Intact Chickens Research Articles

Thyroid hormone, glucagon, and medium-chain fatty acids regulate transcription initiated from promoter 1 and promoter 2 of the acetyl-CoA carboxylase-α gene in chick embryo hepatocytes

High-carbohydrate feeding and triiodothyronine (T3) increase the abundance of acetyl-CoA carboxylase-α (ACCα) mRNA in avian hepatocytes, whereas starvation, glucagon, and medium-chain fatty acids decrease the abundance of ACCα mRNA. These changes in ACCα mRNA levels are mediated by alterations in the rate of transcription of the ACCα gene. In liver, ACCα transcription is initiated from two promoters, promoter 1 and promoter 2, resulting in transcripts that contain heterogeneity in their 5′-untranslated regions. Here, we investigated the role of promoter 1 and promoter 2 in mediating nutrient- and hormone-induced changes in ACCα mRNA abundance by measuring the level of transcripts expressed from promoter 1 and promoter 2 using a ribonuclease protection assay. The results indicated that both promoter 1 and promoter 2 were regulated by starvation/refeeding in livers of intact chicks and by T3, glucagon, and medium-chain fatty acids in chick embryo hepatocyte cultures and that alterations in the activity of promoter 2 accounted for a greater proportion of the changes in total ACCα mRNA abundance caused by nutrient and hormone treatment. Five DNase-hypersensitive sites were also identified between −500 and +1 bp relative to the transcription start site of promoter 2 in livers of intact chicks and in chick embryo hepatocyte cultures. In transient transfection analyses, this region of DNase hypersensitivity conferred regulation of transcription by T3, glucagon, and medium-chain fatty acids in chick embryo hepatocytes. Data from this study demonstrate that diet-induced changes in the activities of promoter 1 and promoter 2 in livers of intact chicks are mimicked in chick embryo hepatocyte cultures by manipulating the concentrations of T3, glucagon and medium-chain fatty acids in the culture medium and that cis-acting sequences mediating the effects of nutrients and hormones on promoter 2 activity are located immediately upstream of the transcription start site of this promoter.

Secondary poisoning of kestrels by white phosphorus

Since 1982, extensive waterfowl mortality due to white phosphorous (P4) has been observed at Eagle River Flats, a tidal marsh near Anchorage, Alaska. Ducks and swans that ingest P4 pellets become lethargic and may display severe convulsions. Intoxicated waterfowl attract raptors and gulls that feed on dead or dying birds. To determine if avian predators can be affected by secondary poisoning, we fed American kestrels (Falco sparverius) 10-day-old domestic chickens that had been dosed with white phosphorus. Eight of 15 kestrels fed intact chicks with a pellet of P4 implanted in their crops died within seven days. Three of 15 kestrels fed chicks that had their upper digestive tracts removed to eliminate any pellets of white phosphorus also died. Haematocrit and haemoglobin in kestrels decreased whereas lactate dehydrogenase-L, glucose, and alanine aminotransferase levels in plasma increased with exposure to contaminated chicks. Histological examination of liver and kidneys showed that the incidence and severity of lesions increased when kestrels were fed contaminated chicks. White phosphorus residues were measurable in 87% of the kestrels dying in the study and 20% of the survivors. This study shows that raptors can become intoxicated either by ingesting portions of digestive tracts containing white phosphorus pellets or by consuming tissues of P4-contaminated prey

Abrogation of Age-Related Resistance to Chicken Infectious Anemia by Embryonal Bursectomy

Embryonally bursectomized (Ebx) chickens developed signs and lesions typical of chicken infectious anemia (CIA) when infected with CIA-1 isolate of chicken infectious anemia virus (CIAV) at 21 or 38 days of age. In both cases, the chickens had low hematocrit values after the 14th day of inoculation, and the percentage of CD4+ and CD8+ cells in the thymus was markedly reduced at 21 days postinoculation. Even though intact chickens became infected, they never developed low hematocrit values. The data support the hypothesis that age-related resistance to CIA is antibody-mediated and is not due to disappearance of the CIAV target cell; the data also suggest that CD4+/CD8+ cells are the target for infection.

Effect of in ovo bursectomy on the course of an infectious bronchitis virus infection in line C White Leghorn chickens.

SummaryWhite Leghorn line C chicks were surgically bursectomised (Bx) in ovo to eliminate antibody production. After inoculation with infectious bronchitis virus (IBV) at 14 days after hatching, Bx chicks experienced a more severe and longer lasting infection than intact chicks. The severity and duration of clinical infection in the Bx chicks resembled that previously observed in the highly susceptible line 15 I chicks, however no increase in mortality was observed, in contrast to the high levels of mortality recorded in IBV-inoculated line 15 I chicks. After secondary challenge the degree of damage to the ciliated epithelium of the trachea was greater in the Bx chicks than in the intact chicks.The results indicate that, although antibodies play an important role in recovery from IBV infection, other immunological factor(s) may also be involved.

