• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.319-325
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• 2021

In this study, we investigated the effects of feeding diets with different levels of energy and nutrient density on the egg quality of laying hens during the pre-peak and peak periods. A total of 192 (Hy-line brown) laying hens were used in a 15-week trial. The hens were randomly allotted to one of four treatments, each with four replicates (12 hens per replication). We assessed the effects of four level of dietary energy (2,710, 2,850, 2,870 and 2,890 kcal/kg) and three levels of nutrient density (Methionine + Cysteine: 0.56%, 0.85%, 0.80% and Crude Protein: 14.5%, 19%, 18%). Differences in the energy and nutrient density contents of diets showed no significant effect (P>0.05) on the average daily gain, average daily feed intake, feed conversion ratio, egg weight, or egg production of hens during the pre-peak and peak periods. However, hens subjected to 2,890 kcal/kg during the pre-peak period were found to lay eggs with significantly thicker shells, and yolk color was found to be significant enhanced in hens fed this diet during the pre-and peak periods. In contrast, we detected no significant effects of dietary energy or nutrient density on the Haugh unit or eggshell strength. In summary, increasing the energy level of diets from 2,710 to 2,890 kcal/kg was found to have positive effects on the shell thickness and yolk color of eggs produced by laying hens.

• 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 food and cookery science
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• v.17 no.1
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• pp.7-12
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• 2001

Yackwa was prepared by different amounts of egg yolk and then instrumental characteristics and sensory evaluation were investigated during storage periods. In texture profile analysis, hardness, gumminess and chewiness of Yackwa were increased during storage and texture parameters were increased by increasing egg yolk level. In Hunter's color value, lightness and redness were increased by increment of egg yolk level, whereas. yellowness was increased in negative region. During storage all values were increased. In the results of sensory evaluation, crispiness and overall acceptance were significantly different during storage and other parameters didn't showed significant difference among samples. The results showed that Yackwa prepared with 20g of egg yolk had good sensory quality and nutritious improvement.

• Korean Journal of Poultry Science
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• v.25 no.2
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• pp.71-77
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• 1998

This study was investigated to study split diets on laying performance and eggshell quality with Hy-Line brown layers 43 weeks old for 12 weeks Layers fed a conventional diet and split diets were divided into morning and afternoon diet. The conventional diet contained 3.4 % Ca was given constant nutrients all day. Hens of the split diets fed morning diets contained 0.5 % Ca constantly and afternoon diets contained 5.9, 8.0, and 10.0 % Ca in T1to T3. Split diets were given morning diets from 04:00 to 15:00 and afternoon diets 15:00 to 21 :00 alternately. Egg production, egg weight, and egg mass were not significantly different among diets. Abnormal eggs decreased in T1 and T2, but no significantly differed(P>0.05). Feed intake decreased in all of split diets compared to control diets (P <0.05). So, feed conversion ratio also improved in split diets(P<0.05). ME and CP intake decreased in T2 and T3, and Ca intake increased in proportion to Ca content of diets(P<0.05). ME and CP requirements per kg eggs decreased in the split diets, and that of Ca increased. Although there were not different significantly, egg shell strength and thickness improved slightly in T2 at 12 week. Yolk color, haugh unit and yolk index were not different among diets. Therefore, we concluded that split diet feeding to layer could improve feed and economic efficiency with normal egg production.

• Korean Journal of Organic Agriculture
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• v.26 no.3
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• pp.393-408
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• 2018

This study was carried out to investigate how chlorella dry powder added to the feed of laying hens influences on the egg quality and the composition of egg yolk's fatty acid. Moisture content, ash content, crude protein content, and crude fat content were 12.8%, 10.8%, 18.0% and 2.5%, respectively. The moisture content of the chlorella powder added to the feed was about 1.54%, the ash content was 6.53%, the crude protein content was 54.56%, and the crude fat content was 2.45 %. After feeding chlorella, compared to the control, the color of egg shell significantly became darker. The hardness of egg shell was increased for 10 days after chlorella feeding and was significantly strengthened. Thickness of egg shell was significantly thicker. The height of egg whites was increased. After 10 days of providing chlorella, the quality of egg white was 92.0 HU (Haugh Unit), which was significantly higher than 84.8 HU, the quality of the control. The color of egg yolk significantly revealed more yellow than that of the control. Egg weight was increased by 7.5% after 15 days of feeding chlorella. Protein content was increased by 11.9% and 10.7% after 10 and 15 days of feeding, respectively. The major compositions of fatty acid content of egg yolk fed with chlorella diet were oleic acid, trans-linoleic acid, palmitic acid, ${\alpha}$-linolenic acid, stearic acid, DHA, EPA, palmitoleic acid, and heptadecanoic acid, respectively. Palmitoleic acid was decreased in the eggs fed with chlorella diet compared to the control. The Saturated Fatty Acid (SFA) content of the control was higher than that of the eggs fed with chlorella. The content of Unsaturated Fatty Acid (UFA) was higher in egg yolks fed with chlorella than in the control. The ratio of UFA to Saturated Fatty Acid (SFA) was higher in egg yolks fed with chlorella than in the control. These results suggest that the addition of chlorella to the feed of the laying hens brings positive effects on the improvement of egg quality and lowering of the Unsaturated Fatty Acid of egg yolk.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.10
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• pp.1450-1455
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• 2017

