Rami A Dalloul

Natural Resources Research Institute, Silver Spring, Maryland, United States

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Publications (54)95.31 Total impact

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    ABSTRACT: The study was conducted to determine effects of dietary supplementation with a blend of antioxidants (AOX, ethoxyquin and propyl gallate) on carcass characteristics, meat quality, and fatty acid profile in finishing pigs fed a diet high in oxidants. A total of 100 crossbred barrows (10.9 ± 1.4 kg BW, 36 ± 2 d of age) were randomly allotted to 5 diet treatments (5 replicate pens per treatment, 4 pigs per pen). Treatments included: 1) HO: high oxidant diet containing 5% oxidized soy oil and 10% PUFA source which contributed 5.56% crude fat and 2.05% docosahexanoic acid (DHA) to the diet; 2) VE: the HO diet with 11 IU/kg of added vitamin E; 3) AOX: the HO diet with AOX (135 mg/kg); 4) VE+AOX: the HO diet with both vitamin E and AOX; and 5) SC: a standard corn-soy control diet, with non-oxidized oil, and no PUFA source The trial lasted for 118 d; on d 83, the HO diet pigs were switched to the SC diet due to very poor health. From that point, the VE pigs displayed the poorest performance. On d 118, 2 pigs from each pen were harvested for sampling. Compared to pigs fed SC diet, the HO and VE pigs (P < 0.05) showed lighter carcass weight, less back fat, less lean body mass, and smaller loin eye area. In addition, compared to the SC pigs, decreased dressing percentage (74.2 vs. 65.7%), greater moisture percentage (74.7 vs. 77.4%), and less extractable lipid content (2.43 vs. 0.95%) were found in VE fed pigs (P < 0.05). Drip loss of loin muscle in VE pigs was less than SC pigs (0.46 vs. 3.98%, P = 0.02), which was associated with a trend for a greater 24 h muscle pH (5.74 vs. 5.54, P = 0.07). The AOX addition in the high oxidant diet attenuated all of these effects to levels similar to SC (P > 0.05), except a* value (redness) and belly firmness. Visible yellow coloration of backfat and lipofuscin in HO and VE pigs was observed at harvest at d 118. The high oxidant diet resulted in greater concentration of DHA in backfat (P < 0.001); switching the diet on d 83 resulted in HO pigs having a similar fatty acid profile to SC at d 118 pigs. Vitamin E concentration in plasma and muscle was greater in HO and SC than VE, AOX, and VE+AOX on d 118. Feeding the high oxidant diet caused a series of changes in carcass characteristics and meat quality. Addition of AOX attenuated many of these, whereas the protective effects of supplemental vitamin E at 11 IU/kg were minimal during the finisher phase of the study.
    Journal of animal science. 11/2014;
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    ABSTRACT: The objective of the study was to determine the effects of a dietary antioxidant blend (AOX, ethoxyquin and propyl gallate) and vitamin E on growth performance, liver function, and oxidative status in pigs fed diets high in oxidants. Crossbred barrows (n = 100, 10.91 ± 0.65 kg BW, 36 ± 2 d of age, Landrace × Duroc) were allotted to 5 treatments based on BW (5 replicate pens per treatment, 4 pigs per pen). Treatments included: 1) HO: high oxidant diet containing 5% oxidized soybean oil and 10% PUFA source (providing 2.05% docosahexaenoic acid in the diet); 2) VE: the HO diet with 11 IU/kg of added vitamin E; 3) AOX: the HO diet with AOX (135 mg/kg); 4) VE+AOX: the HO diet with both vitamin E and AOX; and 5) SC: a standard corn-soy control diet. The trial lasted for 118 d; on d 83, the HO diet pigs were switched to the SC diet because the animals were displaying very poor health. Compared with SC pigs, HO pigs had decreased ADG (0.92 vs. 0.51 kg, d 26 to 55; 1.29 vs. 0.34 kg, d 56 to 82, P < 0.05) and ADFI (1.84 vs. 0.96 kg, d 26 to 55; 3.41 vs. 1.14 kg, d 56 to 82, P < 0.05). However, switching the HO pigs to the SC diet resulted in HO pigs having a greater ADG than VE fed pigs from d 83 to 118 (0.90 vs. 0.60 kg, P < 0.05). The AOX restored pig performance to a level similar to pigs fed the SC diet (P > 0.05) with greater G:F for the entire period (0.43 vs. 0.38, P < 0.05). A greater liver to BW ratio was found in HO compared to other treatments on d 55 and in VE on d 118. Total bilirubin concentration in plasma of HO pigs on d 55 was greater than VE+AOX pigs (2.92 vs. 0.90 mg/dL, P < 0.05), whereas on d 118, bilirubin concentration in VE was higher than in VE+AOX and SC (1.67 vs. 0.01 and 0.00 mg/dL, P < 0.05). A similar trend was observed in aspartate transaminase. Plasma concentrations of thiobarbituric acid reactive substances (TBARS) and carbonyl were elevated (P < 0.05) in the HO compared to the SC pigs on d 55 but not on d 118. Liver TBARS and carbonyl concentrations showed a similar trend, except that VE pigs had the greatest carbonyl concentration on d 118. Pigs fed AOX diets had similar plasma and liver TBARS and carbonyl concentrations as those fed SC diets. In the oxidative stress model used in this study, dietary addition of AOX or AOX+VE was effective in improving growth, liver function, and plasma markers of oxidative stress, but VE alone was not.
