• Proceedings of the Zoological Society Korea Conference
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• 1995.10a
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• pp.68-73
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• 1995

Most female Great Tits lay one egg each day until the clutch is complete. However, some exceptions are found. “Pause day/s” most frequently occur after the 1st egg is laid. In general, egg-size increase with laying sequence, but there is year-to-year variation. The relationship between egg size and laying sequence is found more significantly in relatively larger clutches than in smaller ones. Great Tits tend to advance the hatching of their chicks by starting to incubate earlier in relation to clutch completion as the breeding season progresses. hatching asynchrony affects chick´s growth rate, but when the effect of laying date on hatching asynchrony is controlled, the effect of hatching asynchrony on growth rate is not found. These findings support the ´hurry-up´ hypothesis.

• Animal Bioscience
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• v.34 no.2
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• pp.256-264
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• 2021

Objective: The purpose of this experiment was to investigate the effects of the Agaricus bisporus stem residue (ABSR) on the performance, nutrients digestibility, antioxidant activity of laying hens, and its effects on egg storage to determine the appropriate dosage of ABSR, so as to provide a scientific basis for the effective utilization of ABSR. Methods: A total of 384 53-wk-old Nongda III layers were randomly divided into six treatments, four replicates in each treatment and 16 birds in each replicate. The control treatment was fed with basic diet, while experimental treatments were fed with diets of 2%, 4%, 6%, 8%, and 10% ABSR respectively. The experimental period was 56 d. Results: The results showed that compared with the control treatment, ABSR had no significant effect on laying performance (p>0.05). The crude protein and total energy digestibility of experimental treatments was significantly higher than those of control treatment (p<0.05). When eggs were stored for 1 wk, 2 wk, and 3 wk at 25℃, there were no significant differences in egg storage between the experimental treatments and the control treatment (p>0.05). The superoxide dismutase (SOD) activity and glutathione peroxidase (GSH-Px) activity in the serum of the experimental treatments were significantly higher than those of the control treatment (p<0.05), and the malonaldehyde (MDA) content did not change dramatically. SOD activity in yolk of experimental treatments was significantly higher than that in control treatment (p<0.05); MDA content in yolk was markedly lower than that in control treatment (p<0.05). The activity of GSH-Px and SOD in yolk of experimental treatments was significantly higher than that of control treatment stored at 25℃ for 21 d, and the content of MDA was significantly lower than that of control treatment (p<0.05). Conclusion: ABSR can be used to improve the antioxidant activity of laying hens without affecting laying performance.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.11
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• pp.1715-1724
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• 2019

Objective: As laying hens become aged, laying performance and egg quality are generally impaired. One of the practical methods to rejuvenate production and egg quality of aged laying hens with decreasing productivity is a forced molting. However, the changes in intestinal microbiota after forced molting of aged hens are not clearly known. The aim of the present study was to analyze the changes in excreta bacterial communities after forced molting of aged laying hens. Methods: A total of one hundred 66-wk-old Hy-Line Brown laying hens were induced to molt by a 2-d water removal and an 11-d fasting until egg production completely ceased. The excreta samples of 16 hens with similar body weight were collected before and immediately after molting. Excreta bacterial communities were analyzed by high-throughput sequencing of bacterial 16S rRNA genes. Results: Bacteroidetes, Firmicutes, and Proteobacteria were the three major bacterial phyla in pre-molting and immediate post-molting hens, accounting for more than 98.0%. Lactobacillus genus had relatively high abundance in both group, but decreased by molting (62.3% in premolting and 24.9% in post-molting hens). Moreover, pathogenic bacteria such as Enterococcus cecorum and Escherichia coli were more abundant in immediate post-molting hens than in pre-molting hens. Forced molting influenced the alpha diversity, with higher Chao1 (p = 0.012), phylogenetic diversity whole tree (p = 0.014), observed operational taxonomic unit indices (p = 0.006), and Simpson indices (p<0.001), which indicated that forced molting increased excreta bacterial richness of aged laying hens. Conclusion: This study improves the current knowledge of bacterial community alterations in the excreta by forced molting in aged laying hens, which can provide increasing opportunity to develop novel dietary and management skills for improving the gastrointestinal health of aged laying hens after molting.

• Korean Journal of Poultry Science
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• v.14 no.2
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• pp.113-123
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• 1987

This study was carried out to investigate the effects of age of hen and oviposition time on egg weight, egg shell quality and e88 shape index in White Leghorn laying hens. The data were collected from 150 laying hens for about 4 months from September 1, 1986 to January 6, 1987. The results obtained from this study were summarized as follows; The percentage of the eggs produced before noon was decreased and that of the eggs produced after noon was increased as the hen gets older. Egg weight was increased rapidly to 270 days of age but after 270 days of age the rate of egg weight increase was slowly downed. The egg shell thickness became thinner and egg shell breaking strength was reduced and egg shape index was increased as the hen gets older. The egg weight was decreased as the oviposition time was proceeded and the regression coefficients of egg weight on oviposition time were -0.6788--0.4170, which means that the egg weight was decreased 0.4170-0.6788g per one hour delay of oviposition time. Egg shell thickness was increased 0. 0.00377-0.00643mm and egg shell breaking strength improved 0.0287-0.034kg/$\textrm{cm}^2$ per one hour delay of oviposition time. But it seems that there was no relationship between the oviposition time and the egg shape index.

