• Korean Journal of Poultry Science
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• v.33 no.4
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• pp.283-293
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• 2006

Two experiments were conducted to investigate the effects of dietary activated charcoal mixed with wood vinegar (AC) on broiler performance and antibiotics residue in eggs. In experiment 1, a total of low hundred fifty, 1-day-old male broile. chicks (Ross) were divided into 6 groups, consisting 3 replicates of 25 birds each, and 134 one of the six experimental diets: devoid of AC and antibiotics (negative control), devoid of AC with 0.1% antibiotics (positive control), devoid of antibiotics with 1% AC, with 0.1% antibiotics and 1% AC, devoid of antibiotics with 2% AC, with 0.1% antibiotics and 2% AC, for 5 wks. Feed consumption and body weights were measured weekly. At the end of the experiment, eight birds from each group were selected and sacrificed. The relative weight of organs and characteristics of breast muscle were investigated. There were no significant differences in feed intake, body weight gain and feed conversion rate among the treatments. There were also no significant differences in the relative weight of breast meat, leg and liver. The abdominal fat tended to be decreased by the dietary AC. Significant differences were shown (P<0.05) in meat redness (a) and yellowness (b) among the treatments. However, the sensual characteristics of breast muscle was not affected by the dietary treatments. There were significant differences in total microbes, Coli forms and lactic acid bacteria (P<0.05) among the treatments. In experiment 2, a total of ninety, 40-wk-old Hy-line Brown laying hens were divided into 3 groups, consisting 3 replicates of 10 birds each and fed medicated control diet devoid of AC or diets containing 1% AC and 2% AC for 2 wks. The residue of antibiotics in Plasma and egg Yolk were significantly decreased (P<0.05) in 2% AC group compared to that of control. This study suggest that dietary AC may improve the external quality of edible meat and reduced antibiotics residue in chicken eggs without affecting laying performance.

• 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.34 no.3
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• pp.207-215
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• 2007

This work was carried out to assess the effect of microbial phytase (MP) on the performance, retention and excretion of phosphorus, and nutrients availability in broiler chicks. Two hundred and sixteen one day old Ross strains broiler chicks were used to investigate on performance for 5 weeks (earlier $(0{\sim}2wk)$, finisher $(3{\sim}5wk)$) and were divided 3 treatments, three cages per treatment and 12 birds per cage. Treatments are P0 (basal diet), P1 (microbial phytase 300 FTU/kg), and P2 (microbial phytase 600 FTU/kg). After 5 weeks, three diets containing 0, 300, 600 FTU/kg of microbial phytase were fed to 5-wk-old broilers to assess the digestibility. Twenty seven broilers were divided into 3 treatments (9 birds per treatment) to investigate on the absorption and retention of phosphorus and nutrient digestibility. Body weight gain and feed efficiency were highly significant at P1 and P2 treatments compared to those of P0 (P<0.05), however, feed intake was no significant difference among all treatments (P>0.05). The excretion of phosphorus decreased in P1 and P2 compared to P0 (P<0.05). The digestibility of nutrients and amino acid was high in P1 and P2 treatments compared to P0 (P<0.05). Ileal digestibility was lower about $1{\sim}2%$ than feces digestibility (P>0.05). Finally, microbial phytase influenced on the performance, the retention and excretion of phosphorus and ileal and feces digestibility in broilers.

• Korean Journal of Poultry Science
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• v.34 no.3
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• pp.217-222
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• 2007

This study was conducted to investigate the effects of mud flat bacteria origin protease supplementation by crude protein level on growth performance, nutrient digestibility, total protein and BUN (blood urea nitrogen) concentration in broilers. A total of four hundred eighty broilers were randomly allocated into four treatments with six replications for five weeks. Dietary treatments included 1) high crude protein diet, 2) high crude protein diet + 0.1% protease, 3) low crude protein diet and 4) low crude protein diet + 0.1% protease. During the entire experimental period, weight gain and feed/gain were improved in treatments of high crude protein diets and low crude protein diet added protease compared with treatment of low crude protein diet without protease (P<0.05). Similarly, DM digestibility was also improved in treatments of high crude protein diets and low crude protein diet added protease compared with treatment of low crude protein diet without protease (P<0.05). N digestibility was improved in treatment of high crude protein diet added protease compared with low crude protein diet without protease (P<0.05). Total protein concentration in blood was increased in treatment of high crude protein diet without protease compared with other treatments (P<0.05). In conclusion, mud flat origin protease was effective in improving weight gain, feed/gain and nutrient digestibility, and influenced blood total protein in broilers.

