Poultry Day '98
Abstracts

The cAMP pathway has differential effects on trunk neural crest cells in primary cell culture.

The neural crest (NC) is an excellent model system for studying the molecular mechanisms which modulate differentiation in embryonic progenitor cells. NC is a transient population of ectodermal cells which arises during neurulation. These migratory stem-like cells are multipotent and differentiate to a variety of cell types such as neurons, neuroendocrine cells, smooth myocytes, osteoprogenitor cells, and melanocytes. The regulatory networks that direct the NC to form such diverse cell types are not well understood. Earlier studies have identified members of the bone morphogenic protein (BMP) family which promote differentiation of NC cells to adrenergic, tyrosine hydroxylase immunoreactive (TH⁺) cells. Using a similar approach, we employed the Japanese quail trunk NC primary culture system and investigated the role of the cAMP pathway in NC differentiation. In our studies, treatment of the cultures with forskolin (a cAMP elevating agent) increases the number of melanocytes but reduces the number of non-pigmented cells. Interestingly, treatment with both forskolin and BMP-2 increases the number of melanocytes, inhibits the BMP-2-stimulated differentiation of TH⁺ cells, and reduces the numbers of non-pigmented and total cells. While treatment with H-89 (a PKA inhibitor) alone does not have significant effects on the NC cultures, co-treatment with H-89 and BMP-2 slightly reduces the number of BMP-2-stimulated TH⁺ cells and increases the numbers of non-pigmented and total cells. From these data we conclude that BMP-2 predominantly influences the development of non-pigmented cells and that the cAMP pathway has differential effects in determining NC cell fate. Specifically, the cAMP pathway stimulates melanocyte development and reduces non-pigmented cell survival.

The opportunity to discover career possibilities in avian sciences regarding research, industry, and academics is the mission of the Purdue University Avian Sciences Club. The mission began in October 1997, with a callout meeting. Since that time club membership has risen to twenty undergraduate and graduate students. The club's success has been highly correlated with financial support derived from the Indiana State Poultry Association and the Turkey Market Development Council. Financial support has precipitated into some unique opportunities for the club. These opportunities include tours of several leading poultry operations within the state of Indiana and refreshments at club functions. Industry tours have proven instrumental in two respects, 1) in exposing club members to the poultry industry and career opportunities with the industry and 2) in enabling the industry to meet outstanding students with an avian interest. In a short time period, one year, the club has participated in many Purdue University Animal Sciences extracurricular activities. Not only has the club participated, the club has been in the spotlight at two of these activities, Tot’s Day (spring 1998) and Springfest (spring 1998). Both activities attracted large public audiences as well as the attention Purdue University faculty and staff. The Avian Sciences Club owes further gratitude to the Turkey Market Development Council for their support of the 1997 Thanksgiving Turkey Sale, in which they donated all turkeys that were sold (n=150) in cooperation with Block & Bridle. The sale served as the organization's first fundraiser, which of course proved to be successful. The future looks bright for the Avian Science Club after 1997's positive first year. Currently, many activities are on the horizon, 1) the Second Annual Thanksgiving Turkey Sale and 2) the fall Tot’s Day Activity. The Avian Sciences Club's past performance at youth activities indicates these activities will once again place the club in the spotlight. Also in the works for 1998-1999, is the continuance of tours of the poultry industry within Indiana, and a wider variety of guest speakers at meetings. The Avian Sciences Club at Purdue University is a highly successful student organization due to industry support and efforts of outstanding students.

Our lab is examining the function of naturally occurring peptides during avian skeletal muscle and bone development. To perform these analyses, we are using the RCAS-transgenic model and ectopically expressing fibroblast growth factors (FGFs) in the developing limb skeletal muscle and bone of chicken embryos. We have evidence that FGF5 and FGF8 are important and powerful regulators of skeletal muscle and cartilage development in vivo. We are currently examining the role of FGF5, FGF8 and other FGFs during the major events of limb organogenesis in vivo. The ultimate goal of these experiments is to identify factors which can be endogenously regulated via analogs, agonists, or natural selection, in order to enhance avian health and production.

