• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.189-197
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• 2022

This study was conducted to compare the egg productivity, egg quality, and blood characteristics of laying hens with different laying rates, and the frequency and cumulative duration of the sitting behavior observed before laying was investigated. Twelve 45-week-old Hy-Line Brown laying hens were randomly assigned to two treatment groups with three replicates. Treatment groups were classified as layers laying over 80%(high egg performance layers; HEP) and layers laying below 50%(poor egg performance layers; PEP). The experiment lasted 4 weeks. HEP showed higher hen-house egg production ratio and egg mass and lower feed conversion ratio(FCR) (P<0.05) compared with PEP, although egg weight was higher in PEP (P<0.05). In terms of egg quality, PEP showed differences in eggshell quality (eggshell color, eggshell thickness, and eggshell weight) (P<0.05). Additionally, HEP showed high triglycerides(TG), and PEP showed high alanine transaminase(ALT) level (P<0.05) in serum collected in the morning. In the afternoon, the HEP showed higher lactate dehydrogenase(LDH) levels (P<0.05). No differences in the Ca: P ratio were observed between layers with different laying rates. One hour before egg laying, HEP exhibited sitting behavior 4 times on average, each lasting 25 minutes. In conclusion, egg production and quality differ between HEP and PEP, and HEP showed frequent sitting behavior before egg laying. However, additional research is necessary to explore approaches other than specific behavioral observation to distinguish poor layers in the flock for application in farms.

• Korean Journal of Poultry Science
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• v.31 no.2
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• pp.101-108
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• 2004

This study was conducted to evaluate the effect of iron reinforcing agent on the performance in laying hens for seven weeks. One hundred ninety eight 30-wk-old Brown Tetran layers were assigned to 9 treatments: control containing 45 mg Fe from iron sulfate per kg diet (FE-45), FE-90 (control multiplied two times), FE-180 (control multiplied four times), YM-45 containing 45mg Fe from yeast mutant, YM-90 (YM-45 multiplied two times), YM-180 (YM-45 multiplied four times), YF-45 containing 45mg Fe from ferritin containing yeast, YF-90 (YF-45 multiplied two times), YF-180 (YF-45 multiplied four times) in the experiment. Each treatment had four replications of 6 birds each. In the average egg production, the YF-180 was highest and the FE-45 (the control) was lowest; the YM-180, YF-90, and YF-180 were significantly (P＜0.05) higher than the control. In the comparisons of egg weight and egg mass, the YF-180 was significantly higher (P＜0.05) than the FE-90 or the control. In the FCR, the YM-90 was highest and the YF-45 was lowest. There was no significant difference between the control and YM-90 although the YF-45 was significantly (P＜0.05) lower in FCR than the control. In the eggshell thickness, the YF-180 was the thickest and the FE-90 was the thinnest; the YF-45 or the YF-180 was significantly thicker (P＜0.05) than the control. In the eggshell strength, the YF-45 was the strongest and the YM-45 was the weakest; the YM-90, YF-45, and YF-180 were significantly stronger (P＜0.05) than the control. In the cholesterol level of egg yolk, the control (FE-45) was the highest and the YF-45 was the lowest; there was a significantly different (P＜0.05) between these two treatments. In conclusion, in case of adding organic iron to feed for layers, it gives improvement on performance of layers and develop chemical composition of eggs.

• 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.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.10
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• pp.1391-1399
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• 2009

