• Asian-Australasian Journal of Animal Sciences
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• v.30 no.12
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• pp.1674-1678
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• 2017

Objective: The aim of the study was to evaluate genetic correlations between the behavioural profile and performance in laying hens as an indirect answer to the question whether the observed behavioural responses are associated with increased levels of stress in these birds. Methods: The assessment of birds' temperament was carried out using the novel objects test. The behavioural test was conducted in two successive generations comprising 9,483 Rhode Island White (RIW) birds (approx. 4,700 individuals per generation) and 4,326 Rhode Island Red (RIR) birds (approx. 2,100 individuals per generation). Based on the recorded responses, the birds were divided into two groups: a fearful profile (1,418 RIW hens and 580 RIR hens) and a brave/curious profile (8,065 RIW hens and 3,746 RIR hens). The birds were subjected to standard assessment of their performance traits, including SM, age at sexual maturity; ST, shell thickness; SG, egg specific gravity; EW, mean egg weight; IP, initial egg production; and HC, number of hatched chicks. The pedigree was three generations deep (including two behaviourrecorded generations). Estimation of the (co)variance components was performed with the Gibbs sampling method, which accounts for the discrete character of the behavioural profile denotation. Results: The analyses revealed negative correlations between the performance traits of the laying hens and the behavioural profile defined as fearful. In the group of fearful RIW birds, delayed sexual maturation (0.22) as well as a decrease in the initial egg production (-0.30), egg weight (-0.54), egg specific gravity (-0.331), shell thickness (-0.11), and the number of hatched chicks (-0.24) could be expected. These correlations were less pronounced in the RIR breed, in which the fearful birds exhibited a decline in hatchability (-0.37), egg specific gravity (-0.11), and the number of hatched chicks (-0.18). There were no correlations in the case of the other traits or they were positive but exhibited a substantial standard error, as for the egg weight. Conclusion: To sum up the results obtained, it can be noted that behavioural responses indicating fearfulness, i.e. escape, avoidance, and approach-avoidance may reflect negative emotions experienced by birds. The negative correlations with performance in the group of fearful hens may indirectly indicate a high level of stress in these birds, especially in the white-feathered birds, where stronger performance-fearfulness correlations were found. Fearful birds should be eliminated from breeding by inclusion of the behavioural profile in the selection criterion in the case of laying hens.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.9
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• pp.1310-1319
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• 2005

This experiment was conducted to determine the effects of cage density (CD) and humate supplementation (HS) on laying performance, metabolic profile, and egg quality during the peak production period in hens. Lohman layers (n = 180, 46 wks of age) were blocked according to the location of cages and then allocated randomly to two levels of CD (4 or 6 hens per cage or 540 vs. 360 $cm^2$/hen) and three levels of HS (0, 0.15, and 0.30%). Egg production (EP) and feed consumption (FC) were measured daily; egg weight was measured bi-weekly; and BW was measured before and after the experiment. Blood and additional egg samples were obtained at the end of the experiment for determination of metabolic profile and egg quality. The data were analyzed using two-way ANOVA as repeated measures. Except for FC, CD did not affect laying performance parameters. Hens placed in high-density cages had lower FC than hens placed in normal-density cages. Increasing HS level linearly increased FC, EP, and feed conversion ratio (FCR). There was a CD by HS interaction effect on FC and EP. Hens placed in high-density cages had greater serum glucose, total protein, albumin, globulin, Ca, and P concentrations and tended to have greater serum corticosterone concentration than hens placed in normaldensity cages. Increasing HS level linearly increased serum glucose, total protein, albumin, globulin, creatine, and Ca concentrations and linearly decreased serum triglyceride and very low-density lipoprotein concentrations. There was a CD by HS interaction effect on serum glucose and albumin concentrations. There were no alterations in egg quality parameters in response to increasing CD. Albumen index and Haugh unit decreased linearly and other egg quality parameters did not change as HS level increased. In conclusion, increased caging density adversely affected metabolic profile, despite insignificantly deteriorating laying performance. Moreover, benefits from humate supplementation seem to be more noteworthy for hens housed in stressing conditions than for hens housed in standard conditions.