• Korean Journal of Poultry Science
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• v.34 no.3
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• pp.231-236
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• 2007

A feeding trial was conducted to study the effects of dietary supplement of fermented clay mineral (FCM) on the growth performance and immune stimulation in broiler chickens. A total of 36,800 broilers, (of) Ross strain-208, were randomly allotted into 2 experimental (diet) groups. Control group was fed the basal diet (corn-soybean meal based), and treatment group was fed the natural clay mineral that was fermented with aboriginal microorganisms at $37^{\circ}C$ for 72 h. Feed and water were provided ad libitum throughout the experiment for 5 weeks of experimental feeding period. Daily weight gain of treatment group fed 0.3% fermented clay mineral was significantly increased in comparison with control group. Feed intake of treatment group was significantly increased 21.4% (p<0.05), and feed efficiency was also increased 2.7% compared to control group. Especially, growth rate and production index of treatment group were significantly higher as much as 4.4% and 4.8%, respectively, than those of control group (p<0.05). By the feeding of dietary 0.3 % FCM, the antibody productions against Newcastle Disease and Infectious Bursal Disease antigens were shown to increase 13.8 % and 15.7 %, respectively, more than control group chickens. From these results, it appears that the supply of fermented clay mineral at 0.3 % level in the broiler chicken diet could enhance the growth performance and immune stimulation of broiler chickens.

• Korean Journal of Poultry Science
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• v.34 no.3
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• pp.173-180
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• 2007

This study was conducted to evaluate conjugated linoleic acid (CLA) precursor and produce supplementation on egg production, egg quality and blood immunological parameters in laying hens. The total of 252 (32-wk) Hy-line brown commercial hens were used for 5 weeks. Dietary treatments included 1) CON (basal diet + oat 1% + soybean oil 1%), 2) WOS (basal diet + whey 0.5% + oat 0.5% + soybean oil 1%), 3) WS (basal diet+ whey 1% + soybean oil 1%), 4) WOCLA (basal diet + whey 0.5% + oat 0.5% + CLA produce 1%), 5) WCLA (basal diet + whey 1% + CLA produce 1%) and 6) FOCLA (basal diet + Fish oil 0.5% + oat 1% + CLA produce 0.5%). For 4 weeks egg shell thickness was higher in WOS and FOCLA treatments than WOCLA and WCLA treatments (P<0.05). Egg weight was significantly increased (P<0.05) in WOS and FOCLA treatments compared to WS and WCLA treatments for 4 weeks. From 4 to 5 weeks yolk high, yolk color and haugh unit were significantly higher in FOCLA treatment than CON treatment (P<0.05). IgG concentration of blood was increased in WOS and FOCLA treatments compared to CON, WS and WOCLA treatments(P<0.05). In conclusion, fish oil, CLA produce and oat supplementation in laying hens diet improve egg shell thickness, yolk high, yolk color and haugh unit, also, CLA precursor supplementaion in laying hens diet improve IgG concentration of blood higher than CON treatment.

• Korean Journal of Poultry Science
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• v.35 no.1
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• pp.15-20
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• 2008

This study aimed at evaluating the effects of a molting diet method in molt induction and post-molt performance of laying hens. Eighty-one ISA Brown hens at 62 wk of age were randomly divided into three groups. After a 4-wk preliminary period, a control group was fed a corn-soybean-based layer diet, and for the other groups, molting was induced by starvation (MS) or feeding a molting diet (MD). For the MS group, feed was withdrawn for 2 wk; this was followed by feeding a layer diet every other day for 1 wk and then the control diet. The MD group was fed a molting diet containing low-protein and low-energy diet based for 4 wk; this was followed by feeding a layer diet. They had a free access to their diet and water. Egg production, egg quality, feed intake, and ovary and oviduct weights were measured throughout the experimental period. During molting, the feed intake in the MD group was lower than that of the control. Body weight of the molted groups was significantly reduced. The MS group feeding totally ceased egg production within 4d; after the initiation of feeding and decreased; in the MD group, egg production to 9.3% by d 10. On d 14, the ovaries and oviducts of the molted groups were distinctly lighter than those of the control. Throughout the post-molt period, egg production and egg shell thickness of the molted group improved; but there were no significant differences. Eggs from the MD-fed or control group were heavier than those of the MS-fed or control group. Finally, feeding of a low-protein and low-energy diet effectively induces molting and increase post-molt production, but further research will be conducted to determine the effects of the molt diet with other ingredients and to reduce the energy level of the molt diet for maximizing molt induction and post-molt egg quality.

