Expression profiles of Toll-like receptors 1, 2 and 5 in selected organs of commercial and indigenous chickens.
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ABSTRACT:
SUBMITTER: Slawinska A
PROVIDER: S-EPMC3825276 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:A comparative study of cytokine and toll-like receptor (TLR) mRNA expression in 3 weeks old indigenous and commercial chickens infected with a very virulent strain of Infectious bursal disease virus (IBDV) was performed using a custom-made microarray chip. In uninfected indigenous chickens, the basal levels of interleukin (IL) 15 were lower and IL 16 was higher than their commercial counterparts. In the IBDV infected indigenous chickens, only IL16 gene expression was down regulated, while TLR3 expression was up regulated significantly. In the IBDV infected commercial chickens IL15, IL16 and TLR3 were down regulated. But, IL1-β, IL2, IL8, IL12, IL17, interferon (IFN)-α and β were significantly increased compared with the control. In IBDV infected indigenous chickens, IL15, IFN-γ, beta-defensin and TLR3 were up regulated compared to virus-infected commercial chickens. The results suggested that up regulation of TLR3, a ligand for double-stranded (ds) RNA probably could account for the possible clinical resistance in these birds. There was a 5.2 fold difference by quantitative real-time RT-PCR between indigenous and commercial chickens in TLR3 mRNA expression. Therefore, TLR3, a receptor for dsRNA could be a putative molecule that could play a role in differential innate and adaptive immune responses to IBDV in commercial and indigenous chickens.
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Project description:In this study, indigenous chickens were collected from eight different regions in Kenya and kept at InCIP-Egerton University. These were studied using eighteen microsatellite markers to determine genetic variation. Statistics related to genetic variation were estimated using GenALEx6. Mean percentage polymorphic loci (PPL) was 96.71% and 4% genetic variance (p ≥ 0.003) was seen between the eight populations. MCW0123 marker had the highest genetic variance of 13% among populations (p ≥ 0.003) at 95% CI. Mean He ranged from 0.351 ± 0.031 (SIB) to 0.434 ± 0.022 (BM) with a grand mean He of 0.399 ± 0.011 across the populations using the microsatellite markers. Nei's genetic distance ranged from 0.016 (SIB and WP) to 0.126 (NR and SIB). DARwin6.501 analysis software was used to draw the population dendrogram and two major population clusters were observed, also seen with PCoA. This study found a lot of genetic variation and relatedness within and among populations. Based on the phylogenetic tree result, it is concluded that the clustering of the chicken populations in the present study is not based on geographical proximity. The microsatellite markers used in this study were suitable for the measurement of the genetic biodiversity and relationship of Kenyan chicken populations. These results can therefore serve as an initial step to plan the conservation of indigenous chickens in Kenya.
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Project description:The increased demand for chicken meat products has led to chickens with increased growth rates and heavier slaughter weights. This has had unintentional negative effects on the genetics of these animals, such as spontaneous, idiopathic muscle abnormalities. There has also been a shift in customer preference towards products from alternative farming systems such as organic and free-range. Indigenous purebred chickens, such as the Polverara, show potential in these systems as they are adapted to more extensive systems. The aim of the present study was to characterize the meat quality traits of the Polverara, by comparing the proximate composition and amino acid profile with that of a commercial Hybrid. In addition, the lipid and protein oxidation was analyzed after eight days of storage. A total of 120 leg meat samples, 60 Polverara and 60 Hybrid were analyzed. Polverara exhibited higher protein content, lower lipid content, and a better amino acid profile. These results indicate that the Polverara has better nutritional meat quality. However, Polverara also showed higher levels of lipid and protein oxidation. Therefore, further research is needed, especially in regards to the fatty acid profile and mineral content of the meat, which is known to affect oxidative stability.
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Project description:Toll-like receptors (TLRs) are innate immune receptors expressed in all parts of the alimentary tract. However, analyses comparing expression in different segments and data on germ-free animals are lacking. Alimentary tract cancers show increased TLR expression. According to the field effect concept, carcinogenetic factors induce subtle cancer predisposing alterations in the whole organ. We studied TLR1 to TLR9 expression in all segments of the alimentary tract from cancer patients' tumor-adjacent normal mucosa, healthy organ donors, and conventional and germ-free mice by using immunohistochemistry and quantitative PCR. All TLRs were expressed in all segments of the alimentary tract. Expression was most intensive in the small intestine in humans and conventional mice, but germ-free mice showed less expression in the small intestine. TLR expression levels were similar in cancer patients and organ donors. We provide systematic baseline data on the TLR expression in the alimentary tract. Normal epithelium adjacent to tumor seems to have similar TLR expression compared with healthy tissues suggesting absence of any field effect in TLR expression. Accordingly, specimens from cancer patients' normal tumor-adjacent tissue can be used as control tissues in immunohistochemical TLR studies in gastrointestinal cancer.
