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[GFP reporter gene under the direction of chicken ovalbumin gene promoter expressed in the CHO cell and in the primary cell cultures of chicken oviduct].

To reseach GFP reporter gene under the control of chick ovalbumin gene regulatory elements express in the CHO cell and in the primary cell cultures of chicken oviduct. 1.5kb fragment and 2.9kb fragment were amplicated by PCR method, two fragments were subeloned to manmalian expression vector pGFP-N2 by recombinant DNA technology, the CMV promoter was cut off from pGFP-N2, so two expression vectors were constructed, one is the P2.9koval-GFP including promoter, first exon, first intron of chicken ovalbumin gene, the other is the P1.5koval-GFP including first intron of chicken ovalbumin gene. Restriction enzyme digestion and DNA sequence analysis revealed that 5'upstream regions of ovalbumin gene were not only identical to those of the published chicken ovalbumin gene, but also were contained in the recombinant vector. They were transfected into the CHO cell and the primary cell cultures of chicken oviduct by Lipofectin, they were used for fluorescence detection. GFP protein existed in GFP transfected the CHO cell and the primary cell cultures of chicken oviduct. It is demonstrated that GFP reporter gene under the direction of chick ovalbumin gene promoter could be expressed in the CHO cell and in the primary cell cultures of chicken oviduct.

Animals↗

Identification of candidate genes at quantitative trait loci on chicken chromosome Z using orthologous comparison of chicken, mouse, and human genomes.

This study was undertaken to identify novel candidate genes at quantitative trait loci (QTL) on chicken chromosome Z (GGAZ) by comparing orthologous regions of chicken, human and mouse genomes. Primer sequences from marker flanking QTL positions (https://acedb.asg.wur.nl/) were obtained from www.iastate.edu/chickmap and blasted against the chicken genome (www.ensembl.org) using BLASTN. The best matches were those with the highest score, lowest E-values and highest percent identity. Orthologous regions in mice and humans, together with genes located on or around those loci were identified using the Ensembl website. Forty-six chicken genes, 91 mouse genes and 60 human genes associated with QTL on GGAZ were identified in the current study. Among the most promising candidate genes for egg production and egg shell quality are annexin A1 (ANXA1), osteoclast stimulating factor (OSF), thrombospondin-4 (THBS4), programmed cell death proteins (PDCD), follistatin (FST), growth hormone receptor (GHR), interferon (IFN) alpha and beta. The chicken IFN alpha and beta were located on GGAZ around position 13,000,000 bp on the draft chicken sequence map. The neuronal nicotinic acetylcholine receptor (nAChR) is located at a QTL region for abdominal fat (GGAZ 25483091 bp). Nicotine is an agonist at the nAChRs and has been shown to decrease lipolysis and triglyceride uptake, thereby reducing net storage in adipose tissue. Therefore, the nAchRs could be used as therapeutic targets for regulating feed intake and obesity. This study has identified 197 putative candidate genes in probable QTL regions of chicken chromosome Z.

Animals↗

Susceptibility to Eimeria tenella of chickens and chicken embryos of partly inbred lines possessing homozygous major histocompatibility complex haplotypes.

Susceptibility to Eimeria tenella infection of chicken embryos and chickens of partly inbred lines possessing different major histocompatibility complex haplotypes was investigated. Chicken embryos of line H-B2 possessing B2 homozygous haplotype showed lower mortality and higher oocyst production than embryos of line H-B15 possessing B15 homozygous haplotype. Embryos of line H-B2 chickens were considered more resistant to E. tenella infection than those of line H-B15. Seven days after 10-day-old chickens were infected with E. tenella, the two lines showed no significant differences in percent bodyweight gain, cecal lesion score, and oocyst production; they differed significantly only in cecal shrinkage. Results suggest that the B system affects chicken embryos and chickens differently in susceptibility to E. tenella infection.

Animals↗

Systemic and local antibody responses to infectious bronchitis virus in chickens inoculated with infectious bursal disease virus and control chickens.