Two experiments were conducted to determine the effect of sucrose thermal oligosaccharide caramel (STOC) and dietary vitamin-mineral (V/M) level on growth performance and intestinal microflora of broiler chickens. In Experiment 1, Peterson x Arbor Acres male broilers (n=384) were randomly allocated into four groups that were fed either the control diet or diets containing the antibiotic virginiamycin (11 mg/kg), 3.7% STOC or 7.5% STOC for 4 wk at brooding temperatures of 32 to 29.7 C. Weight gains for broilers in Experiment 1 were greater (P<0.001) for birds fed STOC diets, with weight gains of 763, 822, 1,124, and 1,080 g for birds on the control, antibiotic, 3.7% STOC, and 7.5% STOC diets, respectively. Feed intake and feed conversion by birds fed STOC diets were also significantly improved. Cecal bifidobacterial numbers were increased (P<0.03) over the control diet with number being 5.98, 6.99, 7.47, and 7.39 log₁₀ cfu/g cecal DM, respectively. In Experiment 2, Peterson x Hubbard male broilers (n=384) were used in a 2 x 2 x 2 factorial arrangement with two levels of V/M premix (0.5 or 1% of the diet), two levels of STOC (0 or 3.5% of the diet), and two brooding temperatures, normal (32 to 23.6 C) or high (32 to 29.7 C) for 4 wk. Feeding the STOC diet improved (P<0.05) weight gain, feed intake, and feed conversion of broilers. The effect of STOC on animal performance was less evident when broilers were fed twice the NRC recommended levels of V/M. Feeding the STOC diets resulted in a significantly greater increase in weight gain at high brooding temperatures than at normal brooding temperatures. There was also a reduction (P<0.05) in numbers of total aerobes and coliforms in the ceca of birds fed diets containing STOC. Feeding STOC has potential to improve growth performance of broiler chickens.

Cleavage and Inhibition of Infectious Bursal Disease Virus RNA Polymerase Gene Expression by A Ribozyme,

Infectious bursal disease virus (IBDV) replicates in bursal lymphocytes of chickens and causes bursal atrophy, resulting in immunosuppression. Infectious bursal disease virus could predispose chickens to opportunistic and secondary bacterial or viral infections. Infectious bursal disease (IBD) is mainly controlled by vaccination. However, there are antigenic variations among different strains of IBDV and the vaccination is not always effective. Therefore, development of new method that targets viral nucleic acids, their transcription or translation products, or viral replication stages has become one of the choices for anti-IBDV approach. Ribozyme is one of the most intensively explored tools among these virus replication interfering approaches. Ribozymes are catalytic small RNAs that can form base pairs with their single-stranded complementary nucleic acid targets and induce cleavage at a defined site to achieve the antiviral effect.

Five ribozymes were designed and cloned to cleave IBDV RNA. Two ribozymes (R1 and R2) were directed to the large segment RNA gene and three ribozymes (R3, R4, R5) were directed to the small RNA gene of IBDV. The ribozyme oligodeoxyribonucleotides were synthesized commercially, annealed, and cloned into an eukaryotic expression vector, yielding plasmids pR1, pR2, pR3, pR4, and pR5. The ribozymes were produced as in-vitro transcripts of their corresponding vectors. The targets for the ribozymes were produced from cloned full-length coding regions of both small and large segment genes obtained by amplification of IBDV cDNA in long and accurate PCR procedures. The ribozyme and target RNA were heat denatured and incubated together. The results of cleavage were analyzed by gel electrophoresis followed by autoradiography.

All of the ribozymes and the full-length targets for large and small segment genes were successfully cloned into the eukaryotic expression vector. After successful run-off transcription, in-vitro cleavage assays were done to find catalytically active ribozymes. The transcripts of the target templates were full length and there was no autocatalytic cleavage without the addition of ribozymes. Despite several attempts at different temperatures, no cleavage with four of the ribozymes (R1, R2, R3, and R5) was observed after denaturing gel electrophoresis and autoradiography for 16 h. The only enzymatically active ribozyme was R4. When the small segment RNA transcript and R4 transcript were incubated together, there was a specific cleavage producing expected bands on autoradiograph.

The results suggested that the ribozyme R4 is a potential anti-IBDV agent.

Outbreaks of turkey poult enteritis or poult enteritis mortality syndrome occurred in southern Indiana in the early 1990s and remain as a major concern in the turkey industry in North Carolina. The clinical signs of turkey poults with acute enteritis and the continuing finding of coronavirus from the affected poults are similar to the bluecomb disease (coronaviral enteritis) of turkey encountered in Minnesota between 1951 to 1971.

