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PubMed1997

Characterization and application of an avian in vitro spermatozoa-egg interaction assay using the inner perivitelline layer from laid chicken eggs.

The inner perivitelline layer, separated from laid chicken eggs, was investigated as readily available material for studying the spermatozoa-egg interaction in vitro. This layer was found to have a similar response to hydrolysis by spermatozoa as the inner perivitelline layer from ovulated and follicular ova, in terms of the numbers of points of hydrolysis made by spermatozoa during a 5 min incubation at 40 degrees C. Initiation of hydrolysis of the inner perivitelline layer was found to occur within 2.5 min, after which the size, but not the number of holes, increased with time. The frequency of the points of hydrolysis per unit area of the inner perivitelline layer was positively correlated with the concentration of spermatozoa in the incubation medium. The perivitelline hydrolysis assay was able to detect more damaged spermatozoa in samples that had been either stored at 5 degrees C or cryopreserved in liquid N2 than did other tests of sperm quality, which are known to overestimate the fertilizing ability of stored avian semen.

Animals↗
PubMed1993

Comparison of the rates of proliferation of adipocyte precursor cells derived from two lines of chicken which differ in their rates of adipose tissue development.

1. Putative adipocyte precursor cells were isolated from the white adipose tissue of young broiler and layer chickens and cultured in vitro. 2. The cells from both sources were shown to have the characteristics of adipocyte precursor cells. On reaching confluence, lipoprotein lipase activity was induced and the cells from both strains accumulated large amounts of lipid in the presence of chicken serum. 3. Measurement of cell number over time in culture and calculation of cell doubling times showed that cells from broilers proliferated at a faster rate than those derived from layer-strain chickens. This was the case whether primary or secondary cell cultures were used. Primary cultures of broiler cells had a doubling time of 22 h versus 39 h for layer cells. 4. The contribution of such a difference in proliferative rate to the differential rate of adipose tissue growth between broiler and layer strains observed in vivo is discussed.

Adipose Tissue↗
PubMedDate not supplied

Variant serotypes of infectious bronchitis virus isolated from commercial layer and broiler chickens.

Twenty infectious bronchitis virus (IBV) field isolates obtained from commercial layer and broiler chickens in 1987 and 1988 were serotyped using the virus-neutralization (VN) test. Six different previously unrecognized variant serotypes were identified from a total of seven isolates from layer chickens. Only two isolates, both from Maine, were the same variant serotype. Variant serotypes also were recovered from layer flocks in Illinois and Washington and the province of Ontario, Canada. Two different variants were isolated from the same multi-age layer complex in Connecticut. Only one of 13 broiler chicken isolates was found to be a new variant serotype, that being from birds reared in Delaware. Cross-protection studies in specific-pathogen-free chickens indicated that vaccines containing the Holland, L-1, or Connaught strains of Massachusetts (Mass) combined with Arkansas produced a broader spectrum of immunity against challenge with the layer variants than Mass (Holland) alone or Mass (L-1) + Connecticut. All vaccines tested produced solid immunity (greater than or equal to 80% protection) against the broiler variant virus.

Animals↗
PubMed1979

Pathological changes of experimental polychlorinated biphenyl poisoning in chickens.

Two experiments were carried out to study pathological changes of polychlorinated biphenyl (PCB) "KC 400" poisoning. In them chickens were administered with this agent for a relatively short time. Eleven experimental diets were prepared to contain 11 different PCB concentrations, 4,800 ppm being the highest, respectively. They were given to broiler chickens in initial feeding and later. All the chickens fed 300 ppm and higher concentrations of PCB died, showing the serious dilatation of uriniferous tubules and involution of the bursa of Fabricius, by the time when they reached 12 days of age. All the chickens, except a very few, fed 100 ppm remained alive at the end of the experimental period, when they were 41 days of age and exhibited such edematous changes as hydropericardium. Few chickens fed 50 ppm and less manifested pathological changes until the end of the experimental period, when they were 22 days of age. Two experimental diets were prepared to contain 600 and 200 ppm of PCB, respectively. They were given to layer chickens in initial feeding and later. These layers were sacrificed for autopsy every fourth day. A gain in body weight was retarded mostly in those fed 600 ppm. Dilatation of uriniferous tubules and involution of the bursa of Fabricius began in the very early stage of experimental feeding in both groups. Hydropericardium occurred to many of the chickens fed 200 ppm in the late stage of the experimental period. The results of both experiments indicated that there was no essential difference in changes of PCB poisoning between broiler and layer chickens. The principal changes of the poisoning were dilatation of uriniferous tubules, involution of the bursa of Fabricius, and edematous alterations. They appeared in a relatively early stage of the experimental period of PCB feeding. Their severity was strongly dependent upon the concentration of PCB contained in the diet.