Pineal influence on the diurnal rhythm of nonspecific immunity indices in chickens

The effect of pinealectomy and melatonin injections on the diurnal rhythms of serum lysozyme and blood granulocytes was examined in White Leghorn cockerels kept from time of hatching for 5 weeks in L:D 12:12 conditions and immunized twice with sheep red blood cells (SRBC). Pinealectomy or sham-operation was made during first week of life. Pinealectomized chickens were injected daily with a melatonin dosage increased over 4 consecutive weeks (the dosage was 10, 13, 16, and 20 ng per bird daily during the 4 weeks, respectively; MEL I) at the beginning of darkness. The same treatment was performed on chickens with an intact pineal gland using additional melatonin doses increased 10 times (MEL II) and 500 times (MEL III). Intact chickens were also injected with MEL II and MEL III 4 hr before the end of light. Control birds received equivalent injections of vehicle. Five-week-old chickens were sacrificed during a 24-hr period every 4 hr. The existence of diurnal rhythm was evaluated by cosinor analysis. Pinealectomy shifted the acrophase of the diurnal rhythm of granulocytes and abolished that of serum lysozyme. Both rhythms were restored in pinealectomized chickens by MEL I but not by vehicle injections. The same melatonin dose was unable to change the granulocyte rhythm but delayed the acrophase of that of serum lysozyme in chickens with an intact pineal gland. Two higher melatonin doses influenced the diurnal rhythm of granulocytes as a function of dose and time of administration. The rhythm of serum lysozyme was dependent only on the time of injection. The pineal gland seems to control, via its hormone melatonin, the diurnal rhythm of nonspecific immunity in chickens.

Is dopamine involved in the generation of the light peak in the intact chicken eye?

The implication for dopamine (DA) in the modulation of the standing potential (SP) and the light peak (LP) was tested in intact chickens using ah indirect EOG method. After an intravenous or intravitreal injection of DA, a transient, dose-dependent increase in the SP was observed. The LP, recorded after an intravenous injection, was preserved. But after an intravitreal injection, the LP was strongly reduced or even abolished depending on the dose of DA, whereas the photoreceptor response was unchanged. The data supports the hypothesis that the light peak, which is generated by a neural retina-pigment epithelium interaction, could be triggered by dopamine released at light onset from the inner retinal layers.

Intestinal IgA response and immunity to rotavirus infection in normal and antibody‐deficient chickens

Rotavirus inoculation by oesophageal cannulation resulted in subclinical infection without decreasing intestinal D-xylose absorption in both intact and embryonally bursectomised, antibody-deficient (EBx) 8-week-old specific-pathogen-free chickens. In intact chickens, rotavirus-specific IgM, IgG and IgA responses were detected in serum, while the intestinal antibody response consisted almost entirely of IgA Serum IgG and intestinal IgA levels were increased for at least 70 days following a single inoculation with the virus. Intact chickens recovered from a primary rotavirus infection between 4 and 14 days post inoculation (dpi) and developed resistance to homotypic challenge between 14 and 28 dpi. These responses were only slightly delayed in EBx birds, which recovered from primary infection between 8 and 28 dpi and developed resistance between 14 and 42 dpi. This suggested that the intestinal IgA response in chickens participated in both recovery from and resistance to rotavirus infection, but that it was not the only mediator of recovery and resistance.

The role of mucosal antibody in immunity to infectious laryngotracheitis virus in chickens

The role of mucosal antibody in recovery from a primary infection and resistance to reinfection with infectious laryngotracheitis (ILT) herpesvirus was studied in bursectomized chickens, which were unable to synthesize specific antibodies. Viral antigen in the infected trachea was assessed by indirect immunofluorescence on tissue sections and by ELISA. The ability of bursectomized chickens to resolve primary infections as effectively as intact chickens and of vaccinated-bursectomized chickens to prevent the replication of challenge virus without the participation of mucosal antibody, is evidence for the importance of local cell-mediated rather than humoral immune mechanisms in the outcome of infection with ILT virus.