The immunofluorescent antibody (IFA) test has been established for the diagnosis of turkey coronavirus (TCV) induced turkey poult enteritis in the branch laboratory of Animal Disease Diagnostic Laboratory in southern Indiana (SIPAC). However, the IFA test is labor-intensive and time-consuming when the test was applied to evaluate large numbers of clinical samples. In order to rapidly diagnose as well as effectively control turkey poult enteritis, development of an antibody-capture enzyme-linked immunosorbent assay (ELISA) for quantitative serological evaluation of TCV infection in turkey flocks is essential. Due to the lack of an appropriate tissue culture system to propagate large quantity of TCV for purification, other coronaviruses with cross-reactivity to antibody against TCV were investigated and intended to use as an alternative antigen in antibody-capture ELISA for TCV.

Based on the positive cross-reactivity between anti-infectious bronchitis virus (IBV) antibody and TCV-infected intestines in IFA assay and between anti-TCV antibody and IBV in ELISA, utilization of commercially available IBV-coated ELISA plates in antibody-capture ELISA for TCV was attempted. The dilutions of turkey serum samples and horseradish peroxidase (HRPO)-conjugated goat anti-turkey IgG for the ELISA system were optimized by checkerboard tests. Anti-TCV hyperimmune turkey serum and normal turkey serum were used as positive or negative control serum for optimization of the ELISA system. The performance of the ELISA system was done by evaluating 45 normal turkey sera and 95 turkey sera from the field. The results of ELISA were compared to that of IFA.

Forty five normal turkey sera had very low absorbance readings ( range from 0.031 to 0.082) in the ELISA using IBV ELISA plates. Of the 95 sera from field, 48 were positive for TCV by IFA. Ninety-eight percent (n=47) of the IFA-positive sera to TCV had very high absorbance readings (range from 0.289 to 3.180) in the ELISA. The responses of the IFA-positive sera to TCV were much higher than that of normal turkey sera in the ELISA. The absorbance readings of most of the IFA-negative sera to TCV were in between that of normal turkey sera and that of IFA-positive sera to TCV. If the normal turkey sera and the IFA-positive sera to TCV were used as known negative and positive controls, the sensitivity and specificity of this antibody-capture ELISA for TCV antibody were 98% and 100%, respectively.

The result indicates that commercially available ELISA plates coated with IBV antigens could be utilized for the detection of antibodies to TCV in antibody-capture ELISA.

Deprivation of Calcium Activates A Potassium Current in Chicken Ovarian Granulosa Cells.

Calcium (Ca²⁺) plays important roles in ovarian granulosa cell function. Both extracellular and intracellular Ca²⁺ have been shown to participate in many metabolic processes in granulosa cells. Here, we report an unexpected effect of omission of extracellular Ca²⁺ on potassium currents. Granulosa cells were isolated from the largest preovulatory follicle of hen ovary by collegenase dispersion and cultured for 0.5-10 hr in M199. Membrane currents were recorded with the patch clamp technique in the conventional whole-cell configuration. With a pipette solution of KCl 132 mM, NaCl 5 mM, ATPNa₂ 3 mM, GTPNa₃ 5 mM, HEPES 10 mM, EGTA 0.1 mM, CaCl₂ 70 m M, MgCl₂ 1 mM and bath solution containing NaCl 134.3 mM, KCl 5.4 mM, CaCl₂ 2.5 mM, MgCl₂ 1.1 mM, Glucose 5.6 mM, HEPES 10 mM, two different types of outward currents could be observed when the holding potential was -80 mV. One type of the outward current was fast activating and fast inactivating (transient) and was observed in about 10% of all successful experiments. This fast activating and transient current was eliminated at a holding potential of -40 mV and is referred to as A-current. In addition, a delayed and non-transient outward current was observed and referred to as K-current. When Ca²⁺ was removed from the bath solution and EGTA (5 mM) added, a large fast activating and inactivating current (A-like current) could be seen in some cells that expressed only the delayed K-current. This Ca²⁺ deprivation-induced transient current was activated in less than 1 ms after onset of the step command, reached a peak in less than 2 ms, and was inactivated in a few ms to 100 ms. The greater the amplitude of the Ca²⁺ deprivation-induced current, the longer its duration. When the membrane potential was held at -40 mV, the Ca²⁺ deprivation-induced A-like current disappeared completely. Ca²⁺ deprivation also activated the A-like current when 5 mM EGTA was included in pipette solution. The Ca²⁺ deprivation-induced A-like current was not affected by the removal of chloride from the bath solution. In other experiments, both Ca²⁺ and Mg²⁺ were sequentially removed from the bath solution. The substitution of Mg²⁺ for Ca²⁺ in the bath (extracellular) solution, had no apparent effect on the delayed non-transient current (K-current). However, when both Ca²⁺ and Mg²⁺ were removed and 5 mM EGTA introduced into the bath solution an A-like fast and transient outward current was activated at a step potential more positive than +20 mV. The time course of activation and decay of this current was similar to that observed for the A-current. Because, the A-like current disappeared at a holding potential of -40 mV, and because the outward currents were not affected in chloride-free bath solution, the outward currents may be carried by K⁺. The mechanism by which removal of extracellular Ca²⁺ activates the A-like current remains to be elucidated.

