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PubMed1988

Developmental expression in embryonic rat and chicken brain of a polysialoganglioside-antigen reacting with the monoclonal antibody Q 211.

The monoclonal mouse antibody Q 211 binds to an antigen, which is expressed by postmitotic growing neurons of embryonic chicken and rat brain. In chicken, thin layer chromatography (TLC) immunostaining confirms the presence of the Q 211 antigen in at least 3 different polysialoganglioside fractions. One comigrates on TLC plates with GP1c and the others with gangliosides, which have been previously preliminary characterized as GQ1c, and as a hexasialoganglioside. Thus, 3 sialic acid residues linked to the inner galactose of a complete tetraose moiety is suggested as the common epitope of the different Q 211-antigen-active gangliosides. Also in the embryonic rat brain, immunohistochemistry reveals a transient expression of the Q 211 antigen in areas containing growing nerve fibres. Unlike chicken, however, in the rat the staining is restricted to early thalamocortical innervations and to a fibre system (probably long distance projections) connecting the mamillary body with the hippocampus formation. In ganglioside extracts from rat forebrain 2 polysialogangliosides are shown by immuno-TLC to bind Q 211. One of these fractions, occurring transiently and in parallel with histochemical staining, comigrates on TLC plates with chicken GP1c. The other comigrates with the second main Q 211 antigen-containing band of chicken, which was preliminary identified as GQ1c.

Animals↗
PubMed2004

Effect of duration of cold stress on plasma adrenal and thyroid hormone levels and immune responses in chicken lines divergently selected for antibody responses.

There is increasing evidence that stress affects various immune processes. Some of these changes are due to hormonal changes involving corticosterone (CORT), triiodothyronine (T3), and thyroxine (T4). Effects of stress depend on the nature of specific stressors (e.g., thermal extremes, diet, pollutants), and stress-modifiers (e.g., genetic make-up, duration and severity of the stressors). We studied the effects of a specific stress (cold stress) with stress-modifiers (duration of stress and genotype of the bird) on immune responses and plasma adrenal and thyroid hormone levels in 3 layer-type chicken lines. Two lines were divergently selected for high (H line) or low (L line) antibody responses to SRBC, and the third line was a randombred control (C) line. Growing chicks (3- to 4-wk-old) of the 3 lines were feed-restricted at 80% of ad libitum consumption, and subjected to cold stress (CS) at 10 degrees C continuously for 7, 5, 3, 1, or 0 d before immunization with keyhole limpet hemocyanin (KLH). Specific antibody titers to KLH, and in vitro lymphocyte proliferation (LP) upon mitogen stimulation were measured. In addition, adrenal and thyroid hormone levels were measured in the plasma samples collected at the end of CS. No significant effect of duration of CS on specific antibody titers was found in the 3 lines. A significant enhancing effect of CS was found on LP. A significant dose-dependent suppressive effect of CS was found on plasma CORT levels. One day of CS had a significant enhancing effect on T3 levels. There was no significant effect of duration of CS on T4 levels. We conclude that CS does not affect specific antibody responses, but may have a modulating effect on cellular immunity and plasma CORT levels, depending on the duration of the stress. The present study suggests an inverse relationship between LP and CORT. This is the first study that reveals an absence of significant differences in adrenal and thyroid hormone levels in the described selection lines.

Animals↗
PubMed2000

The magnetic field effect affecting on the metallic chemical components of egg shell as demonstrated for breeding chicken.

The chickens were raised under fixation of the permanent magnet (80 mT) and the effect of extra magnetic field, which affects on the content of the several inorganic chemical elements of egg shell, was investigated by X-ray fluorescence spectroscopy. From 3 days after fixing the magnet, the relative concentration of Ca begun to increase. After 10 days, the relative contents of Ca were decreased, while conversely the contents of K were increased. Though there was a linear relationship between Ca content and P content in inner layer of chicken egg shell, the relationship was greatly hindered by applying the static magnetic field. The experimental result suggests that both Ca and K ion transport can be perturbed by addition of extra magnetic field in the incubation processes of chicken egg, and that Ca, P and K ions play the important role in egg shell formation.