Animals↗
PubMed1987

Contribution of whole-body protein synthesis to basal metabolism in layer and broiler chickens.

The effect of starvation on whole-body protein synthesis and on the contribution of protein synthesis to basal metabolic rate was investigated in young chickens (Expt 1). Strain differences between layer and broiler chickens in whole-body protein synthesis and degradation rates were examined when the birds were starved (Expt 2). In Expt 1, 15-d-old White Leghorn male chickens were used, while in Expt 2 Hubbard (broiler) and White Leghorn (layer) male chickens at 14 d of age were used. They were starved for 4 d, and heat production was determined by carcass analysis after 2 and 4 d of starvation. Whole-body protein synthesis rates were measured on 0, 2 and 4 d of starvation (Expt 1), and on 0 and 4 d of starvation (Expt 2). The results showed that starving reduced whole-body protein synthesis in terms of fractional synthesis rate and the amount synthesized. Whole-body protein degradation was increased by starvation both in terms of fractional synthesis rate and the amount degraded on a per kg body-weight basis. Reduced fractional synthesis rate of protein in the whole body was accounted for by reductions in both protein synthesis per unit RNA and RNA:protein ratio. In the fed state, whole-body protein synthesis and degradation rates, whether expressed as fractional rates or amounts per unit body-weight, tended to be higher in layer than in broiler chickens. In the starved state, the difference in the rate of protein synthesis between the two strains virtually disappeared, while the degradation rates were higher in layer than in broiler birds.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Nutritional Physiological Phenomena↗
PubMed1989

Growth, food intake and energy balance of layer and broiler chickens offered glucose in the drinking water and the effect of dietary protein content.

1. Four experiments were carried out to study the effect of offering a 91.5 g/l solution of glucose, compared to tap water, on fluid intake, food intake and growth of individually-caged immature chickens of both layer and broiler strains. 2. Male chicks of an egg-laying strain were offered glucose solution or tap water from 27 to 62 d after hatching. There was no effect of glucose on fluid intake but it depressed food intake (P less than 0.01) to give equal total energy intakes for each treatment. Body weight gain was reduced (P less than 0.001) and carcase fat content increased (P less than 0.001) by the glucose to yield no difference to total carcase energy. 3. When birds were placed in a respiration chamber for two 23-h periods there was no effect of treatment on outputs of energy as faeces + urine or as heat. 4. Male broilers were offered glucose solution or tap water with diets containing either 150 or 195 g protein/kg from 20 to 55 d after hatching. With the low-protein diet glucose depressed food intake (P less than 0.01) but total energy intake and carcase energy were not significantly affected. With the high-protein diet glucose did not depress food intake but increased total energy intake and total body fat. 5. Layer and broiler chicks were offered either a choice of the low- and high-protein diets or a single diet intermediate in protein content, with glucose solution or tap water. With broilers total food intake was depressed by glucose, mainly by a reduced intake of the low-protein diet. Intake of neither diet by the layer chicks was significantly affected by glucose. 6. It is concluded that provision of extra energy in glucose solution depresses food intake when the resultant energy:protein ratio becomes limiting. With a higher protein diet, or with birds having lower protein requirements, glucose solution does not depress food intake and increased fat deposition occurs.

Animals↗
PubMed2001

Identical amyloid precursor proteins in two breeds of chickens which differ in susceptibility to develop amyloid arthropathy.

Chickens (Gallus gallus domesticus) can suffer from AA amyloidosis featuring the joints as major targets of amyloid accumulation. Analysis of post-mortem recordings from commercial chickens revealed that amyloid arthropathy frequently occurred in brown layer chickens, but never in white layers. The suspected higher susceptibility of brown layers was confirmed experimentally by inducing amyloidosis with an arthropathic and amyloidogenic strain of E. faecalis. Sequence analysis of cDNA coding for SAA, the amyloid precursor protein, revealed that the SAA proteins are identical in both breeds, although some nucleotide differences existed in the untranslated regions of the mRNAs. The chicken SAA gene was found to be a single copy gene which comprises 4 exons. The first of these exons apparently occupies a conserved position and is not translated. Investigation of the affected joints using in situ hybridization demonstrated local SAA gene expression. It is concluded that the likelihood of an E. faecalis induced arthritis to progress to amyloidosis is breed-dependent, but is not a consequence of a more amyloidogenic SAA.

