• Korean Journal of Poultry Science
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• v.36 no.4
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• pp.311-316
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• 2009

The study was conducted to evaluate the effects of dietary acid hydrolysates of cocoon on laying performance, egg quality, blood level of immune substance and cholesterol in laying hens. The animals used in the experiment were a total of 240 Hy-Line Brown laying hens (41 weeks old). Dietary treatments included 1) CON (basal diet), 2) SP1 (basal diet + acid hydrolysates of cocoon 0.05%), 3) SP2 (basal diet + acid hydrolysates of cocoon 0.1%) and 4) SP3(basal diet + acid hydrolysates of cocoon 0.2%) twelve laying hens were allotted to a block (pen) with five replicated. Through the whole period of experiment, egg production, egg weight, egg shell breaking strength and egg shell thickness were no significant difference. However, acid hydrolysates of cocoon treatments (SP1, SP2, SP3) significantly increase their egg yolk height and Haugh unit compared to control (P<0.05). IgG and WBC (white blood cell) contents in blood were higher in SP1, SP2, SP3 treatment compared to control (P<0.05). However, albumin and total protein content in blood were no significant difference. Phospholipid, HDL-cholesterol, LDL-cholesterol and total cholesterol contents in serum were higher in SP1, SP2, SP3 treatment compared to control (P<0.05). In conclusion, supplement dietary acid hydrolysates of cocoon improved egg yolk height, Haugh unit, and blood level of phospholipid, HDL-cholesterol, LDL-cholesterol, total cholesterol in laying hen.

• Food Science of Animal Resources
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• v.43 no.2
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• pp.282-304
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• 2023

This study aimed to investigate the effectiveness of carotenoid supplementation on the performance, egg quality, and immunity of laying hens using a meta-analysis approach. The database was searched using Google Scholar and Scopus, from 2012 to 2022. The literature was published in English. 47 Articles were selected for meta-analysis. Analyses were performed using the Open Meta-analyst for Ecology and Evolution (OpenMEE) software. The heterogeneity and data validation against publication bias were analyzed using JASP 0.16.2 software. Overall, the results showed that carotenoid supplementation improved feed intake by 0.32 g/day/hen [95% confidence interval (CI)=0.02 to 0.61], final body weight by 0.33 g/hen (95% CI=0.05 to 0.60), egg production by 0.38% (95% CI=0.14 to 0.63), egg weight by 0.29 g (95% CI=0.09 to 0.5), yolk colour by 2.11 (95% CI=1.71 to 2.51), Haugh unit (HU) by 0.26 (95% CI=0.11 to 0.42), yolk carotenoids by 1.17 ㎍/kg (95% CI=0.59 to 1.75), immunoglobulin A (IgA) by 0.74 mg/L (95% CI=0.18 to 1.29), and lower yolk cholesterol by -0.38 mg/g (95% CI=-0.59 to -0.16). Feed conversion ratio (FCR), eggshell thickness, and white blood cells were unaffected by the application of carotenoids. The heterogeneity analysis showed variability in all studies (<0.05). In conclusion, carotenoid supplementation can elevate productivity, enhance egg quality, and improve immunity. However, based on Kendall's test, there was a publication bias in several parameters, namely FCR, egg weight, HU, yolk carotenoids, and IgA.

• Korean Journal of Poultry Science
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• v.36 no.2
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• pp.125-131
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• 2009

This study was conducted to investigate the effects of dietary supplementation of mannan-oligosaccharides (MOS) and fructo-oligosaccharides (FOS) on the performance, immune response and small intestinal microflora in laying hens. A total of 960 Hy-Line $Brown^{(R)}$ laying hens of 27 wks old, housed in 2 bird cages, were assigned in a completely randomized block design into one of the following 6 dietary treatments: control, antibiotic (6 ppm avilamycine), 0.025% MOS, 0.05% MOS, 0.25% FOS, and 0.5% FOS. Each treatment had 4 replicates of 40 birds and was fed ad libitum for 6 wks under 16 h lighting regimen. There were significant differences among treatments in hen-day and hen-housed egg production. Hen-day egg production in 0.025% MOS was significantly higher than that of control. Hen-housed egg production in antibiotic-treated group was significantly higher compared with control. Egg weight, feed intake and feed conversion were not significantly different among treatments. Egg shell thickness was highest in 0.25% FOS, but was not significantly different among the rest of treatments. There were no significant differences among treatments in egg shell strength, egg shell color, egg yolk color and Haugh unit. IgG concentrations in serum were not significantly different among treatments. On the other hand, IgA concentrations of the treated birds tended to be increased compared with control. Dietary treatments tended to decrease Cl. perfringens and E. coli, and to increase Lactobacillus spp. The result of this experiment showed that dietary supplementation of MOS and FOS in laying hens tended to improve egg production comparable to the supplementation of antibiotics. The level of serum IgA and small intestinal microflora were also significantly affected by the treatments.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.8
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• pp.1174-1178
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• 2006