• Korean Journal of Poultry Science
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• v.49 no.1
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• pp.25-32
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• 2022

This study was conducted to produce a nutrient-balanced complex fertilizer using compost from laying hens fed with phytase levels. A total of 30 laying hens were randomly assigned in individual cages. The dietary treatments were fed from 51 to 60 wks of age, and included a phytase; 0, 1,000, and 2,000 FTU/kg in basal diets. Fresh feed (110 g) and drinking water were supplied to the laying hens every day. Feces from hens were collected daily and analyzed for N, P₂O₅, and K₂O after compost maturity. This result showed there was no difference on the fecal excretion per feed intake of laying hens supplemented with phytase levels in the diets. On the other hand, the excretions of dried feces, N, P₂O₅, and K₂O were significantly (P<0.05) reduced in 2,000 FTU/kg treatment than 0, 1,000 FTU/kg treatments. There was no difference on the compost composition and nutrient contents in compound fertilizer using compost from hens fed dietary phytase levels. However, compost content in the fertilizer was 69.6~71.6% when compost of 25~30% moisture content was used, and 13.0~47.1% at compost of 40~60% moisture content. As a result of this study, it was confirmed that hen's compost controlled moisture content could be produced as a nutrient-balanced compound fertilizer.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.980-985
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• 2000

Influences of Japanese green tea powder (GTP) supplementation to commercial diet on laying performance and egg quality were studied by using 60 laying hens. The experimental diet with or without 0.6% GTP was given ad libitum to the birds during the period from 6 to 71 weeks of age. The birds started egg production from 21 wk of age regardless GTP feeding. Body weight, feed intake, egg weight tended to decrease with GTP supplementation, while egg production rate tended to increase. Haugh unit score was significantly increased with GTP, which accompanied with the increased albumen height. These were observed almost throughout the laying period over 50 wk. Gel proportion in thick albumen was decreased as storage time is prolonged, then higher values of the gel proportion were recorded in the eggs from GTP group. Thick albumen of the eggs from GTP-fed layers had more carbohydrate than that from control layers. All these indicate physical stability of thick albumen in the eggs from GTP group. Thiobarbituric acid content of egg yolk tended to remain lower in the eggs from GTP group during 5-10 days of storage at room temperature. Levels of egg yolk cholesterol and yolk lipid were significantly reduced by GTP feeding. There were no significant differences in eggshell weight, shell thickness and shell strength between the two groups. Thyroid gland and liver from hens slaughtered at 71 wk of age did not differ in weight irrespective of GTP feeding. The present results suggest that GTP could modify components of edible part of egg, leading to the characteristics favourable to consumers such as high durability of thick albumen and less cholesterol in yolk, without altering general performance of the layers throughout this year round experiment.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.9
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• pp.1407-1413
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• 2019

Objective: This experiment aimed to investigate the effect of different sources and inclusion levels of dietary fat on productive performance and egg quality in laying hens raised under hot environmental conditions. Methods: A total of 480 Hy-Line Brown laying hens at 31 wk of age were randomly allotted to 1 of 5 experimental diets. The control diet contained 2,800 kcal/kg nitrogen-corrected apparent metabolizable energy with no fat addition. Four additional diets were prepared by adding 2.0% or 4.0% of animal fat (AF) or soybean oil (SO). Energy and nutrient concentrations were consistent among all diets. Diets were fed to hens for 4 weeks. Average daily room temperature and humidity were $26.7^{\circ}C{\pm}1.52^{\circ}C$ and $77.4%{\pm}4.50%$. The heat stress index was approximately 76, indicating that hens were raised under heat stress conditions. Results: Final body weight (BW) was greater (p<0.05) for hens fed diets containing 2.0% or 4.0% AF than for those fed the control diet or diets containing 2.0% or 4.0% SO. The BW gain and feed intake were greater (p<0.05) for hens fed diets containing additional AF or SO than those fed the control diet. Eggshell thickness was the greatest (p<0.05) for hens fed the control diet, but the least (p<0.05) for hens fed diets containing 4.0% SO. Egg yolk color was the greatest (p<0.05) for hens fed the control diet, but the least (p<0.05) for hens fed diets containing 4.0% SO. Conclusion: Inclusion of supplemental fat (AF and SO) in diets exhibits preventative effects on BW loss for hens raised under hot environmental conditions when energy and nutrient concentrations in diets were maintained. The effects were greater for AF than for SO. However, inclusion of supplemental fat in diets decreases eggshell thickness and egg yolk yellowness, possibly due to a reduction in Ca absorption and intake of egg yolk colorants.

