• Korean Journal of Poultry Science
• /
• v.13 no.1
• /
• pp.1-14
• /
• 1986

The subject of this study was to obtain some genetic information for developing superior layer chickens. Heterosis and combining ability effects were estimated with 5,759 progenies of full diallel crosses of 6 strains in White Leghorn. Fertility, hatchability, brooder-house viability, rearing- house viability, laying-house viability, age at 1st egg laying, body weight at 1st egg laying, average egg weight, hen-day egg production, hen-housed egg production, and feed conversion were investigated and analyzed into heterosis effect, general combining ability, specific combining ability and reciprocal effect by Grilling's model I. The results obtained were summarized as follows; 1. The general performance of each traits was 94.76% in fertility, 74.05% in hatchability, 97.47% in brooder-house viability, 99.72% in rearing-house viability, 93.81% in laying-house viability, 150 day in the age at 1st egg laying, 1,505g in the body weight at 1st egg laying, 60.08g in average egg weight, 77.11% in hen-day egg production, 269.8 eggs in hen-housed egg Production, and 2.44 in feed conversion. 2. The heterosis effects were estimated to -0.66%, 9.58%, 0.26%, 1.83%, -3.87%, 3.63%, 0.96%, 4.23%, 6.4%, and -0.8%, in fertility, hatchability, brooder-house viability, laying-house viability, the age at 1st egg laying, the body weight at 1st egg laying, average egg weight, hen-day egg Production, hen-housed egg production and feed conversion, respectively. 3. The results obtained from analysis of combining ability were as follows ; 1) Estimates of general combining ability, specific combining ability and reciprocal effects were not high in fertility. It was considered that fertility was mainly affected by environmental factors. In the hatchability, the general combining ability was more important than specific combining ability and reciprocal effects, and the superior strains were K and V which the additive genetic effects were very high. 2) In the brooder-house viability and laying-house viability, specific combining ability and reciprocal effects appeared to be important and the combinations of K${\times}$A and A${\times}$K were very superior. 3) In the feed conversion and average egg weight, general combining ability was more important compared with specific combining ability and reciprocal effects. On the basis of combining ability the superior strains were F, K and B in feed conversion, F and B in the average egg weight. 4) General combining ability, specific combining ability and reciprocal effects were important in the age at 1st egg laying and the combination of V ${\times}$F, F${\times}$K and B${\times}$F were very useful on the basis of these effects. In the body weight at 1st egg laying, general combining ability was more important than specific combining ability and reciprocal effects, relatively. The K, F and E strains were recommended to develop the light strain in the body weight at 1st egg laying. 5) General combining ability, specific combining ability and reciprocal effects were important in the hen-day egg production and hen-housed egg production. The combinations of F${\times}$K, A${\times}$K, and K${\times}$A were proper for developing these traits. 4. In general, high general combining ability effects were estimated for hatchability, body weight at 1st egg laying, average egg weight, hen-day egg production, hen-housed egg production, and feed conversion and high specific combining ability effects for brooder-house viability, laying house viability, age at 1st egg laying, hen-day egg production and hen-housed egg production, and high reciprocal effects for the age at 1st egg laying.

• Asian-Australasian Journal of Animal Sciences
• /
• v.25 no.4
• /
• pp.524-530
• /
• 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.

• Korean Journal of Poultry Science
• /
• v.21 no.3
• /
• pp.195-205
• /
• 1994

Effects of the addition of \beta-glucanase to barley-based layer diets were examined by feeding 200 Leghorn layers with corn-based (Control) and \beta-glucanase supplemented diets (Barley+ Enzyme). The results obtained are sumrrarized as follows. 1. There were no siginificant (P>0.05) differences in hen-day egg production(%) and average egg weight between two treatments, indicating that the \beta-glucanase supplemented barley could successfully replace the commonly used corn in the layer diets. 2. Although there was no statistical difference (P>0.05) between two treatments, the daily feed consumption was numerically high in layers fed the barly diet compared to the corn-based diet. 3. Availabilities of crude fat and crude fiber of the barley diet were significantly poor (P<0.05) as compared to corn diet. 4. The \beta-glucarase supplementation depressed the viscosity of barley diets and excreta from therm. 5. Both serum and egg yolk cholesterol were not significantly affected by the addition of \beta-glucarase in the barley based diet. Our data indicate that the barley grain supplemented with \beta-glucarase can be sucessfully used as an energy source of layer diet when there is a price advantage. Although some possibilities to produce low cholesterol egg were recognized in this study, further studies pertaining to long-term feeding experiment and elucidaton of the metabolic interrelationship between serum and yolk cholesterol, are required to confirm the result.