Two hundred and sixteen 68-week-old Hy-Line brown laying hens were used in a 6-week feeding trial to compare the efficacy of phytases Optiphos (OPT) and Natuphos (NAT), which were isolated from Escherichia coli and Aspergillus niger, respectively. Hens were randomly allotted into six treatments with six replications (six layers in three adjacent cages) per treatment according to their initial BW. The hens were then subjected to one of the following dietary treatments: i) Positive Control (PC; available phosphorus (AP) 0.4%); ii) Negative control (NC; AP 0.2%); iii) NAT1 (NC+250 FTU/kg NAT); iv) NAT2 (NC+500 FTU/kg NAT); v) OPT1 (NC+250 FTU/kg OPT); vi) OPT2 (NC+500 FTU/kg OPT). Feed intake, egg production, egg quality, apparent nutrient digestibility and serum P and Ca concentration were evaluated to compare the effect of the two phytases. Feed intake and eggshell thickness were not affected by the treatments. Superior effects (p<0.05) of OPT were only observed in egg production and egg weight compared with NAT. Characteristics such as eggshell breaking strength, apparent digestibility of N, Ca and P and serum P concentration were equally increased with the supplementation of both phytases (p<0.05), where no significant difference was observed in those characteristics between PC and phytase supplementation at 500 FTU/kg. Equally effective improvements (p<0.05) were also observed in egg production and DM digestibility, where no improvements were observed (p<0.05) between the PC group and the groups with phytase supplementation at 500 FTU/kg. Equal increases in the serum Ca level were observed when the groups with phytase supplementation were compared to the PC group. Overall, the results of this study suggest that NAT and OPT are equally effective at liberating phytate-bound complexes when included in 0.2% available phosphorus diets for 68-week laying hens; either source of phytase can be fed to commercial 68-week laying hens at 500 FTU/kg to correct the negative effects associated with a 0.2% available phosphorus diet. In conclusion, either source of phytase can be fed to commercial first cycle laying hens at 500 FTU/kg to effectively replace inorganic phosphorus when economically justified.

• Korean Journal of Poultry Science
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• v.44 no.4
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• pp.235-243
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• 2017

This experiment was aimed at investigating the effects of dietary supplementation with fermented rice bran (FRB) or fermented broken rice (FBR) on egg-laying performance, egg quality, blood parameters, and cholesterol level in egg yolk of Hy-Line Brown egg-laying hens. Altogether, 144 Hy-Line Brown egg-laying hens (32-week-old) were randomly allocated to one of 4 dietary treatment groups, with 4 replicates per treatment. Of them, 3 treatments diets were prepared by supplementing the basal diet with 0.1% probiotics (PRO), 1% fermented rice bran (FRB), or 1% fermented broken rice (FBR) at the expense of corn. Hen-day egg production was higher (P<0.05) in PRO and FRB treatment groups than in the basal treatment groups. However, feed intake, egg weight, egg mass, and feed conversion ratio did not differ among the treatment groups. Additionally, supplementation with FRB or FBR did not affect eggshell strength, eggshell thickness, egg yolk color, and Haugh unit during the feeding trial. There was no significant difference in leukocyte count. Total cholesterol level was lower (P<0.05) in the FRB treatment group than in the basal treatment groups. Asparate aminotransferase, alanine transferase, glucose, and albumin levels were unaffected by dietary supplementation with FRB or FBR. Egg yolk cholesterol level was lower (P<0.05) in the FRB and FBR treatment groups than in the basal treatment groups. In conclusion, dietary supplementation with FRB or FBR improved egg-laying performance, and reduced the levels of total serum cholesterol and cholesterol in egg yolk of Hy-Line Brown egg-laying hens.

• Journal of Animal Environmental Science
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• v.18 no.3
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• pp.183-190
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• 2012

The objective of this study was to evaluate the effects of an unexpected change in housing environment on stress in poultry. Laying hens (Hy-line Brown), adapted to a free-range housing system for more than a month, were randomly divided into two groups to be subjected to an unexpected change of their housing environment: one half of them were individually housed into conventional battery cages and the other continually left in the same housing system throughout the entire period of the study. The sudden change resulted in an increase in egg production and albumen height (P<0.05), but decrease in eggshell thickness (P<0.05). The change had tendency to increase Haugh unit ($P{\leq}0.061$) and to decrease eggshell color ($P{\leq}0.074$), but did not affect body weight for 5 days thereafter. No significant changes were detected in liver color. Plasma concentrations of corticosterone was acutely increased one day after the change (P<0.05), then returned to similar control levels. The results of the present study indicate that unexpected changes in housing environment cause acute increase in stress hormone concentrations, but interpretation of the results should be cautious due to the experimental conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.2
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• pp.203-208
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• 1999