• Animal Bioscience
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• v.34 no.2
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• pp.276-284
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• 2021

Objective: The objective of this study was to determine whether a dietary vitamin E (VE) supplement could alleviate any detrimental effects of aged corn on lipid metabolism and antioxidant status in laying hens. Methods: The experiment consisted of a 2×3 factorial design with two corn types (normal corn and aged corn (stored for 4 yr) and three concentrations of VE (0, 20, and 100 IU/kg). A total of 216 Lohmann laying hens (50 wk of age) were randomly allocated into six treatment diets for 12 wk. Each treatment had 6 replicates of 6 hens per replicate. Results: The results show that aged corn significantly decreased the content of low-density lipoprotein cholesterol (p<0.05), and reduced chemokine-like receptor 1 (CMKLR1) mRNA expression (p<0.05) in the liver compared to controls. Diet with VE did not alter the content of crude fat and cholesterol (p>0.05), or acetyl-CoA carboxylase, lipoprotein lipase, fatty acid synthase or CMKLR1 mRNA expression (p>0.05) in the liver among treatment groups. Aged corn significantly increased the content of malondialdehyde (MDA) (p<0.05) and decreased superoxide dismutase (SOD) activity (p<0.05) in the liver. The VE increased the content of MDA (p<0.05) but decreased glutathione peroxidase (GSH-Px) activity in serum (p<0.01) and in the ovaries (p<0.05). Adding VE at 20 and 100 IU/kg significantly increased GSH-Px activity (p<0.05) in liver and in serum (p<0.01), 100 IU/kg VE significantly increased SOD activity (p<0.05) in serum. Aged corn had no significant effects on GSH-Px mRNA or SOD mRNA expression (p<0.01) in the liver and ovaries. Addition of 100 IU/kg VE could significantly increase SOD mRNA expression (p<0.01) in the liver and ovary. Conclusion: Aged corn affected lipid metabolism and decreased the antioxidant function of laying hens. Dietary VE supplementation was unable to counteract the negative effects of aged corn on lipid metabolism. However, addition of 100 IU/kg VE prevented aged corninduced lipid peroxidation in the organs of laying hens.

• Journal of Animal Science and Technology
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• v.54 no.1
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• pp.43-49
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• 2012

This study was carried out to investigate the effects of age of laying hens and grade of shell abnormality on internal egg quality. At each week, 1,000 eggs were randomly selected from 21,000 eggs laid by Hy-Line hens (100,000 birds) aged from 56 to 62 wk. The samples were divided into normal and externally abnormal eggs by an official egg grader. Then, egg quality including egg weight, egg white height, Haugh unit and yolk color was evaluated from each normal and abnormal eggs. The production rate of externally normal and abnormal eggs was 81.22 and 18.78%, respectively. No difference found in the production rate by the increase of hen's age, but Haugh unit of eggs from hens of 60-wk-old was higher (p<0.05) than that of 56-wk-old. When the same age groups were compared, egg white height and Haugh unit were lower in eggs which were externally abnormal. When the grade of abnormality increased, egg white height and Haugh unit were decreased further (p<0.05). Among the externally abnormal eggs, malformation showed the lowest Haugh unit. In conclusion, the shell abnormality of eggs laid by hens aged 56 to 62 wk was closely related with internal egg quality. Therefore, the grading external egg quality in the present egg grading system is directly related with the internal egg freshness.

• Korean Journal of Poultry Science
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• v.33 no.1
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• pp.41-47
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• 2006

A study was conducted to investigate the effect of supplementing earthworm meal(EWM) on the egg quality and performance of laying hens. A total of 360 laying hens at 55 weeks of age were fed the experimental diets containing 0(Control), 0.3 and 0.6% of EWM for 5 weeks. Eggs were collected and weighed in every day and egg production and feed conversion were weekly recorded. However egg quality were measured fer last week of experimental period. When fed both 0.3 and 0.6% of EWM, egg production and daily egg mass tended to increase but were not different between those treatments. Feed intake and feed conversion ratio of laying hens were not different among three groups. Egg shell thickness, breaking strength, color and egg yolk color were tend to improve in both 0.3 and 0.6% of EWM compared to those of control. The haugh units(HUs) showed no difference among each treatments at 14 after laying egg, but increased in EWM treatments compared to control for storage period. As, Cd, Cr, Hg and Pb detected 4.41, 1.23, 1.18, 0.00 and 3.39ppm in EWM, respectively, but which were not detected in control. It assumed that supplementing 0.3% of earthworm meal in the 55 weeks old laying hens diet, improved the laying performance and egg quality.