    Journal of animal science. 11/2014;
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    ABSTRACT: Coccidiosis is an inherent risk in the commercial broiler industry and inflicts devastating economic losses to poultry operations. Probiotics may provide a potential alternative to the prophylactic use of anticoccidials in commercial production. This study evaluated the effects of probiotic applications (feed and water) on bird performance and resistance to a mixed Eimeria infection in commercial broilers. On day of hatch, 1,008 commercial male broilers (Cobb 500) were assigned to 1 of 6 treatments (8 replicate floor pens; 21 birds/pen), including noninfected negative control (NEG), Eimeria-infected positive control (POS), anticoccidial control (0.01% salinomycin, SAL), intermittent high-dose water-applied probiotic (WPI), continuous low-dose water-applied probiotic (WPC), and feed-supplemented probiotic (FSP). On d 15, all birds except those in NEG were challenged with a mixed inoculum of Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Measurements were taken on d 7, 15, 21, 28, 35, and 42. Fecal samples were collected from d 20 to 24 for oocyst counts, and lesion scores were evaluated on d 21. Data were analyzed using the Fit Model platform in JMP Pro 10.0 (SAS Institute Inc.). Differences in experimental treatments were tested using Tukey's honestly significant difference following ANOVA with significance reported at P ≤ 0.05. Overall, NEG birds outperformed all other groups. For performance, the probiotic groups were comparable with the SAL-treated birds, except during the 6 d immediately following the Eimeria species challenge, where the SAL birds exhibited better performance. The WPC birds had lower duodenal and jejunal lesion scores, indicating a healthier intestine and enhanced resistance to Eimeria species compared with POS. Birds in the WPI treatment shed fewer oocysts in the feces, although this was not a trend for all of the probiotic treatment groups. The results of this study suggest probiotic supplementation without anticoccidials can enhance performance and help alleviate the negative effects of a mixed Eimeria infection.
    Poultry Science 09/2014; · 1.52 Impact Factor
  • C M Cox, R A Dalloul
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    ABSTRACT: Recently, there has been an increasing debate regarding the use of sub-therapeutic antibiotics in animal feed. This stems from worries that this practice may result in microbial resistance to human antibiotics employed in treating infections, thus causing a human health concern. Due to this tension, the poultry industry is under mounting pressure to reduce the use of these agents as feed additives and alternative control methods have taken the forefront in the research community. Investigators are searching for the latest alternative that will protect flocks from disease, while not hindering performance or negatively impacting profit margins. Probiotic supplementation is one option currently being explored as a means of improving performance and reducing the amount and severity of enteric diseases in poultry, and subsequent contamination of poultry products for human consumption. Probiotics are live, nonpathogenic microorganisms known to have a positive effect on the host by beneficially modifying gut microbiota and modulating the immune system. This review will discuss the role of probiotics in poultry, including their effects on performance, immune response and host defence against disease. Also addressed will be the recent applications of supplementing probiotics in ovo as an innovative means to administer such additives to promote early colonisation of beneficial bacteria.
