Tract Of Chickens Research Articles

In vitro model to assess the adsorption of oral veterinary drugs to mycotoxin binders in a feed- and aflatoxin B1-containing buffered matrix

ABSTRACTMycotoxin binders are feed additives which are mixed in the feed to adsorb mycotoxins and thereby reducing their toxic effects on animals. Interactions with orally administered veterinary medicinal products, such as antimicrobials or coccidiostats, have been reported previously. This paper describes an in vitro model to screen the interaction between mycotoxin binders and veterinary drugs with respect to the non-specific binding of drugs. It is designed as a static setup using a single concentration of drug and binder in a feed-containing or a feed-plus-mycotoxin-containing matrix, buffered at different pH values. The model was applied to two frequently used antimicrobials in veterinary medicine, doxycycline (DOX) and tylosin (TYL), one major mycotoxin, aflatoxin B1 (AFB1), and four mycotoxin binders. Proportions of feed, DOX or TYL, AFB1, and binder are equivalent to the in vivo situation for broiler chickens, while pH and volume of the buffer are representative of the gastrointestinal tract of chickens. A substantial binding of DOX (~ 88%) and TYL (~ 66%) to the feed-matrix was observed. For the mycotoxin binders, similar results were obtained for DOX and TYL; more specifically up to an inclusion rate of 20 g binder/kg feed, no significant binding was demonstrated, determined as the free concentration of DOX and TYL. A single exception was noticed for TYL and one specific bentonite-based mycotoxin binder, for which no significant interaction could be demonstrated up to 10 g binder/kg but there was an effect at 20 g/kg. In all cases, there was no competition between the tested drugs DOX or TYL and the mycotoxin AFB1 for binding to the bentonite-based mycotoxin binder.

Molecular detection and phylogenetic properties of isolated infectious bronchitis viruses from broilers in Ahvaz, southwest Iran, based on partial sequences of spike gene.

Infectious bronchitis (IB) is a highly contagious disease involving mostly upper respiratory tract in chickens, leading to significant economic losses in the poultry industry worldwide. One of the major concerns regarding to IB is the emergence of new types of infectious bronchitis viruses (IBVs). The purpose of this study was to identify the IBVs isolated from Iranian broiler chickens with respiratory symptoms. Twenty-five broiler flocks around Ahwaz (southwest of Iran) were examined for IBV. The specimens including trachea, lung, liver, kidney, and ceacal tonsil, were collected from diseased birds and inoculated into chicken embryonated eggs. Harvested allantoic fluids were subjected to reverse transcription polymerase chain reaction (RT-PCR) using primers in order to amplify spike 1 (S1) gene of IBV. The RT-PCR products of four IBV isolates were sequenced. The results showed that from 25 examined flocks with respiratory disease, 12 flocks (48.00%) were positive for IBV. In phylogenetic analysis, our isolates were closely related to the QX-like viruses such as PCRLab/06/2012 (Iran), QX, HC9, HC10, CK/CH/GX/NN11-1, CK/CH/JS/YC11-1, CK/CH/JS/2010/13, CK/CH/JS/2011/2 (China), QX/SGK-21, QX/SGK-11 (Iraq) with nucleotide homology up to 99.00%. This study indicates the role of IBVs in the respiratory disorders of broiler flocks located in southwest Iran, and also the existence of a variant of IBV, which is distinguishable from the other Iranian variants.

RAS-related protein 1: an estrogen-responsive gene involved in development and molting-mediated regeneration of the female reproductive tract in chickens