Since the mid-1980's, shell eggs have become increasingly involved in foodborne outbreaks of Salmonella enteritidis (SE). Egg-related outbreaks of S. enteritidis are potentially life-threatening to many segments of the population. Although proper cooking will kill the bacteria, many outbreaks have resulted from insufficient cooking or cross contamination from contaminated eggs. The long-time, low-temperature process was necessary to provide a pasteurization method that would produce minimal changes in the aesthetic and functional properties of egg. Our previous studies demonstrated the possibility of a five log cycle reduction of SE in inoculated eggs at 55oC without a significant change in the quality of the eggs. Later we obtained a seven log cycle reduction in inoculated intact eggs at 57oC. The process is simultaneously being scaled up to pilot scale to demonstrate commercial feasibility of the process. Currently we are working with the Stein Laboratories and observed that, their existing processing equipment can be effectively used for pasteurization of intact shell eggs. These results are gratify the chances of adopting this existing processing equipment for pasteurization of shell eggs. Further we used the microwave energy to pasteurize shell eggs and observed that Microwaves can be successfully used either alone or in combination with this new technology to kill the target  bacteria. The present microwave technology needs some modifications in order to adopt for pasteurization of shell eggs. From this study we observed that this new technology is feasible to achieve and it is not far to get a pasteurized shell eggs on our dining table.

The purpose of this study was to evaluate the effects of conjugated linoleic acids (CLA) on embryonic growth, fatty acid metabolism, and circulating lipids. Forty hens were divided into four equal groups and given the following treatments. Group A served as the control, Group B received 1 g of CLA every other d, Group C received 1 g of CLA every forth d and Group D was sham-supplemented with 1 g of safflower oil every other d. After four months of feeding, hens were inseminated from a pool of collected rooster semen. Eggs corresponding to the various hen groups were gathered and incubated. At hatch and through six d of life, chick BW was not changed; however, relative yolk weight was suppressed by two-fold in chicks hatched from Groups C, B, and D fed hens. At two and four d chicks hatched from Group B hens exhibited the highest percentage of retained yolk (two-fold) when compared to any other group. Serum triglycerides was highest in chick hatched from hens in Groups A and B with Group C chicks being intermediate and not different from the lowest, Group D hatched chicks. Free cholesterol was highest in chicks hatched from Group C fed hens. These results would indicate that CLA alters lipids in newly hatched chicks.

Virtually all of the cholesterol (CHOL) found in avian egg yolk originates from the liver, where it is synthesized, incorporated into VLDL particles, and transported to the ovary. We have previously shown that lovastatin (LV) and PD123244-15, both inhibitors of HMG-CoA reductase (HMGR), can lower egg cholesterol levels by 15% or 30%, respectively, when orally administered to laying hens. HMGR is the key enzyme which controls the rate of CHOL biosynthesis in the liver. In the present study, we compared the effects of atorvastatin (AV), LV, and simvastatin (SV) on cholesterol and lipoprotein metabolism in chickens. Ten White Leghorn hens were fed an unmedicated diet (CON), while 5 hens each were fed AV, LV, or SV at either 0.03% or 0.06% of the diet (daily intake of ~30 or 60 mg drug/bird) for 5 weeks. As compared to CON birds, hens fed 0.06% AV exhibited significantly lower plasma total CHOL (63% reduction), plasma triglycerides (71% reduction), and total egg CHOL (47% reduction). The latter figure, accounted for by a 19% decrease in yolk weight combined with a 35% reduction in the amount of CHOL/g yolk, represents the largest statin-mediated reduction in egg CHOL reported to date. Despite a 220% increase in hepatic HMGR activity after 5 weeks of treatment, the mean diameters of plasma VLDL particles from hens fed 0.06% AV were smaller (34.7 nm vs 35.7 nm) and contained 38% less total CHOL than those of CON birds. For all of the above variables, the magnitude of response was AV>SV>LV>CON, with the 0.06% dose of each drug generally producing a greater effect than the 0.03% dose.