    Beneficial Microbes 09/2014; · 1.47 Impact Factor
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    ABSTRACT: The aim of the current study was to determine the effects of a dietary antioxidant blend and vitamin E on fatty acid profile, inflammatory response, and liver function. Cobb 500 male broilers (n = 1,200, d 0) were randomly distributed into 6 treatments with 10 replicate floor pens. Treatments included (1) a high-oxidant diet, with vitamin E at 10 IU/kg, 3% oxidized oil, 3% polyunsaturated fatty acids (PUFA) source (HO); (2) the HO diet with vitamin E at 200 IU/kg (VE); (3) the HO diet with an antioxidant blend at 135 mg/kg (AOX); (4) the HO diet with both vitamin E at 200 IU/kg and an antioxidant blend at 135 mg/kg (VE+AOX); (5) standard control (SC); and (6) a positive control, which was the SC diet with an antioxidant blend at 135 mg/kg. The concentrations of 20:4, 20:5, 22:5, 22:6, and all the n-3 fatty acids were greater in the abdominal fat of HO, VE, AOX, and VE+AOX birds than SC and positive control birds on d 21 and 42 (P < 0.001). Compared with HO treatment, AOX and VE+AOX preserved the deposition of PUFA better (P < 0.001). The HO birds had greater concentrations of aspartate aminotransferase on d 21 and 42, and γ-glutamyl transferase on d 21, whereas AOX and VE+AOX chickens had restored γ-glutamyl transferase concentration (P < 0.01). The inflammation scores of abdominal fat of AOX and VE+AOX birds were lower than the HO on d 21 (P < 0.001). Compared with SC, the VE and VE+AOX birds exhibited greater vacuole scores on d 21 and 42 (P < 0.01). The lower vacuoles score in SC was associated with a greater expression of peroxisome proliferator activated receptor -γ and -α (P < 0.05). The expression of inflammatory genes in the liver did not differ among treatments. In conclusion, the AOX and AOX+VE diets were effective in preserving PUFA in the abdominal fat, moderately improved liver function, and reduced inflammation in fat.
    Poultry science. 05/2014;
  • T Lu, A F Harper, J Zhao, R A Dalloul
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    ABSTRACT: The aim of the study was to determine the effects of a dietary antioxidant blend (AB) and vitamin E on performance, oxidative status, and meat quality. Cobb 500 male broilers (n = 1,200, d 0) were randomly distributed into 6 treatments with 10 replicate pens. Treatments included 1) HO: high oxidant diet, vitamin E at 10 IU/kg, 3% oxidized soybean oil, 3% polyunsaturated fatty acid (PUFA) source; 2) VE: the HO diet with vitamin E at 200 IU/kg; 3) AOX: the HO diet with AB at 135 mg/kg; 4) VE+AOX: the HO diet with vitamin E at 200 IU/kg and AB at 135 mg/kg; 5) SC: standard control; and 6) PC: positive control, the SC diet with AB at 135 mg/kg. From d 0 through d 21, high oxidant diet treatment birds had greater BW, ADG, and ADFI than the SC birds; the AOX birds had better G:F on d 10 and 42, and from d 0 to 42 than SC birds (P < 0.05). The plasma TBA reactive substance level was lower in the AOX birds than the VE treatment birds in all phases (P < 0.05). High oxidant diet treatment birds had greater α-1-acid glycoprotein levels on d 10 than SC and PC birds (P < 0.05). The AOX, PC, and SC birds had a greater level of uric acid than the HO and VE+AOX birds on d 10. Superoxide dismutase expression in the liver was less with the HO treatment compared with the SC treatment on d 7 (P < 0.05). The vitamin E concentration in the breast muscle was greatest in the VE birds, whereas vitamin A concentration was greater in the PC birds compared with the SC birds on d 21 (P < 0.05). Compared with VE and AOX, the HO treatment had greater drip loss (P < 0.05). In conclusion, dietary addition of AOX was effective in improving growth, moderately restored the whole body antioxidant capability, and reduced drip loss.
