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Breeding and Genetics bronchitis


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									Volume 77, August 1998 Number 8

Breeding and Genetics
1065.- Responses to Ten Generations of Divergent Selection for Tibial
Dyschondroplasia in Broiler Chickens: Growth, Egg Production, and Hatchability
Departments of *Poultry Science and †Animal and Dairy Sciences, Alabama
Agricultural Experiment Station, Auburn University, Alabama 36849-5416
ABSTRACT Continued genetic selection for improved BW gain has met an obstacle of
skeletal disorders in broiler chickens. Two broiler chicken lines (HTD and LTD) were
developed by 10 generations of divergent selection for tibial dyschondroplasia (TD)
incidence originating from commercial primary breeders. The reference population was
a randombred control line maintained along with the selected lines. Relationships of TD
incidence with BW, egg production (EP), and hatchability were assessed using these
lines. The response of TD to selection was asymmetric, favoring an increased TD
incidence. Mean TD incidence increased 7.6 percentage points per generation during
Generation 1 through 10 in males and 9.1 percentage points in females of the HTD line
but did not change significantly in the LTD line at 4 wk of age. Responses of the HTD
line in early (1 to 4) generations were greater than in later (6 to 10) generations, in
contrast to nonsignificant responses for both durations in the LTD line. The 4-wk BW of
the HTD line was slightly heavier than or similar to that of the LTD line within
generations. The HTD line birds tended to decrease 7-wk BW with advancing
generations. The trend of changes in BW was not as clear in the LTD line as in the HTD
line. The variability of 7-wk BW had an increased trend with advancing generations in
the HTD line, accompanied by a decreased additive genetic variability of TD due to
continued selection. The average EP in the LTD hens was 7.6 percentage points higher
than in the HTD from Generations 1 through 10. Mean hatchability in the LTD line did
not differ from that in the HTD line within generation. Responses of EP and hatchability,
components associated with fitness, appeared slower towards increased fitness than
towards decreased fitness.
Key Words: body weight, broiler, egg production, hatchability, tibial dyschondroplasia
1998 Poultry Science 77:1065-1072

1073.- Mode of Inheritance of Unselected Traits in Lines of Chickens Selected for
High or Low Antibody Response to Sheep Red Blood Cells. 1. Resistance to
Marble Spleen Disease Virus and Juvenile Body Weight
YANG,* and P. B. SIEGEL,*
*Department of Animal and Poultry Sciences and †Department of Large Animal
Clinical Sciences, Virginia Tech, Blacksburg, Virginia 24061-0306
ABSTRACT Two lines of White Leghorns that had undergone long-term selection for
high (HH) or low (LL) antibody response to sheep red blood cell antigen(s) formed the
nuclear lines for this experiment. Matings were made in a full diallel cross to produce in
a single hatch from age-contemporary breeders the parental lines, reciprocal F1 and F2
crosses, and backcrosses for 16 progeny types. For males and females, there were
parental line differences in BW to 42 d of age, after which there was a decline between
lines for males. Differences in BW between reciprocal F1 crosses and maternal
heterosis declined with age, primarily reflecting dissipation of effects of egg weight.
Heterosis of BW was dependent on the particular F1 cross and recombination effects
were not important. At 50 d of age chicks were inoculated with either a 1 or 10%
suspension of spleen extract from chickens infected with marble spleen disease virus
(MSDV). A third group served as uninjected controls. Response to MSDV was
evaluated by spleen weight 6 d after inoculation. Spleen weights relative to BW of
control chicks were heavier for the HH than LL line with evidence from the crosses of
sex-linkage and negative heterosis. Line LL chicks were more resistant to MSDV than
Line HH chicks with F1 crosses intermediate to and different from either parental line
with no evidence of heterosis.
Key Words: heterosis, sheep red blood cells, spleen, marble spleen disease, body
1998 Poultry Science 77:1073-1080

1081.- Mode of Inheritance of Unselected Traits in Lines of Chickens Selected for
High or Low Antibody Response to Sheep Red Blood Cells. 2. Heterophils,
Lymphocytes, and Hematocrits
Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, Virginia
ABSTRACT The nuclear lines for this experiment were White Leghorns that had
undergone long-term selection for high (HH) or low (LL) antibody response to sheep red
blood cell antigen(s). Sixteen progeny types consisting of parental lines, reciprocal F1
and F2 crosses, and backcrosses were produced in a single hatch from age-
contemporary parents. At 30 d of age, blood was obtained from a random sample of 10
males per progeny type (n = 160) and slides prepared for subsequent determination of
number of heterophils and lymphocytes. Twelve days later, blood was collected from
random samples of 10 males and 10 females per progeny type (n = 320) for measuring
hematocrits. There were no differences between parental lines for heterophils,
lymphocytes, or the heterophil:lymphocyte ratio. Reciprocal effects were evident in the
F1 crosses and directional heterosis was present in one cross but not the other. Neither
maternal heterosis nor recombination effects were significant for either heterophils or
lymphocytes. Although hematocrits were similar for males and females and parental
lines, sex-linked and recombination effects appeared to be important.
Key Words: chicken, sheep red blood cells, hematocrits, heterophils, lymphocytes
1998 Poultry Science 77:1081-1084