Journal Article↗
PubMed1997

National surveillance of poultry diseases in Lebanon.

From 1992 to mid-1996, a national survey of poultry diseases in Lebanon was conducted. This surveillance included meat breeder, layer breeder, commercial layer and chicken broiler flocks. The history, signs, lesions and laboratory tests of poultry were used in the diagnosis of prevalent poultry diseases. Culture techniques were used to screen for bacterial diseases; serological techniques and, to a lesser extent, culture techniques were used to diagnose viral diseases; and both serological and culture techniques were used to diagnose Mycoplasma infections. The outbreaks of diseases detected in broiler breeder flocks and the number of such flocks experiencing these diseases were as follows: femoral head necrosis (6), egg-drop syndrome (3), reovirus-associated malabsorption syndrome (3), synovitis (Mycoplasma synoviae infection) (7), swollen head syndrome (SHS) (3), tenosynovitis (viral arthritis) (1), lymphoid leukosis (3), avian encephalomyelitis (1), fowl pox (1) and aortic rupture (1). The disease outbreaks detected in layer breeders were as follows: SHS (2), bumble foot (2), egg-drop syndrome (3) and avian infectious bronchitis (IB) (1). The disease outbreaks detected in commercial layer flocks were as follows: egg-drop syndrome (5), avian infectious laryngotracheitis (2), avian IB (nephrogenic strain) (1), malabsorption (1), avian tuberculosis (Mycobacterium avium) (1), Marek's disease (1), fowl pox (1), Salmonella enterica subsp. enterica Enteritidis infection (1), salpingitis (1) and Heterakis gallinae infestation (1). The disease outbreaks detected in broiler flocks were as follows: colibacillosis (40), infectious bursal disease (Gumboro disease) (15), malabsorption syndrome (8), avian infectious laryngotracheitis (8), paratyphoids (salmonellosis) (7), femoral head necrosis (8), SHS (6), avian mycoplasmosis (Mycoplasma gallisepticum infection) (6), synovitis (7), avian IB (6), botulism (1), avian encephalomyelitis (1) and gangrenous dermatitis (1). Diseases which occurred and which were reported for the first time in Lebanon were as follows: bumble foot, femoral head necrosis, avian IB (nephrogenic strain), malabsorption syndrome and SHS. This surveillance helped to establish baseline data concerning the predominant poultry diseases in Lebanon. Such information is a prerequisite for future regional and international collaboration to identify the source of the aetiological agents and to control their spread to neighbouring countries.

Adenoviridae Infections↗
PubMed1996

Cryopreservation of rooster sperm using methyl cellulose.

Experiments were designed to determine when, during the cryopreservation process, sperm lose fertilizing capacity and whether the cryoprotectant, methyl cellulose (MC), could be used in combination with glycerol to cryopreserve sperm and remain in the inseminate without reducing fertility. Semen diluted in Minnesota Avian extender (MNA) and inseminated immediately had greater fertility (75%) than semen processed for cryopreservation (12 to 60%). The largest decreases in fertility were due to addition of glycerol to sperm and to cryopreservation. In another experiment, fertility of inseminates containing 0, 1, and 2% glycerol were 82, 29, and 21%, respectively, for eggs collected 2 to 5 d after insemination. When 0.5% MC was added to the same three treatments, fertility rates were 88, 63, and 69%, respectively. Semen cryopreserved in MNA containing 9% glycerol; MC + 3% glycerol; MC + 4% glycerol; MC + 9% glycerol; or 9% glycerol with the cryoprotectant removed post-thaw by dilution and subsequent centrifugation exhibited 59, 30, 35, 60, and 69% viable cells, respectively; and 65, 38, 46, 69, and 65% motile sperm, respectively. Sperm cryopreserved with MC and either 4 or 9% glycerol exhibited similar numbers of sperm binding to chicken perivitelline layers in vitro as did fresh sperm, whereas sperm frozen with MC and 3% glycerol bound oocytes with only 31% efficiency (P < 0.05). The extent to which cryopreserved sperm penetrated the perivitelline layer in vitro was independent of glycerol concentration, but was four times more efficient than that of fresh sperm (P < 0.05). The fertility rates of fresh semen, semen frozen in 9% glycerol with the cryoprotectant removed after thawing, and semen frozen in MC with either 3 or 4% glycerol were 87.4, 27.6, 0.8, and 0.5%, respectively (P < 0.05). The MC reduces the contraceptive effects of glycerol when inseminated with fresh sperm, but does not maintain fertilizing capacity in frozen-thawed sperm when used in combination with 3 or 4% glycerol.