It is important to identify molecular candidates involved in morphological and functional changes in the female reproductive system. We have discovered several candidate genes that were significantly altered in chick oviducts by exogenous estrogen and those candidates included dexamethasone (DEX)-induced RAS-related protein 1 (RASD1). RAS-related protein 1, a member of the Ras family of monomeric G proteins, is involved in various cellular processes including cell growth, proliferation and differentiation, as well as a cell-signaling protein regulating hormonal actions. Although the RASD1 gene was first identified as a DEX (a corticosteroid) inducible gene, there is evidence that it is also an estrogen-responsive gene. However, hormone-mediated expression and biological functions of RASD1 in the avian female reproductive system are poorly understood. Therefore, we tested the hypothesis that RASD1 may be involved in the development and remodeling of the chicken reproductive system as an estrogen-responsive gene. Here we demonstrate differential expression of RASD1 gene and candidate microRNAs (miRNAs) targeting chicken RASD1 transcripts in chicken oviducts in response to diesthylstilbestrol (DES, a synthetic non-steroidal estrogen) and the estrogen-mediated molting process. Result of the present study indicated that expression of RASD1 messenger RNA (mRNA) increased in the developing oviducts of chicks treated with DES, particularly in the glandular (GE) and luminal (LE) epithelia of the magnum and the shell gland. Also, during induced molting by zinc feeding, RASD1 expression changed in concert with changes in concentrations of estrogen in blood of laying hens. Our results revealed that expression of RASD1 mRNA decreased as the oviduct regressed and then increased as the oviduct underwent re-growth and recrudescence in hens. Furthermore, RASD1 mRNA was expressed predominantly in GE and LE of the oviduct of laying hens during regeneration of the oviduct after induced molting, but not during the period of regression of the oviduct during molting. In addition, the relative expression of candidate miRNAs (miR-30a-5p, miR-30b-5p, miR-30c-5p and miR-30d) regulating RASD1 transcripts changed in response to estrogen stimulation of chick oviducts. These results indicate that transcription of the RASD1 gene and miRNAs regulating post-transcriptional aspects of expression of RASD1 are modulated by estrogen which is critical for growth, development, remodeling and maintenance of function of the chicken oviduct.

Immunohistochemical and clinical changes in the respiratory tract of chickens, naturally infected with the fowlpox virus

It is clear that currently the question of study of the pathological changes in the respiratory tract of chickens due to the impact of the fowlpox virus remains relevant, as the pathogenesis of nutritional deficiency, the presence of mycotoxins or the papilloma virus are characterized by the same clinical manifestations. We analyzed 88 chickens, naturally infected with the fowlpox virus, using clinical and immunohistochemical methods of investigation. Among all species of birds, we studied only chickens, data on which were collected for five years from veterinary clinics. The investigation revealed lesions basically characterized by the presence of changes in the typical structure of the chicken’s respiratory tract. As a result, we found clear criteria for the pathological process in the respiratory tract of chickens, which are typical for fowlpox. Thus, we discovered respiratory tract obstruction, as well as many intracytoplasmic pale eosinophilic inclusions in hyperplastic cells. We found an accumulation of mononuclear cells consisting mainly of macrophages, lymphocytes, plasma and mononuclear cells inside the mucous and muscle membranes. Bronchial lumens were blocked by necrotic and desquamated epithelial cells, red blood cells, bacterial colonies and amorphous eosinophilic material. We found accumulations of lymphocytes and macrophages in the parenchyma of the lungs. The hyperplastic epithelial cells reacted immunohistochemically with antibodies against the fowlpox virus in the respiratory tract. Immunoreaction occurred mainly in the cytoplasm of infected cells, inclusions, and necrotic and desquamated cells. The study proved immunohistochemical methods of investigation can be a useful additional tool for establishing a final diagnosis, especially in acute and subacute phases of the disease. The following respiratory signs were observed in severe cases of fowlpox: damage to the lungs in 33 cases (46.5%), parabronchium – 20 (28.2%), parabronchial connective tissue – 8 (11.3%), and mucous membrane of the larynx and trachea – 10 (14.1%). In mild and moderate cases of fowlpox, the following respiratory signs were observed: hyperemia and thickening of the mucous membrane of the trachea – 14 (82.4%), as well as hyperemia in the nasal conchae and paranasal sinuses – 3 (17.7%). In the future, it will be necessary to conduct deeper studies to detect pathological manifestations of this disease, not only in the respiratory tract, but also in other organs and systems of chickens.

Immune responses to vaccination and infection with Mycoplasma gallisepticum in turkeys