In terms of its energy content and protein digestibility, tannin-free sorghum grain is considered to be somewhat inferior to corn as a feedstuff for nonruminants. Thus, the recent discovery of sorghum cultivars with higher than normal protein digestibilities is noteworthy. Since the protein quality assessment of these novel grains has been limited to in vitro procedures and short-term chick feeding trials, we sought to determine the nutritional value of a highly digestible sorghum genotype in a broiler grow-out study. Three pens of 36, one-day-old male chicks each were assigned to one of eight diets during each of two consecutive 3-wk periods. The starter diets (0-3 wk) and finisher diets (4-6 wk) contained either 23 or 20% CP, or 20 or 17% CP, respectively, with corn, two normal sorghums (P721N and 611Y), and a highly digestible sorghum (P851171) serving as the cereal sources. Chicks fed 23% CP diets from 0-3 wk were fed 20% CP diets from 4-6 wk, while those fed 20% CP diets from 0-3 wk, were fed 17% CP diets from 4-6 wk. Within each 3-wk period, a 4 x 2 factorial arrangement of treatments was employed and within each CP level, the four cereals were compared on an isonitrogenous basis. All three sorghums supported weight gains equal to those of corn-fed chicks at all stages of the study. Suboptimal levels of dietary CP resulted in reduced weight gains regardless of cereal source, with no observed benefit of P851171 at the deficient CP levels. Furthermore, chicks fed P851171 exhibited poorer feed efficiency values as compared to those fed the other cereals. Based on TME_n values, it is possible that the starch content/availability of P851171 was inferior to that of P721N or 611Y, which could have offset its superior protein digestibility and resulted in poorer broiler performance. Studies are underway to assess the starch quality of the highly digestible cultivars.

Space biology studies using avians have included the chicken and quail. Chicken embryos exposed to microgarvity aboard shuttle STS-29 resulted in the premature deaths of all of the younger embryos (day 2 to 7 of space flight) as compared to 100% development in the controls. Older embryos, which incubated from the 9^th to the 14^th day of incubation in microgravity, developed normally with the exception that more afferent fibers inside the macular epithelia of the inner ear were apparent in flight embryos (Fermin et al., 1996, Histol Histopathol 11:407). Half of the older embryos were allowed to hatch and the post hatch performance which included a second generation of chicks, was unaffected by microgravity (Hester et al., 1993, Acta Brno, Suppl. 6, 42:S43) with the exception of vestibular function. Three of the 8 flight chicks had elevated vestibular thresholds (Jones et al., 1993, Acta Vet. Brno Suppl. 6, 42:S35).

The use of food-producing avian species for studies in an orbital biological laboratory requires consideration for available space and hardware compatible to space station conditions for the development of such species. The Japanese quail (coturnix quail) appears to be suitable for development in biological studies within the closed shuttle ecosystem. Experimental trials using quail as a possible biological life-support system in space have shown that quail meets the requirements of the system in energy efficiency, productivity, quality of reproduction, rearing techniques, and stability in extreme conditions (Meleshko et al., 1993, Acta Vet. Brno, Suppl. 6, 62:S9). However, the production of quail in a microgravity environment for research or regeneration of food, requires the study of the complete life cycle of the quail from embryogenesis to the hatched chick and growth performance thereafter. The problem of hardware and habitat for quail development became obvious when quail eggs were allowed to hatch in space. The quail hatchlings in the weightless environment were not able to feed on their own during the first 3-4 days (Guryeva et al., 1993, Acta Vet. Brno, Suppl. 6, 42:S25). Other observations (Kostal et al., 1993, Acta Vet. Brno, Suppl. 6, 42:S65) indicated that quail hatchlings on the orbital space station, Mir, experienced spinning behavior and were not able to feed themselves. Thus, habitat hardware with a feed restraining device will be necessary. Other quail studies showed high mortality rate of the developing embryo in microgravity.