Animals↗
PubMed1998

Comparison of skeletal muscle characteristics in chicken bred for meat or egg production. I. Histopathological and electron microscopic examination.

A comparative histopathological and electron microscopic study based on selected skeletal muscle in layer-type and meat-type chickens was carried out to detect possible effects of selection for rapid growth and increased muscularity on muscle health. Disseminated fibre degeneration and other myopathological changes occurred more frequently in muscles of meat-type chickens than in layer-type chickens of the same age. The breast region of meat-type chickens--highly developed as a breeding aim--was particularly affected. Experimental exertion demonstrated the limited adaptability of skeletal muscle to psychomotor stress in meat-type chickens. Meat-type chickens showed a higher increase of histopathological muscular lesions after repeated wing exercise than layer-type chickens. Ultrastructural lesions caused by experimental exertion were classified as adaptive-reversible in layer-type chickens. As opposed to this, irreversible destruction of myofibrillar architecture in meat-type chickens are an indication for muscle ischaemia after exertion. Significant changes of structural, metabolic and functional parameters of skeletal muscle related to breeding aims in meat type chickens contribute to finding an explanation for their increased susceptibility to pathological reactions.

Animals↗
PubMed1975

Cytological differentiation in the uropygial gland.

Ultrastructural changes were studied in the cells undergoing secretory differentiation in zone I of the tubules of the uropygial gland of White Plymouth Rock chickens. A layer of basal cells and four secretory stages are recognized as the cells migrate from the periphery to the lumen of tubules and progressively elaborate a secretion product. Basal cells, containing rough endoplasmic reticulum and free ribosomes, rest on the basement membrane and are the source from which secretory cells arise. Dilated perinuclear cisternae and the proliferation of smooth endoplasmic reticulum in the form of vesicles, invaginated sacs and cusp-shaped cisternae indicate the onset of lipgenesis in stage I cells. The perinuclear cisternae are more dilated and the endoplasmic reticulum is composed on saccules and cisternae in stage II cells. Stage III cells are characterized by concentric lamellae of endoplasmic reticulum surrounding secretory droplets. Dilated cisternae of endoplasmic reticulum and secretory droplets both contain a reticular substance. The perinuclear cisternae of stage III cells have returned to normal dimensions. Large mature lucent secretory droplets, lined with electron-dense material, fill the cytoplasm ostage IV cells which degenerate and release their secretory product into the tubule lumen. Spherical membrane-bound compartments containing a mottled substance of moderate electron density occur in basal cells and all subsequent secretory stages. These mottled bodies are surrounded by saccules of endoplasmic reticulum in stage II cells and are intimately associated with secretory droplets in stage III cells, but there is no evidence that they give rise to secretory droplets and their role in secretory differentiation is unknown.

Animals↗
PubMed2004

Quantification of bioaerosols in automated chicken egg production plants.