Serum and local (respiratory) antibody responses to infectious bronchitis virus (IBV) were studied in 5-wk-old white leghorn-type control chickens and chickens inoculated with infectious bursal disease virus (IBDV) at 1 day of age. Of the chickens inoculated with IBV alone, 93% had detectable levels of IBV antibodies in the sera and 87% had detectable antibodies in the respiratory lavage fluids. Compared to this group, only 73% and 65% of IBDV-IBV inoculated chickens had serum and respiratory antibodies, respectively. In chickens inoculated with IBV alone, the IBV antibodies were evenly associated with immunoglobulin classes IgM, IgG, and IgA, whereas the IBDV-IBV inoculated chickens mainly produced IgM-associated antibodies with low to negligible levels of IgA- and IgG-associated antibodies. These results suggest that the lack of adequate IgA- and IgG-associated antibody production in IBDV-infected chickens may account for their increased susceptibility to IBV infection.

Animals↗

Chicken anemia virus and infectious bursal disease virus interfere with transcription of chicken IFN-alpha and IFN-gamma mRNA.

Chicken anemia virus (CAV) and infectious bursal disease virus (IBDV) are the two most important viruses that cause immunosuppression in commercial chickens. Because inapparent, subclinical infections by these viruses cause immunosuppression, there is need for assessment of the immune status of chickens. Interference with induction of transcription for chicken interferon-alpha (ChIFN-alpha) and ChIFN-gamma was noted after subclinical infections with either CAV or IBDV. Because the immunosuppressive viruses of chickens may interfere with transcription for ChIFN-alpha and ChIFN-gamma, we propose using this interference to assess the immune status of chickens.

Animals↗

GCRP: Integrated Global Chicken Reference Panel from 11,951 Chicken Genomes.

Chickens are a crucial source of protein for humans and a popular model animal for bird research. Despite the emergence of imputation as a reliable genotyping strategy for large populations, the lack of a high-quality chicken reference panel has hindered progress in chicken genome research. To address this, here we introduce the first phase of the 100K Global Chicken Reference Panel (100K GCRP). Currently, two panels are available: a comprehensive mix panel (CMP) for domestication diversity research and a commercial breed panel (CBP) for breeding broilers specifically. Evaluation of genotype imputation quality showed that CMP had the highest imputation accuracy compared to imputation using existing chicken panels in Animal-SNPAtlas and Animal Genotype Imputation Database (AGIDB), whereas CBP performed stably in the imputation of commercial populations. Additionally, we found that genome-wide association studies using GCRP-imputed data, whether on simulated or real phenotypes, exhibited greater statistical power. In conclusion, our study indicates that the GCRP effectively fills the gap in high-quality reference panels for chickens, providing an effective imputation platform for future genetic and breeding research. The project includes 11,951 samples and provides services for various applications on its website at http://farmrefpanel.com/GCRP/#/.

Animals↗

Humoral immune responses to chicken infectious anemia virus in three strains of chickens in a closed flock.

This is a comparative study on seroconversion to chicken infectious anemia virus (CIAV) in a closed flock of specific-pathogen-free chickens undergoing a natural outbreak and after vaccination of some of these flocks with a commercial, live vaccine. The N2a strain (B21B21 haplotype) had the highest seroconversion after natural infection (94%) or vaccination (100%), followed by the P2a strain (B19B19) at 75%-82% seroconversion after natural infection and 85% seroconversion after vaccination. The S13 (B13B13) chickens were 26% seropositive after natural infection and 75% seropositive after vaccination. N2a chickens with polymerase chain reaction (PCR)-positive tissues were 97% seropositive compared to 80%-83% PCR-positive and seropositive for the P2a chickens and only 8% seropositive and PCR-positive for the S13 chickens. Seroconversion occurred at or near sexual maturity after natural infection in seven flocks studied.

Animal Husbandry↗

Immune capacity of the chicken bursectomized at 60 hours of incubation: transplantation of bone marrow cells of the bursectomized chickens into cyclophosphamide-treated newly hatched recipients.