An experiment was conducted to investigate the effects of dietary supplementation of copper chelates in the form of methionine, chitosan and yeast on the performance of laying hens. Four hundred ISA Brown layers, 84 wks old, were assigned to 4 treatments: control, 100 ppm Cu in methionine chelate (Met-Cu), 100 ppm Cu as chitosan chelate (Chitosan-Cu) and 100 ppm Cu as yeast chelate (Yeast-Cu). Each treatment had five replicates of 20 hens. Hen-day and hen-housed egg production and egg weight were significantly (p<0.05) increased by Met-Cu supplementation. The increase by Chitosan-Cu and Yeast-Cu supplementation was not significant. Contrast of the control vs. Cu chelates showed egg weight was significantly (p<0.05) increased by Cu chelate supplementation. Soft-shell egg production was significantly (p<0.05) reduced by supplementation of Cu chelates. Met-Cu treatment showed the lowest incidence of soft egg production. Gizzard erosion index was increased by Cu chelate supplementation. Crude fat in liver, total cholesterol in yolk and Cu content in liver and yolk were not significantly influenced by Cu chelate supplementation. It was concluded that dietary supplementation of 100 ppm Cu as Met-Cu significantly increased egg production and egg weight. Cu-Met chelate was also effective in reducing soft-shell egg production but increased gizzard erosion index.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.11
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• pp.1766-1772
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• 2018

Objective: This experiment was to investigate the effect of increasing levels of apparent metabolizable energy ($AME_n$) on the laying performance, egg quality, blood parameters, blood biochemistry, intestinal morphology, and apparent total tract digestibility (ATTD) of energy and nutrients in diets fed to laying hens. Methods: A total of three-hundred twenty 33-week-old Hy-Line Brown laying hens (Gallus domesticus) were evenly assigned to four experimental diets of 2,750, 2,850, 2,950, and 3,050 kcal $AME_n/kg$ in pens with floors covered with deep litter of rice hulls. There were four replicates of each treatment, each consisting of 20 birds in a pen. Results: $AME_n$ intake was increased (linear, p<0.05) with inclusion level of $AME_n$ in diets increased. Feed intake and feed conversion ratio were improved (linear, p<0.01), but hen-day egg production tended to be increased with an increasing level of $AME_n$ in diets. During the experiment, leukocyte concentration and blood biochemistry (total cholesterol, triglyceride, glucose, total protein, calcium, asparate aminotransferase, and alanine transferase were not influenced by increasing level of $AME_n$ in diets. Gross energy and ether extract were increased (linear, p<0.01) as the inclusion level of $AME_n$ in diets increased. Conclusion: Laying hens fed high $AME_n$ diet (i.e., 3,050 kcal/kg in the current experiment) tended to overconsume energy with a positive effect on feed intake, feed conversion ratio, nutrient digestibility, and intestinal morphology but not on egg production and egg mass.

• 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.42 no.3
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• pp.205-214
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• 2015

This study aimed to investigate the effects of reducing feed intake on performance and meat quality in old laying hens. A total of 200 Hy-Line Brown laying hens (100 weeks old) were randomly allotted to five dietary treatments: control (100% daily feed intake), 90%, 60%, 50%, and 20% daily feed intake. Each treatment was replicated four times with 10 birds per replication and two birds per cage. Ten-bird units were arranged according to a randomized block design. The feeding trial lasted for 4 weeks under a 16L:8D lighting regimen. The results indicated that the daily feed intake correlated with hen-day egg production and feed conversion ratios (P<0.05). The carcass yields and partial ratios were also correlated with daily feed intake (P<0.05). The levels of leukocytes (without basophils) were higher in the 50% and 20% daily feed intake groups than in the other groups. The concentrations of dry matter, crude ash, crude fat, and crude protein, water holding capacity, cooking loss, and fatty acids in the breast meat did not decrease as the daily feed intake decreased. In conclusion, reducing daily feed intake decreased laying performance and carcass yield but had no effect on breast meat quality.