Education and Production
1085.- The Effect of Dietary Protein and Phosphorus on Ammonia Concentration
and Litter Composition in Broilers
*Animal Science and Poultry Science Department, University of Natal, P Bag X01,
Scottsville, 3209, South Africa, †Department of Biosystems and Agricultural
Engineering and ‡Department of Animal Sciences, University of Kentucky,
Lexington, Kentucky, 40546, and §Heartland Lysine Inc., 8430 W. Bryn Mawr Ave,
Chicago, Illinois, 60631
ABSTRACT An experiment was conducted to determine whether broiler litter
concentration of N and P and equilibrium NH3 gas concentration can be reduced by
reducing dietary CP and P levels and supplementing with amino acids and phytase,
respectively, without adversely affecting bird performance. Equilibrium NH 3 gas
concentration above the litter was measured. The experiment was divided into a starter
period (1 to 21 d) and grower period (22 to 42 d), each having two different CP and P
levels in a 2 x 2 factorial arrangement. The CP treatments consisted of a control with a
mean CP of 204 and 202 g/kg for starter and grower periods, respectively, and a low
CP diet with means of 188 and 183 g/kg, respectively, but with similar amino acid levels
as the control. The P treatments comprised starter and grower control diets containing
means of 6.7 and 6.3 g/kg P, respectively, and low P treatment means of 5.8 and 5.4
g/kg P supplemented with 1.0 g/kg phytase.
Reducing starter diet CP by 16 g/kg reduced weight gain by 3.5% and, hence, body
weight at 21 d of age, but did not affect feed intake or feed efficiency. Reducing P did
not affect feed intake and weight gain, but improved feed efficiency by 2.0%.
Responses in feed intake and efficiency to CP depended on the level of dietary P. For
the grower period there were no significant differences in feed intake, weight gain, and
feed efficiency, nor in body weight at 42 d of age, after correcting for 21-d body weight,
between CP and P treatments.
There were significant (P < 0.001) reductions in litter N and P concentrations, but not
equilibrium NH3 gas concentration, moisture content, or pH, for low CP and P diets.
Mean equilibrium NH3 gas concentration was 63 ppm. Litter N concentration was
reduced 16.3% with the low CP diets, and litter P by 23.2% in low P treatments. The
results suggest that dietary manipulation shows merit for reducing litter N and P
concentrations while maintaining acceptable production performance from broilers.
Key Words: crude protein, phytase, ammonia, litter composition, broiler
1998 Poultry Science 77:1085-1093

Environment, Health and Behaviour
1094.- Aflatoxicosis in Turkey Poults is Prevented by Treatment of Naturally
Contaminated Corn with Ozone Generated by Electrolysis
*Department of Veterinary Anatomy and Public Health, Faculty of Toxicology,
College of Veterinary Medicine, Texas A&M University, College Station, Texas
77843-4458, †USDA, Agricultural Research Service, Food Animal Protection
Research Laboratory, 2881 F&B Road, College Station, Texas 77845, and
  Lynntech, Inc., 7610 Eastmark Drive, Suite 105, College Station, Texas, 77840
ABSTRACT Previous studies have demonstrated that a novel source of ozone gas (O 3)
may be used to chemically degrade numerous mycotoxins, including aflatoxin (AF) B 1.
Subsequent in vitro analyses demonstrated detoxification of AFB1, suggesting a
potential method to remediate AF-contaminated grain. The objective of this study was to
evaluate the capability of electrochemically produced ozone to degrade AFB 1 in
naturally contaminated whole kernel corn and confirm detoxification in turkey poults.
Corn was procured from the southern coastal area of Texas and HPLC revealed 1,220
± 73.3 ppb AFB1. Control and contaminated corn were treated for 92 h with O 3 at 200
mg/min in 30 kg batches; greater than 95% reduction of AFB1 in contaminated corn was
achieved. One-day-old female turkey poults were fed 1) control corn, 2) control corn +
O3, 3) AFB1 corn, or 4) AFB1 corn + O3 mixed in rations (46% by wt.) and consumed ad
libitum for 3 wk. When compared with controls, turkeys fed AFB1 corn had reduced body
weight gain and relative liver weight, whereas turkeys fed control corn + O 3 or AFB1
corn + O3 did not differ from controls. Furthermore, alterations in the majority of relative
organ weights, liver discoloration, serum enzyme activity, hematological parameters,
and blood chemistry caused by AFB1 were eliminated (no difference from controls) by
treatment with O3. These data demonstrate that treatment of contaminated corn with
electrochemically produced O3 provided protection against AFB1 in young turkey poults.
It is important to note that treatment of control corn with O3 did not alter the performance
of the turkey poults.
Key Words: aflatoxin, detoxification, ozone, corn, turkey
1998 Poultry Science 77:1094-1102

1103.- Hypothermia, Hypoglycemia, and Hypothyrosis Associated with Poult
Enteritis and Mortality Syndrome
Department of Poultry Science, North Carolina State University, Raleigh, North
Carolina 27695-7635
ABSTRACT A metabolic dysfunction contributes to the poor performance and mortality
associated with Poult Enteritis and Mortality Syndrome (PEMS). Within 2 d after
contact-exposed poults were removed from the presence of PEMS-infected poults and
returned to their respective treatment rooms to infect experimental poults, the
experimental poults began to huddle together and show signs of the disease. When
separated from the huddle, body temperatures of exposure poults were depressed
significantly. Body temperatures decreased progressively through 8 d after exposure
with a maximum depression of 2 C and returned to a normal level at 18 d after PEMS
exposure. Similar decreasing patterns in serum glucose, inorganic phosphorus,
triiodothyronine, and thyroxine were observed, with maximum decreases in these serum
constituents being found between 8 and 13 d after PEMS exposure. There were
significant correlations among decreasing body temperatures, decreasing serum
constituents, and mortality in the PEMS-exposed poults. Daily mortality rates associated
with PEMS began at 6 d and peaked at 9 d after PEMS exposure. Mortality rates
decreased from 9 to 15 d after experimental PEMS exposure. Depressions in serum
constituents, body temperature, and increased mortality rates did not coincide with
decreased feed intake associated with PEMS. Therefore, it was concluded that the
agent(s) causing PEMS may have a direct effect on energy metabolism in afflicted
Key Words: poult enteritis, mortality, thyroxine, triiodothyronine, body temperature
1998 Poultry Science 77:1103-1109