Chickens bursectomized at 60 h of incubation are known to be able to produce immunoglobulins (Ig) but not specific antibodies. In the present work bone marrow (BM) cells of 2- and 10-week-old embryonically bursectomized (Bx) chickens were transferred to newly hatched cyclophosphamide-treated chickens for the purpose of studying whether the transplanted cells home into the bursa and gain a capacity to produce specific antibodies. BM cells of normal 2- and 10-week-old chickens were transferred as controls. Cells of 2-week-old control (Co) and of 2- and 10-week-old Bx chickens could to some extent reconstitute serum Ig of the recipients, but were totally incapable of homing into the bursa and of restoring the specific antibody production. Only BM cells of 10-week-old Co chickens could restore the production of specific antibodies without homing into the bursa, indicating their postbursal nature. These findings indicate (a) that 2- and 10-week Bx BM cells have irreversibly bypassed the bursal phase of education, (b) that also the normal BM at the age of 2 weeks contains cells that are capable of Ig but not of specific antibody synthesis and (c) that bursal microenvironment is not necessary for isotype switch, but is essential for creation and expansion of the antibody repertoire.

Aging↗

Extraintestinal sporozoites of chicken Eimeria in chickens and turkeys.

Oocysts were found in the feces of chickens (recipients) dosed orally with whole blood, liver, lung, or heart homogenates from chickens and turkeys (donors) inoculated 3 and 4 days previously with a mixture of 3.5 X 10(6) oocysts of chicken Eimeria. No oocysts were found in the feces of recipients given spleen homogenates from these same chickens and turkeys and none were found in the feces of recipients given similar material from uninoculated donors. Intracellular sporazoites were found in the peripheral blood of a turkey inoculated with chicken Eimeria. The results indicate that a small number of sporozoites are capable of invading and surviving for at least 4 days in the peripheral blood of chickens and turkeys.

Animals↗

Antibody production in rabbits and chickens immunized with human IgG. A comparison of titre and avidity development in rabbit serum, chicken serum and egg yolk using three different adjuvants.

The antibody response in rabbits and chickens (serum and egg yolk) immunized with human immunoglobulin G was studied during a 1-year immunisation period comparing the efficacy of three adjuvants: Freund's complete adjuvant (FCA), Freund's incomplete adjuvant (FIA) and Hunter's TiterMax adjuvant (HTM). Monthly boosters of the antigen in saline were administered. Adjuvants were used in the initial immunisation and in a booster at week 26. FCA was found to result in the highest titre in both species. FIA was more efficient than HTM in mediating an antibody response in rabbits. In chickens, FIA resulted in similar antibody titres in serum and egg yolk. The effect of HTM was similar to FIA in chicken serum but lower in egg yolk. The titres obtained in rabbits were approximately a factor 1.5-2.0 higher than in the corresponding chicken groups. However, the antibody productivity of the chicken, when using the egg yolk as the antibody source, was a factor 5-10 higher than that of the rabbit depending on the adjuvant used. FCA and FIA resulted in similar antibody avidity in rabbits whereas HTM had a lesser effect. In chickens FCA initially resulted in the highest antibody avidity in both serum and egg yolk, but after the booster with adjuvant the antibody avidity became similar for all three adjuvants.

Adjuvants, Immunologic↗

A long term observation of antibody status to chicken anaemia virus in individual chickens of breeder flocks.

The antibody status to chicken anaemia virus (CAV) in four layer breeder flocks was evaluated. Sera were periodically collected from the same 17 to 20 individual chickens of each flock ranging in age from 10 to 63 weeks old. The neutralising and fluorescence antibody were detectable in individual chickens during the observation periods ranging from 13 to 44 weeks. A high prevalence of both neutralising and fluorescence antibodies was observed; however, the prevalence of fluorescence antibody in older chickens was lower than that of neutralising antibody. The geometric mean (GM) of neutralising antibody titres, after all the chickens examined had seroconverted in flocks 1, 2 and 4, ranged from 373.2 to 2940.6. In flock 1, the GM titre at 63 weeks old was significantly lower than that at 37 and 52 weeks old. In flock 4, the GM titre at 48 weeks old was significantly lower than that at 24 and 35 weeks old. In flock 2, the GM titre at more than 31 weeks old significantly increased compared with that at 25 weeks old; this tendency was not seen in the GM of the fluorescence antibody titres. The results indicate that immunity to CAV can last a long time in naturally infected individual chickens.

