Dallas Center, IA, United States
Dallas Center, IA, United States

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Lupiani B.,Texas A&M University | Lee L.F.,U.S. Department of Agriculture | Kreager K.S.,Dallas Center | Witter R.L.,U.S. Department of Agriculture | Reddy S.M.,Texas A&M University
Avian Diseases | Year: 2013

Marek's disease (MD) is a lymphoproliferative disease of chickens caused by serotype 1 MD virus (MDV). Vaccination of commercial poultry has drastically reduced losses from MD, and the poultry industry cannot be sustained without the use of vaccines. Retrovirus insertion into herpesvirus genomes is an efficient process that alters the biological properties of herpesviruses. RM1, a virus derived from the virulent JM strain of MDV, by insertion of the reticuloendotheliosis (REV) long terminal repeat (LTR), was attenuated for oncogenicity but retains properties of the parental virus, such as lymphoid organ atrophy. Here we show that insertion of the REV LTR into the genome of vaccine strain CVI988 resulted in a virus (CVRM) that replicated to higher levels than parental CVI988 in cell culture and that remained apathogenic for chickens. In addition, CVRM showed protection indices similar or superior to those afforded by CVI988 virus in laboratory and field protection trials, indicating that it could be developed as a safe and efficacious vaccine to protect against very virulent plus MDV. © American Association of Avian Pathologists.


Fulton J.E.,Dallas Center | Soller M.,Hebrew University of Jerusalem | Lund A.R.,Dallas Center | Arango J.,Dallas Center | Lipkin E.,Hebrew University of Jerusalem
Animal Genetics | Year: 2012

Avian eggshell quality is an important trait for commercial egg production, as the eggshell is the primary packaging material and antimicrobial barrier for the internal food resource. Strong eggshells are essential to ensure that eggs can reach their final destination without damage. Ovocalyxin-32 (OCX32) is a matrix protein found within the outer layers of the eggshell and in the cuticle. Numerous reports in the literature have identified association between variants in the gene encoding this protein, OCX32, and various eggshell quality traits. Thus, OCX32 is a candidate gene for selection for eggshell traits in commercial poultry populations. Sequencing of exons 2-6 of the OCX32 gene in eight elite brown and white eggshell commercial egg-laying lines revealed 28 SNPs and one SNP/indel. Eighteen of these SNPs were predicted to alter the amino acid sequence of the protein. Clusters of SNPs in complete linkage disequilibrium were found in both exons 2 and 6. A total of 19 different versions or protein-sequence haplotypes of the OCX32 protein were inferred, revealing considerable variation within commercial lines. Genotypes for 13 of the SNPs were determined for 330-1819 individuals per line. Trait association studies revealed a significant effect of OCX32 on shell color in white egg lines and line-specific significant effects on albumen height, early egg weight, puncture score, and yolk weight. Three of the lines showed a significant change in OCX32 frequency over time, indicating selection pressure for certain variants of this gene during the breeding program. © 2012 Stichting International Foundation for Animal Genetics.


Lee L.F.,U.S. Department of Agriculture | Kreager K.S.,Dallas Center | Arango J.,Dallas Center | Paraguassu A.,Dallas Center | And 5 more authors.
Vaccine | Year: 2010

Marek's disease virus (MDV) oncogene meq has been identified as the gene involved in tumorigenesis in chickens. We have recently developed a Meq-null virus, rMd5ΔMeq, in which the oncogene meq was deleted. Vaccine efficacy experiments conducted in Avian Disease and Oncology Laboratory (ADOL) 15I5 × 71 chickens vaccinated with rMd5ΔMeq virus or an ADOL preparation of CVI988/Rispens indicated that rMd5ΔMeq provided superior protection than CVI988/Rispens when challenged with the very virulent plus MDV 648A strain. In the present study we set to investigate the vaccine efficacy of rMd5ΔMeq in the field compared to several commercial preparations of CVI988/Rispens. Three large-scale field experiments, in which seeder chickens were inoculated with a very virulent plus strain of 686, vv+ MDV, were conducted in a model developed by Hy-Line International. In addition, comparisons were made with bivalent vaccine (HVT + SB-1), HVT alone and several serotype 3 HVT-vectored vaccines individually or in combination with CVI988/Rispens. Experimental results showed that addition of HVT to either of the two commercial CVI988/Rispens preparations tested (A or B) did not enhance protection conferred by CVI988/Rispens alone and that rMd5ΔMeq was a better or equal vaccine compared to any of the CVI988/Rispens vaccines tested under the conditions of the field trials presented herein. Our results also emphasized the complexity of factors affecting vaccine efficacy and the importance of challenge dose in protection.


