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Siloam Springs, AR, United States

Talaty P.N.,Purdue University | Katanbaf M.N.,Cobb Vantress Inc | Hester P.Y.,Purdue University
Poultry Science | Year: 2010

Broilers selected for increased body size and breast muscle have imposed stress on the skeletal system, resulting in poorer walking ability. Our objectives were to determine the relationship between bone mineralization and gait score in 4 crosses of commercial broilers and to ascertain if mineralization of the toe is correlated to the tibia. Three chickens per pen each with good (gait score of 0 or 1) or poorer (gait score of 3) walking ability were killed and weighed. The left humerus, the left middle toe, and both drumsticks were collected for determination of bone mineral density (BMD), bone mineral content, and bone size traits using dual-energy x-ray absorptiometry. The BMD and bone size traits were similar among the 4 crosses of commercial broilers at 6 wk of age. However, gait scores differed among genotypes, with cross C having better gait scores than crosses A and B, but did not differ from cross D. The bone mineral content and bone size traits did not differ between birds with good walking ability as compared with those broilers of poorer walking ability. However, birds with poorer walking ability had higher BMD (P < 0.05) and BW (P < 0.001) than males with good walking ability. Within a cross, the correlation between gait score and BMD was not significant except for cross D birds. Broilers of cross D with better walking ability had decreased bone mineralization (r = 0.19, P = 0.03). The stronger correlation between gait score and BW for all crosses of commercial broilers (r = 0.38, P < 0.0001) suggests that the low association between gait score and bone mineralization for cross D was mainly due to BW. The BMD of the left toe was correlated to the BMD of the left tibia (r = 0.91, P < 0.0001) and right tibia (r = 0.87, P < 0.0001). In conclusion, bone mineralization was similar among crosses of meat-type chickens, and it had little influence on the gait score of male broilers. © 2010 Poultry Science Association Inc. Source

Kerstens H.H.D.,Wageningen University | Crooijmans R.P.M.A.,Wageningen University | Dibbits B.W.,Wageningen University | Vereijken A.,Research and Technology Center | And 2 more authors.
BMC Genomics | Year: 2011

Background: Variation within individual genomes ranges from single nucleotide polymorphisms (SNPs) to kilobase, and even megabase, sized structural variants (SVs), such as deletions, insertions, inversions, and more complex rearrangements. Although much is known about the extent of SVs in humans and mice, species in which they exert significant effects on phenotypes, very little is known about the extent of SVs in the 2.5-times smaller and less repetitive genome of the chicken.Results: We identified hundreds of shared and divergent SVs in four commercial chicken lines relative to the reference chicken genome. The majority of SVs were found in intronic and intergenic regions, and we also found SVs in the coding regions. To identify the SVs, we combined high-throughput short read paired-end sequencing of genomic reduced representation libraries (RRLs) of pooled samples from 25 individuals and computational mapping of DNA sequences from a reference genome.Conclusion: We provide a first glimpse of the high abundance of small structural genomic variations in the chicken. Extrapolating our results, we estimate that there are thousands of rearrangements in the chicken genome, the majority of which are located in non-coding regions. We observed that structural variation contributes to genetic differentiation among current domesticated chicken breeds and the Red Jungle Fowl. We expect that, because of their high abundance, SVs might explain phenotypic differences and play a role in the evolution of the chicken genome. Finally, our study exemplifies an efficient and cost-effective approach for identifying structural variation in sequenced genomes. © 2011 Kerstens et al; licensee BioMed Central Ltd. Source

Swaggerty C.L.,U.S. Department of Agriculture | Pevzner I.Y.,Cobb Vantress Inc | Kogut M.H.,U.S. Department of Agriculture
Poultry Science | Year: 2014