Amino Acid Sequence↗
PubMed1999

Quantitative studies of the optic nerve fiber layer in the chicken retina.

The optic nerve fiber layer (NFL) of the chicken retina was studied quantitatively and morphologically at 17 positions along seven radially arranged bands from the dorsal tip of the pecten oculi using electron microscopy. The number of nerve fibers was counted in areas 6 microm in width x the full thickness of the NFL. Myelinated nerve fibers in the NFL were also identified immunohistochemically using anti-myelin basic protein serum. The dorsal area (dorsal, dorso-temporal and dorso-nasal bands) in the retina had thin NFL and contained the largest number of nerve fibers, which were mainly thin and unmyelinated. The ventral area (ventral and ventro-temporal bands) had a thick NFL and contained a relatively small number of nerve fibers, many of which were myelinated. The nasal band had the thickest NFL and contained as many nerve fibers as the dorsal area, with the temporal band showing a high ratio of myelinated fibers. The band had a thick NFL and contained many nerve fibers with a relatively low ratio of myelinated fibers. The relationship between the number and composition of nerve fibers in the NFL to the chicken visual characteristics was discussed. Although the myelin in the chicken retina was loose type, the myelin-forming cells were similar in appearance to dense oligodendrocytes. retina, morphometry, myelinated fiber, nerve fiber layer.

Animals↗
PubMed1991

The serological responses of chickens to mass vaccination with a live V4 Newcastle disease virus vaccine in the field and in the laboratory. 2. Layer pullets.

Layer chickens on a commercial started pullet farm were vaccinated once at 31 to 52 days of age by drinking water or aerosol with live V4 Newcastle disease virus (NDV) vaccine. Flockmates which had been rehoused in laboratory isolation pens shortly beforehand were similarly vaccinated. Samples of birds were bled at intervals and the serums tested for haemagglutination inhibiting antibody to NDV. Log2 mean titres of up to 4.88 and assumed protection levels (based on the percentage of birds with log2 titres of 4 or greater) of up to 81%, were obtained in the field trials within 4 weeks of vaccination. A subsequent laboratory trial further compared the response of different breeds of chicken to different routes of vaccination. Differences were observed between breeds, routes of vaccination, and parallel field and laboratory trials. The results show that this V4 vaccine can produce an adequate serological response following mass vaccination of Australian layer pullets housed under commercial conditions, and that care should be exercised in extrapolating results obtained under laboratory conditions.

Aerosols↗
PubMed1993

Formation of the myelinated nerve fiber layer in the chicken retina.

Oligodendrocytes in the ganglion cell layer, the myelinating cells in the chicken retina, were investigated morphologically and quantitatively. Oligodendroblasts divided in the inner retinal layer around the 14th day of incubation and differentiated into oligodendrocytes. The oligodendrocytes started sheathing an axon in the nerve fiber layer at the 14th day of incubation. The number of myelin lamellae increased rapidly during the first week after chicks had hatched. An immunological reaction of anti-myelin basic protein was observed on the myelin sheaths in the nerve fiber layer and on the oligodendrocytes in the ganglion cell layer. These results suggest that the oligodendrocytes form the myelinated nerve fiber layer of the chicken and that they act independently of the Müller cells during myelination.

Age Factors↗
PubMed2004

Different serum haemolytic complement levels in indigenous chickens from Benin, Bolivia, Cameroon, India and Tanzania.

Titres of classical (CPW) and alternative (APW) complement pathways were measured in clinically healthy local chicken populations (ecotypes) from Africa (Benin, n = 78; Cameroon, n = 299; Tanzania, n = 101), Asia (India, n = 96) and South America (Bolivia, n = 64). A wide variation was found in haemolytic complement levels between the various ecotypes. Distributions of the classical and alternative complement titres were not normal but were skewed to the right. Differences in complement were found both within and between ecotypes. Furthermore, CPW titres of the indigenous chickens were lower than those determined in commercial layer chickens. This suggests that complement levels background and husbandry. The relationships between complement levels, the chicken MHC(B) complex, environmental antigenic pressure, and survival of the scavenging local chickens are discussed.

Africa↗
PubMed1988

Effect of vitamin C administration on serum and egg-yolk cholesterol level of the chicken.

Ascorbic acid (vitamin C) was given to 144-days-old layer chickens mixed with their ration at three concentrations: 30, 60 and 90 p.p.m. for 6 months. Cholesterol levels in blood serum (CS) and egg yolk (CE) were measured every 6 weeks (four periods); there was a marked decrease in CS in most treated birds, especially those receiving the highest concentration of vitamin C. There was also a slight decrease in CE in most treated birds. Thyroidal weight showed a significant increase in most treated groups, especially those receiving the highest concentration of vitamin C.