Objective: The objective of this experiment was to investigate the effect of dietary ${\beta}-mannanase$ on productive performance, egg quality, and utilization of dietary energy and nutrients in aged laying hens raised under hot climatic conditions. Methods: A total of 320 84-wk-old Hy-line Brown aged laying hens were allotted to one of four treatments with eight replicates in a completely randomized design. Two dietary treatments with high energy (HE; 2,800 kcal/kg nitrogen-corrected apparent metabolizable energy [$AME_n$]) and low energy (LE; 2,700 kcal/kg $AME_n$) were formulated. Two additional diets were prepared by adding 0.04% (MN4) or 0.08% ${\beta}-mannanase$ (MN8) to LE treatment diets. The feeding trial was conducted for 28 d, covering a period from July to August in South Korea. The average daily room temperature and relative humidity were $29.2^{\circ}C$ and 83%, respectively. Results: Productive performance, egg quality, and cloacal temperature were not influenced by dietary treatments. The measured $AME_n$ values for MN8 diets were similar to those for HE diets, which were greater (p<0.05) than those for LE and MN4 diets. However, the $AME_n$ values for MN8 diets did not differ from those for LE and MN4 diets. Conclusion: The addition of ${\beta}-mannanase$ to low energy diets increases energy values for diets fed to aged laying hens. However, this increase has little positive impacts on performance and egg quality. These results indicate that dietary ${\beta}-mannanase$ does not mitigate the heat stress of aged laying hens raised under hot climatic conditions.

• Food Science of Animal Resources
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• v.40 no.6
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• pp.1044-1054
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• 2020

This study was performed to investigate the effects of lotus leaf hot water extracts treatment on the quality and stability of eggs using impregnation treatment through ultrasonication during storage. A total of 480 eggs were categorized into four treatment groups (n=30 each)-non-treated (CON), soaked for 30 min in lotus leaf hot water extracts without ultrasonication (T1), sonicated in distilled water (T2), and sonicated in lotus leaf hot water extracts (T3)-and stored for 15 d at 30℃. The egg weight, Haugh unit (HU), egg grade, albumen height, yolk color, eggshell thickness, eggshell breaking strength, and weight loss were measured for egg quality assessment. 2-Thiobarbituric acid reactive substance (TBARS) and volatile basic nitrogen (VBN) contents were measured as stability indicators. Additionally, total phenolic contents (TPC), total flavonoid contents (TFC), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were evaluated. The HU, egg grade, albumen height, and yolk color of T3 were significantly higher than those of CON (p<0.05). No significant differences in eggshell thickness and eggshell breaking strength are observed among the groups. The weight loss of T3 was significantly lower than that of the other groups during storage (p<0.05). The application of lotus leaf hot water extracts also significantly reduced TBARS and VBN (p<0.05). The TPC, TFC, and DPPH radical scavenging activity of T3 were significantly higher than those of the other groups (p<0.05). These results suggest that lotus leaf hot water extracts may be useful as a natural ingredient for improving the quality and stability of eggs during storage.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.8
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• pp.1179-1189
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• 2006