Symposium: Infectious Poultry Diseases
1110.- Introduction
*Food Animal Health Research Program, Ohio Agriculture Research and
Development Center, The Ohio State University, Wooster, Ohio 44691, and †USDA,
Agricultural Research Service, Southeast Poultry Research Laboratory, 934
College Station Road, Athens, Georgia 30605
ABSTRACT The Poultry Science Association (PSA) and the American Association of
Avian Pathologists (AAAP) are professional associations that provide support to the
poultry and allied industries of North America in the areas of nutrition, engineering,
management, processing, food safety and veterinary medicine. In 1995, Mary Ann
Ottinger, President of the PSA, and Y. M. Saif, President of the AAAP, met during the
annual meeting of the PSA in Edmonton, Alberta, Canada and discussed ways to bring
about a closer working relationship between the two organizations. The emphasis was
on three areas of interaction: 1) exchange of speakers at annual meetings of the
organizations, 2) special scientific symposia, and 3) joint lecture programs.
The jointly sponsored symposium on Infectious Poultry Diseases preceded the annual
meeting of the PSA in Athens, Georgia on August 2 and 3, 1997. Funding for this
historic joint symposium was obtained by the symposia organizing committee
specifically for this event, and did not come from the operational funds of either PSA or
AAAP. Funds were solicited from potential corporate donors with emphasis on not
reducing funding to the programs or annual meetings of PSA and AAAP. The
symposium had 19 invited speakers and 260 participants.
Key Words: infectious poultry diseases, Poultry Science Association, American
Association of Avian Pathologists
1998 Poultry Science 77:1110

1111.- Impact of Genetics on Disease Resistance
Department of Animal Science, Iowa State University, Ames, Iowa 50011-3150
ABSTRACT The genetics of a bird or flock has a profound impact on its ability to resist
disease, because genetics define the maximum achievable performance level. Careful
attention should be paid to genetics as an important component of a comprehensive
disease management program including high-level biosecurity, sanitation, and
appropriate vaccination programs. Some specific genes (e.g., the MHC) are known to
play a role in disease resistance, but resistance is generally a polygenic phenomenon.
Future research directions will expand knowledge of the impact of genetics on disease
resistance by identifying non-MHC genetic control of resistance and by further
elucidating mechanisms regulating expression of genes related to immune response.
Key Words: genetics, disease, Major Histocompatibility Complex, immunoglobulins,
Salmonella enteritidis
1998 Poultry Science 77:1111-1118

1119.- Nutritional Modulation of Resistance to Infectious Diseases
Department of Avian Sciences, University of California, Davis, California 9561
ABSTRACT Dietary characteristics can modulate a bird's susceptibility to infectious
challenges and subtle influences due to the level of nutrients or the types of ingredients
may at times be of critical importance. This review considers seven mechanisms for
nutritional modulation of resistance to infectious disease in poultry. 1) Nutrition may
impact the development of the immune system, both in ovo and in the first weeks
posthatch. Micronutrient deficiencies that affect developmental events, such as the
seeding of lymphoid organs and clonal expansion of lymphocyte clones, can negatively
impact the immune system later in life. 2) A substrate role of nutrients is necessary for
the immune response so that responding cells can divide and synthesize effector
molecules. The quantitative need for nutrients for supporting a normal immune system,
as well as the proliferation of leukocytes and the production of antibodies during an
infectious challenge, is very small relative to uses for growth or egg production. It is
likely that the systemic acute phase response that accompanies most infectious
challenges is a more significant consumer of nutrients than the immune system itself. 3)
The low concentrations of some nutrients (e.g., iron) in body fluids makes them the
limiting substrates for the proliferation of invading pathogens and the supply of these
nutrients is further limited during the immune response. 4) Some nutrients (e.g., fatty
acids and vitamins A, D, and E) have direct regulatory actions on leukocytes by binding
to intracellular receptors or by modifying the release of second messengers. 5) The diet
may also have indirect regulatory effects that are mediated by the classical endocrine
system. 6) Physical and chemical aspects of the diet can modify the populations of
microorganisms in the gastrointestinal tract, the capacity of pathogens to attach to
enterocytes, and the integrity of the intestinal epithelium.
Key Words: nutrition, immune response, acute phase response, infectious disease,
1998 Poultry Science 77:1119-1125

1126.- Understanding Immunology in Disease Development and Control
Department of Poultry Science, North Carolina State University, Raleigh, North
Carolina 27695-7608
ABSTRACT Two functional aspects of the avian immune system, the humoral and the
cell-mediated arms, provide the basis for the preventive and protective response
against disease-causing microorganisms. On the other hand, certain avian diseases
may induce a transient or permanent immunosuppressive state in one or both of these
arms, leading to increased disease susceptibility. In addition to the classical immune
response, manifested as antibody production or effector cell activation, several
cytokines and metabolites are also produced. The consequence of cytokine- and
metabolite-mediated microenvironments may be either beneficial or result in a
noninfectious immunopathology. Nevertheless, the integrity of the immune system and
its functional modulation by factors such as genetics, nutrition, and prophylactic
approaches continue to be an important focus of attention in current poultry research
and production efforts.
Key Words: immunosurveillance, cytokines, immunomodulation
1998 Poultry Science 77:1126-1129

