• Animal Bioscience
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• 제35권9호
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• pp.1426-1433
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• 2022

Objective: The present research was conducted to evaluate the interactive effect of dietary concentration of calcium (Ca) and 25-hydroxy vitamin D3 (25OHD3) on the performance, blood composition and digestibility of laying hens. Methods: A total of 540 Hy-line brown laying hens aged 61 to 70 weeks were randomly allotted in a 3×3 factorial arrangement, consisting of three levels of 25OHD3 (0, 25, and 50 ㎍/kg) and three levels of Ca (3.5%, 4.0%, and 4.5%). All diets had basal concentration of 3,000 IU/kg of vitamin D3 including the 2,800 kcal/kg of metabolic energy and 16% of crude protein. Results: The results showed that interactive effect (p<0.05) between Ca and 25OHD3 was such that dietary 25OHD3 linearly increased interleukin-6 at all levels of Ca inclusion. Interaction (p<0.05) occurred with the highest parathyroid hormone in laying hens that received dietary concentration of Ca (3.5%) with 25OHD3 (50 ㎍/kg), and Ca (4.0%) with 25OHD3 (50 ㎍/kg). Egg production and egg weight significantly (p<0.05) increased in the 4.5% Ca group compared to the 3.5% to 4.0% Ca groups. Egg shell thickness and tibia bone length also increased (p<0.05) in groups fed a high-Ca diet (4.0% to 4.5%). Phosphorus digestibility significantly (p<0.05) increased along with dietary Ca level. Among the tested 25OHD3 groups, higher (p<0.05) egg production and tibia thickness were present in hens fed 50 ㎍/kg of 25OHD3. Furthermore, Ca digestibility serum Ca and 25OHD3 were significantly increased in group offered 50 ㎍/kg of 25OHD3. Conclusion: The results gathered in this study indicate that dietary concentrations of 4.0% to 4.5% Ca and 50 ㎍/kg 25OHD3 improve the performance of hens from 61 to 70 weeks of age.

• Journal of Animal Science and Technology
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• 제62권4호
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• pp.521-532
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• 2020

The production performance of broiler breeder hens in response to different levels of total lysine during the early laying period was investigated. A total of 126 Ross 308 parent stock hens were offered one of seven dietary treatments formulating elevated contents of total lysine ranging from 0.55% to 0.79% (0.04 scale; 133 g of feed) from 23 to 29 weeks of age. Each treatment had six replicates with three birds per pen. Body weight was recorded triweekly and eggs were collected and weighted at 9:00 am daily. One hen from each pen was euthanized to collect blood samples and visceral organs were harvested and weighed. Egg production, egg weight and egg mass were lower (p < 0.05) in hens offered a diet containing 0.55% total lysine compared to those fed the diet containing higher total lysine. Hens offered a diet containing 0.71%, 0.75%, and 0.79% total lysine had greater (p = 0.008) egg production rate compared to those offered a diet containing lysine less than 0.71%. The number of total eggs produced tended to be greater (p = 0.083) in hens offered a diet containing 0.71 and 0.75% total lysine compared to the other treatments. The number of settable egg production was higher (p < 0.001) in hens offered a diet contacting 0.79% total lysine compared to those fed the diet containing lower levels of total lysine. The relative weights of oviduct and ovary were lower (p < 0.05) in hens offered a diet containing 0.59% total lysine compared to the other treatments. No difference found in body weight, the number of total eggs, double-yolk eggs and abnormal shell eggs among the treatments. The urea nitrogen, estradiol-17 beta and progesterone in plasma were not affected by treatments. Based on linear- and quadratic-plateau models, total lysine requirements for egg production, settable egg production and egg mass at the early laying period were to be 0.73%, 0.77%, and 0.71%, respectively. Modern broiler breeder hens likely require higher total lysine than NRC recommendation in a diet for enhancing productivity during the early-laying period.