This experiment was designed to examine the effects of supplemental vitamin D on laying performance, metabolic profile and egg quality of hens fed diets containing different fat sources and levels. Lohman strains (n = 480) were assigned to one of 10 diets: basal diet (BD), BD plus 2.5 and 5.0% sunflower oil (SO) or tallow (T) at vitamin D provided $1{\times}$ and $3{\times}$ of the current recommendation. The experiment lasted from week 30 to 44 of age. Each diet was tested in 12 replicate cages of 4 hens. Production, metabolism, and egg quality data were subjected to three-way ANOVA. Both fats decreased feed intake (FI) as compared to BD. Increasing SO and T levels linearly decreased and quadratically increased FI, respectively. The dietary factors did not affect egg production (EP) and egg weight. Vitamin D supplementation increased and decreased EP when diets contained SO and T, respectively. Feed conversion efficiency (FCE) for hens fed SO was lower than for hens fed T. However, increasing T level improved FCE, whereas increasing SO level worsened FCR. Vitamin D supplementation increased serum vitamin D and glucose concentrations. Vitamin D supplementation also caused a decrease and an increase in serum vitamin D concentration when diets contained SO and T, respectively. Serum glucose concentration for hens fed SO was lower than hens fed T. Increasing fat level linearly increased serum triglyceride and VLDL concentrations, regardless of the fat type. Increasing SO level linearly decreased serum cholesterol concentration. Vitamin D supplementation did not alter lipid metabolites. The dietary factors did not affect serum total protein, Ca, and P concentrations. As compared with BD, feeding SO decreased dry tibia and ash weights more than feeding T. Vitamin D supplementation tended to increase dry tibia weight and decrease tibia ash weight. Eggshell strength and thickness, yolk and albumen indexes, and Haugh unit were not responsive to the dietary factors. Eggshell strength quadratically increased with increasing T level. Yolk color for hens fed SO was lower than for hens fed T. The dietary factors did not affect most of yolk fatty acids. Increasing SO level quadratically decreased yolk $C_{18:2}$ concentration. Vitamin D supplementation increased and decreased yolk $C_{18:2}$ concentration when diets contained SO and T, respectively. In conclusion, increasing fat level improved laying performance without altering metabolic profile and egg quality. Vitamin D supplementation had minor alteration effects on laying performance, metabolic profile, and egg quality in response to fat feeding.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.3
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• pp.400-409
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• 2017

Objective: This study was conducted to evaluate the effects of dietary protein sources (soybean meal, SBM; low-gossypol cottonseed meal, LCSM; double-zero rapeseed meal, DRM) on laying performance, egg quality, and plasma parameters of laying hens. Methods: A total of 432 32-wk-old laying hens were randomly divided into 6 treatments with 6 replicates of 12 birds each. The birds were fed diets containing SBM, $LCSM_{100}$, or $DRM_{100}$ individually or in combination with an equal amount of crude protein (CP) ($LCSM_{50}$, $DRM_{50}$, and $LCSM_{50}-DRM_{50}$). The experimental diets, which were isocaloric (metabolizable energy, 11.11 MJ/kg) and isonitrogenous (CP, 16.5%), had similar digestible amino acid profile. The feeding trial lasted 12 weeks. Results: The daily egg mass was decreased in the $LCSM_{100}$ and $LCSM_{50}-DRM_{50}$ groups (p<0.05) in weeks 41 to 44. The $LCSM_{50}$ group did not affect egg production compared to the SBM group in weeks 41 to 44 (p>0.05) and showed increased yolk color at the end of the trial (p<0.05). Compared to the SBM group, the $LCSM_{100}$ and $LCSM_{50}-DRM_{50}$ groups showed decreased albumen weight (p<0.05), CP weight in the albumen (p<0.05) and CP weight in the whole egg (p<0.05) at 44 weeks. Plasma total protein (TP) levels were lower in the $LCSM_{100}$ group than in the SBM group at 44 weeks (p<0.05); however, TP, albumin, and globulin levels were not significantly different between the $LCSM_{50}$ group and the SBM group or between the $DRM_{50}$ group and the SBM group (p>0.05). Conclusion: Together, our results suggest that the $LCSM_{100}$ or $DRM_{100}$ diets may produce the adverse effects on laying performance and egg quality after feeding for 8 more weeks. The 100.0 g/kg LCSM diet or the 148.7 g/kg DRM diet has no adverse effects on laying performance and egg quality.

• Korean Journal of Poultry Science
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• v.29 no.2
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• pp.135-140
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• 2002

An experiment was conducted to determine the effects of vitamin C supplementation on the performance and egg quality of layers. A total of 800 ISA Brown layers of 71 weeks old were assigned to one of the following diets containing 0, 3, 10, 50 or 100 ppm LG-vitamin C, 100ppm free ascorbic acid, 100 ppm Rovimix stay C-35 or 50 ppm LG-vitamin C supplemented with 100 ppm Zn methionine chelate. The feeding trial was conducted for flour weeks during the period of May to June when the average ambient temperature was $23.8^{\circ}C$ (5 :00 PM). Each treatment was replicated five times with 20 birds housed in 2 birds cage units. Vitamin C supplementation did not improve the overall performances (egg Production and egg Quality). Birds fed 100 ppm of LG vitamin C had the lowest egg Production while birds fed 100 ppm of Rovimix-35 had the lowest egg weight among birds fed different sources of vitamin C. Although supplementation of vitamin C over 50 ppm increased soft and broken egg Production, supplementation of 10 ppm LG vitamin C showed lowest soft and broken egg Production among all treatments. E99she11 thickness was highest in the treatment of 50 ppm LG vitamin C. In conclusion, supplementation of vitamin C at the level of 3 ~ 100 ppm did not significantly influence the laying performance and eggshell quality of laying hens under normal ambient(20 ~$26^{\circ}C$ ) condition.