The quantity and composition of bioaerosols in a typical automated chicken egg layer management system (LMS) with a controlled internal climate (B) and without (A) were compared. The LMS-A used a fecal matter disposal system featuring a central opening in the floor through which the matter automatically dropped to an open-air lower level; the LMS-B used a conveyer belt below each hen battery set, which removed the fecal matter frequently. Bioaerosols were collected by impaction on agar. Humidity, wind velocity, temperature, and dust particle concentration were also analyzed at several locations in the LMS. The average bioaerosol concentrations (total viable aerobic bacteria) associated with the inside of LMS-A reached X = 1.1 x 10(5) cfu/m3 with counts in LMS-B being X = 9.2 x 10(4) cfu/m3. In both systems, the bacterial counts were significantly higher on the inside of the LMS than the outside. The LMS-A showed yeast counts of X = 6.7 x 10(1) cfu/m3 with none detectable in LMS-B. Total culturable mold counts were X = 7.0 x 10(2) cfu/m3, with significantly higher presumptive Salmonella spp. counts (X = 6.6 x 10(1) cfu/m3) inside both LMS when compared with the outside. Escherichia coli and total culturable gram-negative counts were significantly higher in LMS-B at concentrations of X = 3.6 x 10(1) cfu/m3. These counts were significantly higher compared with the outside environment. We concluded that the live birds were the major source of bioaerosols in both LMS, with the fecal matter disposal systems attributing to the difference in bioaerosol composition. Modifications to the operation protocols of both LMS to limit the contamination of eggs by bioaerosols are suggested.

Agriculture↗
PubMed2003

Genetic relationships among avian isolates classified as Pasteurella haemolytica, 'Actinobacillus salpingitidis' or Pasteurella anatis with proposal of Gallibacterium anatis gen. nov., comb. nov. and description of additional genomospecies within Gallibacterium gen. nov.

Bacteria of the avian [Pasteurella haemolytica]-'Actinobacillus salpingitidis' complex have been associated with different pathological conditions in birds, among which salpingitis and peritonitis in chickens of layer type seem to dominate. The aim of this study was to classify these bacteria by comparison of 37 strains tentatively classified as biovars of the avian [P. haemolytica]-'A. salpingitidis' complex or as Pasteurella anatis. PFGE, AFLP and plasmid profiling showed that strains representing different biovars were genotypically different. Phylogenetic analysis of 22 strains characterized by 16S rRNA gene sequence comparison showed that strains classified as biovars 5, 8 and 9 were closely related to the suggested type strain of 'A. salpingitidis' (98.4-99.9% similarity), whereas the remaining strains classified in 12 biovars or as P. anatis were closely related to the type strain of P. anatis (98.1-100% similarity). The two groups were related at 95.7-97.1% similarity. The closest similarity outside this group was 94.6%, between biovar 15 and Bisgaard taxon 3. DNA-DNA hybridization was performed with 34 strains and showed binding above 85% for strains of biovars 5 and 8, including the suggested type strain of 'A. salpingitidis'. Two strains of P. anatis (F 149T and F 279) were closely related at 79% DNA binding to 27 strains of biovars 1,3, 4, 11, 12, 17-20, 22 and 24. A new genus, Gallibacterium gen. nov., is proposed to include the avian [P. haemolytica]-'A. salpingitidis'-P. anatis complex, since these taxa form a monophyletic unit with similarities above 95% on the basis of 16S rRNA sequence comparison and they are unrelated to other genera of the family Pasteurellaceae Pohl 1981. The new genus consists of Gram-negative, non-motile, rod-shaped or pleomorphic bacteria. The bacteria are catalase-, oxidase- and phosphatase-positive. Nitrate is reduced and acid is produced without gas formation from glycerol, (-)D-ribose, (+)D-xylose, (-)D-mannitol, (-)D-fructose, (+)D-galactose, (+)D-glucose, (+)D-mannose, sucrose and raffinose. The genus Gallibacterium can be separated from other genera of Pasteurellaceae by differences in catalass, symbiotic growth, haemolysis, urease, indole, acid production from (+)D-xylose, (-)D-mannitol, (-)D-sorbitol, (+)D-mannose, maltose, raffinose and dextrin and ONPG and PNPG tests. Pasteurella anatis Mutters et al. 1985 is transferred to the new genus as Gallibacterium anatis gen. nov., comb. nov. Genomospecies 1 of Gallibacterium is proposed to include the former biovars 5 and 8 of the avian [P. haemolytica]-'A. salpingitidis' complex. The type strain of Gallibacterium anatis is F 149T (=ATCC 43329T = NCTC 11413T) and the reference strain of Gallibacterium genomospecies 1 is CCM 5974.

