• Asian-Australasian Journal of Animal Sciences
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• v.21 no.7
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• pp.1048-1052
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• 2008

The objective of this study was to determine the effect of sodium selenite and zinc-L-selenomethionine on performance and egg Se concentration in laying hens. Two hundred and twenty-four CP Browns aged 71 weeks were divided according to a $2{\times}3$ factorial in a completely randomized design. One more group without additional Se supplementation was used as a negative control. Each treatment consisted of four replicates and each replicate contained eight laying hens. The dietary treatments were T1: basal diet; T2, T3 and T4: basal diets plus 0.3, 1.0 and 3.0 mg Se from sodium selenite/kg, respectively; T5, T6 and T7: basal diets plus 0.3, 1.0 and 3.0 mg Se from zinc-L-selenomethionine/kg, respectively. The findings revealed that feed conversion rate/kg eggs, egg production, egg weight, Haugh units and eggshell thickness were not affected by source and level of Se (p>0.05). Increasing level of dietary Se significantly increased (p<0.05 the Se content of eggs. Zinc-L-selenomethionine markedly increased p<0.05 egg Se concentration as compared with sodium selenite. The results indicated that Se source did not influence performance of laying hens. However, zinc-L-selenomethionine increased p<0.05 egg Se concentration more than sodium selenite.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.7
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• pp.1053-1058
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• 2008

A total of 392 twenty eight week-old laying hens was used to study the effects of dietary inclusion of solvent-extracted palm kernel cake (PKC) (0%, 12.5% and 25%) and enzyme (mixture of mannanase, ${\alpha}$-galactosidase and protease) supplementation (0 kg/t, 1 kg/t and 2 kg/t) on the performance of laying hens. The levels of PKC did not significantly influence nitrogen corrected true metabolizable energy (TMEn) of the diets. Enzyme-supplemented PKC had significantly higher AME and TMEn values than PKC diets with no enzyme supplementation. Dietary inclusion of 12.5% and 25% PKC in the diets of laying hens did not adversely affect mean egg production or daily egg mass. However, layers consumed significantly more PKC-based diets and had significantly poorer feed conversion ratios (FCR) than controls. However, the feed intake and FCR of hens provided the 12.5% PKC-based diets with enzyme supplementation at 1 kg/t did not differ from the controls. Dietary inclusion of PKC or enzyme did not affect eggshell quality, but egg yolk colour was significantly paler when layers were fed the 25% PKC diet.

• Food Science of Animal Resources
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• v.34 no.1
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• pp.127-132
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• 2014

Optimization of carnosine and anserine extraction from chicken breast was performed using response surface methodology (RSM) to obtain the maximized physiological activities for anti-glycation and anti-oxidation. The optimum extraction conditions were water extraction for 1.6 h in the case of the 20-wk laying hen muscle and water extraction for 2.12 h in the case of 90-wk laying hen muscle. Higher carnosine and anserine contents were measured in the 20-wk laying hen muscle, along with higher physiological activities, which increased in direct proportion with the dipeptide contents. The extracts prepared from the 20-wk laying hen under optimum conditions showed 57% inhibition of advanced glycated end-product formation, 64% inhibition of lipid peroxidation, and 61% of DPPH radical scavenging effects. On the other hand, 52% inhibition of AGE formation, 62% inhibition of lipid peroxidation, and 53% of DPPH radical scavenging effect were demonstrated within the 90-wk laying hen. In addition, the ratio of carnosine was a key indicator for the physiological activities of the extracts.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2004.11a
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• pp.103-104
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• 2004

This study was evaluated the dietary affect of ceramics on laying performance, intestinal microflora population, NH$_3$ and VFA gas emission from excreta and fatty acids composition of egg yolk in laying hens. A total of 180 layer at 34 weeks of age were fed the experimental diets containing 0.0 % (Control), 0.4 % and 0.8 % of ceramics powder for 6 weeks. It is concluded that 0.4 % ceramics powder supplementation in the 34 to 40 weeks laying hens diet, improves the laying performance and ratio of egg yolk n-6/n-3 fatty acids contents and decreasing emission of NH$_3$ and VFA gas from excreta.

• Korean Journal of Veterinary Research
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• v.48 no.4
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• pp.469-472
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• 2008

Necropsy was performed on a total of twenty three either white leghorn or ogol chickens which were more than 150 weeks of age. Among twenty three chickens examined, fifteen chickens were laying and the rest eight chickens were non-laying. On necropsy, neoplastic mass in the five chickens among non-laying chickens was found. These neoplastic masses were present mostly in the ovaries and one case in the liver and characterized by multifocal to coalescing 1 to 5 mm tan firm nodular formation. On histopathology, ovarian adenocarcinoma with widespread abdominal seeding and hepatic metastasis was diagnosed in the three chickens. Oviductal leiomyoma was also found in two chickens that had a focal well-demarcated nodules in the oviduct. Taken together, the number with ovarian adenocarcinoma among non-laying chickens over 150 week old was 37.5%. As most animal species do rarely develop ovarian tumors, the high rate of spontaneous ovarian adenocarcinoma in non-laying hen suggest that the hen is a proper model for human ovarian cancer study.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2006.11a
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• pp.17-27
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• 2006

