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William A. Powell - One of the best experts on this subject based on the ideXlab platform.
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transgenic american Chestnuts do not inhibit germination of native seeds or colonization of mycorrhizal fungi
Frontiers in Plant Science, 2018Co-Authors: Andrew E Newhouse, Allison D Oakes, Hannah C Pilkey, Hannah E Roden, Thomas R Horton, William A. PowellAbstract:The American Chestnut (Castanea dentata) was once an integral part of eastern US deciduous forests, with many environmental, economic, and social values. This ended with the introduction of an invasive fungal pathogen that wiped out over three billion trees. Transgenic American Chestnuts expressing a gene for oxalate oxidase successfully tolerate infections by this blight fungus, but potential non-target environmental effects should be evaluated before new restoration material is released. Two greenhouse bioassays evaluated belowground interactions between transgenic American Chestnuts and neighboring organisms found in their native ecosystems. Potential allelopathy was tested by germinating several types of seeds, all native to American Chestnut habitats, in the presence of Chestnut leaf litter. Germination was not significantly different in terms of number of seeds germinated or total biomass of germinated seedlings in transgenic and non-transgenic leaf litter. Separately, ectomycorrhizal associations were observed on transgenic and non-transgenic American Chestnut roots using field soil inoculum. Root tip colonization was consistently high (>90% colonization) on all plants and not significantly different between any tree types. These observations on mycorrhizal fungi complement previous studies performed on older transgenic lines which expressed oxalate oxidase at lower levels. Along with other environmental impact comparisons, these conclusions provide further evidence that transgenic American Chestnuts are not functionally different with regard to ecosystem interactions than non-transgenic American Chestnuts.
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Transgenic American Chestnuts Do Not Inhibit Germination of Native Seeds or Colonization of Mycorrhizal Fungi
Frontiers Media S.A., 2018Co-Authors: Andrew E Newhouse, Allison D Oakes, Hannah C Pilkey, Hannah E Roden, Thomas R Horton, William A. PowellAbstract:The American Chestnut (Castanea dentata) was once an integral part of eastern United States deciduous forests, with many environmental, economic, and social values. This ended with the introduction of an invasive fungal pathogen that wiped out over three billion trees. Transgenic American Chestnuts expressing a gene for oxalate oxidase successfully tolerate infections by this blight fungus, but potential non-target environmental effects should be evaluated before new restoration material is released. Two greenhouse bioassays evaluated belowground interactions between transgenic American Chestnuts and neighboring organisms found in their native ecosystems. Potential allelopathy was tested by germinating several types of seeds, all native to American Chestnut habitats, in the presence of Chestnut leaf litter. Germination was not significantly different in terms of number of seeds germinated or total biomass of germinated seedlings in transgenic and non-transgenic leaf litter. Separately, ectomycorrhizal associations were observed on transgenic and non-transgenic American Chestnut roots using field soil inoculum. Root tip colonization was consistently high (>90% colonization) on all plants and not significantly different between any tree types. These observations on mycorrhizal fungi complement previous studies performed on older transgenic lines which expressed oxalate oxidase at lower levels. Along with other environmental impact comparisons, these conclusions provide further evidence that transgenic American Chestnuts are not functionally different with regard to ecosystem interactions than non-transgenic American Chestnuts
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Data_Sheet_1_Transgenic American Chestnuts Do Not Inhibit Germination of Native Seeds or Colonization of Mycorrhizal Fungi.XLSX
2018Co-Authors: Andrew E Newhouse, Allison D Oakes, Hannah C Pilkey, Hannah E Roden, Thomas R Horton, William A. PowellAbstract:The American Chestnut (Castanea dentata) was once an integral part of eastern United States deciduous forests, with many environmental, economic, and social values. This ended with the introduction of an invasive fungal pathogen that wiped out over three billion trees. Transgenic American Chestnuts expressing a gene for oxalate oxidase successfully tolerate infections by this blight fungus, but potential non-target environmental effects should be evaluated before new restoration material is released. Two greenhouse bioassays evaluated belowground interactions between transgenic American Chestnuts and neighboring organisms found in their native ecosystems. Potential allelopathy was tested by germinating several types of seeds, all native to American Chestnut habitats, in the presence of Chestnut leaf litter. Germination was not significantly different in terms of number of seeds germinated or total biomass of germinated seedlings in transgenic and non-transgenic leaf litter. Separately, ectomycorrhizal associations were observed on transgenic and non-transgenic American Chestnut roots using field soil inoculum. Root tip colonization was consistently high (>90% colonization) on all plants and not significantly different between any tree types. These observations on mycorrhizal fungi complement previous studies performed on older transgenic lines which expressed oxalate oxidase at lower levels. Along with other environmental impact comparisons, these conclusions provide further evidence that transgenic American Chestnuts are not functionally different with regard to ecosystem interactions than non-transgenic American Chestnuts.