Influence of androgens on plasma concentrations of growth hormone in growing castrated and intact chickens

Castrated chicks implanted with testosterone or 5α-dihydrotestosterone (5α-DHT) had circulating concentrations of the respective androgen similar to or less than in shamoperated chicks. In castrated chicks, 5α-DHT or 19-nortestosterone (19-NorT) inhibited growth as indicated by body weight, while testosterone and 5β-dihydrotestosterone (5β-DHT) were without effect. In intact male or female chicks, growth was inhibited by either testosterone or 5α-DHT but was unaffected by 5β-DHT or estradiol-17β. Plasma concentrations of luteinizing hormone (LH) were reduced in castrated chicks receiving implants of either testosterone or 19-NorT. Only the highest dose of 5α-DHT depressed the circulating concentration of LH; lower doses of 5α-DHT being without effect. During the first 6 weeks of growth, plasma concentrations of GH were unaffected by most steroid treatments (5α-DHT, 5β-DHT, low doses of testosterone, estradiol-17β) in castrated or in intact male or in female chicks. Similarly, 19-NorT did not affect plasma concentrations of GH in castrated chicks. The high dose of testosterone, however, depressed plasma concentrations of GH in castrated chicks between 2 and 6 weeks of age. Between 8 and 12 weeks of age, all steroids tested, except 5α-DHT, were without effect on plasma concentrations of GH. Plasma concentrations of GH were increased in 5α-DHT-treated chickens. This effect was observed irrespective of dose of 5α-DHT or whether the androgen was administered to castrated or to intact male or to female chicks.

Effects of Intravitreal and Intravenous Administrations of Dopamine on the Standing Potential and the Light Peak in the Intact Chicken Eye

We studied the modifications of the standing potential (SP) of the eye and of the light peak (LP) after exposure to dopamine, a neurotransmitter released at light by the inner retina and known to affect electrical properties of the retinal pigment epithelium. Intravenous or intravitreal injections of dopamine (DA) were performed on intact chickens. "Choroidal" application (through an intravenous injection) induced a transient increase of the SP and the LP was preserved. On the other hand, "apical" applications of DA (through an intraocular injection) also increased the SP but considerably depressed the LP. These results are in agreement with the hypothesis that the light-induced release of dopamine from the neuroretina may be responsible for the LP generation in the intact chicken eye.

Identification of the Chicken Anemia Agent, Reproduction of the Disease, and Serological Survey in the United States

An agent with antigenic, physicochemical, and pathological characteristics of chicken anemia agent (CAA) was isolated from broiler chickens and was designated chicken infectious anemia (CIA)-1. CIA-1 was resistant to chloroform treatment and passed through 50-nm-diameter-pore membranes. When inoculated in embryonally bursectomized and/or intact chickens, CIA-1 produced signs and lesions characteristic of CIA: low hematocrit values, pale bone marrow, thymic and bursal atrophy, and enlarged liver. Microscopic lesions were a reflection of macroscopic observations. When injected into 4-week-old chickens CIA-1 induced antibodies against the Cux-1 CAA isolate. In CsCl, CIA-1 had a density of 1.36 g/ml. Antibodies against CAA were found in breeder and commercial chicken flocks from Arkansas, Connecticut, Georgia, Kansas, Maine, Michigan, New York, and Pennsylvania. The age of these flocks ranged from 10 to 78 weeks.

The Effect of Harderian Adenectomy on the Antibody Response in Chickens

Intact chicks and those that had their glands of Harder (GH) removed (GHx) at 1 day of age were studied for their response to optically or intraperitoneally (IP) applied antigens. Following exposure of the chicks to sheep red blood cells (SRBCs), killed Brucella abortus, or bovine serum albumin (BSA), serum and tear samples were collected and assayed for antibodies. Of the two sources of antibodies, the serum generally had higher levels than did the tears. The only exception to this occurred in the intact chicks inoculated by the eye, in which serum and tear levels were equivalent. With SRBCs, no difference could be detected between the two routes of inoculation. However, IP inoculation produced higher levels of antibody in the serum of intact and GHx chicks inoculated with B. abortus or BSA and in the tears of the GHx chicks exposed to B. abortus. Removal of the GH resulted in a consistent decrease in antibody levels in the tears, regardless of the route of exposure. Although this effect was noted with all three antigens, it was more pronounced in the trials using B. abortus and BSA. This finding is discussed in terms of describing the importance of the GH as a source of antibodies to optically applied antigens, and its importance as a route of circulating antibody egress. Furthermore, the feasibility of using the antibody response in tears to a test antigen is discussed as a means of measuring the immune status of a functioning GH.

Absorption and elimination of an oral dose of 3H-deoxynivalenol in colostomized and intact chickens.

