• Korean Journal of Poultry Science
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• v.36 no.1
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• pp.15-21
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• 2009

A 10-wk layer feeding trial was conducted to investigate the effects of high quality corn distiller's dried grains with solubles (DDGS) on performance, egg qualities, and yolk fatty acid composition. The economics of using DDGS in the Korean situation was also analyzed. A total of 216 Hy-line Brown layers, 23-wk of age, were employed in this trial consisting of three dietary treatments (0%, 10%, and 20% DDGS), and six replicates per treatment. All experimental diets were prepared as iso-protein (17%) and iso-calorie (2,780 kcal/kg). The use of DDGS up to 20% in layer diets did not affect the feed intake, laying rate, egg weight, and feed conversion ratio (P>0.05). At 5th and 10th wk of the trial, the eggshell color, albumen height, and Haugh unit were not influenced by the DDGS supplementation. At 5th wk of the trial, the eggshell qualities, like eggshell weight, eggshell thickness, and eggshell strength, were not affected by the DDGS feeding; however, these eggshell qualities were decreased at 10th wk due to the 20% DDGS feeding (P<0.05). Yolk color of DDGS 20% increased compared to DDGS 0% at 5th and 10th wk of the trial (P<0.05). At 10th wk, yolk/egg ratio of DDGS 20% decreased compared to DDGS 0% (P<0.05). The yolk fat content was not changed due to DDGS feeding. The monounsaturated fatty acid content of yolk decreased linearly by feeding DDGS (P<0.05). The yolk polyunsaturated fatty acid content of DDGS 20% increased significantly compared to DDGS 0%. The DDGS feeding was not found to affect the degree of yolk fat unsaturation. The cost of feed (￦/kg feed) decreased as the level of DDGS increased. The production costs of egg (￦/kg egg) were cheap in the order of DDGS 10%, DDGS 20%, and DDGS 0%, indicating that DDGS is a viable alternative feed ingredient to corn and soybean meal. In conclusion, high quality DDGS ($L^*$ 61.72) could be used economically up to 20% level without any harmful effect on laying performance: however, the use of DDGS up to 10% is more economical than DDGS 20%.

• Korean Journal of Poultry Science
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• v.35 no.3
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• pp.303-311
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• 2008

This study was conducted to investigate the effect of dietary supplementation of Cu-methionine chelate(Cu-Met) and Cu-soy proteinate(Cu-SP) on the performance, small intestinal microflora and immune response in laying hens. A total of 960 Hy-line $Brown^{(R)}$ laying hens of 39 wks old were assigned to one of the following 6 dietary treatment: control(C), antibiotic(Avilamycine 6 ppm), Cu-Met 50 and Cu-Met 100(50 and 100 ppm Cu as Cu-methionine chelate), Cu-SP 50 and Cu-SP 100(50 and 100ppm Cu as Cu-soy proteinate). Each treatment was replicated 4 times with forty birds per replication, housed in 2 birds per cages. Forty birds units were arranged according to randomized block design. Feeding trial lasted 6 wks under 16 hours lighting regimen. Hen-day and hen-house egg production of groups treated with Antibiotic and Cu supplements tended to be higher than the control with significant difference (P<0.05) shown between Cu-Me 100 and control. Egg weight was significantly (P<0.05) heavier in antibiotic and Cu-SP treatments than Cu-Met treatments but they were not significantly different from the control. Eggshell strength, egg shell thickness, egg yolk color and Haugh unit were not significantly different among treatments. There were no significant differences in leukocytes and erythrocytes in the chicken blood. But mean corpuscular hemoglobin value(MCH) was significantly (P<0.05) higher in Cu-SP 100 than antibiotic treatment. The concentrations of serum IgG and IgA were not significantly different among treatments. Copper concentration in the liver tended to increase as the level of copper supplementation increased, that of Cu-SP 100 being significantly (P<0.05) higher than those of the control and antibiotic treatment. Concentrations of iron and zinc of the liver were not significantly influenced by treatments. Populations of Cl. perfringens and Lactobacilli in the small intestinal content were significantly (P<0.05) influenced by treatments. Population of Cl. perfringens decreased and that of Lactobacilli increased in the copper supplemented groups. The result of this experiment showed that Cu-Met and Cu-SP are comparable to antibiotic in improving egg production in laying hens. Birds fed diets supplemented with Cu-SP produced heavier eggs than those fed diets with Cu-Met. There were no significant differences in the performances between 50 ppm and 100 ppm copper supplementation as organic forms.