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Project description:Following chicken domestication, diversified chicken breeds were developed by both natural and artificial selection, which led to the accumulation of abundant genetic and phenotypic variations, making chickens an ideal genetic research model. To better understand the genetic structure of chicken breeds under different selection pressures, we genotyped various chicken populations with specific selection targets, including indigenous, commercial, gamecock, and wild ancestral chickens, using the 600K SNP array. We analyzed the population structure, genetic relationships, run of homozygosity (ROH), effective population number (Ne), and other genetic parameters. The wild ancestral population, red junglefowl (RJF), possessed the highest diversity, in comparison with all other domesticated populations, which was supported by linkage disequilibrium decay (LD), effective population number, and ROH analyses. The gamecock breeds, which were subjected to stronger male-biased selection for fighting-related traits, also presented higher variation than the commercial and indigenous breeds. Admixture analysis also indicated that game breed is a relatively independent branch of Chinese local breeds. Following intense selection for reproductive and productive traits, the commercial lines showed the least diversity. We also observed that the European local chickens had lower genetic variation than the Chinese local breeds, which could be attributed to the shorter history of the European breed. ROH were present in a breed specific manner and 191 ROH island were detected on four groups (commercial, local, game and wild chickens). These ROH islands were involved in egg production, growth and silky feathers and other traits. Moreover, we estimated the effective sex ratio of these breeds to demonstrate the change in the ratio of the two sexes. We found that commercial chickens had a greater sex imbalance between females and males. The commercial lines showed the highest female-to-male ratios. Interestingly, RJF comprised a greater proportion of males than females. Our results show the population genetics of chickens under selection pressures, and can aid in the development of better conservation strategies for different chicken breeds.
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Project description:Eimeria species parasites can cause the enteric disease coccidiosis, most notably in chickens where the economic and welfare implications are significant. Seven Eimeria species are recognized to infect chickens, although understanding of their regional occurrence, abundance, and population structure remains limited. Reports of Eimeria circulating in chickens across much of the southern hemisphere with cryptic genotypes and the capacity to escape current anticoccidial vaccines have revealed unexpected levels of complexity. Consequently, it is important to supplement validated species-specific molecular diagnostics with new genus-level tools. Here, we report the application of Illumina MiSeq deep sequencing to partial 18S rDNA amplicons generated using Eimeria genus-specific primers from chicken caecal contents collected in India. Commercial Cobb400 broiler and indigenous Kadaknath type chickens were sampled under field conditions after co-rearing (mixed type farms, n = 150 chickens for each) or separate rearing (single type farms, n = 150 each). Comparison of MiSeq results with established Internal Transcribed Spacer (ITS) and Sequence Characterised Amplified Region (SCAR) quantitative PCR assays suggest greater sensitivity for the MiSeq approach. The caecal-dwelling Eimeria tenella and E. necatrix dominated each sample set, although all seven species which infect chickens were detected. Two of the three cryptic Eimeria genotypes were detected including OTU-X and OTU-Y, the most northern report for the latter to date. Low levels of DNA representing other Eimeria species were detected, possibly representing farm-level contamination with non-replicating oocysts or Eimeria DNA, or false positives, indicating a requirement for additional validation. Next generation deep amplicon sequencing offers a valuable resource for future Eimeria studies.
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Project description:Using a variety of genetic resources, the aim of this study is to see how genetic background affects egg traits in chickens. Three different chicken genotypes (a commercial Brown layer, BOR; 2 Japanese indigenous breeds, NGY and YKD) were investigated effects on genotype in 10 external and internal egg quality traits along with 20 yolk and albumen free amino acid traits. Significant effects on genotype in 10 external and internal egg quality traits and 18 yolk and 17 albumen amino acid traits were found (P < 0.05). In sizes and weights of egg and eggshell redness, there were significant differences among all combinations of genotype (BOR > NGY > YKD). In 14 yolk (Asn, Ser, Gln, Gly, His, Arg, Ala, Pro, Tyr, Val, Met, Leu, Phe, and Lys) and 8 albumen amino acid traits (Gln, Gly, His, Arg, Val, Ile, Leu, and Lys), BOR was significantly higher than NGY and YKD, while the opposite relations were seen in 2 amino acid traits (Cys and GABA). Moreover, phenotypic correlation analyses revealed that positive correlations among amino acid traits within each yolk and albumen were broadly seen (0.30 < r < 0.98, P < 0.05). However, there are almost no phenotypic correlations in amino acids between yolk and albumen in BOR and NGY, but negative correlations in YKD, which implying a potential use of untapped genetic resources for modifying amino acid balance. These results indicate genetic background affects not only sizes and weights of egg but also amino acid contents and their balance of yolk and albumen.