Deoxynivalenol (DON or 3, 7, 15-trihydroxy-12, 13-epoxy-trichothec-9-en-8-one) is a mycotoxin produced by Fusarium graminearum that can contaminate grain. Domestic fowl are particularly tolerant to DON ingestion. Prelusky et al. orally administered {sup 14}C-DON to chickens and observed high radioactivity in the liver and bile with over 90% of the original label accruing in the excreta before 48 h. DON cannot be detected in portal blood concurrent to its disappearance from the gastrointestinal tract. Presumably, DON was structurally modified upon absorption then hepatically retrieved and excreted in bile. In the present experimentation, {sup 3}H-DON was intubated into colostomized and intact hens. The objective was to measure the progressive changes in distribution of radioactivity along the gastrointestinal tract, among body tissues and between urine and feces.

Cytotoxic T lymphocytes in reticuloendotheliosis virus‐infected chickens

Cytotoxic T lymphocytes were functionally demonstrated in spleen cells from chickens 7 days post inoculation with reticuloendotheliosis virus using a Cr-release assay. Major histocompatibility complex (MHC)-restricted cytotoxicity was demonstrated using effector and target cells from two different strains of chickens of known avian MHC haplotype. Anti-viral specificity was shown and in vivo generation of MHC-restricted cytotoxicity was evaluated. Cytotoxic T cells were distinguished from macrophages and natural killer cells. Their cytotoxicity was not antibody dependent. Higher levels of cytolysis were found with cytotoxic T cells from embryonally bursectomized vs. intact chickens over a large range of effector to target cell ratios. Using monoclonal antibodies, cytotoxic T cells were further defined as Ia+ T cells by immunofluorescence, antibody plus complement-mediated lysis of effector cells and blocking of cytolysis in the Cr-release assay.

Pathogenicity of chicken anaemia agent in bursectomised chickens

Bursectomised (Bx) chickens, but not intact chickens, developed anaemia when inoculated with chicken anaemia agent (CAA) at 2 weeks of age. No antibodies against CAA were produced in the Bx chickens and CAA was persistently recovered from them. In contrast, CAA disappeared from the intact chickens with the development of high titres of antibody. It was strongly suggested that the pathogenicity of CAA was dependent on the production of humoral antibody against CAA in infected chickens. Histopathologically, no inclusion bodies suggestive of parvovirus infection were observed in the tissues of affected chickens.

Stimulation of corticosterone release in the fowl by recombinant DNA-derived chicken growth hormone

The effects of recombinant DNA-derived chicken growth hormone (rcGH) on plasma corticosterone in young broiler cockerels were investigated. A single injection of 200 μg/kg rcGH significantly increased plasma corticosterone concentrations 2 hr (but not 20 or 40 min) after treatment. Administration of 10 or 100 μg/kg rcGH also significantly increased plasma corticosterone levels after 2 hr, with the higher dose eliciting greater responses. Chronic treatment with seven daily injections of the same doses of rcGH gave similar increases in plasma concentrations of corticosterone. No obvious difference in magnitude of plasma corticosterone was observed between acute and chronic exposure to rcGH. In a further experiment in which serial blood sampling was performed after a single injection or five daily injections of vehicle or 200 μg/kg rcGH, there were significant increases in plasma corticosterone concentrations 40 min after acute rcGH treatment and 40 and 80 min after chronic treatment when compared with plasma corticosterone concentrations of vehicle-injected controls. However, the increases could have incorporated a stress response due to repeated sampling because the control birds also showed elevated plasma corticosterone concentrations. The corticosterone response did not diminish with repeated GH challenge. These results suggest that GH may play a role in the acute regulation of corticosterone secretion in intact chickens.

Effect of Eimeria maxima infection upon the invasion of Salmonella serovar typhimurium through the intestine of chicken.

Two experiments were conducted to examine invasion of salmonella through the intestine of chickens infected with Eimeria maxima. In experiment 1, 1.6-4.0×105 Salmonella serovar typhimurium (S. typhimurium) were injected into the small-intestinal loop established in E. maxima-infected and -uninfected chickens under anesthesia, and cardiac blood, spleen and liver were examined for the presence of S. typhimurium. The organism was more frequently recovered from these samples, particularly from spleen 10 days after coccidial inoculation, than from the samples of uninfected birds given only S. typhimurium into small-intestinal loop. When S. typhimurium was injected into small-intestinal loop or ligated cecum of intact chickens, more samples were positive for S. typhimurium from small-intestinal loop than those from ligated cecal group. Significant difference was seen in the spleen samples. In experiment 2, number of S. typhimurium in cardiac blood, spleen and liver was counted after injection of 1.8-8.4×107 S. typhimurium into small-intestinal loop of chickens 10 days after E. maxima inoculation. The counts in spleen were approximately 102 CFU/g 3 hr after the injection and were higher than those in liver and blood of both E. maxima infected and uninfected birds. In liver, the counts in E. maxima infected birds 30 min after the injection were significantly higher than those in uninfected birds. In cardiac blood, a few S. typhimurium were recovered from E. maxima infected birds, whereas no organism was found from uninfected birds until 2 hr after the injection. It is concluded that in chickens salmonella penetrated more readily through small intestine than ceca, and E. maxima infection enhanced the penetration.