• Korean Journal of Poultry Science
• /
• v.34 no.2
• /
• pp.119-128
• /
• 2007

The effects of microbial phytase on laying performance, egg quality, and ileal digestibility of nutrients and amino acids were examined at three levels of phytase (0, 300, 600 unit/kg) in 55-wk-old White Leghorn for 4 weeks. Egg productivity tended to increase with supplemental phytase compared to that of control. Daily feed intake of hens fed phytase also increased. Egg shell thickness was not significantly different among the treatments. Haugh unit and yolk color were not statistically different. However, egg shell breaking strength was high at phytase treatment. Excretion and absorption of nitrogen were no difference among all treatments, but those of phosphorus was higher in the phytase treatment than control. The digestibility was high at crude fiber, crude ash, calcium and phosphorus in nutrients, at lysine, methionine and phenylalanine in essential amino acids, and alanine, cystine, glutamic acid, glycine and tyrosine in non-essential amino acids. In conclusion, supplemental microbial phytase in laying hens diet may help to improve egg production and to decrease P of feces. But, further studies were needed to investigate on the digestibility.

• Korean Journal of Poultry Science
• /
• v.13 no.1
• /
• pp.23-30
• /
• 1986

The Calorimetric experiment was made firstly to measure the difference in energy metabolisms of laying hens among their three different laying periods, secondly to estimate the energy requirements of the layers on their respective laying periods. The laying period was divided into three chronological periods of 25-40, 41-55, and 56-69 weeks old of laying hens, which are refered to as period I, II, and III respectively. 1) The fasting heat production (FHP) of laying hen on the three laying periods were 81.5 Kcal/kg$\^$0.75/ for period I, 72.3 Kcal/kg$\^$0.75/ for perod II, and 97.5 Kcal/kg$\^$0.75/ for perod III. The marked increase in FHP was found in period m, while there was a small difference in FHP between period I and II. The present study have observed among the birds in period in the high degree of plumage defectiveness, and this condition of bird might have accounted for the increase in FHP. 2) The regression equation between ME intake and energy retention (ER) were calculated, and the equations indicated that, for the period I, II, and III, the ME requirements for maintenance (MEm) were 123, 111, and 131 Kcal/kg$\^$0.75/ respectively, and that the Net Availabilities of Metabolizable energy (NAME) were 76, 79, and 74 percent respectively. For the whole laying period measured, MEm was 119 Kcal/kg$\^$0.75/ and NAME was 79 percent. There was a tendancy of higher MEm, and lower NAME during Period III, comparing with period I and II.

• Journal of the Korean Data and Information Science Society
• /
• v.27 no.5
• /
• pp.1307-1316
• /
• 2016

This study was to execute the random arrangement of total 120 heads (10 heads per treatment plot ${\times}$ 3 repeats ${\times}$ 4 treatment plots) for four breeds [Blue arakana commercial Fowl (BC), Yeonsan silky fowl (YS), Korean native fowl (KN), White leghorn fowl (WL)] with the initiation of laying hens at 32 weeks old in order to comparatively analyze egg quality and composition by sorts of laying hens. In case of evaluation of the quality of eggs, this study has shown that BC had higher degree of Haugh unit coefficient (82.82) and in case cholesterol content of eggs, BC had significantly low content as 317.55mg/100g, but YS had rather higher content as 381.30mg/100g. Furthermore, this study has found out that BC had significantly low Oleic acid (C18:1n9) and WL had higher Amino acid content by breeds than those of other breeds (p<0.05).

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.7
• /
• pp.1015-1019
• /
• 2003