    Poultry science. 05/2014;
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    ABSTRACT: The turkey genome sequencing project was initiated in 2008 and has relied primarily on next-generation sequencing (NGS) technologies. Our first efforts used a synergistic combination of 2 NGS platforms (Roche/454 and Illumina GAII), detailed bacterial artificial chromosome (BAC) maps, and unique assembly tools to sequence and assemble the genome of the domesticated turkey, Meleagris gallopavo. Since the first release in 2010, efforts to improve the genome assembly, gene annotation, and genomic analyses continue. The initial assembly build (2.01) represented about 89% of the genome sequence with 17X coverage depth (931 Mb). Sequence contigs were assigned to 30 of the 40 chromosomes with approximately 10% of the assembled sequence corresponding to unassigned chromosomes (ChrUn). The sequence has been refined through both genome-wide and area-focused sequencing, including shotgun and paired-end sequencing, and targeted sequencing of chromosomal regions with low or incomplete coverage. These additional efforts have improved the sequence assembly resulting in 2 subsequent genome builds of higher genome coverage (25X/Build3.0 and 30X/Build4.0) with a current sequence totaling 1,010 Mb. Further, BAC with end sequences assigned to the Z/W and MG18 (MHC) chromosomes, ChrUn, or not placed in the previous build were isolated, deeply sequenced (Hi-Seq), and incorporated into the latest build (5.0). To aid in the annotation and to generate a gene expression atlas of major tissues, a comprehensive set of RNA samples was collected at various developmental stages of female and male turkeys. Transcriptome sequencing data (using Illumina Hi-Seq) will provide information to enhance the final assembly and ultimately improve sequence annotation. The most current sequence covers more than 95% of the turkey genome and should yield a much improved gene level of annotation, making it a valuable resource for studying genetic variations underlying economically important traits in poultry.
    Poultry Science 02/2014; 93(2):479-84. · 1.52 Impact Factor
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    ABSTRACT: The turkey is a major protein source with little known about the early development of key organs including the brain. Here we report on the first use of RNA-Seq to gain insight into the transcriptional profiles associated with brain development in the domesticated turkey. Brain tissues were collected from 4 males and 4 females at five early age points. Total RNA was extracted and RNA-Seq libraries were prepared and sequenced on an Illumina HiSeq 1000 (101-cycle single-end). After trimming and filtering, approximately 488M sequencing reads remained, of which 239M reads from females and 249M reads from males. Total reads were assembled and clustered using a combination of Velvet/Oases suite and PASA using the newly updated turkey genome build (Ver. 5.0), resulting in 22,022 and 21, 875 clusters for females and males, respectively. HTSeq/DESeq analyses showed over 90% and 87% of clusters were constitutively expressed across all ages in females and males, respectively; whereas less than 1.6% and 2.0% of clusters were uniquely expressed at each age in female and male brains, respectively. In addition, the ten most highly expressed clusters at each age contributed roughly 12–20% of clusters. Comparing female and male brain transcriptomes, patterns of differentially expressed clusters and abundance of highly expressed clusters were similar within each age, except for day 14 males, which exhibited the highest number of unique clusters. As further analyses are completed, this comprehensive overview of gene expression will provide detailed insight into transcriptomic changes of the brain during turkey development.
    Plant and Animal Genome XXII, San Diego, CA, US; 01/2014
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    ABSTRACT: Transcriptomic analysis of the turkey reproductive tract is important in understanding development and evolution of the reproductive system. Analysis of molecular signaling is critical for identification of genes affecting fertility, a key factor in the poultry industry. In this study, we investigated the transcriptional profiles associated with early development of reproductive tissues in the domesticated turkey using RNA-Seq. Gonads were collected from 4 males and 4 females at 14 and 28 days of age. Total RNA was extracted and RNA-Seq libraries were prepared and sequenced on an Illumina HiSeq 1000 (101-cycle single-end). After trimming and filtering, approximately 248M sequencing reads remained with 125M reads from ovaries and 123M reads from testes. Total reads were assembled and clustered using a combination of Velvet/Oases suite and PASA using the newly updated turkey genome build (Ver. 5.0), resulting in 24,716 and 23,261 clusters for females and males, respectively. The results of HTSeq/DESeq showed that 14,440 clusters in females and 13,796 clusters in males are constitutively expressed between D14 and D28, with approximately 3% of clusters being uniquely differentially expressed on D28 in both females and males. Between genders, over 87% of clusters were constitutively expressed in both testes and ovaries. Ovaries exhibited higher numbers (1,887 and 1,710 clusters on D14 and D28, respectively) of uniquely expressed clusters than those of testes (728 and 1,072 clusters on D14 and D28, respectively). This comprehensive overview of gene expression will provide detailed insight into transcriptomic changes of reproductive tract development in young turkeys.