Animals↗

Differential effects of age on chicken heterophil functional activation by recombinant chicken interleukin-2.

Interleukin-2 (IL-2) exercises an array of biological effects on many cells including the functional activation of cells of the innate immune response. Heterophils, the avian equivalent of the neutrophil, function as professional phagocytes to aid in regulation of innate host defenses. The objective of the present studies was to examine the effects of recombinant chicken IL-2 (rChIL-2) on functional activities of heterophils from chickens during the first 3 weeks after hatch. Peripheral blood heterophils were isolated and incubated with either COS cell-derived rChIL-2 or supernatants from mock-transfected COS cells. rChIL-2 had no effect on the functional activities of heterophils from day-of-hatch chickens, but significantly increased the phagocytosis and bactericidal activity of heterophils from 7- and 14-day-old chickens. rChIL-2 induced no direct stimulation of the respiratory burst by heterophils, but primed heterophils from 7- and 14-day-old birds for an enhanced respiratory burst in response to phorbol ester stimulation. Lastly, rChIL-2 had neither direct nor priming effects on heterophil degranulation. The enhancing effects on heterophil functional activity by rChIL-2 were abated by a neutralizing anti-chicken IL-2 mAb and were therefore specific for this cytokine. These results show that rChIL-2 can directly activate chicken heterophils to exert effector functions, and that heterophil activation by rChIL-2 is also an age-dependent event.

Age Factors↗

EA-rosette-forming cells in chickens: presence in spleens of bursectomized chickens and relationships to B-lymphocytes.

Spleen cells from 3-month-old chickens which had been surgically and chemically bursectomized were examined for rosette-forming lymphocytes (RFL). Finding no correlation between the degree of agammaglobulinemia in bursectomized chickens and the percentage of RFL in their spleens demonstrated a dissociation between two B-cell dependent functions, namely, immunoglobulin production and rosette-forming ability. In fact, the percentage of RFL in the spleens of agammaglobulinemic chickens was found to be slightly higher than those of normal chickens. The data indicate that RFL in spleens of normal chickens are B cells, and suggest the existence of a population of rosette-forming B lymphocytes in agammaglobulinemic bursectomized chickens.

Agammaglobulinemia↗

The virulence of salmonella strains for chickens: their excretion by infected chickens.

Inoculated orally, 16 Salmonella typhimurium strains belonging to 12 phage types varied greatly in their ability to kill 1-day-old chickens; variation was noted even between strains of the same phage type. Fourteen strains belonging to 11 food poisoning serotypes other than S. typhimurium were practically non-lethal when examined in this manner. All of them were lethal by the intramuscular route but some were more so than others. Two were more lethal by this route than one of the S. typhimurium strains that was highly lethal when given orally. With age, chickens rapidly became resistant to fatal infection with the food poisoning strains; given orally, a S. typhimurium strain killed 79% of 1-day-old chickens but only 3% of 2-day-old chickens. Of 2 specific poultry pathogenic strains, one, of S. gallinarum, was lethal by oral inoculation to chickens of all ages but the other, of S. pullorum, was only lethal to very young ones. Some salmonella strains, such as those of S. infantis and S. menston, were more efficient at infecting and colonizing the alimentary tract of chickens than were the more virulent S. typhimurium strains, the S. gallinarum and S. pullorum strains and a S. cholerae-suis strain.

Animals↗

Is chicken green-sensitive cone visual pigment a rhodopsin-like pigment? A comparative study of the molecular properties between chicken green and rhodopsin.

Chicken green is a visual pigment present in chicken green-sensitive cones and has an amino acid sequence more similar than any other cone visual pigments to the rod visual pigments, rhodopsins. Here we have investigated the molecular properties of chicken green and compared them with those of rhodopsin to elucidate whether or not chicken green is a rhodopsin-like pigment. While chicken green has a molecular extinction coefficient and a photosensitivity very similar to those of rhodopsin, it displays faster regeneration from 11-cis-retinal and opsin and faster formation and decay of the physiologically active meta II intermediate than rhodopsin. These differences correlate with the physiological difference between cones and rods. Thus in spite of the similarity in amino acid sequence, chicken green displays molecular properties required for a cone visual pigment that are clearly different from those of rhodopsin.