ABSTRACTInfection with Mycoplasma gallisepticum induces severe lymphoproliferative lesions in multiple sites along the respiratory tract in chickens and turkeys. These immunopathological responses have been well-characterized in chickens, but have not been studied closely in turkeys. The aim of the study described here was to examine the immune responses of turkeys after live vaccination and infection with M. gallisepticum. In a strain comparison study, the mean log10 antibody titre of birds exposed to an aerosol culture of M. gallisepticum strain Ap3AS was found to be significantly higher at day 14 than that of birds exposed to strain 100809/31. In a dose–response study, there was a significant difference in the mean log10 antibody titre between birds exposed to mycoplasma broth and birds exposed to the highest dose of strain Ap3AS at day 7 after exposure. Immunohistochemical analysis of the tracheal mucosa and the air sacs revealed similar patterns of distribution of CD4+ and CD8+ lymphocytes to those seen in the tracheal mucosa of chickens, implicating these cell types in the pathogenesis of respiratory mycoplasmosis in turkeys. Turkeys that had been vaccinated with M. gallisepticum GapA+ ts-11 had significantly higher antibody titres than unvaccinated birds at both 7 and 14 days after challenge with strain Ap3AS. Vaccination with GapA+ ts-11 protected against the lymphoproliferative response to infection with virulent M. gallisepticum in both the tracheal mucosa and the air sacs, suggesting that this strain may be a useful vaccine candidate for use in turkeys.

Prevalence And Improvement Of Culture Independent Quantification Of Clostridium Perfringens In Broiler's Intestine

Clostridium Perfringens represent one of the natural inhabitant bacteria in the gastrointestinal tract of chickens. However, predisposing factors, mainly co-infection with Coccidia, represent a favorable condition for over growth of C. perfringens that induce necrotic enteritis (NE). The prevalence of C. perfringens in commercial broilers with enteric disease in Egypt was investigated via bacteriological isolation and identification and then confirmed by toxin typing by PCR. Furthermore, culture-independent quantitative real time PCR targeting alpha toxin gene was improved via reducing the effect of PCR inhibitors in the intestinal content (IC). Out of 61 broiler flocks, 40 were positive for C. perfringens with a higher incidence in winter (81.25%) and in 20-30 days old broilers (66.67%). All isolates belonged to C. perfringens type A with the absence of enterotoxin or Beta2 toxin genes. Pretreatment of the intestinal content with acetone improve the detection limit of quantitative real time PCR assay to 102 cells/gm which was highly correlated to the culture-based counting method using cooked meet media. C. perfringes type A widespread in broilers in Egypt and the extraction method used herein could be used for direct quantification of C. perfringens in the intestinal content of broiler chickens without prior enrichment.

Effects of Probiotic on the Expression of IL-7 Gene and Immune Response to Newcastle Disease Vaccine in Broilers

Probiotics have potential as prevention strategies or therapies for multiple diseases in chickens, such as Newcastle Disease (ND), heat stress, and Coccidiosis, but the mechanism still partially understood. It is an important and warranted issue for further investigation that how probiotics modulated gene expression in disease. In this study, 80 Specific-pathogen-free (SPF) broilers were treated with probiotics, and inoculated La Sota vaccine, then detected the changes of the number of antibody-producing cells (IgA + , IgM + , and IgG + ) and the expression of IL-7 mRNA in mucosa associated lymphoid tissue (MALT: Harder's gland, cecal tonsils, duodenum and ileum Peyer's patch), and the content of Immunoglobulins (IgA, IgM, and IgG) in local humor (tear, trachea fluid, bile and intestinal fluid) by immunohistochemistry staining, RT-qPCR, and IELISA, respectively. Results showed that the contents of IgA, IgM and IgG in local humor, the number of IgA + , IgM + , and IgG + and the expression of IL-7 mRNA in MALT of inoculated birds were significantly higher than control birds (P < 0.05 or P < 0.01) after 7 days post-inoculation (PI), and chickens showed higher immunity response after treated with probiotics. These results indicated that probiotics could enhance the humoral immunity in the respiratory and digestive tracts of chickens, and the immunological response to ND vaccine, and ND vaccine in combining with probiotics will get a better effect on humoral immunity. Both the probiotics and ND vaccine could increase the expression of IL-7 mRNA, and then improve the humoral immunity in the chickens, and the IL-7 maybe one of the ways by which the probiotics improve the humoral immunity.

Effects of Dietary Selenium on Inflammation and Hydrogen Sulfide in the Gastrointestinal Tract in Chickens.