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comparisons of ectomycorrhizal colonization of transgenic american Chestnut with those of the wild type a conventionally bred hybrid and related fagaceae species
Applied and Environmental Microbiology, 2015Co-Authors: Katherine M Damico, Charles A. Maynard, Allison D Oakes, Thomas R Horton, Stephen V Stehman, William A. PowellAbstract:American Chestnut (Castanea dentata [Marsh.] Borkh.) dominated the eastern forests of North America, serving as a keystone species both ecologically and economically until the introduction of the Chestnut blight, Cryphonectria parasitica, functionally eradicated the species. Restoration efforts include genetic transformation utilizing genes such as oxalate oxidase to produce potentially blight-resistant Chestnut trees that could be released back into the native range. However, before such a release can be undertaken, it is necessary to assess nontarget impacts. Since oxalate oxidase is meant to combat a fungal pathogen, we are particularly interested in potential impacts of this transgene on beneficial fungi. This study compares ectomycorrhizal fungal colonization on a transgenic American Chestnut clone expressing enhanced blight resistance to a wild-type American Chestnut, a conventionally bred American-Chinese hybrid Chestnut, and other Fagaceae species. A greenhouse bioassay used soil from two field sites with different soil types and land use histories. The number of colonized root tips was counted, and fungal species were identified using morphology, restriction fragment length polymorphism (RFLP), and DNA sequencing. Results showed that total ectomycorrhizal colonization varied more by soil type than by tree species. Individual fungal species varied in their colonization rates, but there were no significant differences between colonization on transgenic and wild-type Chestnuts. This study shows that the oxalate oxidase gene can increase resistance against Cryphonectria parasitica without changing the colonization rate for ectomycorrhizal species. These findings will be crucial for a potential deregulation of blight-resistant American Chestnuts containing the oxalate oxidase gene.
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transgenic american Chestnuts show enhanced blight resistance and transmit the trait to t1 progeny
Plant Science, 2014Co-Authors: Andrew E Newhouse, Charles A. Maynard, Linda D Polinmcguigan, Kathleen A Baier, Kristia E R Valletta, William H Rottmann, Timothy J Tschaplinski, William A. PowellAbstract:Abstract American Chestnut ( Castanea dentata ) is a classic example of a native keystone species that was nearly eradicated by an introduced fungal pathogen. This report describes progress made toward producing a fully American Chestnut tree with enhanced resistance to the blight fungus ( Cryphonectria parasitica ). The transgenic American Chestnut ‘Darling4,’ produced through an Agrobacterium co-transformation procedure to express a wheat oxalate oxidase gene driven by the VspB vascular promoter, shows enhanced blight resistance at a level intermediate between susceptible American Chestnut and resistant Chinese Chestnut ( Castanea mollissima ). Enhanced resistance was identified first with a leaf-inoculation assay using young Chestnuts grown indoors, and confirmed with traditional stem inoculations on 3- and 4-year-old field-grown trees. Pollen from ‘Darling4′ and other events was used to produce transgenic T1 seedlings, which also expressed the enhanced resistance trait in leaf assays. Outcrossed transgenic seedlings have several advantages over tissue-cultured plantlets, including increased genetic diversity and faster initial growth. This represents a major step toward the restoration of the majestic American Chestnut.
Jie Ouyang - One of the best experts on this subject based on the ideXlab platform.