Animals↗

Haemolytic complement activity and humoral immune responses to sheep red blood cells in indigenous chickens and in eight German Dahlem Red chicken lines with different combinations of major genes (dwarf, naked neck and frizzled) of tropical interest.

A total of 376 chickens from different ecotypes were immunized with the non-pathogenic multi-determinant antigen sheep red blood cells (SRBC). The ecotypes included indigenous chickens from various locations in Tanzania (n=102), India (n=86) and Bolivia (n=89). In addition, eight German Dahlem Red (GDR) chicken lines with different major genes (dwarf, naked neck and frizzled) of tropical interest were also immunized with SRBC. Immune competence of the breeds was assessed by measuring complement haemolytic activity, both from the classical calcium-dependent complement pathway (CPW) and alternative calcium-independent complement pathway (APW), alongside IgTotal, IgG and IgM antibody responses to SRBC at 7 days post immunization. Large variations in complement activity and antibody responses to SRBC were observed within and between the indigenous breeds. Many indigenous chickens, especially from Bolivia, showed decreased complement activity (APW) following immunization with SRBC. Breeds from India showed the highest CPW activity and humoral (especially IgM) responses to SRBC, suggesting high immune competence. In contrast, Bolivian chickens were characterized by low CPW activity, low APW activity and low antibody levels to SRBC suggesting an overall low immune competence. In the GDR chickens, characterized by high CPW activity and high IgG antibody responses to SRBC, the major genes for naked neck, frizzling and dwarfism had no significant effect on the antibody responses and complement activity to SRBC.

Animals↗

Effect of complement depletion by cobra venom factor on fowlpox virus infection in chickens and chicken embryos.

The course of infection with an attenuated strain of fowlpox virus (FPV), which is known to induce antibody-independent activation of complement via the alternative pathway, was investigated in 1- to 3-day-old chickens and 14-day-old chicken embryos by treatment with cobra venom factor (CVF). CVF was found to inhibit complement activity transiently via the alternative pathway but not via the classical pathway. In chickens treated with CVF, virus growth in the skin was enhanced, and pock lesions tended to disseminate, leading to fatal infection in some birds. Histologically, an acute inflammation at an early stage of infection (within 3 days) was inhibited, and virus content in the pock lesion was increased. In chicken embryos with immature immune capacities, CVF treatment caused changes in pock morphology from clear pocks to diffuse ones, an increase in virus content in the pock, and inhibition of cell infiltration. Thus, FPV infection was aggravated in both CVF-treated chickens and chicken embryos. These results are discussed in relation to roles of complement in the elimination of virus at an early stage of FPV infection.

Animals↗

Efficiency of various bacterial suspensions derived from cecal floras of conventional chickens in reducing the population level of Salmonella typhimurium in gnotobiotic mice and chicken intestines.

The antagonistic effect exerted towards Salmonella typhimurium by the flora issued from conventional chickens was studied in gnotobiotic animals. In germfree chickens and mice inoculated with S. typhimurium, the highest bacterial counts were observed in ceca, and were not significantly different in either host. The protection afforded by the inoculation of cecal flora issued from a conventional chicken was more effective when this flora was inoculated first into germfree chickens than when it was given only after inoculation with S. typhimurium. Administration of a cecal flora from a 15-day-old chick to gnotobiotic mice and chicken resulted in the inhibition of a further intestinal colonization by S. typhimurium in both hosts. Sixteen strains were isolated among the predominant populations of the fecal flora from chicken flora recipient mice. Association of 14 strains of strictly anaerobic bacteria with 2 strains of Escherichia coli and Streptococcus faecium only decreased the number of S. typhimurium in the ileum of gnotobiotic mice, but not in their cecum. Anaerobe cultures were obtained from 10(-6) and 10(-8) dilutions prepared from the fecal flora of gnotobiotic recipient mice. Antagonistic bacteria were present only in cultures from the 10(-6) dilution. Cecal concentrations of volatile fatty acids were shown not to be the sole factor implicated in the antagonistic effect against S. typhimurium.

Animals↗