    Plant and Animal Genome XXII, San Diego, CA, US; 01/2014
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    ABSTRACT: The codon-optimized Eimeria tenella 3-1E gene was introduced into the lactic acid bacterial vector pTX8048 to construct plasmid pTX8048-3-1E. The plasmid pTX8048-3-1E was transformed into Lactococcus lactis NZ9000 by electroporation to create the strain of L. lactis pTX8048-3-1E. The expression of objective protein was verified by Western blot. The live bacteria L. lactis pTX8048-3-1E were administered orally, and an animal challenge experiment was carried out to evaluate the protective efficacy. The results indicated the strain of L. lactis pTX8048-3-1E was constructed successfully. Oral immunization to specific pathogen-free (SPF) chickens with L. lactis pTX8048-3-1E provided partial protection against homologous challenge including significant increased oocyst decrease ratio, reduced average lesion score in cecum, and improved body weight gain compared to control bacteria L. lactis pTX8048. These results demonstrate the use of Lactococcus as live vector for delivery of Eimeria antigen is feasible and promising method to control coccidiosis in poultry.
    Parasitology Research 09/2013; · 2.85 Impact Factor
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    ABSTRACT: RNA-Seq is a routinely used approach to study gene expression profiling taking advantage of the rapidly developing high-throughput sequencing technologies. Here we report on the first use of RNA-Seq to gain insight into the wide range of transcriptional profiles associated with tissue developmental stages in the domestic turkey (Meleagris gallopavo). A total of 16 tissues were collected from 4 males and 4 females at day of hatch and weeks 1, 2, 3, 4 and 24. The collected tissues included brain, thymus, bursa of Fabricius, spleen, heart, liver, proventriculus, gizzard, pancreas, duodenum, jejunum, ileum, and breast and thigh muscles. Reproductive tissues were also collected at weeks 2, 4 and 24. Total RNA was extracted and its quality assessed by an Agilent 2100 Bioanalyzer. RNA-Seq libraries were prepared with Illumina TruSeq DNA Library Preparation kits, followed by sequencing on Illumina HiSeq 1000 using 101-cycle single reads. To generate predicted transcripts, RNA-Seq datasets were first trimmed for adaptor and quality, and then assembled via the Velvet/Oases suite. For Velvet/Oases assembly, the data were assembled across birds within a tissue and sex by day independently using kmers ranging from 23-41. Assemblies were merged across the different days and kmers again keeping tissue and sex separate. CD-HIT was then used to merge the assembled transcripts across both a) sex and then b) tissue to produce a comprehensive and minimal transcriptome. To affect annotation of the de novo assembled transcriptome, a serial BLAST strategy was applied against the turkey genome, chicken genome, and finally Swiss-Prot. Any unnamed transcripts via BLAST were submitted to HMMER. Finally, expression was analyzed using mapping of reads to the transcriptome, counted via HTSeq and fold-change, and significance was determined using DESeq for each development stage/tissue/sex combination. The initial results from liver showed over 88% of reads with higher than 30 mean quality score, and mean number of reads was 20 million. Assembly merging for each sex within day resulted in approximately 230 and 170 thousand transcripts found in 35 and 29 thousand loci (6.5 and 5.8 transcripts per loci in male and female, respectively) from liver of male and female turkeys at day-of-hatch, respectively. Similar results of average transcripts per loci were found at day 7, 14, 21 and 28, showing approximately 6.1 and 6.0 average transcript per loci in male and female. As further analyses are completed, this comprehensive overview of gene expression by RNA-Seq will provide detailed insight into tissue transcriptomic changes during turkey development.