1130.- Relationship of Structure and Function of the Avian Respiratory System to
Disease Susceptibility
Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas
State University, Manhattan, Kansas 66506-5602
ABSTRACT The avian respiratory system exchanges oxygen and carbon dioxide
between the gas and the blood utilizing a relatively small, rigid, flow-through lung, and a
system of air sacs that act as bellows to move the gas through the lung. Gas movement
through the paleopulmonic parabronchi, the main gas exchanging bronchi, in the lung is
in the same direction during both inspiration and expiration, i.e., from the mediodorsal
secondary bronchi to the medioventral secondary bronchi. During inspiration,
acceleration of the gas at the segmentum accelerans of the primary bronchus increases
gas velocity so it does not enter the medioventral secondary bronchi. During expiration,
airway resistance is increased in the intrapulmonary primary bronchus because of
dynamic compression causing gas to enter the mediodorsal secondary bronchi.
Reduction in air flow velocity may decrease the efficiency of this aerodynamic valving
and thereby decrease the efficiency of gas exchange.
The convective gas flow in the avian parabronchus is orientated at a 90o angle with
respect to the parabronchial blood flow; hence, the cross-current designation of this gas
exchanger. With this design, the partial pressure of oxygen in the blood leaving the
parabronchus can be higher than that in the gas exiting this structure, giving the avian
lung a high gas exchange efficacy. The relationship of the partial pressure of oxygen in
the moist inspired gas to that in the blood leaving the lung is dependent on the rate of
ventilation. A low ventilation rate may produce a low oxygen partial pressure in part of
the parabronchus, thereby inducing hypoxic vasoconstriction in the pulmonary arterioles
supplying this region.
Inhaled foreign particles are removed by nasal mucociliary action, by the mucociliary
escalator in the trachea, primary bronchi, and secondary bronchi. Small particles that
enter parabronchi appear to be phagocytized by the epithelial cells in the atria and
infundibulum. These particles can be transported to interstitial macrophages but the
disposition of the particles from this site is unknown. The predominant site of respiratory
infections in the caudal air sacs, compared to other parts of the respiratory system, can
be explained by the gas flow pathway and the mechanisms present in the parabronchi
for particle removal.
Key Words: lung, air sacs, ventilation, defense system, pulmonary blood flow
1998 Poultry Science 77:1130-1138
1139.- Bacterial Respiratory Diseases of Poultry
Department of Avian Medicine, University of Georgia, Athens, Georgia 30602-4875
ABSTRACT Bacterial pathogens play an important role in causing respiratory disease
in domestic poultry species. In many cases, the bacterial component of a respiratory
disease colonizes the respiratory system only after a primary viral or environmental
insult. Colonization of the airsacs of a chicken by Escherichia coli following an infectious
bronchitis virus infection is an example of secondary bacterial invasion. In other cases,
the bacterial component of the respiratory disease is the primary initiating cause of the
disease. Examples of primary bacterial respiratory disease are infectious coryza in
chickens and fowl cholera in chickens and turkeys.
Key Words: respiratory system, bacteria, poultry
1998 Poultry Science 77:1139-1142

1143.- Viral Diseases of the Respiratory System
Department of Avian Medicine, University of Georgia, Athens, Georgia 30602-4875
ABSTRACT Infectious bronchitis, Newcastle disease, infectious laryngotracheitis, avian
influenza, and pneumovirus are the viruses that more frequently affect the respiratory
tract of chickens. Because of the tendency to change its antigenic properties, infectious
bronchitis is currently the viral disease present in most poultry producing areas of the
world. New serotypes and variant strains are reported in several countries. Current
commercially available vaccines do not always provide protection against new field
isolates. Vaccination programs are constantly adjusted in an attempt to improve
protection against this disease. Infectious laryngotracheitis has appeared in the broiler
industry as a serious disease. Improved vaccines are needed to control the disease in
broilers. In the U.S., the control of the highly pathogenic forms of avian influenza and
the velogenic forms of Newcastle disease have been achieved by eradication. In other
countries, effective vaccines have been used to control Newcastle and avian influenza.
Avian pneumovirus infection is also an emerging disease of chickens and turkeys.
Key Words: infectious bronchitis virus, Newcastle disease virus, infectious
laryngotracheitis virus, avian influenza virus, avian pneumovirus
1998 Poultry Science 77:1143-1145

1146.- Mycoplasmas in the Etiology of Multifactorial Respiratory Disease
Department of Avian Medicine, University of Georgia, Athens, Georgia 30602-4875
ABSTRACT The avian mycoplasmas pathogenic for commercial poultry, Mycoplasma
gallisepticum and Mycoplasma synoviae in chickens and turkeys, and Mycoplasma
meleagridis and Mycoplasma iowae in turkeys are egg-transmitted infections and exhibit
wide variations in clinical manifestations. Mycoplasma gallisepticum strains vary widely
in virulence, tissue tropism, and antigenic makeup and have the ability to alter the
expression of major surface antigenic proteins. Although less well studied, strains of M.
synoviae, M. meleagridis, and M. iowae appear to exhibit similar variability. Intraspecies
variability among mycoplasma strains and their ability to interact with other disease-
producing factors explain the wide variability of clinical manifestations, difficulties in
diagnosis, their ability to persist within the host for long periods of time, and many of the
difficulties involved in control and eradication programs. Mycoplasmas are also well
known for their interactions with other infectious agents and environmental factors in
producing clinical disease. Control of the clinical manifestations of Mycoplasma
infections is simplified when concurrent infections are minimized and optimum
environmental conditions are provided.
Key Words: Mycoplasma gallisepticum, Mycoplasma synoviae, Mycoplasma
meleagridis, Mycoplasma iowae, respiratory disease
1998 Poultry Science 77:1146-1149