Actinobacillus↗
PubMed1996

Genetic markers linked to quantitative traits in poultry.

This study utilized DNA fingerprints and crosses of two genetically distinct lines of layer-type chickens to identify genetic markers linked to quantitative trait loci (QTL). In phase I, backcross (BC1) hens were separately ranked for each of eight traits and then blood pools were produced in groups along each phenotypic distribution. The DNA was isolated from the blood pools and used in a gradient analysis to screen for DNA fingerprint bands that exhibited intensity gradients associated with the phenotypic traits. To identify linkage of bands with QTL and to estimate band effects, F2 progeny were produced in phase II from the phase I BC1 population. A single-trait animal model was used for analysis of associations of all individual DNA fingerprint bands of sires and their progeny phenotypic performance. Twenty fingerprint bands, only two of which had shown trait-associated gradients in phase I, were identified by the animal model analysis of the progeny test as QTL linked (P < or = 0.05) to specific traits of growth, reproduction and egg quality. These 20 bands warrant further study as potentially valuable molecular markers for QTL.

Animals↗
PubMed2004

NOISE 2 imaging system: seeing through scattering tissue with a reference point.

We propose a fly-eye-like imaging system for seeing objects embedded in scattering media. Objects are recovered from many speckled images observed by a digital camera through a microlens array. Each microlens in the array generates a speckle image of the object buried between two layers of chicken breast tissue. In the computer each image is Fourier transformed jointly with an image of the speckled pointlike source captured under the same conditions. A set of the squared magnitudes of the Fourier-transformed pictures is accumulated to form a single average picture. This final picture is again Fourier transformed, resulting in the reconstruction of the hidden object.

Animals↗
PubMedDate not supplied

Safety and efficacy of the avirulent Mycoplasma gallisepticum strain K5054 as a live vaccine in poultry.

A Mycoplasma gallisepticum (MG) isolate from an atypically mild outbreak in turkey breeders was found to be similar to house finch isolates by DNA analyses. A preliminary study in turkeys showed that this isolate (K5054) caused very mild lesions and protected turkeys against subsequent challenge with a virulent MG strain. In this study, K5054 was further evaluated as a potential vaccine strain in commercial layer-type chickens and turkeys. The safety of K5054 was evaluated by aerosol challenge followed by evaluation of gross and histopathologic lesions as well as serologic reactions and isolation of MG from the trachea and air sacs. Infection of chickens (trial 1) and turkeys (trial 2) with K5054 resulted in little evidence of MG lesions. There was weak seroconversion, and K5054 was consistently reisolated from the tracheas of chickens and turkeys. The efficacy of K5054 as a vaccine was evaluated by aerosol challenge of vaccinated chickens (trial 3) and turkeys (trial 4) with virulent R strain. There was evidence of protection from lesions associated with MG.

Animals↗
PubMed2006

Microbiological and chemical properties of litter from different chicken types and production systems.