    Poultry Science Association Annual Meeting, San Diego, CA, US; 07/2013
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    ABSTRACT: Macrophage migration inhibitory factor (MIF) is recognized as a soluble factor produced by sensitized T lymphocytes and inhibits the random migration of macrophages. Recent research shows a more prominent role of MIF as a multi-functional cytokine mediating both innate and adaptive immune responses. Our group has identified both chicken and Eimeria MIF, and characterized its molecular function in enhancing innate immune responses during inflammation. In this study, we report that chicken CD74 (ChCD74), a type II transmembrane protein, functions as a macrophage surface receptor that binds to MIF molecules. The results of flow cytometry and fluorescent microscopy showed that incubation of macrophages with recombinant chicken MIF (rChMIF) led to binding of rChMIF on the surface of HTC cells. To verify that ChCD74 acts as a surface receptor for MIF molecules, the recombinant form of ChCD74 (rChCD74) was transiently over-expressed with green fluorescent protein at its N-terminus in HEC cells. Fluorescence analysis showed that incubation of HTC cells transiently over-expressing rChCD74 with rChMIF showed co-localization of the two molecules. These results were confirmed by immunoprecipitation assay, indicating their close interaction. Since Eimeria sp. also produce and secrete Eimeria MIF (EMIF) molecules during infection, we examined the binding of rEMIF to chicken macrophages via ChCD74. Our analysis showed binding of rEMIF to chicken macrophages via rChCD74 as a surface receptor. Together, this study concludes that both host and parasite MIF molecules bind to chicken macrophages via the surface receptor ChCD74.
    Poultry Science Association Annual Meeting, San Diego, CA, US; 07/2013
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    ABSTRACT: Macrophage migration inhibitory factor (MIF) is a soluble factor produced by sensitized T lymphocytes that inhibits the random migration of macrophages. Homologues of MIF from invertebrates have been identified, making it an interesting molecule from a functional perspective. In the present study, the localization of a parasite MIF protein as well as its effect on the host was characterized. Western blot analysis shows that Eimeria MIF (EMIF) is found during all parasite developmental stages tested. Transmission electron microscopy shows that MIF is distributed throughout cytosol and nucleus of Eimeria acervulina merozoites. Immunohistochemical analysis suggests that EMIF may be released into the surrounding tissues as early as 24 h after infection, while later during oocyst formation, MIF expression is localized to areas immediately surrounding the oocysts, as well as in wall-forming bodies. The chemotaxis assay revealed an inhibitory function of EMIF on chicken monocyte migration. Quantitative real-time PCR was performed to examine the effect of EMIF on host immune system by measuring the transcripts of inflammatory mediators. An ex vivo stimulation study showed that E. acervulina MIF (EaMIF) enhanced expression of pro-inflammatory cytokines and chemokines in the presence of lipopolysaccharide (LPS). Furthermore, sequential treatment of adherent peripheral blood mononuclear cells with EaMIF, chicken MIF, and LPS in 2-h intervals led to the highest levels of interleukin (IL)-1B, chemokine CCLi3, IL-18, and interferon-gamma mRNA expression. This study shows that parasite MIF is widely expressed and may have potential effects on the immune system of the host.
    Parasitology Research 02/2013; · 2.85 Impact Factor
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    ABSTRACT: As a member of the interleukin (IL)-10 family, IL-22 is an important mediator in modulating tissue responses during inflammation. Through activation of STAT3-signaling cascades, IL-22 induces proliferative and anti-apoptotic pathways, as well as antimicrobial peptides (AMPs), that help prevent tissue damage and aid in its repair. This study reports the cloning and expression of recombinant chicken IL-22 (rChIL-22) and its soluble receptor, rChIL22BP, and characterization of biological effects of rChIL-22 during inflammatory responses. Similar to observations with mammalian IL-22, purified rChIL-22 had no effect on either peripheral blood mononuclear cells (PBMCs) or lymphocytes. This was due to the low expression of the receptor ChIL22RA1 chain compared to ChIL10RB chain. rChIL-22 alone did not affect chicken embryo kidney cells (CEKCs); however, co-stimulation of CEKCs with LPS and rChIL-22 enhanced the production of pro-inflammatory cytokines, chemokines and AMPs. Furthermore, rChIL-22 alone stimulated and induced acute phase reactants in chicken embryo liver cells (CELCs). These effects of rChIL-22 were abolished by pre-incubation of rChIL-22 with rChIL22BP. Together, this study indicates an important role of ChIL-22 on epithelial cells and hepatocytes during inflammation.
