• Korean Journal of Poultry Science
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• v.30 no.1
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• pp.61-66
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• 2003

This study was conducted to investigate the effects of dietary germanium biotite supplementation on egg quality and fecal noxious gas content in laying hens. One hundred and forty-four 40-wk-old, ISA Brown layers were used in this experiment. Dietary treatments were 1) CON(control diet), 2) GB0.5(control diet + 0.5% germanium biotite), 3) GB1.0 (control diet + 1.0% germanium biotite) and 4) GB1.5(control diet + 1.5% germanium biotite). Hen-day egg Production and egg shell breaking strength were not influenced by germanium biotite supplementation. However, egg weight decrease as the level of germanium biotite supplementation increased in the diets increased(Cubic effect, p<0.02). Eggshell thickness, yolk color and yolk index were not influenced by garmanium biotite supplementation. Serum triglyceride concentration as dietary germanium biotite increased (linear effect P<0.02; quadratic effect, p<0.05). Dietary supplementation of germanium biotite reduced fecal NH$_3$-N concentration (P<0.01), propionic acid(P<0.01), butyric acid( P<0.05) and acetic aicd(P<0.01) concentrations in the feces. In conclusion, the results of this experiment indicated that dietary germanium biotite supplementation did not affect egg shell quality, but reduced fecal NH$_3$-N concentration.

• Korean Journal of Poultry Science
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• v.34 no.2
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• pp.119-128
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• 2007

The effects of microbial phytase on laying performance, egg quality, and ileal digestibility of nutrients and amino acids were examined at three levels of phytase (0, 300, 600 unit/kg) in 55-wk-old White Leghorn for 4 weeks. Egg productivity tended to increase with supplemental phytase compared to that of control. Daily feed intake of hens fed phytase also increased. Egg shell thickness was not significantly different among the treatments. Haugh unit and yolk color were not statistically different. However, egg shell breaking strength was high at phytase treatment. Excretion and absorption of nitrogen were no difference among all treatments, but those of phosphorus was higher in the phytase treatment than control. The digestibility was high at crude fiber, crude ash, calcium and phosphorus in nutrients, at lysine, methionine and phenylalanine in essential amino acids, and alanine, cystine, glutamic acid, glycine and tyrosine in non-essential amino acids. In conclusion, supplemental microbial phytase in laying hens diet may help to improve egg production and to decrease P of feces. But, further studies were needed to investigate on the digestibility.

• Korean Journal of Poultry Science
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• v.32 no.3
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• pp.219-224
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• 2005

This study was carried out to investigate the effect of feldspar on laying Performance and e99 qualify in hens. A total of 96 'Tetra Brown' layers were assigned to 4 treatments in a completely randomized design. Each treatment consisted 4 replicates accommodating 6 layers per replication. Experiment diets were a control diet without feldspar and supplemented 0.5, 1.0 and $1.5\%$ feldspar. The egg Production rate was significantly increased in layers 134 diets supplemented 0.5 and $1.0\%$ feldspar compared to that of control (P<0.05). Egg weight, egg mass, feed intake, feed conversion ratio, egg shell strength and egg yolk color were not significantly different among the treatments (P>0.05). The haugh unit and blood spot of the eggs were significantly increased in $1.5\%$ feldspa. diets compared to that of control (p<0.05). However, the albumen index and meat spot in the eggs were not statistically different among treatments (P>0.05). Sensory evaluation traits were not significantly differed in terms of appearance, color, texture flavor and overall acceptability of eggs (P>0.05). The juiciness of boiled eggs was significantly increased in eggs of birds fed $1.0\%$ feldspar diets(P>0.05).

• Korean Journal of Poultry Science
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• v.30 no.4
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• pp.281-287
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• 2003

This experiment was carried out to study the effect of dietary Monascus culture on the cholesterol contents of egg yolk, muscle and serum of layers with 180 Isa-Brown laying hens for 10 weeks. Control group(C) was fed the commercial laying hen diet and 2.67(T1), 5.33(T2) and 8.00(T3)% of Monascus culture which contained 0.6% monacolin-k added to control diet so as to supply the monacolin-k 20(T1), 40(T2) and 60(T3) mg respectively, per hen-day with 125g diet. Hen-day egg production and average egg weight were not affected by the dietary Monascus culture, but feed intake and feed conversion per kg egg were significantly decreased(P<0.05) as the dietary Monascus culture increased. Cholesterol contents of egg yolk measured 4~5 weeks after feeding the Monascus culture and those of thigh meat measured at the end of experiment were significantly decreased(P<0.05) as the dietary Monascus culture increased. Average cholesterol contents of serum showed a trend to decrease as the dietary Monascus culture increased without significant difference.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.121-126
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• 2020

This study was conducted to investigate the effect of drinking ion water on the performance, egg quality, and serum biochemical properties of laying hens in a high-temperature environment. A total of 180 laying hens with equal egg production rates were randomly divided into three treatments with five replicates. Treatments were applied from 24 to 27 weeks of age and included the supply of ion water (IW), tap water (TW), and cold water (CW). The results showed that the egg production rate, egg weight, and feed intake of hens were significantly (P<0.01) improved in the IW group compared with those in the TW group but did not differ from those in the CW group. Egg quality parameters such as albumen height, Haugh unit, and eggshell thickness were found to be higher in the IW than in the TW group (P<0.05); however, no significant differences were observed in comparison with the CW group. Serum Ca and P concentrations tended to increase (P<0.10) in the IW group, and serum high-density lipoprotein cholesterol and albumin levels were greater (P<0.05) in response to IW than those to TW. This study provides evidence that the supply of IW can relieve the high-temperature stress during the summer. In particular, because the improved effects of the IW were confirmed to be similar to those of CW, it shows potential as a method to manage the drinking water of hens in the summer season along with the supply of CW.