1150.- Pathogenesis of Enteric Diseases
Department of Pathobiology, College of Veterinary Medicine, Auburn University,
Auburn, Alabama 36830
ABSTRACT The pathogenesis of digestive disease in poultry involves the cellular
events and reactions that result in a deviation from normal structure and function. To a
degree, the differentiation of disease and normal in commercial poultry also involves an
economic perspective. Factors external to the digestive tract may mimic digestive
disease, including reductions in the density of various nutrients and feed refusal.
Antinutritional factors, such as certain storage polysaccharides and proteins, are
inaccessible to endogenous enzymes and are either indigestible or act as blockers of
the digestion of other nutrients. Changes in digestive secretions that result in either
excess or deficiency also influence digestive structure and function. Infectious agents
and toxins that cause degeneration and necrosis are especially injurious because a
series of critical repair events must occur in order to regain function. The consequences
range from lethal injury of the host animal to diminished performance. The digestive
tract has a large component of lymphoid tissue and impairment of the immune system
influences the course of protozoan, bacterial and viral enteric diseases.
Key Words: digestive diseases, immunosuppression, inflammation, degeneration,
1998 Poultry Science 77:1150-1155

1156.- Intestinal Protozoa Important to Poultry
Department of Poultry Science, University of Georgia, Athens, Georgia 30602
ABSTRACT Parasites of two groups are important in poultry, the coccidia and the
mastiogophora (flagellates) (Table 1). Most of the Coccidia in poultry are in the genus
Eimeria, but a few species of Isospora, Cryptosporidium, and Sarcosporidia are
represented. The Eimeria are best known, with seven important species recognized in
chickens and several others in turkeys. Diagnosis of coccidiosis is by recognition of
classic signs and lesions, by gross examination, and can be aided by microscopic
examination of feces and intestinal contents. Control of coccidiosis is by preventive use
of anticoccidials and by immunization. Cryptosporidium are common in poultry but little
is known of their importance, except for the occasional outbreak of respiratory
cryptosporidiosis in turkey poults.
Of the flagellates, Histomonas meleagridis is the best known. Infections in turkeys may
cause near 100% mortality, but outbreaks in chickens are more often marked by
morbidity and subsequent recovery. Recent outbreaks in broiler breeder pullets caused
excessive losses from mortality (5 to 20%) culling, and overall poor flock performance.
Histomonas organisms are carried by eggs of the cecal worm Heterakis gallinarum,
enabling them to survive for long periods in soil as a source of infection. In the U.S.
there are no products available for treatment of blackhead. Preventive use of
anthelminthics to destroy the cecal worm carrier show some promise in reducing
Key Words: coccidia, Eimeria, blackhead disease, Trichomonas, Histomonas
1998 Poultry Science 77:1156-1158

1159.- Bacterial Enteritides of Poultry
Purdue University, Animal Disease Diagnostic Laboratory and Department of
Veterinary Pathobiology, 1175 ADDL, West Lafayette, Indiana 47907-1175
ABSTRACT Enteric bacterial infections in poultry pose a threat to intestinal health and
can contribute to poor feed efficiency and livability of a flock. A variety of enteric
bacterial diseases are recognized in poultry. Three of these bacterial diseases, necrotic
enteritis, ulcerative enteritis, and spirochetosis, primarily infect the intestine, whereas
other bacterial diseases, such as salmonellosis, colibacillosis, mycobacteriosis,
erysipelas, and fowl cholera, affect a variety of organ systems in addition to the
intestine. Diagnosis of bacterial enteritis requires monitoring of clinical signs in the flock
and proper use of diagnostic methods such as necropsy, histopathology, bacteriology,
and serology.
Key Words: poultry, enteritis, intestine, disease, bacteria
1998 Poultry Science 77:1159-1165

1166.- Virus Infections of the Gastrointestinal Tract of Poultry
Department of Microbiology, Pathology and Parasitology, College of Veterinary
Medicine, North Carolina State University, Raleigh, North Carolina 27606
ABSTRACT Several different viruses have been identified as causes of gastrointestinal
tract infections in poultry. These include rotaviruses, coronaviruses, enteroviruses,
adenoviruses, astroviruses, and reoviruses. In addition, a number of other viruses of
unknown importance have been associated with gastrointestinal diseases in poultry
based on electron microscopic examination of feces and intestinal contents. Viral
infections of the gastrointestinal tract of poultry are known to negatively impact poultry
production, and they likely contribute to the development of other, extra-gastrointestinal
diseases. Our current understanding of the viruses that cause gastrointestinal tract
infections in poultry is reviewed, with emphasis given to those of greatest importance.
Key Words: enteritis, gastrointestinal tract, infection, rotavirus, virus
1998 Poultry Science 77:1166-1175

1176.- Broiler Industry Strategies for Control of Respiratory and Enteric Diseases
Fakieh Poultry Farms, Taif, Saudi Arabia
ABSTRACT The commercial broiler industry is a modern day agricultural success due
to popular consumer demand, healthy flocks, and least cost production. Preventive
medicine is the key for economical control of disease in integrated broiler companies,
and includes quarantine-eradication, controlled-exposure, and preventive feed
medication. Respiratory and enteric diseases present a continuing, potential threat for
economic loss. Most exotic and egg-transmitted poultry diseases have been controlled
by reduction or eradication policies. Endemic diseases are controlled by mass
vaccination and preventive feed medication. Improvements in genetics, housing,
equipment, and disease surveillance has allowed continued improvements in disease
prevention. Attention to detail and management of risk is crucial to industry success.
With fast industry growth and market maturity of the broiler industry, new challenges
have risen. These challenges include increased poultry house density, increasing
economic pressures, changing industry attitudes, and increased governmental
regulations that will strain the continued success of today's control strategies.
Key Words: broiler, respiratory disease, enteric disease, preventive medicine,
1998 Poultry Science 77:1176-1180