• Korean Journal of Poultry Science
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• v.45 no.2
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• pp.119-124
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• 2018

This study was conducted to assess the effect of dietary addition of Germanium (Ge) on performance, egg quality, serum biochemical properties and yolk fatty acid composition in laying hens. At 74 weeks of age, a total of 360 Hy-line brown commercial layers were divided into four treatments with five replicates per treatment. Four dietary levels of Ge (0, 1, 2 and 4%) were added to the basal diets (ME: 2,750 kcal/kg, CP: 16%) and fed corresponding diet for a period of 12 weeks. The effects of these treatments on production performance and egg quality were measured three times at four week intervals, and at the end of the experiment, blood and egg yolk fatty acid were analyzed. The results showed that production performance parameters including egg production rate, feed intake, egg weight, egg mass and feed conversion ratio were non-significant, but dietary addition of 2% Ge tended to increase egg production rate. Eggshell strength was found to be significantly higher in Ge supplemented groups than in the control group (P<0.05), and eggshell thickness was also trended to be improved in Ge treated groups. In serum, triglyceride content was significantly greater (P<0.05), and the highest total cholesterol was found in hens of the control group as compared with that of the Ge supplemented groups. The yolk fatty acid composition including polyunsaturated fatty acid, unsaturated fatty acid and saturated fatty acid were not affected among the treatments but addition of 2 or 4% Ge in basal diet had significantly (P<0.05) increased monounsaturated fatty acid. Therefore, supplementation of Ge in laying hens diet has positive effects on egg quality and triglyceride in serum.

• 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.35 no.2
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• pp.115-121
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• 2008

The study was conducted to evaluate the effects of dietary microbial phytase on egg productivity, egg quality, phosphorus utilization and nutrient digestibility in laying hens. The animals used in the experiment were a total of 120 Hy-Line Brown laying hens (32 weeks old). Dietary treatments included 1) CON (basal diet), 2) LP (low phosphorus diet) 3) NP (low phosphorus diet + 0.03% normal microbial phytase) and 4) CP (low phosphorus diet + 0.03% coated microbial phytase). Six laying hens were allotted to a block (pen) with five replicated. Through the whole period of experiment, egg production was significantly increased in CON and CP treatments compared to LP treatment (P<0.05). CON, CP and NP treatments significantly increased their egg shell breaking strength and egg shell thickness compared to LP treatment (P<0.05). CON, CP and NP treatments resulted higher yolk color and Haugh unit than LP treatment (P<0.05). Calcium and inorganic phosphorus contents in blood were higher in CP treatment compared to LP treatment (P<0.05). Dry matter digestibility and nitrogen digestibility were greater in CP treatment than CON, LP and NP treatments (P<0.05). Crude ash was increased in CON, CP and NP treatments compared to LP treatment (P<0.05). Calcium digestibility and phosphorus digestibility were significantly improved in CP and NP treatments than CON and LP treatments (P<0.05). Calcium retention of CON, CP and NP treatments were higher than LP treatment (P<0.05). Phosphorus retention was increased in CP and NP treatments compared to CON and LP treatments (P<0.05). LP treatment significantly increased their nitrogen, calcium excretion compared to CON, CP and NP treatments (P<0.05). Phosphorus excretion was decreased in LP, CP and NP treatments compared to CON treatment (P<0.05). In conclusion, CP treatment improved egg production, egg quality, inorganic calcium and phosphorus in blood, calcium and phosphorus retention and nutrient digestibility and decreased nitrogen and calcium excretion in laying hens.