An 8 week feeding trial was conducted with 864 ISA Brown laying hens, 48 weeks old, to determine if microbial phytase $(Natuphos^{(R)})$ supplementation can reduce non-phytate phosphorus (NPP) level in laying diets. The experiment consisted of four dietary treatments: T1, control diet with 0.26% NPP (0.55% total P) wand no supplementary phytase; T2, 0.21% NPP (0.50% total P) diet with 250 U of phytase/kg of diet; T3, 0.16% NPP (0.45% total P) diet with 250 U of phytase/kg of diet; and T4, 0.11% NPP (0.40% total P) diet with 250 U of phytase/kg of diet. T3 showed the highest egg production and egg weight and the lowest feed conversion while T4 gave the lowest egg production and the highest feed conversion and mortality. Daily feed consumption ranged from 130.4 g (T4) to 132.7 g (T2). T1 and T2 were not significantly different in the production parameters. Eggshell strength, egg specific gravity, and eggshell thickness were not significantly different among treatments. However, broken egg ratio was significantly lower in T2 and T4 than in T1. Retentions of Ca, P, Mg, and Cu were greater in phytase supplemented treatments (T2, T3, and T4) than the control (T1), and those in T3 and T4 were greater than in T2. Excretions of P in phytase supplemented treatments (T2, T3, and T4) were significantly (p<0.05) smaller than in T1 but excretions of N were not significantly different among the treatments. Contents of ash in tibiae were not significantly affected by treatments, but contents of Ca, P, Mg, and Zn was increased and that of Cu decreased by phytase supplementation. It is concluded that the NPP concentration in the diet of Brown layers consuming about 130 g/d of feed can be safely lowered from 0.26% (0.55% total P) to 0.16% (0.45% total P). The excretion of P was reduced by the inclusion of 250 U phytase/kg of diet.

• 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.23 no.6
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• pp.786-791
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• 2010

The effects of fermented garlic powder on production performance, egg quality, blood profiles and fatty acid composition of egg yolk in laying hens were studied in a 35-d experiment. Two-hundred and forty (ISA brown) layers aged 41 weeks were randomly allocated into the following four treatments: i) CON (basal diet); ii) G1 (CON+fermented garlic powder 1.0%); iii) G2 (CON+fermented garlic powder 2.0%) and iv) G3 (CON+fermented garlic powder 3.0%). There were no differences (p>0.05) among treatments in egg production, egg weight, eggshell breaking strength and eggshell thickness throughout the whole experimental period. However, yolk height was increased significantly (p<0.05) by the addition of fermented garlic powder during the 5th week while yolk color was greater (p<0.05) in G2 and G3 than in CON and G1 in the 5th week. Compared with CON, Haugh unit was increased (p<0.05) in response to fermented garlic powder treatments during the 5th week. No significant effects on total protein, albumin and IgG were observed in response to any of the treatments over the experimental period (p>0.05). There was a significant (p<0.05) reduction in plasma cholesterol concentration when the dietary level of fermented garlic powder was increased from 0.0 to 3.0%. The levels of saturated fatty acids (SFA) were significantly decreased (p<0.05) in response to G2 and G3 while monounsaturated fatty acids (MUFA) were higher (p<0.05) in G2 and G3 treatment groups than in CON and G1. Compared with other treatments, polyunsaturated fatty acids (PUFA) and PUFA:SFA ratio were higher (p<0.05) in G3. In conclusion, this study demonstrated that addition of fermented garlic powder reduced plasma cholesterol concentration and did not cause adverse effects on production performance. Moreover, addition of 3.0% garlic powder decreased SFA but increased PUFA and PUFA:SFA ratio in egg yolk.