Selenium (Se) is an essential trace element for humans and animals and is associated with many physiological functions. Previous studies have shown that low-Se diet may affect inflammatory cytokine productions and histology in the digestive system and that sulfide hydrogen (H2S) may contribute to the protection against tissue injury and the inhibition of inflammation in the gastrointestinal tract. In this study, we investigated the relationship between Se deficiency-induced inflammation and H2S production in the small intestine in chickens. One hundred twenty 1-day-old chickens were fed with diets with different Se concentrations (0.15mg/kg in the control and 0.028mg/kg in the low-Se-diet group). Chickens were euthanized and small intestinal tissues were extracted. We observed histology, measured H2S concentration, and evaluated the mRNA expression of H2S-producing enzymes cystathionine γ-lyase (CSE), cystathionine β-synthase (CBS), and 3-mercaptopyruvate sulfurtransferase (3-MST), and inflammatory factors TNF-α, NF-κB p50, COX-2, and PTGES. Our results showed that chickens fed with low-Se diet exhibited histological changes, lower H2S production, and lower mRNA expression of H2S-producing enzymes (CSE, CBS, and 3-MST) whereas higher mRNA expression of intestinal inflammatory factors (TNF-α, NF-κB p50, COX-2, and PTGES) compared to controls. Our results indicate that low-Se diet could impact H2S, H2S-producing enzymes, and inflammatory factors in the small intestine, implying that Se is important in maintaining intestinal functions and H2S production is downregulated in Se deficiency-induced inflammation. The downregulation exacerbates the inflammation and impacts H2S-mediated intestinal functions.

How Tissue Mechanical Properties Affect Enteric Neural Crest Cell Migration.

Neural crest cells (NCCs) are a population of multipotent cells that migrate extensively during vertebrate development. Alterations to neural crest ontogenesis cause several diseases, including cancers and congenital defects, such as Hirschprung disease, which results from incomplete colonization of the colon by enteric NCCs (ENCCs). We investigated the influence of the stiffness and structure of the environment on ENCC migration in vitro and during colonization of the gastrointestinal tract in chicken and mouse embryos. We showed using tensile stretching and atomic force microscopy (AFM) that the mesenchyme of the gut was initially soft but gradually stiffened during the period of ENCC colonization. Second-harmonic generation (SHG) microscopy revealed that this stiffening was associated with a gradual organization and enrichment of collagen fibers in the developing gut. Ex-vivo 2D cell migration assays showed that ENCCs migrated on substrates with very low levels of stiffness. In 3D collagen gels, the speed of the ENCC migratory front decreased with increasing gel stiffness, whereas no correlation was found between porosity and ENCC migration behavior. Metalloprotease inhibition experiments showed that ENCCs actively degraded collagen in order to progress. These results shed light on the role of the mechanical properties of tissues in ENCC migration during development.

Metagenomic bacterial community profiles of chicken embryo gastrointestinal tract by using T-RFLP analysis.

Thirty microbial phylotypes of microorganisms were found in the gastrointestinal tract of chicken belonging to the Hajseks White breed, and 38 phylotypes were found in the gastrointestinal tract of chicken belonging to the Hajseks Brown breed. The microbiome of the gastrointestinal tract of the chicken embryos of the Hajseks White breed was dominated by the typical representatives of avian intestinal microflora--bacteria of the family Enterobacteriaceae (47.3%), orders Actinomycetales (13.6%) and Bifidobacteriales (20.6%), and the family Lachnospiraceae (1.1%). The microbiome of the gastrointestinal tract of the chicken embryos of the Hajseks Brown breed was dominated by the pathogenic bacteria of the order Rickettsiales (94.8%). The metagenome of gastrointestinal tract of both breeds also contained a small number of genes of unidentified bacteria.

Histopathological and Molecular Diagnosis of Infectious Laryngotracheitis in Tunisia - First Report

Infectious laryngotracheitis (ILT), an acute infection of the upper respiratory tract of chickens, was absent before the end of 2013, in Tunisia. Severe respiratory signs were observed in 48 layer and broiler flocks (3 weeks to 80 weeks old) between June 2013 and June 2016, and characterized with dyspnea, bloody mucus excretion and decrease in egg production. Clinical signs were dominated by congestive and hemorrhagic inflammation of the upper respiratory tract. Histopathological analyses and PCR tests were performed on respiratory tissues of suspected birds. Suggestive lesions of ILT, such as epithelial necrosis, sero-fibrinous and sero-hemorrhagic exudates, syncytia and intranuclear inclusion bodies were observed in layers of the 25 flocks visited. ILTV was detected in 12 out of 31 flocks by conventional PCR, using specific primers for the gB gene of ILTV. Eight of these were positive in histopathology. Our findings confirmed the introduction for the first time of the ILT virus in commercial poultry farms, in Tunisia.