A 50 day feeding trial was conducted with White Leghorn (WL) laying hens, 42 weeks old, to determine if feeding of varying levels of aflatoxin (AF), ochratoxin A (OA) or their combinations has any effect on their performance and egg quality parameters. Feeding of $T_4$, $T_7$, $T_8$, $T_9$ and $T_10$ caused significant reduction in feed intake of hens. Hen day egg productions were significantly reduced at all the levels of toxins except 0.5 ppm of AF. Maximum reduction in egg production was noticed at 2 and 4 ppm of AF and OA, respectively. Average body weight and egg weight were not affected by toxin feeding. The feed efficiency in terms of net feed efficiency and feed consumed per dozen egg produced was significantly reduced at higher levels of both the toxins and their combinations. Feed consumption for production of 1 kg egg mass remained uninfluenced due to aflatoxin feeding whereas significant increase in the value of the same was noticed at 4 ppm level of OA and combination of 1 and 2 ppm of AF and 2 and 4 ppm of OA ($T_9$ and $T_10$), respectively. Various levels of OA (1-4 ppm) and all the combination of two toxins ($T_8$, $T_9$ and $T_10$) significantly altered the shape index of eggs in laying hens. The shell thickness was significantly reduced by higher level of AF (2 ppm), OA (2 and 4 ppm) and their combination. Albumen index, Haugh Unit and yolk index remained unchanged due to incorporation of toxins in the diet. It is concluded that AF, OA either singly or in combination at higher levels could depress the performance in terms of egg production and feed efficiency significantly. The egg quality parameters i.e. shape index and shell thickness were also significantly affected.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2004.11a
• /
• pp.13-15
• /
• 2004

Telomeres are the end of chromosomes and consist of a tandem repeat sequence of (TTAGGG)n and associated proteins. Telomeres are essential for chromosome stability and are related with cell senescence and apoptosis. This study was carried out to analyze the amount of telomeric DNA of chicken lymphocytes, which is to considered as bio-marker. The amount of telomeric DNA of lymphocytes in Korean Native Chicken and White Leghorn was analyzed by quantitative-fluorescence in situ hybridization (Q-FISH) technique using the chicken telomeric DNA probe. Telomere quantifies were compared among breeds, ages and sex, and the relationship between the amount of telomeres and their productive trait was also analyzed. Comparing the amount of telomeric DNA on lymphocytes during growing period, the amount of telomeres was gradually decreased as growing older. The telomere quantity was also significantly different in breeds and sex. Estimating correlation coefficient, the amount of telomeres was positively correlated to sexual maturity and body weight but negatively correlated to hen day egg production and egg weight. These results implicate the telomere quantity is considered as an individual bio-marker.

• Korean Journal of Poultry Science
• /
• v.16 no.4
• /
• pp.209-217
• /
• 1989

This study was carried out to obtain the information on the genetic characters of Korean native fowls. The data for this study was collected from fowls located at the Gyunggi, Chunscheong, Yeongnam and Jeju area from March, 1989 to November, 1989. The morphology, genetic characters and economic traits of fowls were investigated. Followings are the major results obtained from this study. 1. The morphology and genetic characters of Korean native fowls are similar to those of brown Leghorn, 2. Colored fowls outnumbered white fowls by 402 to 38 in feather color, and wild type fowls outnumbered black fowls by 317 to 38 in feather pattern. 3. For morphology of chromosomes, chromosome size and shape of Korean native fowls were similar to those of other breeds. 4. Body weights of male was 1.2-1.6kg, and of female 1.5-1.9 kg. Hen-housed egg production was 80-120 eggs.

• Journal of Biosystems Engineering
• /
• v.31 no.5 s.118
• /
• pp.436-442
• /
• 2006

This research was conducted to design and develop a wired monitoring system for judging if sick or dead layers (SDL) exist in multi-tier layers battery (MLB) by machine vision, and to analyze its performance. In this study, 20 Brown Leghorn (Hi-Brown) layers aged 37 weeks old, were used as the experimental animals. The intensity of concern paid by layers on feed was over 90% during 5 minutes and 30 seconds after providing feed, and normal layers (NL) had been standing to take feed for that period. Therefore, in this study, the optimal judging time was set by this test result. The wired monitoring system developed was consisted of a driving device for carrying machine vision systems, a control program, a RS232 to RS485 convertor, an automatic positioning system, and an image capture system. An image processing algorithm was developed to find SDL in MLB by the processes of binary processing, erosion, expansion, labeling, and reckoning central coordinate of the captured images. The optimal velocity for driving unit was set up as 0.13 m/s by the test results for wired monitoring system, and the proximity switch was controlled not to be operated for 1.0 second after first image captured. The wired monitoring system developed was tested to evaluate the remote monitoring performance at lab-scale laying hen house. Results showed that its judgement success.ate on normal cage (without SDL) was 87% and that on abnormal cage (with SDL) was 90%, respectively. Therefore, it would be concluded that the wired monitoring system developed in this study was well suited to the purpose of this study.