose was 234.5 mg/dL, 256.9 mg/dL, and 250.1 mg/dL in the three treatments, respectively, with a significant difference between incandescent and LED treatments (P<0.05). These results are used useful as basic data for investigating the effect of lighting in broilers production.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.456-463
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• 2019

Micro climatic conditions within the livestock facility are affected by various factors such as ventilation, cooling, heating, insulation and latent and sensible heat generation from animals. In this study, numerical BES method was used to simulate energy flow inside the poultry house. Based on the BES method and THI concept, degree of thermal stress of poultry was evaluated according to the locations in South Korea. Comparison of THI values within the poultry house was also carried out according to the stocking densities to reflect recent animal-welfare issue. Significant decrease in thermal stress of poultry was observed when the stocking density of $30kg/m^2$ was applied in the change of the seasons(p<0.05) however, there was no statistically significant difference in summer season(p>0.05). It meant that installation of proper cooling system is urgently needed. For Iksan city of Jeollabuk-do province, total 252 hours of profit for thermal stress was found according to decrease in the stocking density.

• Korean Journal of Poultry Science
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• v.35 no.2
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• pp.171-176
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• 2008

Animal welfare advocates, claim that the induced molting by fasting be avoided. This study was conducted to evaluate the effect of molting induced by various feeding methods on productivity and egg quality in laying hens. We used 400 flocks of 60-week-old leghorn laying hens in four treatments(five replicates of 20 hens each): fasting method (C), feeding single corn grain diet (T1), feeding single wheat bran diet (T2) and feeding single alfalfa meal diet (T3). As the result of the experiment, egg production and daily egg mass significantly decreased only in T1 compared with the control during the $1{\sim}4th$ week after the secondary egg laying (P<0.05). Although the amount of feed intake was significantly less in T1 group during the $1{\sim}4th$ week compared to the control, no significant difference was detected during the total period (P>0.05). In addition, no significant difference of feed conversion was observed between treatment groups. In terms of egg quality, the egg shell thickness was significantly improved in T1 group than the control group by feeding only corn at the 10th and 14th week after the secondary egg laying (P<0.05), but the significant decrease was observed at the corn (T1) and wheat bran (T2) fed treatment groups than the control group at the 26th week of the experiment (P<0.05). The eggshell strength and haugh unit did not show any difference by the molting methods. Egg yolk color was significantly decreased in T1 and T2 group than the control group at the 6th week (P<0.05). However, T1 and T2 group resulted to show significantly high egg yolk color at the 18th week of the experiment (P<0.05). As the result of the experiment, no large difference was observed in the productivity by the feeding molting method and by the fasting induced molting method. In addition, the single diet fed feeding induced molting method by using alfalfa revealed to show more satisfactory trend than the corn or wheat bran single diet fed feeding induced molting methods even if no statistically significant difference was found in terms of egg productivity.

• Korean Journal of Poultry Science
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• v.48 no.1
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• pp.13-22
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• 2021

The present experiment was conducted to evaluate the effect of stocking density on the growth performance, immune status, and meat quality of broilers. In total, 385 one-day-old Ross 308 broilers were randomly assigned to one of four distinct stocking densities: 26 birds/㎡, 22 birds/㎡, 19 birds/㎡, and 16 birds/㎡. They were fed the diet ad libitum for 5 weeks. Immunoglobulin (Ig) and corticosterone levels were evaluated, and growth performance, blood parameters, and breast meat quality were determined. It was observed that the weight gain and feed intake of growers (21~35 d) and broilers (0~35 d) were significantly reduced as the stocking density increased (P<0.05). However, the feed intake of starters (0~21 d) significantly increased as the stocking density increased (P<0.05). There were no significant differences in the biochemical profiles among the four different stock densities. Furthermore, no significant differences were observed in the stress parameters: (heterophils / lymphocytes ratio and corticosterone), IgA, and IgM; however, IgG significantly increased with stocking density (P<0.05). The pH, water holding capacity, and cooking loss of the muscle were all unaffected by the stocking density, but the shear force (tenderness) increased slightly as the density increased. The findings of this study suggest that a lower stocking density (16 birds/㎡) significantly improved the shear force of breast meat and IgG in broilers.

• Korean Journal of Poultry Science
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• v.48 no.3
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• pp.143-150
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• 2021

In this study, we investigated the effects of light intensity on broiler chick growth performance, blood parameters, and stress levels. A total of 240 one-day-old male Ross 308 broilers (47.97±0.166 g) were subjected to three different intensities of light (20, 30, and 50 lx), with each treatment being conducted with four replicates. On the seventh day, the growth performance (body weight, feed conversion ratio, and breast muscle and liver weights) and blood parameters were determined; the levels of serum corticosterone, interleukin-6 (IL-6), and tumor necrosis factor-α were also evaluated. The body weight, weight gain, liver weight, and breast muscle weight of chicks exposed to a light intensity of 50 lx were significantly increased compared with those of chicks subjected to 20 lx (P<0.05). No significant differences were observed in the leukocyte, erythrocyte, and platelet counts and the biochemical profile exceptions being the levels of glucose and inorganic phosphorus in the blood of the chicks in the three light intensity groups. However, serum corticosterone and IL-6 levels were the highest in chicks exposed to a light intensity of 20 lx (P<0.05). In conclusion, the findings of this study indicate that broiler chicks exposed to higher light intensity (50 lx) show significant improvements in terms of weight gain and corticosterone and IL-6 levels. Thus, high light intensities enhanced the growth performance, stress levels, and immune status of broiler chicks.