1181.- Turkey Industry Strategies for Control of Respiratory and Enteric Diseases
College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota
ABSTRACT Current strategies to control respiratory and enteric diseases of turkeys
involve sanitation and biosecurity practices to prevent the introduction of infectious
agents. In addition, proper husbandry and management practices reduce stress and
help maintain a competent immune system. Industry-wide monitoring programs are
used in conjunction with isolation, depopulation, and orderly marketing to eliminate
pathogens that cause serious economic loss. Vaccines are available and utilized
against some pathogens. Effective drug treatment is available and used for some
diseases but is most commonly used to control secondary disease losses when
treatment is not available for the primary disease.
Key Words: disease, respiratory system, enteric system, turkeys, control strategies
1998 Poultry Science 77:1181-1185

1186.- Infectious Bursal Disease and Hemorrhagic Enteritis
Food Animal Health Research Program, The Ohio Agricultural Research and
Development Center, Wooster, Ohio 44691
ABSTRACT Infectious bursal disease (IBD) of chickens and hemorrhagic enteritis (HE)
of turkeys are caused by infectious bursal disease virus (IBDV) and hemorrhagic
enteritis virus (HEV), respectively. Both diseases have common features, including an
acute stage followed by immunosuppression, resulting in lowered resistance to a variety
of infectious agents and poor response to commonly used vaccines.
The IBDV and HEV infections are widespread in commercial chicken and turkey flocks,
respectively. The acute stage of the disease, the immunosuppression that follows, and
the widespread distribution of both diseases, are major factors contributing to the
economic significance of both diseases. The mechanism of immunosuppression for
both infections has similarities, both affect lymphocytes and macrophages, and both are
In this report, an overview of both diseases with emphasis on some of the recent
findings will be presented. There has been greater research activity on IBD than on HE,
reflecting the relative economic importance of the species affected and the recent
changes in the antigenic make up and pathogenicity of the IBDV.
Key Words: Infectious Bursal Disease, Hemorrhagic Enteritis Disease,
Immunosuppression, lymphocytes, macrophages
1998 Poultry Science 77:1186-1189

1190.- Chicken Anemia Virus
Department of Animal and Food Sciences, University of Delaware, Newark,
Delaware 19717-1303
ABSTRACT Chicken anemia virus is commonly found in commercially produced
chickens and has a worldwide distribution. It is difficult to inactivate thermally or with
common disinfectants, which limits the utility of normal sanitization practices. The virus
is important because of the disease it produces following transovarian transmission and
because of its potential for inducing immunosuppression alone or in combination with
other infectious agents. Control measures are directed at limiting vertical transmission
and preventing coinfections with other lymphocidal agents.
Key Words: chicken, chicken anemia virus, immunosuppression, anemia, disease
1998 Poultry Science 77:1190-1192

1193.- Poultry Industry Strategies for Control of Immunosuppressive Diseases
Tyson Foods, Inc., Springdale, Arkansas 72764
ABSTRACT Immunosuppression has historically cost the poultry industry in increased
mortality and in performance factors during rearing. In addition, immunosuppression has
had a negative impact on the ability of the poultry industry to process chickens due to
associated health problems. Industry strategies for controlling immunosuppression are
not consistent between broiler companies. The broiler industry is refining their strategies
for controlling immunosuppression based on research and field observations. However,
strategies to control immunosuppression are largely based on vaccination programs for
broiler breeders and broiler progeny, and management to minimize stress during
Key Words: immunosuppression, vaccination, infectious bursal disease, chick anemia
1998 Poultry Science 77:1193-1196

1197.- Control Strategies for Marek's Disease: A Perspective for the Future
USDA-Agricultural Research Service, Avian Disease and Oncology Laboratory,
East Lansing, Michigan 48823
ABSTRACT Marek's disease virus is an evolving pathogen, acquiring virulence in
response to increasingly effective vaccines. Although vaccine efficacy is generally good,
industry has placed a high priority on more effective products. The search for better
vaccines has been conducted mainly in the arena of molecular biology, and has been
thus far disappointing. Various conditions prevail that currently limit the potential to
develop suitable long-term solutions. A new paradigm based on reduction of early
exposure, multiple levels of host resistance, and improved cooperation among
stakeholders is proposed for consideration.
Key Words: Marek's disease, vaccine, serotype, genetic resistance, transgene
1998 Poultry Science 77:1197-1203

1204.- Retrovirus-Induced Disease in Poultry
Institute for Animal Health, Compton, Newbury, Berks, RG20 7NN,
ABSTRACT Three species of avian retrovirus cause disease in poultry: the avian
leukosis/sarcoma virus (ALSV), reticuloendotheliosis virus (REV), and
lymphoproliferative disease virus (LPDV) of turkeys. The ALSV can be classified as
slowly transforming viruses, which lack a viral oncogene, and acutely transforming
viruses, which possess a viral oncogene. Slowly transforming viruses induce late onset
leukoses of the B cell lymphoid, erythroid, and myeloid cell lineages, and other tumors,
by viral promoter insertion into the genome of a host cell and activation of a cellular
proto-oncogene. The various acutely transforming leukemia and sarcoma viruses
induce leukotic or other tumors rapidly and carry one or another (sometimes two) viral
oncogenes, of which some 15 have been identified. The ALSV fall into six envelope
subgroups, A through E, and the recently recognized J subgroup, which induces
myeloid leukosis. With the exception of Subgroup E viruses, these viruses spread
vertically and horizontally as infectious virions, and are termed exogenous viruses.
Subgroup E viruses are usually spread genetically as DNA proviruses (often defective)
in host germ cell genome, and are termed endogenous viruses. Several other families
of endogenous viruses also exist, one of which, endogenous avian retrovirus (EAV), is
related to Subgroup J ALV. Exogenous viruses, and sometimes endogenous viruses,
can have detrimental effects on commercially important production traits. Exogenous
viruses are currently controlled by virus eradication schemes.
Reticuloendotheliosis virus, which lacks a viral oncogene, causes chronic B cell and T-
cell lymphomas in chickens, and also chronic lymphomas in turkeys and other species
of birds. An acutely transforming variant of REV, Strain T, carries a viral oncogene, and
induces reticuloendotheliosis within a few days. In chickens and turkeys, REV spreads
vertically and horizontally. No commercial control schemes are operated. In turkeys,
LPDV infection has occurred in several countries, where it caused a lymphoproliferative
disease of uncertain nature.
Key Words: chicken, oncogenesis, retrovirus, tumors, turkey
1998 Poultry Science 77:1204-1212

