Patricia S. Wakenell

The effect of light intensity on the behavior, eye and leg health, and immune function of broiler chickens

Broilers are typically raised commercially in dim lighting. It has been suggested that providing brighter light intensity could improve health and provide opportunities for more normal behavioral rhythms. We examined the effects of 3 photophase light intensities (5, 50, and 200 lx) on activity patterns, immune function, and eye and leg condition of broilers (n = 753; 6 replicate pens/treatment). Broilers were reared with one of these intensities from 1 to 6 wk of age; photoperiod consisted of 16L:8D with 1 lx intensity during the scotophase. Broilers reared with 5 lx were less active (P = 0.023) during the day than 50 or 200 lx and showed less (P < 0.0001) change in activity between day and night than 50 or 200 lx. There was no difference between treatments for final BW (2.30 +/- 0.02 kg) or for most immune parameters (IgG primary and secondary responses to keyhole limpet hemocyanin, B and T lymphocyte proliferation, plasma lysozyme, haptoglobin, NO, whole blood killing of Escherichia coli and Staphylococcus aureus), but there was a trend (P = 0.072) for a greater IgM response in 50 lx (6.21 titer) than 5 lx (5.78 titer), with 200 lx (5.92 titer) intermediate. There was no effect of light intensity on back-to-front (1.13 +/- 0.01 cm) or side-to-side (1.48 +/- 0.01 cm) diameter of the eyes or on corneal radii (0.82 +/- 0.01 cm), but 5 lx (2.33 +/- 0.07 g) had heavier eyes (P = 0.002) than 50 lx (2.09 +/- 0.04 g) or 200 lx (2.11 +/- 0.04 g). There were no differences in gait score, although 200 lx broilers had more hock and footpad bruising (P = 0.038) but fewer erosions (P = 0.006) than 5 or 50 lx. Increased daylight intensity had little effect on broiler health but resulted in more pronounced behavioral rhythms.

Effect of In Ovo Vaccine Delivery Route on Herpesvirus of Turkeys/SB-1 Efficacy and Viremia

SUMMARY. A study was designed to ascertain the influence of in ovo site of inoculation and embryonic fluid type on the development of Mareks disease (MD) vaccine viremia and efficacy against MD challenge. The experiments were divided into in vitro and in vivo phases. In the in vitro phase, herpesvirus of turkeys/SB-1 vaccine was combined with basal medium eagle (BME) medium (control), amniotic fluid, or allantoic fluid and subsequently titrated on secondary chick embryo fibroblast cultures. There were no significant differences in titer between the virus inoculum carried in BME and the virus inoculum combined with either the allantoic fluid or the amniotic fluid. In the in vivo phase, five routes of inoculation, amniotic, intraembryonic, allantoic, air cell, and subcutaneous at hatch, were compared for generation of protection against virulent MD challenge. Comparisons were made in both specific-pathogen-free and commercial broiler embryos/chicks and, for the amniotic and allantoic routes, injection at either day 17 or day 18 of embryonation. Reisolation of the vaccine virus at day 3 of age was also done for all routes with the exception of the air cell route. Vaccine virus was recovered from all birds tested that were injected in ovo via the amniotic and intraembryonic routes and the subcutaneously at hatch route but was isolated only sporadically from birds inoculated via the allantoic route. Vaccination protective efficacy against virulent MD for all birds vaccinated in ovo via the amniotic or intraembryonic routes and birds vaccinated subcutaneously at hatch was over 90% regardless of day of in ovo injection or bird type. Protective efficacy for vaccines delivered in ovo by either the allantoic or the air cell routes was less than 50% regardless of day of injection or bird type. Therefore, in ovo MD vaccines must be injected either via the amniotic route or the intraembryonic route for optimal performance.