• Korean Journal of Poultry Science
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• v.29 no.2
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• pp.89-94
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• 2002

This study was performed to evaluate effects of different holding temperatures and storing periods during the pre-incubation period on egg hatchability of hens egg in broiler breeders. For the treatments 1(T1)~7(T7), which were stored fur 1(T1) to 7 days(T7) before egg incubation, respectively. There were three replicates per treatment and forty eggs per replicate. This study was performed twice, which were 40(Summer) and 50 weeks of age(Autumn) in broiler breeders. Storing ambient temperature of egg, egg weight, at 0 and 18 days during incubation, fertility, hatchability and embryo mortality were examined. Average hatchability was rapidly decreased only in Summer. Although it was not significantly different in Autumn. This experiment was concluded that storing periods of hatchery egg was influenced hatchability, especially in high ambient temperature conditions(Summer, above $25^{\circ}C$ ). In conclusion, we found out that optimum hatchability can be achieved with a storage temperature of 13 ~$19^{\circ}C$ for broiler breeder eggs stored for up to 7 days.

• Korean Journal of Poultry Science
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• v.30 no.2
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• pp.107-112
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• 2003

This experiment was conducted to study the optimum energy feeding system for broiler breeders peaked in summer season with 400 caged hens of Ross strain. Four of energy supply series which were different in daily energy allotment during laying period were employed for 40 weeks from 24 to 64 weeks of age. All experimental diets were formulated to contain 2,750 kcal ME/kg with adjustments made in total feed allotment to provide the desired energy levels. Total consumption of the feed would provide 20 grams of protein, 4 grams of calcium and 0.35 grams of available phosphorus. There were no significant difference in hen-day egg production and average egg weight among the series of energy supply, but egg production showed a trend to decline as the level of energy allotment increased. Feed, ME and CP conversion and feed cost required per egg or per kg egg were significantly increased as the level of energy allotment increased(p<0.05). It was concluded that the Treatment 1, which supplied 280kcal ME per day at the age of 24 weeks and then increased the energy supply up to 400kcal ME per day at the peak period of 30∼34 weeks of age, was superior in all production parameters.

• Korean Journal of Poultry Science
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• v.25 no.4
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• pp.177-183
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• 1998

A feeding trial was conducted to investigate the performance of various Korean Native Chickens (KNC) for 64 weeks. Eight hundreds and ten KNC one-day birds were arranged to three strains, Dark Brown(D), Light Brown(L) and Black(B). Each strain had three replicates of 90 birds a replicate. Birds fed same diet with Korean standard feeding. Data were obtained growing performance to 20 week of age and laying performance from twenty one to sixty four week. During the growing stage from hatch to 20 week of age, there were not significant difference to three strains on viability, body weight and feed intake. L strain tended to be earlier 50％ egg production day than that of other strains, but was not significantly different. Egg production of L strain was the highest of strains. It showed significantly higher egg production compared to that of D strain(P<0.05), but was not statistically different from that of B strain. Laying peak period was between 28 to 32 week of age in all strains, Egg weight was heavier in D strain(P<0.05). Feed intake was the same as 105g, and feed conversion improved in L strain(P<0.05). There were not difference on interior egg and eggshell quality by strains although eggshell thickness improved slightly in D strain. Fertility of D strain was the highest compared to others(P<0.05) regardless laying stages. Hatchability was not influenced by strains at 39 weeks old, but was significantly higher in B strain at 62 week of age(P< 0.05). The results of this experiment indicated that KNC 3 strains were not effect on egg production, feed intake and feed conversion ratio.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.239-246
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• 2022

This study was conducted to investigate the effects of dietary γ-aminobutyric acid (GABA) and a probiotic mixture on egg production and quality, blood parameters, and stress levels (corticosterone) in Hy-Line parent stock during summer in Korea. A total of 105 Hy-Line parent stock aged 24 weeks were randomly divided into three groups, each containing thirty-five birds: control, γ-aminobutyric acid (GABA), and probiotics (1 × 10⁸/g Bacillus licheniformis, 1 × 10⁷/g Lactobacillus plantarum, and 1 × 10⁷/g Corynebacterium butyricum). The hens were fed a diet containing 50 ppm GABA or 0.1% probiotics for 6 weeks. Compared with the control group, the hen-day egg production, egg mass, and feed conversion ratio over the total period were significantly higher in the probiotic group (P<0.05). In contrast no significant differences were detected among groups with respect to egg weight, albumen height, Haugh units, yolk color, shell thickness or shell strength. Similarly, no significant difference were observed among groups with regards to biochemical profile (total cholesterol, triglyceride, glucose, total protein, aspartate aminotransferase, alanine aminotransferase, albumin, and inorganic phosphorus). However, compared with the control group, we did detect significant reductions in corticosterone levels in the GABA and probiotics groups (P<0.05). On the basis of our findings in this study, it would appear that dietary GABA and probiotics can alleviate heat stress in Hy-Line parent stock, with probiotics in particular being found to promote significant improvements in the hen-day egg production, egg mass, and feed conversion of laying hens during the summer season in Korea.