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effect of thermal processing on the physicochemical properties of Chestnut starch and textural profile of Chestnut kernel
Carbohydrate Polymers, 2016Co-Authors: Lina Kan, Shuangshuang Xie, Jie OuyangAbstract:The present study focused on the effect of thermal processing on the physicochemical properties of Chestnut starch and textural profile of Chestnut kernel. After thermal processing, the total starch content in both boiled and roasted Chestnuts decreased significantly (P<0.05), while the amylose content of boiled Chestnut increased and that of roasted Chestnut remained stable. The granular microstructure of the starch in cooked Chestnut was gradually destroyed during the thermal processing. The starch in cooked Chestnut still exhibited C-type X-ray diffraction patterns, but the intensity of diffraction peaks and the crystallinity were obviously declined compared with those of fresh Chestnut. Textural profile analysis of Chestnut starch gel and Chestnut kernel showed that the main textural characterizations of roasted Chestnut were higher than those of boiled Chestnuts. These results are helpful for better understanding the texture change in fresh, boiled and roasted Chestnuts, which indicated that roasting is an alternative industrial thermal processing method for Chestnut kernel.
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effect of cooking methods on nutritional quality and volatile compounds of chinese Chestnut castanea mollissima blume
Food Chemistry, 2016Co-Authors: Xianhe Shi, Qiaojiao Zhao, Yahui Cui, Jie OuyangAbstract:This study aimed to evaluate the effects of different cooking methods on the content of important nutrients and volatiles in the fruit of Chinese Chestnut. The nutritional compounds, including starch, water-soluble protein, free amino acids, reducing sugar, sucrose, organic acids and total flavonoids, of boiled, roasted and fried Chestnuts were significantly (P 0.05). L-Aspartic acid, L-glutamic acid and L-arginine were found to be the main reduced free amino acids in cooked Chestnuts. The main aromatic compositions in fresh Chestnuts were aldehydes and esters, while ketones, furfural and furan were formed in cooked Chestnuts due to the Maillard reaction and degradation of saccharides, amino acids and lipids. Principle component analysis demonstrated that roasting and frying had a similar effect on the nutritional composition of Chestnuts, which differed from that of the boiling process.
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salicylic acid inhibits enzymatic browning of fresh cut chinese Chestnut castanea mollissima by competitively inhibiting polyphenol oxidase
Food Chemistry, 2015Co-Authors: Dan Zhou, Lin Li, Yanwen Wu, Jie OuyangAbstract:Abstract The inhibitory effect and associated mechanisms of salicylic acid (SA) on the browning of fresh-cut Chinese Chestnut were investigated. Shelled and sliced Chestnuts were immersed in different concentrations of an SA solution, and the browning of the Chestnut surface and interior were inhibited. The activities of polyphenol oxidase (PPO) and peroxidase (POD) extracted from Chestnuts were measured in the presence and absence of SA. SA at concentrations higher than 0.3 g/L delayed Chestnut browning by significantly inhibiting the PPO activity ( P P > 0.05). The binding and inhibition modes of SA with PPO and POD, determined by AUTODOCK 4.2 and Lineweaver–Burk plots, respectively, established SA as a competitive inhibitor of PPO.
Fred Hebard - One of the best experts on this subject based on the ideXlab platform.