Embryo vaccination of chickens with infectious bronchitis virus: Histologic and ultrastructural lesion response and immunologic response to vaccination

Chicken embryos 18 days of age and newly hatched chicks were vaccinated with an infectious bronchitis virus (IBV) vaccine (V-IBV) or with an IBV vaccine that had been serially passaged 40 times in chick kidney tissue culture (P-IBV). Immunologic and pathologic changes in the chicks were compared at selected intervals until the 35th day. Pathologic changes were evaluated by light, transmission, and scanning electron microscopy. Immunologic changes were assayed by a constant virus-diluting serum plaque-reduction test in chicken cell cultures, by 51Cr-release cytotoxicity assays, and by phytohemagglutination (PHA) responses. Embryos vaccinated with P-IBV and 1-day-old chicks vaccinated with V-IBV had similar transient lesions that were confined primarily to the trachea. Embryo vaccination and posthatch vaccination induced similar primary and secondary antibody responses in chicks. It was concluded that neither vaccination technique consistently influenced PHA response of whole blood cells or natural killer cell reactivity of spleen effector cells. Additionally, effector cells cytotoxic to IBV-infected target cells were not detected in chicks vaccinated as embryos or at hatch. The pathologic and immunologic effects of vaccination with P-IBV were comparable to those induced by conventional vaccination of chicks.

Lack of Protection Against Avian Cholera by Vaccination with Recombinant P6-Like Protein from Pasteurella multocida

The gene encoding the P6-like protein of Pasteurella multocida was cloned in the baculovirus expression system. Baculovirus-expressed recombinant protein was used to parenterally immunize 6-wk-old Nicholas broad-breasted white turkeys. Turkeys developed significant antibody titers to the recombinant protein as measured by enzyme-linked immunosorbent assay. Two weeks after the last immunizing injection, vaccinated turkeys were placed in contact with turkeys infected with P. multocida strain P1059, as were nonvaccinated control birds. No differences occurred in percent mortality between the two groups. We conclude that parenterally administered recombinant P6-like protein does not protect turkeys from avian cholera.

Pathogenicity of attenuated infectious bronchitis viruses for oviducts of chickens exposed in ovo.

A fixed effects, completely randomized factorial design was used to study the effect of infectious bronchitis virus (IBV) inoculation at two different exposure ages and three postinoculation (PI) durations on chick oviduct pathology. Maternal antibody-positive chicken embryos at 18 days of embryonation (ED) and newly hatched chicks were inoculated with an IBV vaccine (V-IBV) or with an IBV vaccine that had been serially passaged 21 times in chick kidney tissue culture (P-IBV). Hatchability of eggs inoculated with V-IBV at 18 ED was significantly lower (27%) than eggs that were not inoculated with IBV or were inoculated with P-IBV (45-58%, P < 0.01). Chicks from all treatment groups survived to 5 days after hatch. Pathologic changes in the oviduct were evaluated at 9, 18, and 27 days PI by light microscopy. Inoculation of V-IBV and P-IBV in the presence of maternal antibodies did not result in any oviduct pathology at 9, 18, and 27 days PI. Respiratory clinical signs, however, were observed in 61% and 5% of chicks inoculated with V-IBV at 18 ED and at hatch, respectively. Respiratory clinical signs were not observed in control birds, birds inoculated with P-IBV at 18 ED, or birds inoculated with P-IBV at hatch.

Protective immunity to infectious bronchitis in broilers vaccinated against Marek's disease either in ovo or at hatch and against infectious bronchitis at hatch.

Two experiments were conducted using commercial broiler chickens to determine if Mareks disease (MD) vaccines HVT/SB-1 and HVT plus CVI-988 given either in ovo or at hatch adversely affected the efficacy of infectious bronchitis (IB) vaccines (Ark and Mass serotypes) given by eyedrop on the day of hatch. Nonvaccinated negative controls and controls that received only IB vaccines were included in each study. Birds were challenged with either infectious bronchitis virus (IBV) Mass-41 or IBV Ark-99 on either day 26 or 27 of age. Protection was assessed 5 days post-IBV challenged by virus isolation from the trachea. The day of hatch mean antibody titer to IBV was 12,668 +/- 4704 and 2503 +/- 3243 by enzyme-linked immunosorbent assay in experiments 1 and 2, respectively. In each study, nonvaccinated controls had a significantly higher (P < or = 0.05) incidence (88%-100%) of IBV challenge virus isolation than did controls vaccinated for IB but not for MD. Analysis of data from both studies showed that protection to IB in groups that received only IB vaccines at hatch ranged from 55.0% to 77.3%, whereas protection to IB in groups receiving both MD and IB vaccines ranged from 50.0% to 95.5%. In both experiments and within IBV challenge serotype, broilers given MD vaccines (in ovo or at hatch) and IB vaccines at hatch had protection rates to IBV challenges that were not significantly less (P < or = 0.05) than IB protection rates of groups that received only IB vaccines at hatch. Analysis of these data shows that administration of high-titered MD vaccines either in ovo or at hatch did not affect the efficacy of an IB vaccination (serotypes Ark and Mass) given by eyedrop at hatch.

