• Korean Journal of Poultry Science
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• v.50 no.3
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• pp.133-141
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• 2023

We conducted a 5 × 5 diallel cross-combination test using 1,060 chickens from pure lines of Korean Rhode-C, -D, Korean Leghorn-F, -K, and Korean Native Yellowish-brown chicken (KNC-Y) to develop a new Korean native chicken layer breeder. The laying performance and combining ability, including livability, body weight, age of first egg-laying, hen-day egg production, and egg weight, were analyzed. The livability from birth to 48 weeks was 72.1±24.0%, with the highest observed in the YC and the lowest in the DK combination (P<0.01). The YC combination exhibited the highest general combining ability (GCA), while the YD combination showed the highest specific combining ability (SCA). Regarding body weight, combinations involving Leghorn showed lighter weights compared to combinations with Rhode and KNC-Y (P<0.01). Additionally, the offspring from the KNC-Y combination reached sexual maturity earlier than those from the Rhode combination. The hen-day egg production was 70.7±12.0%, with the highest seen in the CK combination at 86% (P<0.01). The effects of GCA and SCA on hen-day egg production were similar, with the SCA being highest in the YD combination and the GCA being highest in the Rhode-C. Significant differences in egg weight were observed among the combinations, with the eggs from Rhode and Leghorn combinations being heavier than those from combinations with KNC-Y (P<0.01). In conclusion, the YC and YD combinations, characterized by excellent livability, are highly desirable paternal strains, while the CF and CK combinations, with excellent laying performance and moderate egg weight, are preferred maternal strains for Korean native chicken layer breeders.

• Asian-Australasian Journal of Animal Sciences
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• v.1 no.3
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• pp.173-178
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• 1988

To study the effects of utilizing extruded full fat soybean (FFS) in layer diets, 300 White Leghorn pullets were put in trial divided into 5 treatments; control (commercial soybean meal as protein source), FFS 50% (replacing 50% of soybean meal with FFS), FFS 100% (replacing all amount of soybean meal with FFS), soybean oil and tallow added treatment. Each treatment consisted of 5 replicates of 12 birds. Egg production and feed efficiency from hens fed control diet were significantly lower than from hens fed the other diets. Significant differences in egg production and feed efficiency were found between the control and the other treatments. Cholesterol concentration of serum and egg yolk were not affected by any dietary treatment. Feeding extruded full fat soybean did not cause pancreatic hypertrophy nor change in mortality. There was an indication that linoleic acid (C18:2), linolenic acid (C18:3) and iodine contents increased in the thigh and egg yolk lipid of the groups fed FFS or soybean soybean can serve as effective protein source for layer diets if economically justified.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.7
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• pp.921-929
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• 2013

Huoyan goose is a Chinese local breed famous for its higher laying performance, but the problems of variety degeneration have emerged recently, especially a decrease in the number of eggs laid. In order to better understand the molecular mechanism that underlies egg laying in Huoyan geese, gene profiles in the pituitary gland of Huoyan geese taken during the laying period and ceased period were investigated using the suppression subtractive hybridization (SSH) method. Total RNA was extracted from pituitary glands of ceased period and laying period geese. The cDNA in the pituitary glands of ceased geese was subtracted from the cDNA in the pituitary glands of laying geese (forward subtraction); the reverse subtraction was also performed. After sequencing and annotation, a total of 30 and 24 up and down-regulated genes were obtained from the forward and reverse SSH libraries, respectively. These genes mostly related to biosynthetic process, cellular nitrogen compound metabolic process, transport, cell differentiation, cellular protein modification process, signal transduction, small molecule metabolic process. Furthermore, eleven genes were selected for further analyses by quantitative real-time PCR (qRT-PCR). The qRT-PCR results for the most part were consistent with the SSH results. Among these genes, Synaptotagmin-1 (SYT1) and Stathmin-2 (STMN2) were substantially over-expressed in laying period compared to ceased period. These results could serve as an important reference for elucidating the molecular mechanism of higher laying performance in Huoyan geese.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.7
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• pp.1090-1095
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• 1999