Acute injections of corticosterone, norepinephrine and epinephrine retards food passage in the crop of chicks

The purpose of the present study was to clarify whether acute injection of stress-related hormones, corticosterone (CORT), norepinephrine (NE) and epinephrine (E) affect food passage in the crop of chicks (Gallus gallus). Subcutaneous (SQ) injection of CORT significantly retarded the food passage in the crop of chicks. Intraperitoneal (IP) injection of NE and E also significantly decreased the crop emptying rate. Additional experiments by using agonists of adrenergic receptors found that IP injection of phenylephrine and clonidine but not isoproterenol retarded the food passage in the crop of chicks. These results demonstrated that the effect of NE and E would be mediated by alpha-1-, alpha-2- rather than beta-adrenergic receptor. Finally, we found that injection of CORT, NE and E had no effect on the number of defecations while intracerebroventricular injection of corticotropin-releasing hormone and urocortin-3 significantly increased it. These results suggest that CORT, NE and E might affect the food passage in the upper digestive tract in chicks.

Vitamin A Deficiency Impairs Mucin Expression and Suppresses the Mucosal Immune Function of the Respiratory Tract in Chicks.

The chicken immune system is immature at the time of hatching. The development of the respiratory immune system after hatching is vital to young chicks. The aim of this study was to investigate the effect of dietary vitamin A supplement levels on respiratory mucin and IgA production in chicks. In this study, 120 one-day-old broiler chicks were randomly divided into 4 groups consisting of three replicates of 10 broilers and subjected to dietary vitamin A supplement levels of 0, 1,500, 6,000, or 12,000 IU/kg for seven days. Compared with control birds, vitamin A supplementation significantly increased the mucin and IgA levels in the bronchoalveolar lavage fluid (BALF) as well as the IgA level in serum. In the lungs, vitamin A supplementation downregulated TNF-α and EGFR mRNA expression. The TGF-β and MUC5AC mRNA expression levels were upregulated by vitamin A supplementation at a dose of 6,000 IU/kg, and the IL-13 mRNA expression level was increased at the 12,000 IU/kg supplement level. Vitamin A deficiency (control) significantly decreased the mRNA expression levels of MUC2, IgA, EGFR, IL-13 and TGF-β in trachea tissue. Histological section analysis revealed that the number of goblet cells in the tracheal epithelium was less in the 0 and 12,000 IU/kg vitamin A supplement groups than in the other groups. In conclusion, vitamin A deficiency suppressed the immunity of the airway by decreasing the IgA and mucin concentrations in neonatal chicks. This study suggested that a suitable level of vitamin A is essential for the secretion of IgA and mucin in the respiratory tract by regulating the gene expression of cytokines and epithelial growth factors.

Bacterial determinants of importance in the virulence of Gallibacterium anatis in poultry.

Gallibacterium anatis, a member of the Pasteurellaceae family, constitute a part of the normal micro-flora of the upper respiratory tract and the lower genital tract in chickens. However, increasing evidence indicate that G. anatis is also associated with a wide range of pathological changes, particularly in the reproductive organs, which leads to decreased egg production, lowered animal welfare and increased mortality. As a recently defined opportunistic pathogen limited focus has been placed on the pathogenesis and putative virulence factors permitting G. anatis to cause disease. One of the most studied virulence determinants is a large RTX-like toxin (GtxA), which has been demonstrated to induce a strong leukotoxic effect on avian macrophages. A number of fimbria of different sizes and shapes has been described. Particularly fimbriae belonging to the F17-like family appears to be common in a diverse selection of G. anatis strains. Mutants lacking the FlfA fimbria were severely attenuated in experimentally infected chickens. Additional characteristics including the ability to express capsular material possibly involved in serum resistance; secretion of metalloproteases capable of degrading immunoglobulins, and hemagglutinins, which may promote biofilm formation are all factors likely linked to the virulence of G. anatis. A major advantage for the study of how G. anatis interact with its host is the ability to perform biologically relevant experimental infections where natural routes of exposure allows reproduction of lesions observed during spontaneous infections. This review summarizes the current understanding of the G. anatis pathogenesis and discusses the contribution of the established and putative virulence factors described for this bacterium to date.

Identification of a picornavirus from chickens with transmissible viral proventriculitis using metagenomic analysis.