Outbreak of Type C Botulism in Commercial Layer Chickens

SUMMARY This report describes an outbreak of type C botulism in two organic, free-range commercial layer farms in the Midwest. Hens affected were 64-wk-old Hy-Line brown hens and 34-wk-old Hy-Line brown hens owned by the same company, but housed on different premises, with approximately 20,000 birds per house. Mortality over the 2 wk of investigation was estimated to be up to 8% and 2.8%, respectively, with birds acting listless, lethargic, and depressed. Clinical signs consisted of progressive paralysis, and severely affected birds were moribund and laterally recumbent. Hens had ruffled feathers that easily epilated, with loss of muscular tone in the neck, tail, and wings. Hens had closed eyes and were reluctant to move. There were no significant gross or histopathologic lesions. Intestinal samples were submitted to the University of Pennsylvania Botulism Diagnostic Laboratory for real-time PCR and were positive for Clostridium botulinum organisms containing the Type C neurotoxin gene. Speculations on the source of the botulinum toxins include poor mortality removal leading to cannibalism of decomposing carcasses, as well as birds on the farm having access to putrid carcasses in the compost pile from a hole in their outdoor access fence.

Preparation and characterization of chicken intraepithelial leukocytes.

Intraepithelial leukocytes (IELs) form an important component of the intestinal immune system. Several methods of preparing chicken IELs were compared for cell yield, cell populations, and functional activity against a natural killer (NK)-susceptible lymphoblastoid cell line (LSCC-RP9). In addition, an attempt was made to immortalize IELs by infection with reticuloendotheliosis virus (REV) for use in cell-trafficking studies. Intestinal fragments were incubated in 5 mM DL-dithiothreitol at 41 degrees C for 15 min followed by three 45 min incubations in 0.1 mM EDTA. Gentle shaking of the intestinal fragments every 5 min caused considerably less damage to the epithelial cell layer than slow stirring with a magnetic bar. The latter method yielded more cells, but these were not functionally active in the NK-cell assay. The more gentle method resulted in a lower cell yield, but these cells were able to lyse LSCC-RP9; the percentage of lymphocytes present was lower but these contained a higher proportion of large granular lymphocytes. Infection of IELs with REV did not immortalize these cells.

Obstetrics and reproduction of backyard poultry

A short review of selected normal and abnormal conditions of the reproductive tract of backyard poultry is presented. This review includes sex differentiation, natural mating and artificial insemination, egg production, molting, and nutrition. Pathological conditions include fatty liver syndrome, caged-layer fatigue, cloacal prolapse, oviduct obstruction, cystic oviducts, neoplasms, and infectious diseases. This article attempts to include most common poultry species that are maintained for show or pleasure.

Pathogenicity of a quail (Coturnix coturnix japonica)-derived Marek's disease virus rescued from the QT35 cell line.

Abstract The QT35 cell line was established in 1977 from methylcholanthrene-induced tumors in Japanese quail. It was later shown that at least some of the QT35 cell lines were latently infected with Mareks disease (MD) virus (MDV). An MDV-like herpesvirus, named quail MDV (QMDV), was isolated from QT35 cells in 2000 by Yamaguchi et al. To determine the pathogenicity of QMDV, we inoculated 10-day-old specific-pathogen-free chickens with QMDV JM (virulent), RB-1B (very virulent), or 584A (very virulent plus). In addition, we inoculated 5-day-old Japanese quail with QMDV, JM, or RB-1B. QMDV is pathogenic in chickens with a tumor incidence comparable to JM. QMDV also caused MD in three out of 18 infected Japanese quail. In conclusion, QMDV is a virulent MDV, and its presence in QT35 cells has implications for the use of QT35 cells for vaccine production.