• Korean Journal of Poultry Science
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• v.33 no.2
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• pp.127-131
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• 2006

This study was conducted to investigate the effects of expanding feed processing technologies on the egg characteristics and nutrient digestibility in laying hens. A total of two hundred seventy laying hens were randomly allocated into three treatments with fifteen replications for six weeks. Dietary treatments include 1) MS(mash), 2) EC(expanded crumble) and 3) EP(expanded pellet). In the egg production, the EC and EP treatments were significantly higher than MS treatment(p<0.05). However, no significant difference was founded in egg weight(p>0.05). Egg shell breaking was increased in EC and EP treatments compared with MS treatment(p<0.05), however, egg shall thickness showed no significant difference(p>0.05). Egg production and egg shell breaking were significantly higher in EC and EP treatments than MS treatment(p<0.05), but egg weight and egg shell thickness were no significantly difference among treatment(p<0.05). Yolk color was increased in EC treatment compared with other treatments(p<0.05). Also, yolk index was significantly improved in EC and EP treatments compared with MS treatment(p<0.05). Haugh unit was increased in EC treatment compared with MS treatment(p<0.05). EC treatment had improved DM, Ca and P digestibility. In conclusion, Expanded crumble and pellet processing could improve the egg characteristic and nutrient digestibility in laying hens.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.449-457
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• 2010

This study investigated the effects of three kinds of water extract mixtures each with different ratios of A. capillaris, C. sinensis, S. chinensis, and V. coloratum on laying performance, egg quality, blood characteristics, and egg storage stability in laying hens. One hundred and sixty 35-wk-old laying hens (Hy-line brown) were divided into four groups of 10 birds each replicated times four. The treatments involved a basal diet (C, control) or diets containing three kinds of water extract mixtures at 200 ppm (T1, water extract mixture A; T2, water extract mixture B; T3, water extract mixture C). The egg production rate, egg mass, and feed conversion ratio were significantly improved in all treatments compared to those of control (p<0.05). Haugh unit and egg yolk color in all treated groups were significantly improved in comparison with control (p<0.05), but no significant differences were observed for egg shell quality. The content of total cholesterol in blood serum was significantly decreased in all treatments compared to that of control (p<0.05). The blood biochemical parameters of liver and kidney damage were significantly decreased in all treatments compared to those of control (p<0.05). Total antioxidant activity in the blood serum of all treated groups was increased as well. The Haugh unit and malondialdehyde content in the egg yolk during storage were significantly decreased in all treated groups compared to control (p<0.05). Consequently, the dietary supplementation of water extract mixtures of A. capillaris, C. sinensis, S. chinensis, and V. coloratum improved laying performance and egg quality but decreased egg quality deterioration with increased storage. These results suggest that medicinal plant extracts could be used as a feed additive in feed for laying hens.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.4
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• pp.573-581
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• 2006

This experiment was conducted to determine the effects of supplemental methionine, lysine, choline, and sulfur on laying performance, metabolic parameters, and egg quality of hens fed diets containing sorghum (Sorghum vulgare) during the peak laying period. Lohman layers (n = 144), 30-wk of age as 6 replicate cages of 4 hens, were allocated randomly to receive basal diets containing either 22% corn (B) or 22% sorghum (BS) and diets BS plus 0.57% methionine, 0.66% lysine, 0.47% choline, or 0.05% sulfur for 98 d. Feed intake (FI) and egg production (EP) were recorded daily, egg weight (EW) was measured bi-weekly, and body weight (BW) was measured monthly. A sample of 12 eggs from each experimental group was collected every month to evaluate egg quality. At the end of the experiment, blood samples were collected for metabolite concentrations. Data were analyzed using one-way ANOVA as repeated measures and significant differences between the experimental groups were assessed using Duncan's Multiple Range test. Partial replacement of corn with sorghum in the basal diet did not affect BW, EP, and FCR but increased FI by 5.7% and EW by 2.4%. The effects of additives on laying performance were variable. Except for serum total protein (STP) concentration, other metabolic parameters were not affected by partial replacement of corn with sorghum in the basal diet. Hens fed diet BS had lower SPT concentration than hens fed diet B. Except for methionine supplementation, other supplements ameliorated depression in STP concentration. The additives did not affect other metabolic parameters. Egg quality responses to the experimental diets were also variable. Partial replacement of corn with sorghum in the basal diet did not affect eggshell characteristics (both thickness and stiffness), whereas it had variable effects on inner egg quality parameters (increased yolk index, depressed yolk color, and unaltered albumen index and Haugh unit). In conclusion, laying hen diets could include low-tannin sorghum (0.26%) up to 22% without necessitating extra supplements to overcome compromised performance.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.10
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• pp.1425-1434
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• 2011