Animals↗
PubMed1996

Demonstration of serum-neutralising antibody to turkey rhinotracheitis virus in serum from chicken flocks in Japan.

Since between 1989 and 1991, broiler, broiler breeder and layer chickens reared in three different prefectures of Japan, Hyogo, Ibaraki, and Miyazaki, were diagnosed clinically as having swollen head syndrome (SHS) these flocks were survey for antibody to turkey rhinotracheitis (TRT) virus using a serum neutralisation (SN) test. TRT-specific SN antibody was found in flocks of chickens in 2 out of the 3 prefectures. Thereafter, particular in the summers of both 1993 and 1994 outbreaks of SHS occurred in almost all areas of major chicken production in Japan. Almost chicken flocks affected by SHS possessed TRT SN antibody. No chicken sera collected between 1972 and 1988 possessed any SN antibody to TRT virus. It is suggested that in Japan, TRT virus is widely prevalent in areas of major poultry production.

Animals↗
PubMed2005

Virus spread pattern within infected chicken farms using regression model: the 2003-2004 HPAI epidemic in the Republic of Korea.

During the 2003-2004 epidemic in Korea, the infection time and within-farm spread pattern of virus were analysed for the highly pathogenic avian influenza (HPAI) outbreak on chicken farms using regression models based on epidemiological data. Mortality observed on a given day had a positive linear association with time after initial infection. HPAI spread more rapidly on farms managed by employees and on farms with larger numbers of chicken houses in use. The disease spread more rapidly among layer chickens than among broilers. Using statistical model, we found that farmers recognize the abnormally high mortality resulting from HPAI approximately 5 days after infection. Without any intervention, entire flocks would die within 12 days of introduction of the HPAI virus to the infected farm.

Animal Husbandry↗
PubMed1995

Salmonella enteritidis: the egg and I.

The world-wide clinical incidence of Salmonella Enteritidis has increased markedly. The increase is associated with the enhanced ability of the bacterium to systemically colonise layer chickens. Subsequent contamination and consumption of intact shell eggs from colonised layer hens, either directly or in foods containing raw or lightly cooked eggs, causes human disease. Despite investigation, no change in the biology of the bacterium has been correlated with increased colonisation in chickens. To date, no method of control at the production level has proven effective; consumer education is the best means of minimising the public health risk.

Animals↗
PubMed2003

[Eight years of amyloid research in chickens: a review].

The articular localisation of amyloid is not uncommon in Galliformes. In commercial brown layer chickens amyloid artropathy was first described in 1994 as a clinical problem with increasing importance associated with growth depression and lameness. Considering the clinical veterinary and the scientific relevance of amyloid artropathy, it was a subject of poultry research during the past eight years. The outcome of the various studies performed is described in the present update. The occurrence, nature, pathogenesis and possible etiological factors of chicken amyloid artropathy, the identification and characterization of the chicken joint amyloid protein and the gene involved are reported. Finally, the results of immunological studies, which provide a plausible explanation for the difference in breed susceptibility, and summarising conclusions are presented.

Amyloidosis↗
PubMedDate not supplied

Studies of infectious laryngotracheitis vaccines: immunity in layers.

Ten-week-old layer chickens obtained from a commercial source were eye-drop vaccinated with chicken-embryo-origin (CEO) or tissue-culture-origin (TCO) vaccines for infectious laryngotracheitis (ILT). Controls were not vaccinated. Approximately one-third of the layers were challenged with virulent ILT virus at 21, 40, or 60 weeks of age. Serum samples taken from the layers before challenge were used in a virus neutralization (VN) test to determine vaccination titers at those three ages. Both vaccines induced low VN titers (geometric mean titer [GMT] less than 6). At 21 weeks of age, the titers produced by the two vaccines were not significantly different, but at 40 and 60 weeks of age the VN GMT of the CEO-vaccinated group was significantly greater than that of the TCO-vaccinated group. The VN GMTs did not drop over time in either group and actually rose between 21 and 60 weeks of age in the CEO group. Both vaccines protected layers against severe challenge with virulent ILT virus, neither being significantly better than the other under these experimental conditions. Unvaccinated sentinel chickens were maintained in contact with the vaccinated layers during three intervals between 1 day and 6 weeks post-vaccination. Diagnostic tests performed on the sentinels to detect lateral spread of vaccine virus from vaccinated to unvaccinated chickens showed scattered positive results.

Age Factors↗