    Cytokine 09/2012; · 2.52 Impact Factor
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    ABSTRACT: Analyses of the available avian genomes revealed the presence of a second TCRδ locus in the Galliformes. This second TCRδ locus is nonsyntenic to the conventional TCRα/δ and is unusual in that the V genes are more related to IgH V genes (VH) than to TCR V genes. The second TCRδ is not found in another avian lineage, the passerine zebra finch. Rather the finch's conventional TCRα/δ locus contains VH genes that are expressed with the conventional Cδ gene, similar to what has been found in amphibians. A comparison between Galliformes and Passeriformes genomic organization suggests an origin of the second TCRδ in the former lineage involving gene duplication. Expression of these atypical TCRδ transcripts with a VH domain paired with Cδ was found in lymphoid tissues of both avian lineages. The configuration of the second TCRδ in chicken and turkey is reminiscent of the TCRδ duplication that is present in nonplacental mammals and provides insight into the origin of the uniquely mammalian TCRμ locus.
    The Journal of Immunology 03/2012; 188(8):3912-9. · 5.52 Impact Factor
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    ABSTRACT: Chickens genetically selected for low (LA) or high (HA) antibody response to SRBC displayed a correlated change in MHC, so that LA chickens were 96% B13 and HA chickens were 96% B21. The LA line appears to be less susceptible to invasion by extracellular pathogens, whereas HA chickens are more resistant to infection by intracellular organisms. Resistance to Clostridium perfringens is one instance in which the lines do not follow their established trend of pathogen susceptibility, where during a clinical outbreak of necrotic enteritis, B21B21 genotypes experienced significantly less mortality than B13B13 genotypes. A study was carried out to assess immunological differences between LA and HA lines during exposure to C. perfringens α-toxin. Peripheral blood mononuclear cells were isolated from each genetic line, cultured with or without lipopolysaccharide (4 h), and exposed to varying concentrations of α-toxin (1; 10; 100; and 1,000 U/L) for 2 and 4 h. Evaluation of cellular proliferation, percentage of cytotoxicity, and immunological gene expression was carried out in a series of experiments. Cells isolated from HA chickens had significantly increased proliferation than those from LA chickens at low toxin levels (1 and 10 U/L) and significantly decreased proliferation at high toxin levels (100 and 1,000 U/L). Following exposure to lipopolysaccharide, the percentage of cytotoxicity was higher for LA than HA cells. In both assays, HA cells displayed superior performance following lipopolysaccharide-stimulation. Gene expression analysis of immune transcripts by quantitative real-time PCR revealed significantly upregulated expression of interferon (IFN)-γ, interleukin (IL)-8, IL-13 (2 h), IL-15, and CXCLi1 (4 h) in HA than LA chickens. Cells isolated from the LA line displayed significantly elevated expression of IL-2, IL-10, IL-13 (4 h), IL-16, IL-18, inducible nitric oxide synthase (iNOS), CXCLi1 (2 h), and lipopolysaccharide-induced tumor necrosis factor-α factor (LITAF) compared with the HA line. Clearly, these 2 genetic lines display highly divergent immune responses in regards to C. perfringens toxin exposure.
    Poultry Science 03/2012; 91(3):592-603. · 1.52 Impact Factor
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    ABSTRACT: The nucleotide-binding oligomerization domain proteins Nod1 and Nod2 are intracellular pathogen recognition receptors and members of the NLR family. Nod1 recognizes iE-DAP, a component of Gram-negative and some Gram-positive bacteria, whereas Nod2 recognizes MDP, a component of both Gram-negative and Gram-positive bacteria. In mammals, stimulation of Nod1 and Nod2 induces the production of pro-inflammatory cytokines IL-1β, IL-6 and TNF-α via the NF-κB pathway, suggesting an important role of Nod1 and Nod2 as innate immune sensors. Upon turkey genome analysis, we found a candidate sequence of the nod1 gene on turkey chromosome 6; however, there was no evidence of turkey nod2. Similarly, the current chicken and other avian genomes lack the nod2 gene, though they have a candidate nod1. The nod2 gene is located on human chromosome 16 and mouse chromosome 8 along with the nkd1, snx20 and cyld genes. A comparative analysis revealed that turkey chromosome 13 (MGA13) and chicken chromosome 11 (GGA11) are syntenic with human chromosome 16 and mouse chromosome 8, but they both lack nod2. The hagfish are the most primitive in vertebrate evolution, followed by lamprey, cart fish, bony fish, amphibians, reptiles, birds and mammals, respectively. The results of comparative genomics using CMap and GBrowse indicated no evidence of nod2 in the genomes of amphibians, reptiles and birds in terms of vertebrate evolution. In summary, comparative genomic analysis of model vertebrates showed that amphibians, reptiles and birds lack the intracellular innate immune sensor gene nod2, but an explanation for such findings is pending further analyses.