Chicken litter is produced in large quantities from all types of poultry raising activities. It is primarily used for land application, thus it is essential to analyze its properties before it is released to the environment. The objective of this study is to compare the microbiological and chemical properties of litter generated from layer and broiler chickens reared under intensive and free-range production systems. The microbiological analysis consisted of the enumeration of total bacteria, total coliforms, Staphylococcus species, Salmonella species and Clostridium perfringens. Chicken litter from layers reared under intensive and free range systems showed lower mean total bacterial count than the litter collected from chicken broilers reared under either of the two systems (P=0.0291). The litter from intensive layers had the lowest mean total coliform counts (P=0.0222) while the lowest Staphylococcus species count was observed in the litter from free-range layers (P=0.0077). The C. perfringens count was the lowest in chicken litter from intensively raised broilers and layers (P=0.0001). The chemical properties of litter from the different chicken types and production systems were compared based on determination of pH, electrical conductivity, carbon, nitrogen, phosphorus, potassium, cadmium and zinc. Litter from free-range broilers showed the highest pH value (P=0.0005); however, the electrical conductivity was higher in the litter from both intensive and free-range layers compared to the litter from both broiler production systems (P=0.0117). Chicken litter from intensive systems had higher nitrogen content than litter from free-range systems (P=0.0000). The total phosphorus was the lowest in free-range broiler litter (P=0.0001), while the total potassium was the lowest in litter from intensively managed broilers (P=0.0000). Zinc appeared higher in litter from layers compared to that from broilers (P=0.0101). The cadmium content was higher in the litter from free-range broilers and layers compared to that in the litter from intensively managed systems (P=0.0439). Staphylococcus species in the litter as well as cadmium concentrations seem to be the most critical parameters presenting risks on the environment and on human health. Based on the lowest coliform counts (an indication of water pollution), the high nutrient levels and the low cadmium values, litter from intensively managed layers appears as the most suitable for application on agricultural soils.

Animal Husbandry↗
PubMed2000

Expression of neurotrophin-3 (NT-3) and anterograde axonal transport of endogenous NT-3 by retinal ganglion cells in chick embryos.

Anterograde axonal transport of neurotrophins has been demonstrated recently, but to date such transport has only been shown for brain-derived neurotrophic factor and no other endogenous neurotrophin. Endogenous neurotrophin-3 (NT-3) protein is present in the ganglion cell layer of the chicken retina, as well as the superficial layers of the optic tectum. NT-3 immunolabel in these tectal layers is largely reduced or abolished after treatment of the eye with colchicine or monensin, demonstrating that endogenous NT-3 is transported to the optic tectum by retinal ganglion cells (RGCs). Reverse transcription-PCR analysis of RGCs purified to 100% shows that RGCs, but not tectal cells, express NT-3 mRNA. Blockade of the intercellular transfer of NT-3 within the retina does not reduce the anterograde transport of endogenous NT-3 to the tectum, indicating that a major fraction of the anterogradely transported NT-3 is produced by RGCs rather than taken up from other retinal cells. Immunolabel for the neurotrophin receptor p75, but not trkB or trkC, in the superficial tectum coincides with the NT-3 label. The p75 label in the neuropil of superficial tectal layers is largely reduced or eliminated by injection of monensin in the eye, indicating that p75 protein is exported along RGC axons to the retinotectal terminals and may act as a neurotrophin carrier. These results show that NT-3 is produced by RGCs and that some of this NT-3 is transported anterogradely along the axons to the superficial layers of the tectum, possibly to regulate the survival, synapse formation, or dendritic growth of tectal neurons.

Animals↗
PubMed1999

Ubiquitin gene expression and ubiquitin conjugation in chicken muscle do not reflect differences in growth rate between broiler and layer birds.

Previous work has shown that chicken strains selected for growth (broilers) degrade muscle proteins less rapidly than those selected for egg laying. They also have decreased calpain and increased calpastatin content in breast muscle. This study aimed to test the hypothesis that these differences correlate with changes in the ATP- and ubiquitin-dependent proteolytic system. Chickens of a broiler strain (Ross 1) and a layer strain (ISABrown) were reared to the age of 4 wk under identical conditions with ad libitum access to feed and water. Mean fractional growth rates were 10.4%/d for broilers and 7.4%/d for layers. Feed intake measured in the last week of the trial was slightly greater in layer birds (.11 and .12 g x g body weight(-1) x d(-1) for broilers and layers respectively; P < .006). Polyubiquitin (UbI) messenger RNA was abundant in the muscles of these well-fed birds, but it showed little difference between strains. Muscle did not significantly express the UbII polyubiquitin gene. The ATP-dependent system conjugating ubiquitin to endogenous proteins had greatest activity in the gastrocnemius muscle of broiler birds but was not significantly different between breeds. Proteins cross-reactive with antisera to recombinant human proteasome regulatory subunits MSS1 (multicopy suppressor of SUG 1; S7) and TBP1 (tat binding protein 1; S6') were present in muscle homogenates from both strains of bird. The chick equivalent of TBP1 was more abundant in breast muscle of broiler birds than in leg muscle, or in either muscle of layers. Antiserum to recombinant yeast subunit mts2 (mitosis temperature sensitive gene 2; S4) did not react with any protein of the expected size but detected a 30-kDa peptide that was not associated with the 26S proteasome; this was found only in muscle from the layer strain. Hence, during normal growth of chickens, rates of protein degradation are not controlled by the expression of ubiquitin mRNA or the conjugation of ubiquitin. However, the composition of the 26S proteasome may be a regulatory factor.