• Korean Journal of Poultry Science
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• v.35 no.2
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• pp.131-136
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• 2008

This study was conducted to investigate the effects of dietary conjugated linoleic acid (CLA) and oil containing unsaturated fatty acid supplementation on egg production and quality in laying hens. Two hundred-eighty eight, 36 week old ISA brown commercial layer, were employed in a 5 week feeding trial. Dietary treatments are 1) BO (basal diet + 1% soybean oil + 1% oat), 2) BS (basal diet + 1% safflower oil + 1% oat), 3) BF (basal diet + 1% free fatty acid + 1% oat), 4) CD (basal diet + 1% CLA containing diglyceride + 1% oat), 5) CT (basal diet + 1% CLA containing triglyceride + 1% oat) and 6) CP (basal diet + 1% CLA by-product + 1% soybean oil). For overall period, hen-day egg production was not significant among treatments (P>0.05). Egg shell breaking strength at 3 weeks in CP treatment was significantly lower than BS, BF, CD and CT treatments (P<0.05) and that at 4 weeks in BO and CP treatments was significantly lower than others (P<0.05). Egg shell thickness at 3 and 4 weeks in CP treatment was significantly lower than BS, BF, CD and CT treatments (P<0.05). Egg weight at 3 and 4 weeks in CP treatment was significantly lower than others (P<0.05). Yolk height at 4 weeks in BF and CT treatments was significantly highest compared to BO, CD and CP treatments (P<0.05) and among BO, CD and CP treatments, that in BO and CD treatments was significantly higher than CP treatment (P<0.05). At 4 weeks, yolk color in CP treatment was significantly higher than BO and BS treatments (P<0.05). Haugh unit at 3 and 4 weeks in BO and CP treatments was significantly lower than others (P<0.05). In conclusion, supplementing CLA and oil containing unsaturated fatty acid for laying hens improved egg shell breaking strength, egg shell thickness, egg weight, yolk height, yolk color and haugh unit.

• Korean Journal of Agricultural Science
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• v.34 no.1
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• pp.53-60
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• 2007

A layer feeding trial was conducted for 10 weeks to investigate the effects of the addition of corn distillers dried grains with solubles (DDGS) to layer diets on the laying performance, egg qualities, and yolk fatty acid composition. Nine hundred Hyline Brown layers, 24 weeks of age,were randomly allotted to 20 replicate laying cages, 45 birds per replicate. There were four diet treatments (0, 10, 15, and 20% DDGS), and five replicates per treatment. All experimental diets were prepared to contain iso-protein (17%) and iso-calorie (TMEn 2,780 kcal/kg). The use of DDGS up to 20% level in layer diets did not exert any influence on feed intake, laying rate, total egg mass, mean egg weight, and feed conversion ratio. DDGS did not exert any influence in weight of egg, breaking strength, and color of eggshell. The albumen height and Haugh unit was not influenced by DDGS addition. The yolk color was significantly increased by DDGS supplementation. As the DDGS level increased, the oleic acid content decreased, and the linoleic acid increased (P<0.05). The degree of saturation of yolk fatty acids was not affected by dietary DDGS. The inclusion of DDGS up to 20% in layer diets resulted in the decrease of feed cost per kg without any effect in the laying performance. In conclusion, the use of DDGS up to 20% level in layer diets could replace corn and soybean meal without any harmful effect on the laying performances.

• Korean Journal of Poultry Science
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• v.17 no.3
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• pp.167-177
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• 1990