Transmissible viral proventriculitis (TVP), an infectious disease in chickens, is responsible for economic losses in the commercial poultry industry. The major etiologic agent, however, is unknown. Using metagenomics, we compared the diversity of viruses present in proventriculus samples from flocks diagnosed with TVP to those of healthy flocks in South Korea between 2003 and 2012. Each sample had a mean of 21,538,726 sequence reads generated by high-throughput sequencing, with a mean length of 160 nt. Enrichment in viral sequences suggested that at least three viruses were present in each TVP sample. Although we could not determine a pathogen of TVP that matched the known morphology, picornavirus sequences were present in all five disease samples, suggesting an association with TVP. The five samples yielded 1,045-1,720 bp contigs with 81-84 % nt sequence identity to turkey hepatitis virus (accession number: HM751199). Whole-genome analysis indicated that the QIA01 strain of the novel picornavirus was similar to turkey hepatitis virus in the P2 and P3 regions (82.7 % nt and 95.5 % aa sequence identity), but different in the structural region and partial 2A peptides (56.2 % nt and 23.9 % aa sequence identity). In addition, the QIA01 virus was similar (87.0 % nt and 95.6 % aa sequence identity) to chicken megrivirus, recently detected in chickens with malabsorption syndrome in Hungary. Our results are useful for understanding the genetic diversity of avian picornaviruses and for classifying chicken megrivirus as a pathogen affecting the digestive tract of chickens.

Identification of novel regulatory genes in development of the avian reproductive tracts.

The chicken reproductive system is unique in maintaining its functions including production of eggs or sperm, fertilization of the egg by sperm maintained in sperm nests, production of hormones regulating its growth, development and function, and reproduction. Development of the reproductive organs is a highly regulated process that results in differentiation and proliferation of germ cells in response to predominant regulatory factors such as hormones and transcription factors. However, only a few genes are known to determine morphogenesis of the chicken reproductive tract and their mechanisms are unknown. Therefore, in the present study, we investigated the expression patterns of four genes including SNCA, TOM1L1, TTR and ZEB1 in the gonads at embryonic days 14 and 18, and in immature (12-week-old) and mature (50-week-old) chickens, as well as the reproductive tract including ovary, oviduct and testes of the respective sexes by qRT-PCR, in situ hybridization and immunofluorescence analyses. The expression of SNCA, TOM1L1 and ZEB1 genes was higher in immature and mature female reproductive tracts than expression of TTR. In addition, different temporal and spatial patterns of expression of the four genes were observed during maturation of testis in chickens. Specifically, SNCA, TOM1L1 and TTR were highly expressed in testes of 12-week-old chickens. Moreover, several chicken specific microRNAs (miRs) were demonstrated to affect expression of target gene mRNAs by directly binding to the 3′-UTR of their target genes through actions at the post-transcriptional level as follows: miR-153 and miR-1643 for SNCA; miR-1680* for TTR; and miR-200b and miR-1786 for ZEB1. These results suggest that four-selected genes play an important role in development of the male and female reproductive tract in chickens and expression of most candidate genes is regulated at the post-transcriptional level through specific microRNAs.

Detection of QTL controlling digestive efficiency and anatomy of the digestive tract in chicken fed a wheat-based diet

BackgroundImproving digestive efficiency is a major goal in poultry production, to reduce production costs, make possible the use of alternative feedstuffs and decrease the volume of manure produced. Since measuring digestive efficiency is difficult, identifying molecular markers associated with genes controlling this trait would be a valuable tool for selection. Detection of QTL (quantitative trait loci) was undertaken on 820 meat-type chickens in a F2 cross between D- and D+ lines divergently selected on low or high AMEn (apparent metabolizable energy value of diet corrected to 0 nitrogen balance) measured at three weeks in animals fed a low-quality diet. Birds were measured for 13 traits characterizing digestive efficiency (AMEn, coefficients of digestive utilization of starch, lipids, proteins and dry matter (CDUS, CDUL, CDUP, CDUDM)), anatomy of the digestive tract (relative weights of the proventriculus, gizzard and intestine and proventriculus plus gizzard (RPW, RGW, RIW, RPGW), relative length and density of the intestine (RIL, ID), ratio of proventriculus and gizzard to intestine weight (PG/I); and body weight at 23 days of age. Animals were genotyped for 6000 SNPs (single nucleotide polymorphisms) distributed on 28 autosomes, the Z chromosome and one unassigned linkage group.ResultsNine QTL for digestive efficiency traits, 11 QTL for anatomy-related traits and two QTL for body weight at 23 days of age were detected. On chromosome 20, two significant QTL at the genome level co-localized for CDUS and CDUDM, i.e. two traits that are highly correlated genetically. Moreover, on chromosome 16, chromosome-wide QTL for AMEn, CDUS, CDUDM and CDUP, on chromosomes 23 and 26, chromosome-wide QTL for CDUS, on chromosomes 16 and 26, co-localized QTL for digestive efficiency and the ratio of intestine length to body weight and on chromosome 27 a chromosome-wide QTL for CDUDM were identified.ConclusionsThis study identified several regions of the chicken genome involved in the control of digestive efficiency. Further studies are necessary to identify the underlying genes and to validate these in commercial populations and breeding environments.