1213.- Chicken Industry Strategies for Control of Tumor Virus Infections
Hy-Line International, Dallas Center, Iowa 50063
ABSTRACT Marek's disease (MD) and lymphoid leukosis (LL) are two distinct viral
diseases that cause tumor mortality in chickens. Marek's disease, being horizontally
transmitted, is controlled through biosecurity measures and vaccination. Prevention of
early exposure before vaccine immunity is established is most important. Some multi-
house growing farms have converted to all single-age placements to break the ongoing
cycle of transmission. Vaccination against MD involves either in ovo or day-old
administration of live vaccine, including single or multiple serotype products. Field
viruses appear to adapt over time and become resistant to the prevalent vaccine. The
Rispens vaccine (CVI-988) has shown good efficacy against recently emerging very
virulent MD strains in the U.S. Genetic resistance of the host to MD and control of other
immunosuppressive diseases also affects MD susceptibility.
Lymphoid leukosis is primarily vertically transmitted and is therefore controlled by
elimination of shedder hens at the primary breeder level. Depending upon the genetic
type, commercial performance of laying hens may be greatly improved by eradication of
the LL virus from the breeding stock.
Key Words: Marek's disease, lymphoid leukosis, tumor virus, vaccination, genetics
1998 Poultry Science 77:1213-1216

Inmunology and Molecular Biology
Metabolism and Nutrition
1217.- Effect of Dietary Energy Level and Oil Source on Broiler Performance and
Response to an Inflammatory Challenge
Department of Avian Sciences, University of California, Davis, California 95616
ABSTRACT Broiler chicks were fed one of five diets from 3 d of age: a low energy diet
containing 7% cellulose (ME 2,714 kcal/kg), or high energy diets containing ~7% of
either tallow, corn oil, safflower oil, or fish oil (each 3,302 kcal/kg). Half of the chicks
were injected intra-abdominally with Salmonella typhimurium lipopolysaccharide (LPS)
on Day 11, sephadex on Day 13, and Freund's complete adjuvant on Day 15; samples
were collected on Day 16. The uninjected chicks served as controls. In a second
experiment, 3-d-old chicks were fed one of eight isocaloric diets containing tallow as the
sole supplemental fat source, or tallow plus either 2% corn oil, 1, 1.5, or 2% fish oil, or
fish meal at an amount to provide 1, 1.5, or 2% supplemental oil. Half of the chicks were
injected intra-abdominally with S. typhimurium LPS on Days 10, 12, and 14; the
uninjected chicks served as controls. Samples were taken on Day 15. In Experiment 1,
the cellulose diet decreased performance to 10 d of age relative to the other diets,
whereas immunogen injection decreased weight gain and feed efficiency and increased
indices of inflammation among all dietary groups. Fish oil at ~7% of the diet did not
improve weight gain. Fish oil diets improved weight gain and feed efficiency in
Experiment 2 relative to the other diets, in spite of minimal effects on indices of
inflammation. Injection of LPS decreased performance and increased inflammation
across dietary treatment, although the second LPS injection was less potent in altering
performance responses and inflammation compared to the first injection, indicating that
repeated injections of LPS may cause the chicks to become refractory to that stimulus.
The fish meal diets resulted in poorer performance than similar levels of lipid provided
as fish oil. Lower levels of dietary fish oil were more efficacious in improving broiler
performance than higher levels, and fish oil provided from fish meal was not as
efficacious as fish oil per se, possibly due to nonlipid components of the meal.
Key Words: broiler, n-3 fatty acid, immunological stress, dietary oil, inflammatory
1998 Poultry Science 77:1217-1227