Influence of pinealectomy on plasma and extrapineal melatonin rhythms in young chickens ( Gallus domesticus)

A specific radioimmunoassay was validated for the quantitative measurement of melatonin (MT) levels in plasma and homogenates of the pineal gland, Harderian gland, or retinae of young chickens. Single-comb White Leghorn (SCWL) cockerels were raised under a 12L:12D light/dark cycle for two experiments. In Experiment 1, 12 birds were bled and immediately killed for their pineal glands at 4-hr intervals during a single light/dark cycle at 25 days of age (25 da) for simultaneous determination of changes in MT levels in the plasma and pineal gland. Plasma MT levels were low during photophase (100 pg/ml) and reached a distinct peak (390 pg/ml) at mid-scotophase. A parallel MT rhythm was found in pineal homogenates where the average MT content during scotophase (7.4 ng/gland) was 10 times higher than the average MT content of pineal glands obtained during photophase. In Experiment 2, SCWL cockerels were either pinealectomized or sham-operated (PN) at 8 to 10 da. At 25 da, six birds from each surgical treatment group, including unoperated controls (C), were bled at 4-hr intervals, corresponding to those in Experiment 1, during a single light/dark cycle. Immediately after being bled, each bird was killed and the eyes and Harderian glands were removed for measurement of their MT contents. Pinealectomy completely abolished the plasma MT rhythm which in intact chicks (PN and C) reached a sharp peak (298 pg/ml) at mid-scotophase. Although not affected by surgical treatment, retinal MT levels showed a higher amplitude rhythm with a prominent peak (4 ng/retina) at mid-scotophase that was 15 times higher than the average retinal MT content during photophase. A modest nocturnal MT rhythm was found in the Harderian gland where the average MT level for all surgical treatment groups during scotophase (89 pg/100 mg wet wt) was only 51% higher than that observed for photophase. These data indicate that the plasma MT rhythm in chickens is derived solely from MT secreted into blood by the pineal gland and that the extrapineal MT produced rhythmically in both the retina and Harderian gland does not contribute to the plasma MT rhythm.

Effect of Bursal Cell Number on the Pathogenesis of Infectious Bursal Disease in Chickens

The pathogenesis of infectious bursal disease (IBD) in chickens neonatally chemically bursectomized (CB) by cyclophosphamide and subsequently inoculated with various numbers of bursal cells was examined. CB chickens inoculated with at least 62.5 X 10(6) bursal cells were as susceptible to IBD clinical manifestations (as determined by gross and microscopic evaluation of bursal tissues, virus recovery from spleen, and antibody titer) as intact chickens following inoculation with virus at 5 weeks of age. In contrast, CB chickens inoculated with 2.5 X 10(6) or fewer bursal cells were refractory to the IBD clinical manifestations compared with intact chickens or CB chickens inoculated with 62.5 X 10(6) or more bursal cells. Results from this study suggest that the availability of a large number of bursal cells is an essential factor in the development of IBD.

Response of Chickens to Inoculation with a Temperature-Sensitive Mutant of Mycoplasma gallisepticum

Newly hatched chickens were inoculated intranasally with either the S6 or TS 100 strain of Mycoplasma gallisepticum (MG) or they were left uninoculated. The three groups of chickens did not differ discernibly in body, spleen, or bursa weight during the 27-day sampling period. However, the S6-inoculated chickens showed a more pronounced cellular response in the nasal passages and had nearly complete lymphoid depletion in the spleens. The TS 100-inoculated birds expressed only a mild cellular reaction, which was localized in the nasal passages. Uninoculated chickens appeared normal histologically. Serologic tests such as rapid serum plate agglutination, hemagglutination-inhibition, and radioimmunoassay were able to detect antibody responses of chickens to MG inoculations yet could not differentiate the response to TS 100 from the response to S6. Tracheal secretions in intact TS 100-inoculated chickens contained antibodies to MG, yet only one-half of the bursectomized inoculated chickens contained detectable antibody, which appeared to be IgG. This led to the conclusion that bursectomy suppresses the appearance of locally synthesized IgG antibodies to MG in tracheal washings. The locally produced antibody was considered important in the development of resistance induced by intranasal inoculation of TS mutants.