• Korean Journal of Poultry Science
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• v.45 no.3
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• pp.183-191
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• 2018

The study was conducted to investigate the effect of dietary supplementation of Lactobacillus, medicinal plants extract, and essential oil on laying performance, cecal microflora, relative organic weight, leucocyte profiles in laying hens against Salmonella gallinarum. A total of 100 Hy-Line Brown laying hens of 65 weeks of age were assigned into 5 dietary treatments supplemented with no antibiotic (negative control), antibiotic (positive control), Lactobacillus 0.1% (LB), medicinal plants extract 100 ppm (MPE), herb extract 100 ppm (EO). After 7 days of treatment, the 20 hens in each treatment group were divided into challenge group (n=10) and non-challenge group (n=10) for oral administration of Salmonella gallinarums, and were maintained in the same dietary treatments for two additional weeks. Laying hens were selected 20 by each treatment, splitting up into oral Salmonella group and nontreated group. The feeding trial lasted for one weeks and Salmonella gallinarum was orally administered for two weeks. Egg production, egg weight, egg mass, and feed conversion ratio were calculated and cecal microflora, relative organ, and blood were collected at the end of experiment. Compared with the control, laying hens fed Lactobacillus, medical plant extract, and essential oil were not observed to change of laying performance. Salmonella count increased significantly when Salmonella gallinarum was orally administered (P<0.05) but coliform bacteria and Lactobacillus counts were not affected. The relative organs weight was not different in hens with oral administration of Salmonella gallinarum and also in hens fed Lactobacillus, medical plant extract, and essential oil. H/L ratio was not significantly different, but total leucocyte level was somewhat increased in the treatment with oral administration of Salmonella gallinarum and more leucocyte increased in laying hens fed Lactobacillus, medical plant extract, and essential oil than control.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1752-1760
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• 2005

In this experiment, the effects of cage density (CD) and probiotic supplementation (PS) on laying performance, metabolic profile, and egg quality in peak-producing hens were evaluated. After blocking according to the cage location, Lohman layers (n = 180, 46 wks of age) were allocated randomly to two levels of CD (540 vs. 360 $cm^2$/hen) and three levels of PS (0, 0.15, and 0.30%). Probiotic contained Enterococcus faecium culture (10${\times}$10$^9$ cfu/g). Egg production (EP) and feed consumption (FC) were measured daily; egg weight (EW) was measured bi-weekly; BW was measured before and after the experiment; and blood samples were obtained at the end of the experiment. The data were analyzed using two-way ANOVA. Increasing CD decreased FC (125.0 vs. 120.8 g/d, p<0.0001) and FCR (1.93 vs. 1.87, p<0.0001) and did not alter EP, EW, and BW. Increasing level of PS linearly decreased FC (p<0.02) and FCR (p<0.006). Averages were 123.9, 123.2, and 121.6 g/d for FC and 1.91, 1.92, and 1.86 for FCR in hens supplemented with 0, 0.15, and 0.30% probiotic, respectively. Hens placed in high-density cages had greater serum corticosterone concentration than hens placed in normal-density cages (12.8 vs. 11.3 $\mu$g/dL, p<0.04); CD did not affect concentrations of other metabolites. Increasing level of PS linearly increased serum glucose, albumin, and creatine concentrations and quadratically increased total protein, globulin, Ca, and P concentrations. Average concentrations (mg/dL) were 260, 297, and 305 for glucose; 6.28, 8.09, and 7.58 for total protein; 1.98, 2.48, and 2.38 for albumin; 4.30, 5.62, and 5.19 for globulin; 0.40, 0.52, and 0.54 for creatine; 16.0, 16.5, and 16.3 for Ca; and 6.27, 8.14, and 7.17 for P in hens supplemented with 0, 0.15, and 0.30% probiotic, respectively. There was no effect of CD on egg quality. Increasing level of PS linearly improved yolk color (YC) and quadratically increased albumen index (AI) and Haugh unit (HU). The mean values were 9.67, 9.75, and 10.58 for YC; 8.94, 6.93, and 8.72% for AI; and 85.6, 74.9, and 82.9 for HU for hens supplemented with 0, 0.15, and 0.30% probiotic, respectively. There was also CD by PS effect on FC, EP, and serum glucose, total protein, albumin, globulin, creatine, Ca and P concentrations. In conclusion, increased CD partially depressed laying performance and caused stress. Probiotic supplementation improved laying performance and metabolic profile. It also partially alleviated the adverse effects of stress resulting from increased caging density.