Physiology and Reproduction
1228.- Gross Appearance of the Turkey Blastoderm at Oviposition
*Germplasm and Gamete Physiology Laboratory and †Statistical Consulting
Service, Agricultural Research Service, USDA, Beltsville, Maryland 20705
ABSTRACT The blastoderm (fertilized ovum) and unfertilized germinal disc (UGD) of
fresh laid eggs and eggs stored prior to incubation exhibit subtle but definable
morphological variations. Such variations may lead to difficulty when attempting to
determine true flock fertility based on the appearance of the blastoderm/UGD. The
objectives of this study were to define and categorize such morphological variations and
to determine whether sperm influence the frequency distribution of the different
categories. Eleven categories of blastoderms were defined based on the relative density
and appearance of the area alba, area pellucida, area opaca, and the periblast. The
majority of the blastoderms were included in the first four categories. Unfertilized
germinal discs were divided into six categories and were best differentiated from the
blastoderms by the presence of vacuoles around its central dense area. They were also
discernible from blastoderms based on their overall denser appearance. Differences in
the frequency distribution of some of the UGD categories between virgin and
inseminated hens may be due to the effect that supernumary sperm may have on the
organization of the UGD (no fertilization but supernumary sperm present) or blastoderm
(fertilized but failed to develop). It is recommended that before starting true fertility
determinations during fresh egg breakouts, one should study the appearance of the
UGD from virgin hens and then the blastoderm from inseminated hens. One then will
learn to appreciate the subtle differences in shape and density of the blastoderm/UGD
structural components.
Key Words: true fertility, hatchability, infertile germinal disc, blastoderm, turkey
1998 Poultry Science 77:1228-1233
1234.- Age-Related Changes of Plasma Glutathione and Cysteine in Broilers:
Effect of Dithiothreitol Reduction In Vitro on Free and Bound Pools
Department of Poultry Science, Center of Excellence for Poultry Science,
University of Arkansas, Fayetteville, Arkansas 72701
ABSTRACT A study was conducted to determine free and protein-bound pools of
glutathione and cysteine in the plasma of male broiler chicks. Birds were brooded in
battery cages and provided ad libitum access to a starter diet and water. Plasma was
treated with a reducing agent, dithiothreitol (DTT), or left untreated, and analyzed by
HPLC to determine free and protein bound pools of reduced (GSH) and oxidized
(GSSG) glutathione, cysteine (Cys), and cystine (Cyss). With respect to total plasma
pools of GSH and Cys, between 0 and 21 d of age; 1) free GSH increased from 30 to
90% with a reciprocal decrease in protein-bound GSH, but GSSG was not detected;
and 2) free Cys decreased from 20 to 10%, free Cyss increased from 24 to 45%, and
protein-bound Cys decreased from 55 to 44%. The majority of the GSH plasma pool in
this study was present in a free, acid-soluble form, whereas most of the total Cys pool
was present as Cyss or bound to protein.
Key Words: glutathione, cysteine, cystine, broiler, plasma
1998 Poultry Science 77:1234-1240

Processing and Products
1241.- Consumer Acceptance of Stir-Fry and Kabobs from Dark Chicken Meat and
Their Packaging
Center for Food Safety and Quality Enhancement, Department of Food Science
and Technology, University of Georgia, Agricultural Experiment Station, Griffin,
Georgia 30223-1797
ABSTRACT In a study of marketing opportunities for fresh, dark chicken meat, focus
group participants (n = 34) provided qualitative information concerning potential
products and packaging concepts. Results of the focus groups indicated that the
participants were willing to purchase new, convenient poultry products made from dark
chicken meat. Specific dark meat products the participants were willing to buy included
boneless, skinless thighs, kabob cubes, and stir-fry strips. Consumers desired clear
packaging for the products but did not want the packaging to be microwaveable or
ovenproof. Acceptance of chicken kabob chunks and stir-fry strips of varying piece sizes
(2.54, 3.81, and 5.08 cm) and seasoning concentrations (1.6, 2.1, and 2.6%) was
evaluated by consumers (n = 83) using a nine-point hedonic scale. The most preferred
products were a 5.08 cm (2 in) kabob with 2.6% seasoning and a stir-fry strip with 2.6%
seasoning. A simulated supermarket setting test was conducted to verify findings from a
mailed survey (n = 115) and actual purchase behavior by consumers (n = 121). A
calculated desirability index indicated a ranked preference to be: breasts > kabobs >
stir-fry > boneless, skinless thighs > bone-in, skin-on thighs.
Key Words: dark chicken meat, consumer acceptance, stir-fry, kabobs
1998 Poultry Science 77:1241-1252
1253.- Evaluation of Alternative Sampling Methods for Salmonella Critical Control
Point Determination at Broiler Processing
*Department of Poultry Science and †Department of Veterinary Pathobiology,
Texas Agricultural Experiment Station, College Station, Texas 77843, ‡USDA,
Agricultural Research Service, Food and Feed Safety Research Unit, 2881 F&B
Road, College Station, Texas 77845, and §Milk Specialties Company, Bioscience,
P.O. Box 278, Dundee, Illinois, 60118
ABSTRACT Several sampling methods have been developed for the detection of
Salmonella on broiler carcasses during commercial processing. The present study
evaluated three sampling methodologies for sensitivity of Salmonella detection on
processed broiler carcasses. Furthermore, the effect of crop removal or chill tank
exposure on the frequency of Salmonella recovery was also examined. In two
experiments, swab, skin, and carcass rinse samples were compared for sensitivity of
Salmonella detection. The results indicated that culture of swabs was less effective (P <
0.05) for Salmonella detection than either skin or carcass rinse samples. No significant
(P > 0.05) differences were observed in Salmonella recovery from culture of skin or
carcass rinse. In two subsequent experiments, skin and carcass rinse samples were
found to be equally sensitive in their ability to detect Salmonella. Additionally, the stages
of processing between feather and crop removal were observed to cause significant (P
< 0.05) increases in Salmonella recovery within an individual flock. Similar increases (P
< 0.05) in Salmonella recovery were also observed following crop removal and
immediately following immersion chilling in two separate flocks. These results suggest
that culture of skin samples obtained from the thoracic inlet region may be a viable
alternative to the traditional whole carcass rinse method for sensitivity of Salmonella
detection. Furthermore, these experiments provided some evidence that the majority of
Salmonella cross-contamination of carcasses prior to immersion chilling occurred
following evisceration, with the chill tank potentially providing a major site for cross-
contamination between Salmonella-negative and -positive flocks.
Key Words: Salmonella, critical control points, crop, bacterial detection
1998 Poultry Science 77:1253-1257

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