    Plant and Animal Genome XX, San Diego, CA, US; 01/2012
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    ABSTRACT: Pathogen recognition receptors (PRRs) are major molecules stimulating host innate immune system by microbial-associated molecular pattern. Nucleotide-binding oligomerization domain-containing domain 1 (Nod1) and 2 (Nod2) are major intracellular PRRs stimulated by component of bacterial peptidoglycan. Nod1 is stimulated by iE-DAP from mostly Gram-negative bacteria and certain Gram-positve bacteria in mammals, while Nod2 is stimulated by MDP from both Gram-negative and -positive bacteria. Interestingly, Nod2 gene was not found from most avian genome including chicken, turkey and zebrafinch. Goal of this study is to characterize avian Nod1 molecule and determine its various ligands including MDP. Luciferase assay showed that activity of NF-κB was induced by stimulation of avian Nod1 by MDP as well as iE-DAP. Mutant study showed that absence of pathogen recognition domain, Leucine-rich repeated region and signal transduction domain, Casepase activation and recruitment domain could not induce NF-κB activity by Nod1 ligands. Together, avian Nod1 is an essential molecule to stimulate host innate immune system from microbial infection.
    PSA-AAAP Joint Annual Meeting, St. Louis, MO; 07/2011
  • PSA-AAAP Joint Annual Meeting, St. Louis, MO; 07/2011
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    ABSTRACT: Avian coccidiosis is a major disease of poultry caused by the intestinal protozoa Eimeria. Infection leads to reduced feed efficiency and BW gain, resulting in severe economic losses for the poultry industry. Aviagen line A and line B birds show a differential response to Eimeria infection, with line B birds exhibiting higher lesion scores and mortality. The objective of this study was to examine differential intestinal gene expression between 2-wk-old line A and B chicks in response to a challenge with Eimeria maxima. After challenge with 1 × 10(4) oocysts/chick, more than 40% of line A chicks had lesion scores of 0 to 1 (scale of 0 to 4), similar to control chicks. In contrast, all line B chicks challenged at this same dose had lesion scores of 2 to 4. Total RNA was extracted from the jejunum of control and challenged chicks from both lines A and B. Microarray analysis revealed that liver-expressed antimicrobial peptide 2 (LEAP-2), a component of the innate immune system, was downregulated 20-fold in line A challenged chicks with lesion scores of 2 to 4 compared with line A control chicks, and was downregulated 11- to 71-fold in line B challenged chicks with lesion scores of 2 to 4 compared with line B control chicks. Liver-expressed antimicrobial peptide 2 was downregulated less than 2-fold in line A challenged chicks with lesion scores of 1 compared with line A control chicks, indicating that these chicks were similar to control chicks in their expression level of LEAP-2. Other genes (cytochrome P450, heat shock protein 25, keratin 19, and amino acid transporter ASCT1) showed different patterns of over- or underexpression. The expression of LEAP-2 was verified using real-time PCR, revealing a correlation between lesion score and magnitude of LEAP-2 downregulation for both line A and line B chicks. Thus, LEAP-2 may serve as a useful marker for identification of chickens resistant to E. maxima infection and potentially other Eimeria spp.
    Poultry Science 06/2011; 90(6):1212-9. · 1.52 Impact Factor

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1k Citations
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Institutions

  • 2005–2006
    • Natural Resources Research Institute
      Silver Spring, Maryland, United States
  • 2004–2006
    • United States Department of Agriculture
      • Agricultural Research Service (ARS)
      Washington, D. C., DC, United States
    • Loyola University Maryland
      Baltimore, Maryland, United States
  • 2002–2005
    • University of Maryland, College Park
      • • College of Agriculture and Natural Resources
      • • Department of Animal and Avian Sciences
      College Park, MD, United States