A more successful quail study was most recently completed in the orbital space station, Mir which involved researchers from Purdue University (Drs. Patricia Y. Hester and Joseph I. Orban), NASA Research Station, Ames, California, other universities in the United States and Russia. In this study, there was 59% embryonic viability of the 48 eggs incubated on Mir while the controls averaged 91% viability. The report presented herein is focused on calcium uptake from eggshells by the quail embryos as they developed under weightlessness on Mir. One of the objectives of the study was to determine the effect of space flight on mineral uptake or utilization from the eggshell by the developing quail embryos during a 16-day incubation period. Comparisons were made with results obtained from each group of 48 quail eggs incubated on earth under laboratory or synchronous (space simulation) conditions. Eggshells retrieved from eggs incubated in space, as well as laboratory or synchronous controls, were analyzed for calcium content at Purdue University. Results showed that the embryos incubated in space used less calcium from eggshells than those incubated on earth under laboratory or synchronous conditions. In general, calcium uptake by embryos increased with age of incubation, with the most increase occurring by day 16 of incubation. Results showed that space flight impaired calcium uptake by quail embryos. However, it was not clear whether the impairment was due to factors other than microgravity.

The Pathogenesis of Staphylococcosis in Poultry

Staphylococcus aureus is the major bacteria isolated from the bones and joints of birds that have succumbed to osteomyelitis and synovitis. This same bacteria causes footpad dermatitis. Osteomyelitis can be experimentally induced by intravenously injecting S. aureus; however, this exposure is not a natural port of entry for the bacteria. Many birds diagnosed with staphylococcosis have no broken area on the skin to suggest an intravenous route of infection (Riddell, 1983). We are investigating the possibility that birds in the field become sensitized to S. aureus through multiple exposures of the respiratory tract. If these sensitized birds are subsequently challenged with S. aureus, we are hypothesizing that they develop delayed-type hypersensitivity (DTH) which may make them more susceptible to an osteomyelitis outbreak, especially under stressful conditions.

The carrier status of S. aureus in healthy chickens and its effect on the induction of the delayed footpad reaction (DFR) to killed S. aureus antigen were investigated. The recoveries of S. aureus from the choanal slit and trachea in healthy chickens were significantly higher than that of the cloaca. Overall, about 49% of the birds tested for S. aureus were positive carriers. These results indicate the prevalence of S. aureus in our population of birds, and the predominance of the bacteria at the entrance of the bird's respiratory tract. Birds pre-sensitized s.c. with killed S. aureus showed a significant delayed footpad reaction (DFR) following intradermal challenge with S. aureus with no difference in the DFR between carrier and non-carrier birds. Using five criteria, the DFR induced by killed S. aureus in chickens was confirmed to be a cell-mediated DTH reaction. The five criteria were: 1) the DFR with a peak response at 24 to 48 h postchallenge, 2) inhibition of monocyte/macrophage migration, 3) lymphocyte blastogenic response, 4) mononuclear cell infiltration at the challenge site, and 5) passive transfer of DFR by splenic lymphocytes. These results indicate that the DFR can be used as a delayed reaction model in the study of staphylococcosis in poultry.

Is it possible that birds could be sensitized to S. aureus through the respiratory tract and display DTH? Recent results from our laboratory indicate that the DTH reaction can also be induced via multiple intratracheal inoculations of killed S. aureus antigen. Intratracheally sensitized birds showed significant DFR compared to nonsensitized birds, reaching a maximum response at 24 h postchallenge. The histological examination of S. aureus-injected footpads of intratracheally sensitized birds showed typical perivascular infiltration of small lymphocytes.

Whether or not prior exposure to S. aureus would facilitate the systemic infiltration of this pathogen following intradermal footpad challenge with live S. aureus was also investigated. Birds injected in the footpads with live S. aureus as compared to PBS had significantly higher S. aureus recoveries in the spleen, liver, and blood; however, the recovery and distribution of S. aureus between S. aureus-sensitized and polyethylene glycol-injected birds were not significantly different. Stress will be incorporated into future studies to determine if birds displaying DTH are susceptible to an osteomyelitis outbreak.

Sponsors:

Indiana State Poultry Association
The Turkey Market Development Council