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dissecting resistance to phytophthora cinnamomi in interspecific hybrid Chestnut crosses using sequence based genotyping and qtl mapping
Phytopathology, 2019Co-Authors: Fred Hebard, Tetyana Zhebentyayeva, P H Sisco, Laura L Georgi, Steven N Jeffers, Taylor M Perkins, Joseph B James, Christopher A Saski, Dana C NelsonAbstract:The soilborne oomycete Phytophthora cinnamomi-which causes root rot, trunk cankers, and stem lesions on an estimated 5,000 plant species worldwide-is a lethal pathogen of American Chestnut (Castanea dentata) as well as many other woody plant species. P. cinnamomi is particularly damaging to Chestnut and chinquapin trees (Castanea spp.) in the southern portion of its native range in the United States due to relatively mild climatic conditions that are conductive to disease development. Introduction of resistant genotypes is the most practical solution for disease management in forests because treatment with fungicides and eradication of the pathogen are neither practical nor economically feasible in natural ecosystems. Using backcross families derived from crosses of American Chestnuts with two resistant Chinese Chestnut cultivars Mahogany and Nanking, we constructed linkage maps and identified quantitative trait loci (QTLs) for resistance to P. cinnamomi that had been introgressed from these Chinese Chestnut cultivars. In total, 957 plants representing five cohorts of three hybrid crosses were genotyped by sequencing and phenotyped by standardized inoculation and visual examination over a 6-year period from 2011 to 2016. Eight parental linkage maps comprising 7,715 markers were constructed, and 17 QTLs were identified on four linkage groups (LGs): LG_A, LG_C, LG_E, and LG_K. The most consistent QTLs were detected on LG_E in seedlings from crosses with both 'Mahogany' and 'Nanking' and LG_K in seedlings from 'Mahogany' crosses. Two consistent large and medium effect QTLs located ∼10 cM apart were present in the middle and at the lower end of LG_E; other QTLs were considered to have small effects. These results imply that the genetic architecture of resistance to P. cinnamomi in Chinese Chestnut × American Chestnut hybrid progeny may resemble the P. sojae-soybean pathosystem, with a few dominant QTLs along with quantitatively inherited partial resistance conferred by multiple small-effect QTLs.
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nursery performance of american and chinese Chestnuts and backcross generations in commercial tree nurseries
Forestry, 2012Co-Authors: Stacy L Clark, Scott E Schlarbaum, Arnold M Saxton, Fred HebardAbstract:The American Chestnut [Castanea dentata (Marsh.) Borkh.] was decimated by an exotic fungus [Cryphonectria parasitica (Murr.) Barr] in the early 1900s. Breeding efforts with American and Chinese Chestnuts (C. mollissima Blume) produced putatively blight-resistant progeny (BC3F3) in 2007. We compared two nut size classes for differences in seedling quality of bare-root stock grown in commercial nurseries. We compared the BC3F3 generation to parental species and other generations. Nuts in the large size class produced taller trees than nuts in the small size class, but sizing nuts prior to sowing did not reduce variability in nursery seedling size. Results indicate that overall seedling quality could be improved by culling small nuts, but seedling uniformity would only be improved by culling seedlings before planting. We recommend refinement of restoration efforts to match seedling size to site type and planting goals. BC3F3 Chestnuts differed from Chinese Chestnuts in 67% of tests, and were different than American Chestnuts in half the tests, indicating not all American traits were recovered in this early phase of seedling development. Family differences within the BC3F3 generation were most apparent for mean nut weight, and only one BC3F3 family differed from other BC3F3 families in seedling growth characteristics.
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lessons from the field the first tests of restoration american Chestnut castanea dentata seedlings planted in the southern region
In: Butnor John R. ed. 2012. Proceedings of the 16th biennial southern silvicultural research conference. e-Gen. Tech. Rep. SRS-156. Asheville NC: U.S, 2012Co-Authors: Stacy L Clark, Scott E Schlarbaum, Fred Hebard, John Saxton, John Blanton, David M Casey, Barbara S Crane, Russ Macfarlane, Jason A RodrigueAbstract:An exotic fungus, the Chestnut blight (Cryphonectria parasitica Murr. Barr), decimated the American Chestnut tree (Castanea dentata Marsh. Borkh.) throughout eastern North America in the first half of the 20th century. The United States Department of Agriculture, Forest Service (FS), The University of Tennessee, and The American Chestnut Foundation (TACF) are collaborating on Chestnut restoration research on National Forest System lands. In autumn 2007 and 2008, TACF used a back-cross breeding technique (Hebard 2001) to produce Chestnuts, referred to as the BC3F3 generation, that are predicted to be American Chestnut in character with blight resistance from Chinese Chestnut (Castanea mollissima Blume).