• Korean Journal of Poultry Science
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• v.49 no.3
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• pp.139-144
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• 2022

This study was conducted to investigate the effect of three different photoperiods on growth performance, blood properties, and stress indicators in broiler chicks between 1-7 days after hatching. Two hundred and fifty-two 1-day-old male broiler chicks (57.0±0.12 g) were divided into three treatments, with 4 replicates per treatment and 22 birds per replicate subjected to three different photoperiods of 24L, 22L/2D and 18L/6D. A light-emitting diode bulb served as the light source, with an illuminance of 30 lx. As an experimental diet, a commercial feed based on a corn-soybean meal, with 22% CP and 3,150 kcal/kg ME diet, and water were fed ad libitum. Body weight gain, feed conversion ratio, and liver weight ratio showed a statistically significant difference between the 18L/6D and 24L treatments (P<0.05), but with no significant difference between the 22L/2D treatment and either the 24L or 18L/6D treatment. The breast meat ratio was 5.59% in the 18L/6D treatment group, which was lower than that of other treatment groups (P<0.05). The triglyceride levels were highest (P<0.05) in the 18L/6D treatment among treatments, but alanine aminotransferase levels were significantly higher (P<0.05) in the 22L/2D treatment than in the 24L treatment. Levels of cytokines, i.e., Interleukin-6 and Tumor Necrosis Factor-α did not show a significant difference among the treatments, but corticosterone content was significantly higher (P<0.05) in the 24L treatment than in the 18L/6D treatment. In conclusion, 22 hours of lighting is appropriate between 1~7 days after hatching, considering growth performance and the overall health of broiler chicks.

• Korean Journal of Poultry Science
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• v.36 no.4
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• pp.329-335
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• 2009

The aim of the present study was to investigate the behavior and performance of male and female broiler chickens reared under three different colors of light (white, blue and red) in a 23L:1D of lighting program. Day-old broiler chicks were obtained and assigned to six pens (16 males and 16 females per pen). Two pens each were located in three different rooms in an environmentally controlled shed and received the different light colors. All birds received same husbandry conditions. After a 3-day adaptation to the light color, behavior observations (pecking, resting, standing and walking) were made on six focal birds per pen, representing the sex ratio, by direct visual scans for 120 minutes daily for five days a week throughout the 5-week study. Body weights and feed intake were recorded at weekly intervals. On days 19 and 33, welfare indicators (tonic immobility reaction on the 19 and 33 days old; gait scores, foot pad and hock burns scores on 33 days old) were determined. Light color had no significant effect (P>0.05) on the weight gain and feed intake of broilers, but significantly (P<0.05) influenced the feed conversion ratio. Birds receiving the blue light were more (P<0.05) efficient than those receiving white and red lights. Resting was observed to be the major behavior pattern, irrespective of sex or light color. During early growth, resting behavior tended to be lower in birds receiving red light. However, standing and walking behaviors tended to be higher in birds receiving red light in 4 to 18 day-old age and all of experimental periods, respectively. These data indicate that light color can influence broiler performance and behavior.

• Journal of Animal Environmental Science
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• v.18 no.3
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• pp.183-190
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• 2012

The objective of this study was to evaluate the effects of an unexpected change in housing environment on stress in poultry. Laying hens (Hy-line Brown), adapted to a free-range housing system for more than a month, were randomly divided into two groups to be subjected to an unexpected change of their housing environment: one half of them were individually housed into conventional battery cages and the other continually left in the same housing system throughout the entire period of the study. The sudden change resulted in an increase in egg production and albumen height (P<0.05), but decrease in eggshell thickness (P<0.05). The change had tendency to increase Haugh unit ($P{\leq}0.061$) and to decrease eggshell color ($P{\leq}0.074$), but did not affect body weight for 5 days thereafter. No significant changes were detected in liver color. Plasma concentrations of corticosterone was acutely increased one day after the change (P<0.05), then returned to similar control levels. The results of the present study indicate that unexpected changes in housing environment cause acute increase in stress hormone concentrations, but interpretation of the results should be cautious due to the experimental conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.2
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• pp.288-296
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• 2001

The behavior of declawed emus in a farm environment has not been described despite its importance in the husbandry and welfare of the emu. This study examined whether declawing of emus causes chronic pain resulting in permanent changes in the locomotor and general behavior of declawed yearling emus compared to emus not declawed. One group of 40 emus were declawed on the day of hatch by removing the distal phalangeal joint using a Lyon beak-trimming machine. Another group of 40 emus not declawed were the controls. Declawed emus one year of age were allocated to a paddock $250m{\times}125m$, while the control group was placed in an adjoining paddock of the same dimensions. One hour video records of individual emus from each treatment were made from 08:00 and 17:00 h over 2 periods; firstly when food and water was available and secondly during a period when food and water was not available after being withdrawn overnight. Inactive, ingestive, posture change, grooming, aggressive and locomotor behaviors were monitored from the videotape. There was no behavioral evidence to indicate loss of locomotor ability of declawed emus or to suggest declawed emus were suffering from severe chronic pain as indicated by declawed emus engaging in significantly more bouts (p<0.05) and time of searching (p<0.05). Declawed emus also engaged in less stereotype pacing (p<0.05) indicating they were under less stress and not as frustrated as control birds which engaged in more step pushing behavior (p<0.05). Modelling analysis showed that pecking behavior in birds was most closely related to foraging behavior. Birds subject to pecking attacks demonstrated higher levels of stereotype behavior presumably as a method to cope with stress. The behavioral evidence in this study would indicate that declawing does not compromise the locomotor ability of emus and has the benefit of improving the social structure in the groups by reducing stereotype behavior and aggression.