ATPases Associated with Diverse Cellular Activitie↗
PubMed2002

Expressed sequence tags for the chicken genome from a normalized 10-day-old white leghorn whole-embryo cDNA library. 3. DNA sequence analysis of genetic variation in commercial chicken populations.

Single nucleotide polymorphisms (SNPs) have emerged as a major class of DNA markers with the advantage of permitting the development of high-density genetic maps adequate for quantitative trait loci (QTL) identification by linkage-disequilibrium analysis. Here we describe results of a relatively high-depth survey of chicken broiler and layer populations for SNPs in targeted genomic regions of chicken expressed sequence tag (EST) sites. The sequences scanned, representing the composite sequence of 12 amplified fragments for a total of 6489 bp, were randomly distributed, occurring on six different chromosomes or linkage groups in the chicken genome. Although one of the genomic DNA sequences did not match the reference cDNA sequence, another contained an intron that separated two putative exons. The number of SNPs observed within each of the 12 EST-targeted genomic regions ranged from 0 to 10 for a total of 44 and a frequency of 0.7%. About 70% of the polymorphisms were shared between layer and broiler populations. The average heterozygosity within the populations ranged from 0.15 to 0.48, with the layer populations showing the higher heterozygosity. SNPs and oligonucleotides described will provide a resource for genetic analysis in commercial chicken populations. The data appear to indicate that the relative frequency of SNPs in the targeted regions scanned is higher than the frequency reported for any of the other regions scanned to date in other eukaryotic genomes. Additionally, the results suggest that the use of DNA pools may offer an efficient approach to SNP detection in chickens, as has been shown in other vertebrates.

Animals↗
PubMed1993

Increase in ovarian alpha-inhibin gene expression and plasma immunoreactive inhibin level is correlated with a decrease in ovulation rate in the domestic hen.

This study was designed to examine the relationship among ovulation rate, inhibin alpha-subunit gene expression, and plasma immunoreactive inhibin levels between hens laying at a high ovulation rate and hens laying at a low ovulation rate. A porcine inhibin alpha-subunit cDNA was used to examine the expression of inhibin alpha-subunit in the granulosa cell layers of preovulatory chicken follicles. Total RNA was extracted from granulosa layers of hens laying at a high and low rate and used in slot blot analyses. A dose-related increase in signal intensity with increasing doses of RNA for hens laying at a high and low rate was observed. The expression of the alpha-subunit of inhibin (per microgram of RNA) in granulosa layers of hens laying at a low rate was found to be greater than that in hens laying at a high rate (P < 0.001). Different groups of hens laying at the same rates as those used in the RNA determinations were selected for determination of plasma inhibin levels. Plasma samples from those hens laying at a high and low rate were collected from 1000 to 1800 hr at 2-hr intervals. Plasma inhibin, luteinizing hormone (LH), and follicle stimulating hormone (FSH) were determined by RIA. Plasma inhibin level was higher in hens laying at a low rate than that in those laying at a high rate (P < 0.05), while plasma LH level in hens laying at a low rate was lower than that in hens with a high ovulation rate (P < 0.01). There was no difference in plasma FSH level associated with rate of lay. Results in this study suggest that the ovulation rate-related changes in inhibin alpha-subunit gene expression and plasma immunoreactive inhibin level do not directly affect ovulation rate through a modulation of plasma FSH level.

Animals↗