• Korean Journal of Poultry Science
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• v.35 no.1
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• pp.21-27
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• 2008

This study was conducted to evaluate the effects of mineral and vitamin-enhanced supplementation on egg production, egg quality and concentrations of calcium and phosphorus in serum of spent laying hens. A total of 240 (72-wk-old) Hyline brown commercial hens were used in the current trial for 4 weeks. Dietary treatments included 1) CON (basal diet), 2) ESS1 (basal diet + Egg shell strengthen 0.1%), 3) ESS2 (basal diet + Egg shell strengthen 0.2%) and 4) FESS (basal diet + Fe egg shell strengthen 0.2%). During the overall period, egg production was increased in CON and ESS2 treatments compared with ESS1 treatment (P<0.05). Egg shell breaking strength and final egg shell thickness were significantly higher in ESS2 treatment than CON and FESS treatments (P<0.05). Egg yolk color index was significantly lower in ESS1 treatment than other treatments (P<0.05). Moreover, Haugh unit was significantly lower in ESS1 and FESS treatments than CON treatment (P<0.05). Mineral- and vitaminenhanced supplementation did not affect either egg shell color or calcium and phosphorus concentration in serum. In conclusion, mineral- and vitamin- enhanced supplementations of laying hens diet are helpful in improving egg shell breaking strength and thickness by supplementation of Egg shell strengthener 0.2%.

• Korean Journal of Poultry Science
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• v.44 no.1
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• pp.19-28
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• 2017

The eggshell is an intricate and highly ordered structure composed of multiple layers and a calcified matrix. The eggshell is formed at the uterine segment of the chicken oviduct. In this study, histological changes in the uterine endometrium and the expression of the eggshell-related genes were investigated according to hen age. We analyzed the expression of eggshell protein-related genes, such as OCX-32, OCX-36, OC-17, OC-116, and eggshell-ion-related genes, such as CABL-1, SPP1, SCNN1G, ATP2A2, CA2, and CALM1. In chicken uterine endometrium, histological deformation, fibrosis, atrophy and elimination of micro-villi were found with increasing hen age. The concentration of blood-ion components did not significantly change with age. The amount of telomeric DNA in uterine endometrial cells decreased with increasing hen age. The expression of most of the eggshell-related genes changed significantly with increasing hen age. The expression of some ovo-proteins, which play a role in eggshell formation, increased with increasing hen age; however, there were no significant correlations among eggshell protein genes. Eggshell ion-related genes, such as ATP2A2, SCNN1G, CA2, and CALM1, were closely related to each other. The OCX-32 and OCX-36 genes were closely related to some of the eggshell ion genes. Eggshell protein-related genes, such as the OCX-32, OCX-36 genes and ion-related genes such as CALB-1, ATP2A2, SCNN1G, CA2, CALM1, affected eggshell formation, mutually or independently. This study shows that, uterine although endometrial cell damage occurs with increasing hen age, normal eggshells can be formed in old hens. This suggests that eggshell protein-and eggshell ion-related genes also control the homeostasis of eggshell formation.

• Korean Journal of Poultry Science
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• v.44 no.1
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• pp.1-9
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• 2017

The objective of the present study was to determine the expression of genes associated with lipopolysaccharide (LPS)-induced stressor in two breeds of chickens: the Korean native chicken (KNC) and the White Leghorn chicken (WLH). Forty chickens per breed, aged 40 weeks, were randomly allotted to the control (CON, administered the saline vehicle) and LPS-injected stress groups. Samples were collected at 0 and 48 h post-LPS injection, and total RNA was extracted from the chicken livers for RNA microarray and quantitative real-time polymerase chain reaction (qRT-PCR) analyses. In response to LPS, 1,044 and 1,193 genes were upregulated, and 1,000 and 1,072 genes were downregulated in the KNC and WLH, respectively, using a ${\geq}2$-fold cutoff change. A functional network analysis revealed that stress-related genes were downregulated in both KNC and WLH after LPS infection. The results obtained from the qRT-PCR analysis of mRNA expression of heat shock 90 (HSP90), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), activating transcription factor 4 (ATF4), sterol regulatory element-binding protein 1 (SREBP1), and X-box binding protein 1 (XBP1) were confirmed by the results of the microarray analysis. There was a significant difference in the expression of stress-associated genes between the control and LPS-injected KNC and WLH groups. The qRT-PCR analysis revealed that the stress-related $HSP90{\alpha}$ and HMGCR genes were downregulated in both LPS-injected KNC and WLH groups. However, the HSP70 and $HSP90{\beta}$ genes were upregulated only in the LPS-injected KNC group. The results suggest that the mRNA expression of stress-related genes is differentially affected by LPS stimulation, and some of the responses varied with the chicken breed. A better understanding of the LPS-induced infective stressors in chicken using the qRT-PCR and RNA microarray analyses may contribute to improving animal welfare and husbandry practices.