In order to minimize the occurrence of fatty liver, this study investigated how adding a high level of dietary choline or methionine affected the lipid metabolism of Tsaiya ducks. Feeding trials were conducted with sixty Tsaiya ducks during their growing period, when they were 8-12 weeks old, and during their laying period, 10-14 weeks after the onset of laying when they were 26-30 weeks old. The ducks were randomly assigned to one of three groups: a control group (basal diet), a group in which methionine was added to the basal diet, and a group in which choline was added to the basal diet. The levels of methionine and choline added were twice as high as the levels recommended by the NRC for layer-type chickens. Experimental results indicated that adding choline to the basal diet of growing ducks significantly (p<0.05) increased their body weight, while adding methionine significantly (p<0.05)reduced their body weight. Adding either choline or methionine reduced the ducks' liver fat content in both the growing and the laying periods (p<0.05). Ducks receiving added methionine or choline in their diets displayed enhanced egg production (p<0.05). Adding choline increased serum triacylglycerol (TG) in the laying period (p<0.05). Adding either choline or methionine did not significantly (p>0.05) affect the t-globulin level. Adding methionine increased the activity of liver malic dehydrogenase in both the growing and the laying periods, and increased fatty acid synthetase in the laying period (p<0.05). While adding choline markedly (p>0.05) increased VLDL and apo B in both the growing and the laying periods, it decreased HDL and apo A in the laying period (p<0.05). This study found that adding a high level of choline to the basal diets of Tsaiya ducks in both the growing and the laying periods had beneficial effects. Furthermore, adding methionine affected the lipid metabolism of Tsaiya ducks to a lesser extent than adding choline.

• Animal Bioscience
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• v.34 no.5
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• pp.811-823
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• 2021

Objective: Eggshell color is an important indicator of egg quality for consumers, especially for brown eggs. Various factors related to laying hens and their environment affect brown eggshell coloration. However, there have been no studies investigating hepatic functions of laying hens with variable intensity of brown eggshell color. Therefore, this study was aimed to identify potential factors affecting brown eggshell coloration in aged laying hens at the hepatic transcriptomic level. Methods: Five hundred 92-wk-old Hy-line Brown laying hens were screened to select laying hens with different intensity of brown eggshell color based on eggshell color fans. Based on eggshell color scores, hens with dark brown eggshells (DBE; eggshell color fan score = 14.8) and hens with light brown eggshells (LBE; eggshell color fan score = 9.7) were finally selected for the liver sampling. We performed RNA-seq analysis using the liver samples through the paired-end sequencing libraries. Differentially expressed genes (DEGs) profiling was carried out to identify their biological meaning by bioinformatics. Results: A total of 290 DEGs were identified with 196 being up-regulated and 94 being down-regulated in DBE groups as compared to LBE groups. The Kyoto encyclopedia of genes and genomes (KEGG) analysis revealed that these DEGs belong to several biological pathways including herpes simplex infection (toll-like receptor 3 [TLR3], cyclin-dependent kinase 1, etc.) and influenza A (TLR3, radical S-adenosyl methionine domain containing 2, myxovirus [influenza virus] resistance 1, etc.). Genes related to stress response (ceremide kinase like) and nutrient metabolism (phosphoenolpyruvate carboxy-kinase 1, methylmalonic aciduria [cobalamin deficiency] cblB type, glycine receptor alpha 2, solute carrier family 7 member 11, etc.) were also identified to be differentially expressed. Conclusion: The current results provide new insights regarding hepatic molecular functions related to different intensity of brown eggshell color in aged laying hens. These insights will contribute to future studies aiming to optimize brown eggshell coloration in aged laying hens.

• 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.

• Korean Journal of Poultry Science
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• v.19 no.4
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• pp.177-185
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• 1992

This study was carried out to investigate the relationship between frequency of soft and broken eggs and the economic traits for colored laying hens using the data sampled 7 times in Korea from 1985 to 1991. In addition, the correlation coefficients of frequency of soft and broken eggs on the economic traits for colored laying hens in order to decrease the frequency of soft and broken eggs were studied. The results obtained were summarized as follows ： 1. For colored laying hens, mean of the sexual maturity(SM) was 163.6 days, hen-day egg Production(HDEP) was 79.49％, hen-housed egg Production(HHEP) was 272.9 eggs, egg weight (EW) was 62.69g and the frequency of soft and broken eggs was 1.363％ during 18∼72wks. For white laying hens, SM was 157.2 days, HDEP was 77.87％, HHEP was 265.1 eggs, EW was 60. 26g and the frequency of soft and broken eggs (FSBE) was 1.174％ during 18∼72wks. 2. Statistical significances were observed in laying viability, SM, HDEP, FR, BW and FSBE during 18 ∼72wks and 18 ∼78wks by year for colored laying hens. 3. Sexual maturity was shortened from 168.5 days to 155.9 days. FSBE decreased from 1.4∼l.69％ to 0.94∼o.89％ during 18∼72wks, and HDEP was increased from 74.5∼75.1％ to 77.8∼80.6％, HHEP was increased to 302.0∼304.6 eggs and FSBE was increased from 1.54∼2.02％ to 0.98％ during 18∼78wks in colored laying hens. 4. Estimate of correlation coefficients between FSBE and trait of SM, EW, 72 wks BW were 0.3985, 0.1072, 0.4225, and those of HDEP, HHEP, FR were -0.5662, -2896, -0.245 during 18∼72wks In colored laying hens, respectively. 5. Estimate of correlation coefficients between FSBE and traits of SM, EW, 78wks BW were 0.3791, 0.1171, 0.4609, and those of HDEP, HHEP, FR were -0.5041, -0.2372, -0.2421 during 18∼78wks in colored laying hens, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.19-24
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• 2008