• 한국유기농업학회지
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• 제24권1호
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• pp.115-122
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• 2016

The main purpose of the current study was to compare quality of eggs 1) produced from hens housed in battery cages vs. free range, 2) from young vs. old hens, and 3) tagged with the lowest vs. the highest price in a local franchised mart. The ages of hens, at which their eggs were used for the analysis of quality, were 70 weeks old in the experiment 1, 22 and 47 weeks old in the experiment 2, and were unknown in the experiment 3. Eggs were analyzed for weight, albumen height, Haugh unit, shell color, shell strength, shell thickness, shell weight, yolk color, yolk weight, and egg white weight. In the experiment 1, significant differences were detected between two housing systems in shell color, shell weight, yolk color, and yolk weight (P<0.05), but not in egg weight, albumen height, Haugh unit, shell strength, shell thickness, and egg white weight (P>0.05). Although egg weight was slightly but not significantly higher in battery cages by 2.2 g than in free range, yolk weight was significantly higher in battery cage (P<0.05). On the contrary, shell color was greatly increased in free range system by 68.5% compared with battery cage. In the experiment 2, there were significant differences between young and old hens in egg weight, albumen height, Haugh unit, shell strength, shell weight, yolk color and yolk weight (P<0.05). Egg weight, shell weight, yolk color and yolk weight were increased in old hens than young hens while albumen height, Haugh unit, and shell strength were decreased. In the experiment 3, egg weight, albumen height, Haugh unit, shell weight, and egg white weight were significantly higher in the highest priced eggs than the lowest ones (P<0.05), whereas shell strength and yolk color were lower (P<0.05) but shell color, shell thickness and yolk weight were not different (P>0.05). So, egg freshness was clearly higher in the highest priced ones than in the lowest (P<0.05). Due to the limited information on raising and husbandry of laying hens whose eggs were tested for egg quality in the current study, the present results should be cautiously interpreted while contributing to the future study as a basis in this field.

• Asian-Australasian Journal of Animal Sciences
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• 제19권8호
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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.

• 한국동물위생학회지
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• 제26권1호
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• pp.51-56
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• 2003

Avian pneumoviros(APV), also known as avian rhinotracheitis virus(ARTV), affects both turkeys and chickens and is known to be the primary causative agent of turkey rhinotracheitis (TRT). The aim of this study was to establish the presence or absence of antibodies to avian pneumovirus in the commercial poultry population of Korea. For this purpose, chicken serum samples were obtained and tested by an enzyme-linked immunosorbent assay (ELISA). The tested serum was collected in laying hens with reduction of egg production or normal in Gyeongbuk province. A total of 184 sera representing 42 different poultry farms of the Gyeongbuk region of Korea were included in this study. Laying hens of 16 different farms with reduction of egg production and laying hens of 26 different farms with clinically healthy at the time of serum sampling were considered positive to antibody against APV. In the farms with reduction of egg production, positive farm to antibody against avian pneumovirus were 11 of 16 different farms(68.8%) and positive sera were 47(58.8%) of 80 different serum. In the farms with clinically healthy flock, positive farm to antibody against avian pneumovirus were 12(46.2%) of 26 different farms and positive serum sample were 39(37.5%) of 104 different sera. According to the results tested to 42 different farms in 14 city, 8 of 14 city have flocks with antibody positive laying hens against APV, 1 of 14 city have antibody suspicious and 5 of 14 city shown antibody negative, respectively.

• Asian-Australasian Journal of Animal Sciences
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• 제21권7호
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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.

• 한국가금학회:학술대회논문집
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• 한국가금학회 2006년도 제23차 정기총회 및 학술발표회
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• pp.17-27
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• 2006

The effects of dietary betaine on performance, blood compositions, hepatic amino acid concentrations and hormonal secretions were examined in laying hens. Egg production was significantly higher in birds fed the 16.5 % protein diet compared to those fed 14.5 % protein diet(p<0.05), whereas dietary supplementation of betaine did not show any significant effect. The high level of protein and betaine supplementation significantly improved egg weight, egg mass and feed conversion(p<0.05), while eggshell breaking strength, eggshell thickness and Haugh unit were not influenced by betaine and dietary protein levels. Supplemental betaine did not affect serum total protein, albumin and BUN concentration. However, uric acid concentration significantly increased in 600 ppm betaine-fed groups(p<0.05). Concentrations of most hepatic amino acid were influenced by increased protein feeding and dietary betaine supplementation. Hormone studies recorded significantly higher serum and hepatocyte IGF-I concentration in 600 and 1,200 ppm betaine treatments(p<0.05) compared to those of control group. IGF-I mRNA gene expression of hepatocytes revealed statistically correlated increase in 600 and 1,200 ppm betaine-fed groups compared to the controls(p<0.05). Serum IGFBP-3 concentration was significantly elevated in 600 ppm betaine treatments. However, the secretion of IGFBP-1 in hepatocyte of laying hens fed with 600 and 1,200 ppm of betaine showed a significant decrease compared to the control group(p<0.05). Results of these study show that dietary betaine supplementation affects protein and hormone metabolism in laying hens.