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incidence of craesus castaneae hymenoptera tenthredinidae on Chestnut seedlings planted in the daniel boone national forest kentucky
Journal of Entomological Science, 2011Co-Authors: Cornelia C Pinchot, Stacy L Clark, Scott E Schlarbaum, Arnold M Saxton, Callie J Schweitzer, David R Smith, Alex C Mangini, Fred HebardAbstract:American Chestnut [Castanea dentate (Marshall) Borkhausen, Fagales: Fagaceae] was a dominant forest tree in the eastern forests of the U.S. until it was eliminated as a canopy tree species by 2 exotic pathogens. Ink disease, a root rot caused by Phytophthora cinnamomi Rands (Pythiales: Pythiaceae), began to destroy Chestnut populations on bottomland and poorly-drained sites in the mid-1800s, and the Chestnut blight fungus [Cryphonectria parasitica (Murrill) Barr, Diaporthales: Cryphonectriaceae] reduced the species to short-lived sprouts on upland sites in the first half of the 20th Century (cf. Campbell and Schlarbaum 2002, Fading Forests II: Trading Away North America’s Heritage, healing Stones Found., Knoxville, TN). Various organizations have used a backcross breeding approach to integrate blight resistance from Asiatic Chestnut species into American Chestnut in an effort to restore the species to eastern forests (Anagnostakis 1999, In Proc. 2nd Intern Symp. Chestnut; Hebard 2001, Ecol. Restor. 19: 252-254). Putatively blight-resistant hybrid Chestnuts became available for planting in 2008 (Clark et al. 2010, In Proc. 17th Central Hardwoods Forest Conf.).
Charles A. Maynard - One of the best experts on this subject based on the ideXlab platform.
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comparisons of ectomycorrhizal colonization of transgenic american Chestnut with those of the wild type a conventionally bred hybrid and related fagaceae species
Applied and Environmental Microbiology, 2015Co-Authors: Katherine M Damico, Charles A. Maynard, Allison D Oakes, Thomas R Horton, Stephen V Stehman, William A. PowellAbstract:American Chestnut (Castanea dentata [Marsh.] Borkh.) dominated the eastern forests of North America, serving as a keystone species both ecologically and economically until the introduction of the Chestnut blight, Cryphonectria parasitica, functionally eradicated the species. Restoration efforts include genetic transformation utilizing genes such as oxalate oxidase to produce potentially blight-resistant Chestnut trees that could be released back into the native range. However, before such a release can be undertaken, it is necessary to assess nontarget impacts. Since oxalate oxidase is meant to combat a fungal pathogen, we are particularly interested in potential impacts of this transgene on beneficial fungi. This study compares ectomycorrhizal fungal colonization on a transgenic American Chestnut clone expressing enhanced blight resistance to a wild-type American Chestnut, a conventionally bred American-Chinese hybrid Chestnut, and other Fagaceae species. A greenhouse bioassay used soil from two field sites with different soil types and land use histories. The number of colonized root tips was counted, and fungal species were identified using morphology, restriction fragment length polymorphism (RFLP), and DNA sequencing. Results showed that total ectomycorrhizal colonization varied more by soil type than by tree species. Individual fungal species varied in their colonization rates, but there were no significant differences between colonization on transgenic and wild-type Chestnuts. This study shows that the oxalate oxidase gene can increase resistance against Cryphonectria parasitica without changing the colonization rate for ectomycorrhizal species. These findings will be crucial for a potential deregulation of blight-resistant American Chestnuts containing the oxalate oxidase gene.
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transgenic american Chestnuts show enhanced blight resistance and transmit the trait to t1 progeny
Plant Science, 2014Co-Authors: Andrew E Newhouse, Charles A. Maynard, Linda D Polinmcguigan, Kathleen A Baier, Kristia E R Valletta, William H Rottmann, Timothy J Tschaplinski, William A. PowellAbstract:Abstract American Chestnut ( Castanea dentata ) is a classic example of a native keystone species that was nearly eradicated by an introduced fungal pathogen. This report describes progress made toward producing a fully American Chestnut tree with enhanced resistance to the blight fungus ( Cryphonectria parasitica ). The transgenic American Chestnut ‘Darling4,’ produced through an Agrobacterium co-transformation procedure to express a wheat oxalate oxidase gene driven by the VspB vascular promoter, shows enhanced blight resistance at a level intermediate between susceptible American Chestnut and resistant Chinese Chestnut ( Castanea mollissima ). Enhanced resistance was identified first with a leaf-inoculation assay using young Chestnuts grown indoors, and confirmed with traditional stem inoculations on 3- and 4-year-old field-grown trees. Pollen from ‘Darling4′ and other events was used to produce transgenic T1 seedlings, which also expressed the enhanced resistance trait in leaf assays. Outcrossed transgenic seedlings have several advantages over tissue-cultured plantlets, including increased genetic diversity and faster initial growth. This represents a major step toward the restoration of the majestic American Chestnut.