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Project description:Toll-like receptors (TLRs), key initiators of innate immune responses, recognize antigens and are essential in linking innate and adaptive immune responses. Misrecognition and over-stimulation/expression of TLRs may contribute to the development of chronic inflammatory diseases and autoimmune diseases. However, appropriate and mature TLR responses are associated with the establishment of resistance against some infectious diseases. In this study, we assessed the mRNA expression profile of TLRs 1-10 in splenic and ileal mononuclear cells (MNCs) and dendritic cells (DCs) of germ-free (GF) and conventional pigs at different ages. We found that the TLR mRNA expression profiles were distinct between GF and conventional pigs. The expression profiles were also significantly different between splenic and ileal MNCs/DCs. Comparison of the TLR expression profiles in GF and conventional newborn and young pigs demonstrated that exposure to commensal microbiota may play a more important role than age in TLR mRNA expression profiles. To our knowledge, this is the first report that systematically assesses porcine TLRs 1-10 mRNA expression profiles in MNCs and DCs from GF and conventional pigs at different ages. These results further highlighted that the commensal microbiota of neonates play a critical role through TLR signaling in the development of systemic and mucosal immune systems.
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Project description:BACKGROUND:The caecal microbiota plays a key role in chicken health and performance, influencing digestion and absorption of nutrients, and contributing to defence against colonisation by invading pathogens. Measures of productivity and resistance to pathogen colonisation are directly influenced by chicken genotype, but host driven variation in microbiome structure is also likely to exert a considerable indirect influence. METHODS:Here, we define the caecal microbiome of indigenous Indian Aseel and Kadaknath chicken breeds and compare them with the global commercial broiler Cobb400 and Ross 308 lines using 16S rDNA V3-V4 hypervariable amplicon sequencing. RESULTS:Each caecal microbiome was dominated by the genera Bacteroides, unclassified bacteria, unclassified Clostridiales, Clostridium, Alistipes, Faecalibacterium, Eubacterium and Blautia. Geographic location (a measure recognised to include variation in environmental and climatic factors, but also likely to feature varied management practices) and chicken line/breed were both found to exert significant impacts (p?<?0.05) on caecal microbiome composition. Linear discriminant analysis effect size (LEfSe) revealed 42 breed-specific biomarkers in the chicken lines reared under controlled conditions at two different locations. CONCLUSION:Chicken breed-specific variation in bacterial occurrence, correlation between genera and clustering of operational taxonomic units indicate scope for quantitative genetic analysis and the possibility of selective breeding of chickens for defined enteric microbiota.
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Project description:Otitis media is mainly caused by upper respiratory tract infection and eustachian tube dysfunction. If external upper respiratory tract infection is not detected early in the middle ear, or an appropriate immune response does not occur, otitis media can become a chronic state or complications may occur. Therefore, given the important role of Toll-like receptors (TLRs) in the early response to external antigens, we surveyed the role of TLRs in otitis media. To summarize the role of TLR in otitis media, we reviewed articles on the expression of TLRs in acute otitis media (AOM), otitis media with effusion (OME), chronic otitis media (COM) with cholesteatoma, and COM without cholesteatoma. Many studies showed that TLRs 1-10 are expressed in AOM, OME, COM with cholesteatoma, and COM without cholesteatoma. TLR expression in the normal middle ear mucosa is absent or weak, but is increased in inflammatory fluid of AOM, effusion of OME, and granulation tissue and cholesteatoma of COM. In addition, TLRs show increased or decreased expression depending on the presence or absence of bacteria, recurrence of disease, tissue type, and repeated surgery. In conclusion, expression of TLRs is associated with otitis media. Inappropriate TLR expression, or delayed or absent induction, are associated with the occurrence, recurrence, chronicization, and complications of otitis media. Therefore, TLRs are very important in otitis media and closely related to its etiology.
| S-EPMC8346131 | biostudies-literature