The purpose of this study was to detect expression of genes related to egg production in Taiwan Country chickens by suppression subtractive hybridization. Liver samples of mRNA extraction from two Taiwan Country chicken strains (L2 and B), originated from the same population but with very distinct egg production rates after long-term selection for egg and meat production respectively. Two-way subtraction was performed. The hepatic cDNA from the low egg production chickens (B) was subtracted from the hepatic cDNA from the high egg production strain (L2). The reversed subtraction (L2 from B) was also performed. The resulting differentially expressed gene fragments were cloned and sequenced. We sequenced 288 clones from the forward subtraction and 96 clones from the reverse subtraction. These genes were subjected to further screening to confirm the differential expression between the two genetic breeds of chickens. The apolipoprotein B (apoB) was expressed to a greater extent in the liver of the L2 than in the B line chickens. The 5-aminoimidazole- 4-carboxamide ribonucleotide formyltransferase/IMP cyclohydrolase (PURH) was expressed to a greater extent in the liver of the B than in the L2 strain chickens. We demonstrated that both apoB and PURH were more highly expressed in the liver than that in other tissues (muscle, ovary, and oviduct) in laying Taiwan Country chickens. Taken together, these data suggest that after the selection for egg production, expression of apoB and PURH genes were also changed. Whether the changed expression of these genes is directly related to egg production is not known, but these two genes may be useful markers for egg laying performance in Taiwan Country chickens.

• Korean Journal of Poultry Science
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• v.38 no.3
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• pp.165-171
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• 2011

This study was conducted to investigate the effects of dietary supplementation of copper-soy proteinate (Cu-SP) on the performance of laying hens. A total of 1,000 Hy-Line Brown laying hens of 32 wks old were assigned to one of the following 5 dietary treatments: Control, Cu-SP 50, 100, 150, 200 (50, 100, 150, 200 ppm Cu supplementation as Cu-soy proteinate). Each treatment was replicated 4 times with fifty birds per replication, housed in 2 birds cages. Fifty birds units were arranged according to randomized block design. Feeding trial lasted 5 wks under 16L : 8D lighting regimen. There were no significant differences among treatments in hen-day and hen-house egg production, egg weight, broken & soft egg production. Feed intake and feed conversion rate (FCR) were significantly (P<0.01) lower in Cu-SP treated groups than Control. Eggshell thickness was significantly (P<0.01) higher in Control than Cu-SP 100, 150 and 200. Egg yolk color index was significantly (P<0.01) higher in Cu-SP 200 than other treatments. Egg shell color index was significantly (P<0.05) higher in Cu-SP 150 and Cu-SP 200 than Cu-SP 100. Concentration of copper, iron and zinc of the egg yolk were not significantly influenced by treatment. There were no significant differences in the level of leukocytes and erythrocytes in the chicken blood. The result of this experiment showed that dietary supplementation of Cu-SP at the level of 50ppm of Cu can reduce feed intake and FCR.

• Korean Journal of Poultry Science
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• v.33 no.4
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• pp.309-316
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• 2006

This study was conducted to investigate the effects of dietary natural mineral liquid complex on egg production and characteristics in laying hens. A total of two hundreds fifty two, 63-weeks-old, Hy-line brown commercial layers were used for 6 weeks. Seven dietary treatments included CON (Control), C1-M0.25 (CON diet+1% chitosan+0.25% natural mineral complex), C1-M0.5 (CON diet+1% chitosan+0.50% natural mineral complex), C2-M0.25 (CON diet+2% chitosan+0.25% natural mineral complex), C2-M0.50 (CON diet+2% chitosan+0.50% natural mineral complex), C3-M0.25 (CON diet+ 3% chitosan+0.25% natural mineral complex) and C3-M0.50 (CON diet+3% chitosan+0.50% natural mineral complex). For overall period, egg production, egg shall breaking strength, haugh unit, K and Fe concentrations of blood and Fe concentration of yolk were improved in additive natural mineral treatments compared to control treatment(P<0.05). K and Fe concentrations of blood and Fe concentration of yolk were increased in added 0.5% mineral treatment compared to added 0.25% mineral treatment(P<0.05). Additive 3% chitosan + 0.5% mineral treatments were improved on egg Production and egg shall breaking strength in laying hens(P<0.05). In conclusion, chitosan and natural mineral complex supplementation in lay hens diet improved egg oduction, egg all strength and mineral concentrations of blood and yolk.