Salmonella is a leading cause of foodborne illness and can be transmitted through consumption of contaminated poultry; therefore, increasing a flock's natural resistance to Salmonella could improve food safety. Previously, we characterized the heterophil-mediated innate immune response of 2 parental broiler lines and F1 reciprocal crosses and showed that increased heterophil function and expression of pro-inflammatory mediators corresponds with increased resistance against diverse pathogens. A preliminary selection trial showed that individual sires had varying inherent levels of pro-inflammatory mediators and selection based on a high or low phenotype was passed onto progeny. Based on these results, we hypothesized selection of broilers for higher levels of the pro-inflammatory mediators IL- 6, CXCLi2, and CCLi2 would produce progeny with increased resistance against Salmonella Enteritidis. Peripheral blood leukocytes were isolated from 75 commercial broiler sires, screened, and 10 naturally high and low expressing sires were selected and mated to randomly selected dams to produce the first generation of "high" and "low" progeny. The mRNA expression of CXCLi2 and CCLi2 were significantly (P ≤ 0.02) higher in the high progeny and were more resistant to liver and spleen organ invasion by Salmonella Enteritidis compared with low progeny. Production of the second generation yielded progeny that had differences (P ≤ 0.03) in all 3 mediators and further improved resistance against Salmonella Enteritidis. Feed conversion ratio and percent breast meat yield were calculated and were equal, whereas the high birds weighed slightly, but significantly, less than the low birds. These data clearly demonstrate that selection based on a higher phenotype of key pro-inflammatory mediators is a novel means to produce broilers that are naturally more resistant to Salmonella, one of the most important foodborne pathogens affecting the poultry industry. © 2014 Poultry Science Association Inc. Source

Dorshorst B.,North Carolina State University | Okimoto R.,Cobb Vantress Inc | Ashwell C.,North Carolina State University
Journal of Heredity | Year: 2010

The Silkie chicken has been a model of melanoctye precursor and neural crest cell migration and proliferation in the developing embryo due to its extensive hyperpigmentation of dermal and connective tissues. Although previous studies have focused on the distribution and structure of the Silkie's pigment or the general mechanisms by which this phenotype presents itself, the causal genetic variants have not been identified. Classical breeding experiments have determined this trait to be controlled by 2 interacting genes, the sex-linked inhibitor of dermal melanin (Id) and autosomal fibromelanosis (Fm) genes. Genome-wide single nucleotide polymorphism (SNP)-trait association analysis was used to detect genomic regions showing significant association with these pigmentation genes in 2 chicken mapping populations designed to segregate independently for Id and Fm. The SNP showing the highest association with Id was located at 72.3 Mb on chromosome Z and 10.3-13.1 Mb on chromosome 20 showed the highest association with Fm. Prior to this study, the linkage group to which Fm belonged was unknown. Although the primary focus of this study was to identify loci contributing to dermal pigmentation in the Silkie chicken, loci associated with various other morphological traits segregating in these populations were also detected. A single SNP in a highly conserved cis-regulatory region of Sonic Hedgehog was significantly associated with polydactyly (Po). Genomic regions in association with silkie feathering or hookless (h), feathered legs (Pti), vulture hock (V), rose comb (R), and duplex comb (D) were also identified. © 2009 The American Genetic Association. All rights reserved. Source

Fragomeni B.O.,University of Georgia | Misztal I.,University of Georgia | Lourenco D.L.,University of Georgia | Aguilar I.,Instituto Nacional Of Investigacion Agropecuaria | And 2 more authors.
Frontiers in Genetics | Year: 2014

The purpose of this study was to determine if the set of genomic regions inferred as accounting for the majority of genetic variation in quantitative traits remain stable over multiple generations of selection. The data set contained phenotypes for five generations of broiler chicken for body weight, breast meat, and leg score. The population consisted of 294,632 animals over five generations and also included genotypes of 41,036 single nucleotide polymorphism (SNP) for 4,866 animals, after quality control. The SNP effects were calculated by a GWAS type analysis using single step genomic BLUP approach for generations 1-3, 2-4, 3-5, and 1-5. Variances were calculated for windows of 20 SNP. The top ten windows for each trait that explained the largest fraction of the genetic variance across generations were examined. Across generations, the top 10 windows explained more than 0.5% but less than 1% of the total variance. Also, the pattern of the windows was not consistent across generations. The windows that explained the greatest variance changed greatly among the combinations of generations, with a few exceptions. In many cases, a window identified as top for one combination, explained less than 0.1% for the other combinations. We conclude that identification of top SNP windows for a population may have little predictive power for genetic selection in the following generations for the traits here evaluated. © 2014 Fragomeni, Misztal, Lourenco, Aguilar, Okimoto and Muir. Source

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