This experiment was designed to evaluate the effects of the processing method of common vetch seed (CVS) (Vicia sativa) on laying performance, egg quality, metabolic parameters and liver histopatology during the peak production period in hens. Lohman layers, 46 wk of age in 6 replicate cages each containing 4 hens, were allocated randomly to one of four dietary treatments. Diets were control (C) diet containing no common vetch and experimental diets containing 25% raw common vetch (RCV), 25% soaked in water for 72 h with exchange of water every 24 h (SCV) and 25% soaked&boiled at $100^{\circ}C$ for 30 minute common vetch (SBCV). Inclusion of RCV into the diet deteriorated all laying performance variables. SCV did not alleviate the adverse effect of raw common vetch on feed intake, egg weight, feed conversion, final weight and weight change. SCV partially alleviated egg production (p<0.001). SBCV diminished the adverse effect on feed intake, egg weight, feed conversion, final weight and weight change compared to raw vicia sativa (p<0.001). No significant difference was detected between SBCV and the control group in terms of egg production, feed conversion, final weight and weight change. Regardless of the processing method, all the common vetch groups had lower shell strength compared to the control group. Haugh units did differ between all groups (p<0.001). Inclusion of RCV and SCV into the basal diet decreased triglyceride, cholesterol, total protein and serum glucose concentrations (p<0.001). Hovewer, inclusion of SBCV into the basal diet increased these parameters. Liver samples were stained with Hematoxylin and eosin (HE) and evaluated by light microscopy. A biopsy of native liver tissue was used as a control. No histopathologic finding was present in the control group. Raw V. sativa compared with the control caused lipid accumulations in hepatocytes, severe congestion of hepatic blood vessels, inflammation, increased numbers of Kupffer cells and sinusoidal dilatations. Whereas, the livers from groups given treated V. sativa showed only different degrees of sinusoidal dilatations. Findings from the present study point out the risk of increased hepatic damage due to use of raw Vicia sativa. Increasing treatment of V. sativa lead to a decrease of liver damages. Inclusion of raw and soaked vetch seeds in rations affected adversely all parameters examined in laying hens. But alleviation was observed when soaked and boiled vetch seeds (SBCV) were fed. The results of these experiments indicated that soaked&boiled Vicia sativa seeds may safely be used at a 25% level in rations of laying hens.

• Food Science of Animal Resources
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• v.28 no.5
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• pp.667-674
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• 2008

This study was conducted to investigate the effects of germinated and fermented unmarketable soybean (GFS) on laying performance and egg quality in laying hens. A total of two hundred laying hens were divided into 5 groups (5 treatment $\times$ 4 replication $\times$ 10 birds each) and fed with the experimental diets for 8 wk as follows: control, GFS free; T1, GFS 0.15%; T2, GFS 0.3%; T3, GFS 1%; T4, GFS 2%. The laying performance, egg quality, blood profiles, cecal microbial population, isoflavone content in egg yolk were investigated. There were no significant differences laying performance, relative liver and spleen weights, egg yolk color, eggshell color among groups. Eggshell strength in groups fed with diets containing GFS increased, but not significantly. Eggshell thickness significantly increased in the GFS-supplemented group. No significant differences were observed in the blood profiles and intestinal microflora after supplementation. The decrease of Haugh unit during storage was alleviated by feeding of GFS (p<0.05). The concentrations of malondialdehyde in groups fed with GFS were decreased as compared with control (p<0.05). Isoflavones in the egg yolk were detected in group fed with diet containing 2% GFS. These results showed that unmarketable GFS could be used as a favorable feed additive and feedstuff for production of quality enhanced and isoflavone fortified eggs.

• 한국생태학회:학술대회논문집
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• 2002.08a
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• pp.107-111
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• 2002

During the breeding season of 1998, breeding ecology of the Great Reed-Warbler (Acrocephalus arundinaceus orientalis) was studied at Yangsoo-ri and Yongdam-ri of the Yangpyung-gun, Kyunggi province, Korea. Egg-weight (CV: 6.25) was more variable than either length or breadth, and breadth was the least variable of the measures. Significant variations In overall egg-weight occurred between clutches, and that more of the total variation in egg-weight and shape are due to inter-clutch variation as to intra-clutch variation when the data were pooled. The last egg tends to be larger than the remaining eggs in the clutch of the Great Reed-Warbler, suggest- ing the Great Reed-Warbler may adopt the brood-survival strategy. When method 3 was used, the most common incubation period is 12 days. In the Great Reed-Warbler, the length of the incubation period was related to clutch-size when method 1 (r=0.485, p<0.05) and method 2 (r=0.621, p<0.01) were employed, but not related to egg weight. The average number of days of hatching asynchrony was 2.5, raging 0.5∼2.5. Asynchronous hatching was related to the clutch size (r=0.66, p<0.01). Hatching sequence was closely related to the laying sequence (r=0.93, p<0.001), suggesting Great Reed-Warblers incubate their eggs before clutch completion. The effect of egg weight on hatching asynchrony was found in Great Reed-Warblers (t-test, p<0.01).