Long J.A.,U.S. Department of Agriculture | Bongalhardo D.C.,U.S. Department of Agriculture | Pelaez J.,U.S. Department of Agriculture | Saxena S.,Dallas Center | And 3 more authors.
Poultry Science | Year: 2010

The fertility rates of cryopreserved poultry semen are highly variable and not reliable for use in preservation of commercial genetic stocks. Our objective was to evaluate the cryosurvival of semen from 8 pedigreed layer lines at 2 different ages: the onset and end of commercial production. Semen from 160 roosters (20/line) was frozen individually with 11% glycerol at 6 and 12 mo of age. Glycerol was removed from thawed semen by Accudenz gradient centrifugation. The viability of thawed sperm from each male was determined using fluorescent live-dead staining and flow cytometry; sperm velocity parameters were measured using computerized motion analysis. The fertilizing ability of thawed sperm was evaluated in vitro by assessing hydrolysis of the inner perivitelline membrane. The postthaw function of sperm from the elite lines varied widely, despite the fact that fresh semen from all of these lines typically yielded high fertility rates. The percentage of thawed sperm with intact plasma membranes ranged from 27.8 ± 2.1 to 49.6 ± 1.9 and varied among lines and between age groups. Thawed sperm from 2 lines consistently demonstrated the highest and lowest motility parameters, whereas the velocity parameters of the remaining 6 lines varied widely. The mean number of hydrolysis points per square millimeter of inner perivitelline membrane ranged from 12.5 ± 4.1 (line 2) to 103.3 ± 30.2 (line 6). Age effects were observed for 4 out of 8 lines; however, improved postthaw sperm function at 12 mo of age was not consistent for all 3 assays. These results demonstrate variability among pedigreed lines in withstanding glycerol-based semen cryopreservation and provide a model for delineating genotypic and phenotypic factors affecting sperm cryosurvival. © 2010 Poultry Science Association Inc.


Wolc A.,University of Life Sciences in Poznań | Wolc A.,Iowa State University | Arango J.,Dallas Center | Settar P.,Dallas Center | And 5 more authors.
Poultry Science | Year: 2012

Genetic parameters were estimated for egg defects, egg production, and egg quality traits. Eggs from 11,738 purebred brown-egg laying hens were classified as salable or as having one of the following defects: bloody, broken, calcium deposit, dirty, double yolk, misshapen, pee-wee, shell-less, and soft shelled. Egg quality included albumen height, egg weight, yolk weight, and puncture score. Body weight, age at sexual maturity, and egg production were also recorded. Heritability estimates of liability to defects using a threshold animal model were less than 0.1 for bloody and dirty; between 0.1 and 0.2 for pee-wee, broken, misshapen, soft shelled, and shell-less; and above 0.2 for calcium deposit and double yolk. Quality and production traits were more heritable, with estimates ranging from 0.29 (puncture score) to 0.74 (egg weight). High-producing hens had a lower frequency of egg defects. High egg weight and BW were associated with an increased frequency of double yolks, and to a lesser extent, with more shell quality defects. Estimates of genetic correlations among defect traits that were related to shell quality were positive and moderate to strong (0.24- 0.73), suggesting that these could be grouped into one category or selection could be based on the trait with the highest heritability or that is easiest to measure. Selection against defective eggs would be more efficient by including egg defect traits in the selection criterion, along with egg production rate of salable eggs and egg quality traits. © 2012 Poultry Science Association Inc.


Brace R.C.,Iowa State University | Fehr W.R.,Iowa State University | Schnebly S.R.,Dallas Center
Crop Science | Year: 2011

Soybean [Glycine max (L.) Merr.] lines with the transgenic event DP-305423-1 produce a higholeate oil and those with the fan1(C1640) and fan3(RG10) alleles produce a low-linolenate oil. The objective of this study was to evaluate the agronomic and seed traits of high-oleate and low-linolenate (HOLL) lines, high-oleate and normal-linolenate (HONL) lines, and normal-oleate and normal-linolenate (NONL) lines selected from four single-cross populations segregating for the three genes. A minimum of 14 F 3:5 lines of each class in the four populations were evaluated in five environments during 2009. The mean fatty ester concentrations averaged across populations were 786 g kg -1 oleate and 24 g kg -1 linolenate for the HOLL lines, 784 g kg -1 oleate and 56 g kg -1 linolenate for the HONL lines, and 226 g kg -11 oleate and 75 g kg -1 linolenate for the NONL lines. The mean yield of the NONL lines was significantly greater than the HOLL lines by 4.5% and the HONL lines by 3.0%. Of the 10 highest yielding lines in each population, 60% were NONL, 25% HOLL, and 15% HONL, which indicated that it would be possible to select cultivars of both classes that yield as well as NONL cultivars. The overlap among the three classes in the distributions of lines for protein, oil, seed weight, maturity, height, and lodging indicated that it would be possible to develop HOLL and HONL cultivars comparable to NONL cultivars for those traits. © Crop Science Society of America.