Genome Sequences of Campylobacter jejuni 81-176 Variants with Enhanced Fitness Relative to the Parental Strain in the Chicken Gastrointestinal Tract

Campylobacter jejuni is a major cause of food-borne infections in the United States due to its ability to asymptomatically colonize the gastrointestinal tracts of chickens. Using competition assays with parental C. jejuni 81-176, variants with consistently improved fitness in chicken ceca relative to the parental strain were identified and sequenced.

A “successful allele” at Campylobacter jejuni contingency locus Cj0170 regulates motility; “successful alleles” at locus Cj0045 are strongly associated with mouse colonization

Campylobacter jejuni is an important foodborne pathogen of humans and its primary reservoir is the gastrointestinal (GI) tract of chickens. Our previous studies demonstrated that phase variation to specific “successful alleles” at C. jejuni contingency loci Cj0045 (successful alleles carry 9G or 10G homopolymeric tracts) and Cj0170 (successful allele carries a 10G homopolymeric tract) in C. jejuni populations is strongly associated with colonization and enteritis in C57BL/6 IL-10 deficient mice. In the current study, we strengthened the association between locus Cj0170, Cj0045, and mouse colonization. We generated 8 independent strains derived from C. jejuni 11168 strain KanR4 that carried a Cj0170 gene disruption and these were all non motile. Two randomly chosen strains with the Cj0170 gene disruption (DM0170-2 and DM0170-6) were gavaged into mice. DM0170-2 and DM0170-6 failed to colonize mice while the control strain that carried a “successful”Cj0170 10G allele was motile and did colonize mice. In parallel studies, when we inoculated C. jejuni strain 33292 into mice, the “unsuccessful”Cj0045 11G allele experienced phase variation to “successful” 9G and 10G alleles in 2 independent experiments prior to d4 post inoculation in mice while the “successful” 9G allele in the control strain remained stable through d21 post inoculation or shifted to other successful alleles. These data confirm that locus Cj0170 regulates motility in C. jejuni strain KanR4 and is a virulence factor in the mouse model. The data also support a possible role of locus Cj0045 as a virulence factor in strain 33292 in infection of mice.

In vitro and In vivo antimicrobial activity of propolis on the microbiota from gastrointestinal tract of chickens

The aim of this study was to examine the effect of propolis extracts on the microbial colonization of chicken gastrointestinal tract in vivo. The propolis was administered to both feed mixtures in various amounts except of the control group. The addition of 150 mg propolis to 1 kg of feed was included in the first experimental group, the addition of 450 mg.kg−1 in the second experimental group, the addition of 600 mg.kg−1 the third experimental group and 800 mg kg−1 in the fourth one. The highest count of faecal enterococci was found in the third group (8.6 cfu.g−1) where 600 mg of propolis to 1 kg was added to the feed mixture. The highest count of lactobacilli was detected in the fourth experimental group (8.83 cfu.g−1) where was 800 mg of propolis added to 1 kg of feed mixture and number of Enterobacteriaceae genera count was found in control group (8.73 cfu.g−1). With RTQ PCR detected species from the genus Enterococcus were: E. avium, E. casseliflavus, E cecorum, E. faecalis, E. faecium, E. gallinarum, E. hirae and E. malodoratus and from genus Lactobacillus were: Lactobacillus crispatus, L. acidophilus and L. salivarius. With MALDI TOF MS Biotyper from Enterobacteriaceae genera were identified Citrobacter braakii, Raoultella ornithinolytica, Serratia fonticola, Escherichia coli and Klebsiella oxytoca. Antimicrobial activities In vitro of six species of bacteria isolated from gastrointestinal tract of chickens were also tested. The best antimicrobial effect of Citrobacter braakii on ethanolic propolis extract in all concentrations were found.