• Asian-Australasian Journal of Animal Sciences
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• 제19권5호
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• pp.713-719
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• 2006

The effect of dietary iodine and selenium supplementation, alone or in combination, on peripheral blood lymphocyte function was determined in laying hens. Eight-hundred-and-sixty-four New-Loman laying hens were randomly allotted into 12 dietary treatments with different inclusion levels of iodine (0, 0.1 and 0.2 mg/kg), selenium (0, 0.05, 0.1 and 0.2 mg/kg) or their combinations for 24 weeks. The lipopolysaccharide (LPS) stimulation index, concanavalin A (ConA) stimulation index, peroxide enzyme activity and phagocytosis to neutral red particles were tested. There were significant differences in LPS stimulation index, ConA stimulation index, peroxide enzyme activity and phagocytosis to neutral red particles in different iodine or selenium supplementation levels (p<0.05). The highest iodine and selenium supplementation both resulted in highest LPS-/ConA-stimulation indices (p<0.05). However, when iodine was lower than 0.2 mg/kg, the additional effect of different levels of selenium did not always result in significant differences in these indices. The results indicated that iodine and selenium may affect immunity in laying hens and, when the iodine level in the laying hen is lower than 0.2 mg/kg, a selenium allowance higher than 0.1 mg/kg may be necessary to improve immunity.

• 대한수의학회지
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• 제19권1호
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• pp.45-51
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• 1979

The present study was undertaken to observe the immune status of breeding hens and laying hens against Newcastle disease (ND). The methods of extraction of hemagglutination inhibition (HI) antibody from egg yolk, the detection of HI antibody in egg albumen and the correlation between HI antibody titers in maternal sera and egg yolks were discussed. For the purposes of these experiments, 9 flocks of breeding hens and 16 flocks of laying hens immunized against Newcastle disease virus were investigated. The vaccination program of tested flocks was 3-3-3 or 4-4-4 in general. The results obtained are summerized as follows: Freezing-thawing was the best method far antibody extraction from egg yolk for HI test. The HI antibody against NDV was found in egg albumen (geometric mean, 4.5), but lower than that found in egg yolk (32.1). The geometric mean of HI antibody titers of egg yolks (84.1) was higher than that of maternal sera (68.4) and day-old chicken sera (25.3). There was correlation between HI antibody titers of maternal sera(Y) and those of egg yolks(X). The coefficient correlation was r=0.63, and the line of regression of Y on X was $\hat{Y}$=35.91+0.35X.

• Asian-Australasian Journal of Animal Sciences
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• 제25권4호
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• pp.524-530
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• 2012

Laying hens were fed commercial diets added with supplemented fat (SFAT) at 0.6, 1.2, and 1.8% in order to study the long term dietary effects - on - their productive performance from 22 to 75 wk of age. Five hundred and seventy six Single Comb White Leghorn hens were assigned to one of the four dietary treatments. The experimental phase consisted of three periods of 18 wk each. The final body weight and gain of hens fed on diets with SFAT at 1.2% and 1.8% were lower (p<0.05) than those hens given no SFAT. The SFAT at the 1.2% and 1.8% levels improved egg production rate, egg weight and mass, as well as FCR. Mortality and feed consumption were not affected by dietary SFAT. Administration of a diet with SFAT significantly decreased the cracked-broken egg ratio (p<0.01). The beneficial effects of SFAT on egg production performance were particularly more pronounced at intermediate and later ages. Hence, SFAT by period interactions were significant for all traits studied except feed intake. Hens fed SFAT deposited significantly higher abdominal fat than those on the no-SFAT diet. As a result, SFAT at 1.2% and 1.8% inclusion levels provided benefits in terms of efficient table egg production.