In order to investigate an effect of the feed restriction on the laying performance, 208 White Leghorn strain layer of 36 week-old were divided to 4 groups of 52 birds each and raised for 1 week of previous feeding and for the subsequent 3 weeks of experimental restricted feeding. The egg production, daily egg mass and feed efficiency of four groups of birds fed daily 100g, 95g, 90f and 85g of a commercial diet, respectively, which were compared with those of the original 2879 birds fed l13g of diet per day as control. During 3 weeks of experimental restricted feeding, period, daily body weight nam was decreased linearly as the degree of restriction increased in birds fed 100, 95, 90 and 85g of diet. Hen day egg production, egg weight and daily egg mass was linearly related to the diet intake level. then feed intake(x, g day$^{-1}$ ) showed a positive regression equations with the henday egg production(y, % ), egg weight(y, g egg$^{-1}$ ) and egg mass(y, g bird$^{-1}$ ) as y＝38.75＋0.3753$\times$(r＝0.503, n＝15), y＝48.2＋0.08868$\times$(r＝0.835, n＝ 15) and y＝15.69＋0.2786$\times$(r＝0.597, n＝15), respectively. Feed efficiency was increased to a plateau in birds fed 95g of diet. The estimated energy utilization for egg production was reached to a plateau in birds fed 95g of diet and the highst protein utilization was shown in birds fed 90g of diet anions birds fed graded levels of diet. And the feed restriction did not affect on the egg shell contents, while protein contents of egg were shown a trend to be increased and lipids and cholesterol contents of eggs was decreased according to the diet intake lowered. The results suggested that the improved feed efficiencies of birds restricted under 16% of diet(above 95g of diet) will be due to increased energy and protein utilization for egg production and feed restriction above 16% will be aboided. In the range from 113g to 95g of diet feeding, the crude profit was increased as the feed restricted in the case of egg price 600 won kg$^{-1}$ and feed price 200 won kg$^{-1}$ .

• Korean Journal of Poultry Science
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• v.49 no.2
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• pp.115-124
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• 2022

The objective of this study was to investigate the effects of dietary coenzyme Q10 (CoQ10) sources on the antioxidant defense system in the blood and liver of laying hens. Thirty-six 40-wk old Lohmann Brown hens were randomly assigned to three groups based on body weight, with four cages with three layers each. Laying hens were divided into one of the following groups: control (CON), powdered CoQ10 (PCoQ, 100 mg/kg diet), and emulsified CoQ10 (ECoQ, 100 mg/kg diet). All hens were fed a control diet or a control diet supplemented with powdered or emulsified CoQ10 ad libitum for five weeks. There were no differences in body weight, weight gain, and organ weights among the treatment groups, including the liver and spleen. The blood total antioxidant power (TAP) in the ECoQ group increased (P<0.05) by approximately 2-fold compared to that in the CON group. However, there was no significant difference in blood TAP levels between the PCoQ and ECoQ groups, although a decreasing trend (P<0.13) was observed for levels of TAP in the ECoQ group. The mRNA expression and specific activities of superoxide dismutase, glutathione peroxidase, and catalase in the liver were not affected by dietary CoQ10 or type of CoQ10. However, hepatic lipid peroxidation in the ECoQ group was lower (P<0.05) than in the CON group. In conclusion, emulsified CoQ10 increased blood TAP and decreased hepatic lipid peroxidation without affecting antioxidant enzymes, suggesting that emulsified CoQ10 might be more applicable as an active antioxidant supplement than powdered type in laying hens.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.241-249
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• 2023

Following the Animal genetic resource for food and agriculture (AnGR) is considered as an independent resource for the possessing country, ensuring the sovereignty of AnGR is important. The present study investigated the growth and egg production performance of six breed enrolled in DAD-IS for the purpose of securing scientific data on AnGR in Korea. A total of 323 chickens (female 181, male 142) were used in this study, with the following six breeds: Korean Leghorn (LEG), Gyeongbuk Araucana (ARA), Korean native chicken (KNC), Korean Ogye (Ogye), Hyunindak (HIL), Heongseongyakdak (HYD). The body weight of male ARA from hatching to 32 weeks of age was the highest among the breeds, and LEG and Ogye were relatively lower (P<0.0001, excluded body weight data of HYD). The body weight of female ARA was the highest and HYD was significantly the lowest among the female chicken breeds (P<0.0001). The laying percentage was the highest in LEG and was the lowest in HYD among the breeds (P<0.0001). The average egg weight from 20 to 40 weeks of age was the highest in ARA, followed by LEG and was the lowest in Ogye (P<0.0001), and the adapted breed including LEG and ARA was higher than indigenous breed (P<0.05). Egg mass production was the highest in Korean Leghorn. Collectively, these results show that ARA has the best growth ability, and LEG has the best egg production performance among the used breeds. This suggests that the adapted breed with high commercial performance is important AnGR in Korea.