• Korean Journal of Poultry Science
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• v.44 no.2
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• pp.67-73
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• 2017

The purpose of our study was to determine the effects of varying levels of energy, protein, and amino acids on the performances of laying hens. A total of 240 Hy-Line Brown laying hens at 36 weeks of age were used in this 4-week feeding trial. The hens were randomly allocated to five treatment diets, with eight replications of six hens in each replicate cage. The treatment diets were as follows: A- basal diet + 18% crude protein, metabolizable energy 2,800 kcal, total (methionine + cysteine) 0.65%; B- basal diet + 17% crude protein, metabolizable energy 2,700 kcal, total (methionine + cysteine) 0.59%; C- basal diet + 16.5% crude protein, metabolizable energy 2,700 kcal, total (methionine + cysteine) 0.59%; D- basal diet + 16.5% crude protein, metabolizable energy 2,700 kcal, total (methionine + cysteine) 0.54%; and E- basal diet + 16% crude protein, metabolizable energy 2,680 kcal, total (methionine + cysteine) 0.54%. The study results revealed that the hen-day egg production of hens that were fed with low-energy diets (B, C, and D) was comparable with that of hens fed with high-energy diet A, whereas average daily feed intake in hens fed treatment diet D and E was significantly higher (P<0.05) than that in hens fed treatment diet A. Overall, the eggshell thickness was unaffected by any of the treatment diets. Egg weight was comparable among the treatment diets, except for treatment diet E. Haugh unit improved with decreasing levels of dietary energy, protein, and methionine + cysteine in the diet. We can summarize that laying hens fed with low dietary energy and low crude protein treatment diets B, C, and D had satisfactory performance compared with those fed with high-energy treatment diet A. This indicates that there is the potential to reduce feed costs by formulating diets with lower energy and low protein levels.

• Korean Journal of Poultry Science
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• v.21 no.4
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• pp.257-266
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• 1994

Three protein feeding systems for egg-type pullets involving conventional step-down protein 18-15-12%), step-up protein(12-15-18%) and single-stage low protein (13-13-13%) with an iso-energy level of 2,900 ME kcal /kg were compared to examine the effect on pullet growth and subsequent laying performance. During the growing period, pullets subjected to the step-up and single-stage low protein feeding systems were lighter in body weight and consumed less feed and netabolizable energy than those on the conventional step-down protein feeding system(P<0.05). 3ut the pullets on the step-up protein diet consumed more protein, and those on the single-stage low protein diet consumed less protein than those on the step-down protein diet(P<0.05). Also, he feed cost was less in pullets on the single-stage low protein diet than in those on the other systems(P<0.05). During the laying period, sexual maturity was later in hens reared on the step-up and single-stage low protein diets than in those on the step-down protein diet(P<0.05), however, average hen-day egg production and egg weight were not significantly affected by the protein feeding systems in the growing period. Daily feed intake and feed required per egg were significantly reduced in hens on the single-stage low protein diet compared to those on conventional protein feeding system(P<0.05). It was concluded that the 13% single-stage low protein feeding system produced smaller pullets with less feed, energy, protein, and feed cost during the growing period, and hens reared on that system consumed less feed during the laying period without any impairment of production compared to the conventional rearing system.

• Animal Bioscience
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• v.34 no.11
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• pp.1802-1810
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• 2021

Objective: The purpose of this study was to evaluate the effects of supplementing herbal active ingredients (YGF251) which can promote the secretion of insulin-like growth factor-1 (IGF-1) in the diet on production performance, egg quality, blood hematology, and excreta gas emission in laying hens. Methods: A total of 288 ISA Brown (41-week-old) laying hens with an initial body weight of 1.83±0.68 kg were randomly assigned to 1 of 4 dietary treatments in a randomized block design based on body weight. Each treatment had 12 replicate cages having 6 adjacent cages per replicate (hens are kept in cages alone). The experimental period was 35 days. Dietary treatments were based on the corn-soybean meal-wheat-based basal diet and supplemented with 0.00%, 0.05%, 0.10%, or 0.15% YGF251. Results: There was a linear increased egg weight in weeks 1 to 5 (p<0.05), egg mass in week 1 (p<0.05) and weeks 1 to 5 (p<0.05), egg strength on day 7 (p<0.05), 21 (p<0.01), and 35 (p<0.01), eggshell thickness on day 21 (p<0.05) and 35 (p<0.01), haugh unit on day 21 (p<0.01) and 35 (p<0.05), serum IGF-1 concentration on day 21 (p<0.05) and 35 (p<0.01), and serum total protein concentration on day 35 (p<0.05) were observed with the supplementing YGF251 increased in the diet, while feed conversion ratio in weeks 1 to 5 (p<0.05) and excreta ammonia emission (p<0.01) decreased linearly with the dose of YGF251 increased. Conclusion: Dietary supplementation of YGF251 positively affected the production performance and egg quality of laying hens through increasing serum IGF-1 concentration in a dose-dependent manner. Moreover, YGF251 supplementation improved barn environment by reducing excreta noxious gas emission.