The effects of dietary betaine on performance, blood compositions, hepatic amino acid concentrations and hormonal secretions were examined in laying hens. Egg production was significantly higher in birds fed the 16.5 % protein diet compared to those fed 14.5 % protein diet(p<0.05), whereas dietary supplementation of betaine did not show any significant effect. The high level of protein and betaine supplementation significantly improved egg weight, egg mass and feed conversion(p<0.05), while eggshell breaking strength, eggshell thickness and Haugh unit were not influenced by betaine and dietary protein levels. Supplemental betaine did not affect serum total protein, albumin and BUN concentration. However, uric acid concentration significantly increased in 600 ppm betaine-fed groups(p<0.05). Concentrations of most hepatic amino acid were influenced by increased protein feeding and dietary betaine supplementation. Hormone studies recorded significantly higher serum and hepatocyte IGF-I concentration in 600 and 1,200 ppm betaine treatments(p<0.05) compared to those of control group. IGF-I mRNA gene expression of hepatocytes revealed statistically correlated increase in 600 and 1,200 ppm betaine-fed groups compared to the controls(p<0.05). Serum IGFBP-3 concentration was significantly elevated in 600 ppm betaine treatments. However, the secretion of IGFBP-1 in hepatocyte of laying hens fed with 600 and 1,200 ppm of betaine showed a significant decrease compared to the control group(p<0.05). Results of these study show that dietary betaine supplementation affects protein and hormone metabolism in laying hens.

• Reproductive and Developmental Biology
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• v.37 no.1
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• pp.41-49
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• 2013

Ovarian cancer is the most lethal world-wide gynecological disease among women due to the lack of molecular biomarkers to diagnose the disease at an early stage. In addition, there are few well established relevant animal models for research on human ovarian cancer. For instance, rodent models have been established through highly specialized genetic manipulations, but they are not an excellent model for human ovarian cancer because histological features are not comparable to those of women, mice have a low incidence of tumorigenesis, and they experience a protracted period of tumor development. However, the laying hen is a unique and highly relevant animal model for research on human ovarian cancer because they spontaneously develop epithelial cell-derived ovarian cancer (EOC) as occurs in women. Our research group has identified common histological and physiological aspects of ovarian tumors from women and laying hens, and we have provided evidence for several potential biomarkers to detect, monitor and target for treatment of human ovarian cancers based on the use of both genetic and epigenetic factors. Therefore, this review focuses on ovarian cancer of laying hens and relevant regulatory mechanisms, based on genetic and epigenetic aspects of the disease in order to provide new information and to highlight the advantages of the laying hen model for research in ovarian carcinogenesis.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.944-947
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• 2007

This study was conducted to study the effects of dietary garlic powder on laying performance, egg traits and blood serum cholesterol level of quails. A total of three hundred quails (Coturnix coturnix japonica) aged nine weeks were used. They were allocated to 3 dietary treatments. Each treatment comprised 5 replicates of 20 quails. The diets were supplemented with 0, 5 and 10 g/kg garlic powder. The experimental period lasted 21 weeks. The addition of garlic powder did not significantly affect body weight, egg production, feed consumption, feed efficiency, egg shell thickness, egg albumen index, egg yolk index and egg Haugh unit. Adding 5 and 10 g/kg garlic powder to the laying quail diets increased egg weight (p<0.01). Egg yolk cholesterol and blood serum cholesterol concentration were reduced with garlic powder supplementation. The results of this study demonstrated that garlic powder addition had a significant cholesterol-reducing effect in serum and egg yolk without adverse effects on performance and egg traits of laying quails.

• Journal of Environmental Science International
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• v.29 no.10
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• pp.1011-1014
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• 2020

The purpose of this study was to investigate the egg freshness and eggshell characteristics of old laying hens by adding sea urchin shell powder to the feed of such hens to achieve the objectives continuously pursued by environmental management, such as business profitability and waste resource utilization. A total of 90 Hy-Line Brown layers (66 weeks of age) were randomly divided into 2 treatments with 3 replicates, each of which consisted of 15 older layers, for 4 weeks. These treatments included a control (i.e., 0%) and 2% sea urchin shell powder. The 2% supplementation of sea urchin shell powder increased the Haugh unit (HU) at 2 and 4 weeks and eggshell strength at 4 wks compared to the controls (p<0.05). The HU at 0 weeks, eggshell thickness from 0 through 3 weeks, and eggshell strength at 0 and 2 weeks were not different between treatments (p>0.05). These results suggest that the addition of 2% sea urchin powder to the feed of laying hens improves egg freshness and eggshell strength in old laying hens.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.6
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• pp.839-844
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• 2012

This experiment was conducted to evaluate the effects of single or multi-particle size limestone on the egg shell quality, egg production, egg quality and feed intake in laying hens. A total of 280 laying hens (ISA brown) were used in this 10-wk trial. Laying hens were randomly assigned to 4 treatments with 14 replications per treatment and 5 adjacent cages as a replication (hens were caged individually). The experimental treatments were: i) L, basal diet+10% large particle limestone; ii) LS1, basal diet+8% large particle limestone+2% small particle limestone; iii) LS2, basal diet+6% large particle limestone+4% small particle limestone; iv) S, basal diet+10% small particle limestone. The egg production was unaffected by dietary treatments. The egg weight in S treatment was lighter than other treatments (p<0.05). The egg specific gravity in S treatment was lower than other treatments (p<0.05). The eggshell strength and eggshell thickness in S treatment were decreased when compared with other dietary treatments (p<0.05). The laying hens in LS1 and LS2 treatment had a higher average feed intake than the other two treatments (p<0.05). Collectively，the dietary multi-particle size limestone supplementation could be as efficient as large particle size limestone.