Fulton J.E.,Dallas Center | Arango J.,Dallas Center | Arthur J.A.,Dallas Center | Settar P.,Dallas Center | And 2 more authors.
Avian Diseases | Year: 2013

A challenge test following inoculation with a standard amount of a vv+ strain of the Marek's disease (MD) virus in multiple lines and multiple generations of egg type chicken and the corresponding phenotypic trend are described. This program significantly reduced mortality of progeny from selected sires for three to 11 generations in eight of the nine elite lines studied herein. In brown egg lines, a retrospective analysis of DNA indicated an association between the blood type B (major histocompatibility complex) of the sire and the MD mortality in the challenge of its progeny. As a result of the multigeneration stock amplification and crossbreeding processes used in the commercial breeding industry, improvement in survival after challenge at the elite level will translate to improved welfare for millions of birds at the commercial production level. © American Association of Avian Pathologists.


Wolc A.,University of Life Sciences in Poznań | Wolc A.,Iowa State University | Arango J.,Dallas Center | Settar P.,Dallas Center | And 2 more authors.
Poultry Science | Year: 2011

The objectives of this study were to estimate genetic parameters for egg production over the age trajectory in 3 layer lines, which represent different biotypes for egg production, and to validate the use of breeding values for slope as a measure of persistency to be used in the selection program. Egg production of more than 26,000 layers per line from 6 consecutive generations were analyzed with a random regression model with a within-hatch-nested fifth-order fixed-regression polynomial and linear polynomials for random additive genetic and permanent environmental effects. Daily records were cumulated into biweekly periods. In all lines, a nonzero genetic variance for mean and slope and a positive genetic correlation between mean and slope were estimated. Genetic variance of egg production by 2-wk period was low at the beginning of lay and increased as the birds aged for all 3 lines, which resulted in heritability estimates increasing with age. Breeding values for slope reflected the shape of the egg production curve well and can be used to directly select for persistency of egg production. © 2011 Poultry Science Association Inc.


Poultry breeding companies are facing a new paradigm. Since 2004, extensive resources have been developed to increase understanding of the fundamental biology of the chicken. The chicken genome has been sequenced and revised twice, millions of novel DNA variants have been identified, and new tools have been created that allow rapid and inexpensive detection of these DNA variations. These developments have led to the establishment of molecular-based breeding programs within major poultry breeding companies that are revolutionizing the primary poultry breeding industries. Costs of sequencing continue to drop and are predicted to eventually reach the point where it is feasible to sequence the entire genome of elite birds before selection. There are multiple challenges to be resolved before this information can be fully incorporated into a breeding program. These include handling and analyzing the extremely large data sets generated, understanding which genes, variants, or both are relevant for commercial production traits, development of new bio-informatic tools, and integration of molecular information with traditional breeding programs. The novel variation identified within elite commercial lines will lead to enhancements in commercial breeding programs. Applications of this information include whole genomic selection, parentage identification, trait association studies, and quality control. © 2014 Poultry Science Association Inc.


Wolc A.,University of Life Sciences in Poznań | Wolc A.,Iowa State University | Arango J.,Dallas Center | Settar P.,Dallas Center | And 7 more authors.
Genetics Selection Evolution | Year: 2011

Background: The predictive ability of genomic estimated breeding values (GEBV) originates both from associations between high-density markers and QTL (Quantitative Trait Loci) and from pedigree information. Thus, GEBV are expected to provide more persistent accuracy over successive generations than breeding values estimated using pedigree-based methods. The objective of this study was to evaluate the accuracy of GEBV in a closed population of layer chickens and to quantify their persistence over five successive generations using marker or pedigree information. Methods. The training data consisted of 16 traits and 777 genotyped animals from two generations of a brown-egg layer breeding line, 295 of which had individual phenotype records, while others had phenotypes on 2,738 non-genotyped relatives, or similar data accumulated over up to five generations. Validation data included phenotyped and genotyped birds from five subsequent generations (on average 306 birds/generation). Birds were genotyped for 23,356 segregating SNP. Animal models using genomic or pedigree relationship matrices and Bayesian model averaging methods were used for training analyses. Accuracy was evaluated as the correlation between EBV and phenotype in validation divided by the square root of trait heritability. Results: Pedigree relationships in outbred populations are reduced by 50% at each meiosis, therefore accuracy is expected to decrease by the square root of 0.5 every generation, as observed for pedigree-based EBV (Estimated Breeding Values). In contrast the GEBV accuracy was more persistent, although the drop in accuracy was substantial in the first generation. Traits that were considered to be influenced by fewer QTL and to have a higher heritability maintained a higher GEBV accuracy over generations. In conclusion, GEBV capture information beyond pedigree relationships, but retraining every generation is recommended for genomic selection in closed breeding populations. © 2011 Wolc et al; licensee BioMed Central Ltd.

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