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molecular characterization of a gene encoding a cystatin expressed in the stems of american Chestnut castanea dentata
Planta, 2002Co-Authors: Bernadette J Connors, Nathan P Laun, Charles A. Maynard, William A. PowellAbstract:A cDNA clone with similarity to genes encoding cystatin was recently isolated from a cDNA library created using mRNA extracted from stem tissues of Castanea dentata (Marsh.) Borkh. (CASde:Pic1). All of the requisite motifs for inhibitory activity were found upon examination of the deduced amino acid sequence. Reverse transcription–polymerase chain reaction was used to detect the cystatin transcript in healthy stem, leaf and seed tissues, as well as in diseased tissues. Gene fragments encoding this putative cystatin were cloned from American and Chinese (Castanea mollissima Blume) Chestnuts and a comparison of these sequences revealed significant differences within the intron, including deletions and alterations in restriction-enzyme sites. The long-term goal of this study is to determine whether the cystatin allele in Chinese Chestnut correlates to a resistance gene and, if so, if this allele could be used to enhance resistance in American Chestnut.
Inmaculada Franco - One of the best experts on this subject based on the ideXlab platform.
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effect of Chestnuts intake by celta pigs on lipolytic oxidative and fatty acid profile changes during ripening and vacuum packed storage of galician chorizo
Journal of Food Composition and Analysis, 2017Co-Authors: Maria Gomez, Javier Carballo, Sonia Fonseca, Aida Cachaldora, Inmaculada FrancoAbstract:Abstract The effect of the inclusion of Chestnuts in the finishing diet of Celta pig breed on the characteristics of Galician chorizo, a traditional dry-cured sausage, along the ripening process and vacuum-packed storage was studied. In general, no significant differences between diets (Chestnut, mixed and concentrate diet) were obtained for weight losses, chemical composition, physico-chemical characteristics, and lipolytic and oxidative parameters. A significant effect of the diet was observed on some fatty acids from total and neutral lipids, obtaining lower contents of C18:2n-6 and C20:2n-6 and higher contents of C18:1n-9, C18:3n-3 and C20:4n-6 when Chestnuts where included in the diet. In polar lipids, after dry-ripening, lower contents of C18:2n-6 and total polyunsaturated fatty acids and higher contents of C18:1n-9 and the sum of monounsaturated fatty acids were found in sausages from Chestnut diet. Free fatty acids profile during vacuum-packed storage changed to a larger content of C16:0. The distinction between sausages was procured when a discriminant canonical analysis was performed for fatty acid contents.
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fatty acids retinol and cholesterol composition in various fatty tissues of celta pig breed effect of the use of Chestnuts in the finishing diet
Journal of Food Composition and Analysis, 2015Co-Authors: Ruben Dominguez, Javier Carballo, Sidonia Martinez, Maria Gomez, Inmaculada FrancoAbstract:Abstract This investigation was designed to evaluate the effects of Chestnuts use in the finishing diet of Celta pigs. Thirty-six pigs were separated in three different groups (three different diets: compound feed, mixed and Chestnut); fatty acid profile, and cholesterol and retinol content of intramuscular, adipose, perirenal and hepatic fat were evaluated. The inclusion of Chestnuts in the diet fundamentally affected the content of oleic (C18:1 n –9), linoleic (C18:2 n –6) and α-linolenic (C18:3 n –3) acids and other n –6 PUFA with different intensity depending on the anatomical location. The cholesterol and retinol contents were lower in pigs fed on Chestnuts. These pigs showed higher contents of C18:1 n –9 in hepatic fat, perirenal fat and intramuscular fat of Psoas major (PM) muscle. The greatest differences of C18:3 n –3 were found in the liver. The amount of intramuscular fat showed higher values in the pigs fed with Chestnuts. Using discriminant statistical techniques it was possible to classify, in PM muscle and liver, 100% of the pigs fed with Chestnut.