WEB lab. Unggas UGM

Bacteria are microscopic living organisms. All bacteria are not detrimental to animal health. In fact, many bacteria are beneficial and necessary for such processes as food digestion, manufacturing of some dairy products, etc. Classification of bacteria into species is done so disease producing organisms may be separated from those that are harmless or beneficial.

Successful control of bacterial diseases entails isolating and identifying disease-producing species, if present, and preventing multiplication and spread of the organism within the animal’s body or to other animals.

Salmonella and Paracolon Infections

There are more than 2,000 species or serotypes of bacteria belonging to genus Salmonella; all are potential pathogens of poultry. Systemic effects usually are observed when infection occurs, but because the digestive system is primarily affected, they often are referred to as enteric organisms. The same is true of the group of organisms referred to as paracolons. Because of similarities produced by infections by these organisms, they are grouped under one heading. Both groups are found worldwide.

Pullorum disease and fowl typhoid are infectious, acute, or chronic bacterial diseases affecting primarily chickens and turkeys, but most domestic and wild fowl can be infected.

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History

Spiking mortality syndrome of chickens (SMSC) has been classified as such for approximately ten years. During the first experiences with the disease a number of causative agents were implicated, yet the symptoms remained relatively the same.

From approximately 1988 to 1990 the syndrome reached critical epidemic proportions particularly in the Delmarva area of the U.S. Isolated cases were also reported at that time in Georgia, Alabama and Arkansas. In 1990 the problem became so severe that a task force was developed in the Delmarva area in order to bring some definition to the syndrome. Since that time some management changes were made and the incidence of the disease decreased in that area.

Approximately around 1992, the incidence of spiking mortality in chickens took a severe jump in Georgia and to a lesser extent Alabama. Sporadic cases were also still being reported in the Delmarva/North Carolina area. Several possible causes were implicated, but nothing conclusive was identified. Since that time Dr. James Davis of the Georgia Poultry Laboratory, in conjunction with several researchers across the U.S., conducted exhaustive and extensive research and uncovered an emerging virus with other interesting revelations. The conclusions of the Delmarva task force and the research findings of Dr. Davis have helped to reduce the severity of a flock that experiences SMSC. Yet, the syndrome still occurs and no absolute eradication of the problem is in sight.

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A new University of Colorado at Boulder study shows the resistance of the avian flu virus to a major class of antiviral drugs is increasing through positive evolutionary selection, with researchers documenting the trend in more than 30 percent of the samples tested.

The avian flu, an Influenza A subtype dubbed H5N1, is evolving a resistance to a group of antiviral drugs known as adamantanes, one of two classes of antiviral drugs used to prevent and treat flu symptoms, said CU-Boulder doctoral student Andrew Hill, lead study author. The rise of resistance to adamantanes — which include the nonprescription drugs amantadine and rimantadane — appears to be linked to Chinese farmers adding the drugs to chicken feed as a flu preventative, according to a 2008 paper by researchers from China Agricultural University, said Hill.

In contrast, resistance of the avian flu virus to the second, newer class of antiviral drugs that includes oseltamivir — a prescription drug marketed under the brand name Tamiflu — is present, but is not yet prevalent or under positive genetic selection, said Hill of CU-Boulder’s ecology and evolutionary biology department. The CU findings should help health administrators around the world plan for the possibility of an avian flu pandemic.

The CU-Boulder study is the first to show H5N1 drug resistance to adamantanes arose through novel genetic mutations rather than an exchange of RNA segments within cells, a process known as re-assortment, said Hill. The research on the mutations, combined with molecular evolution tests and a geographic visualization technique using Google Earth, "provides a framework for analysis of globally distributed data to monitor the evolution of drug resistance," said Hill.

The CU-Boulder-led study appears online in the journal Infection, Genetics and Evolution. Co-authors included CU-Boulder Associate Professor Robert Guralnick, recent CU-Boulder graduate Meredith Wilson, Farhat Habib of Kansas State University and Daniel Janies of Ohio State University.

"As these adamantanes have gotten into nonhuman vectors like birds, the positive selection for resistance to avian flu is rising," said Hill. "If Tamiflu is ever used in the manner of adamantanes, we could conceivably see a similar resistance developing through positive selection."

The research team used an interactive "supermap" using Google Earth technology that portrays the individual gene mutations and spread of the avian flu around the globe, said Guralnick of CU-Boulder’s ecology and evolutionary biology department. By projecting genetic and geographic information onto the interactive globe, users can "fly" around the planet to see where resistant H5N1 strains are occurring, said Guralnick, also Hill’s doctoral adviser.

For the study, the researchers analyzed 676 whole genomes of Influenza A/H5N1 from National Institutes of Health databases of viruses isolated between 1996 and 2007. The team is comparing how often amino acid sequence changes in genes lead to mutations that affect drug resistance in the H5N1 virus and how often such changes evolve into random mutations that don’t affect resistance, Hill said.

The next step is to analyze 2008 data, he said.

First detected in China in 1996, the avian flu has spread throughout Asia and to India, Russia, Pakistan, the Middle East, Africa and Europe by various carriers, including poultry and migratory waterfowl, Hill said. While H5N1 is not highly communicable to humans from birds or between humans, experts are concerned future evolution of this subtype or other subtypes, or genetic re-assortment between subtypes, could make an avian influenza strain more contagious with the potential to cause a pandemic.

"Even if H5N1 is not the flu subtype that develops into the next pandemic, this technique can help us understand the properties of flu viruses and we can use these methods to track mutations in other viruses," said Guralnick. "We can harvest genetic influenza data and monitor it in near real-time, which should give this project some traction to help governments make decisions on managing potential pandemics."

Like the legend of a road map, colors and symbols on the supermap indicate which types of hosts carry the virus or the distribution of genotypes of interest, said Hill. A click by users on viral "isolates" generates computer windows revealing H5N1 mutations linked to positive genetic selection resulting from the spread and use of adamantanes.

The information is linked by computer to the National Institutes of Health’s GenBank, a database with more than 75 million sequence records.

According to the Centers for Disease Control in Atlanta, an avian flu pandemic could kill millions of people in America, infect 15 percent to 35 percent of the population and cost well over $100 billion.

Source: Andrew Hill (University of Colorado at Boulder)

Are early-life conditions important?

Production systems for laying-hens are continuously exposed to infectious pathogens. To prevent infections from spreading through the flock, various control methods are used nowadays. However, these methods not only increase production costs, but also prevent laying-hens from building up their own reserves to combat these threats.

The capacity to adapt in order to withstand threats is considered to be well-developed, if the individual is resilient to periods of stress. This capacity could also be beneficial during challenges posed by infectious pathogens. Not only the genetic background, but also early life – pre- and postnatal – experiences are thought to influence the propensity and capacity to survive threats in later life. The results of the first experiment indicate that early-life conditions do play an important part in developing the capacity to adapt in later life. Future experiments will explore this indication further.

The first experiment in this Ph.D. project was designed to investigate whether, in rearing hens, early-life conditions could indeed influence their resilience against infection in later life. Two contrasted groups were created during incubation and rearing by using normal practice for one group and what are considered to be optimal conditions for the other group (in a 2×2 design) for the first seven weeks after hatching. In later life, these hens were exposed to various pathogens found in poultry production systems.

The results of this study confirmed that early-life conditions did appear to affect responses to infection in later life. The rearing environment seemed to be the most important factor. The early rearing environment not only affected the immune responsiveness to infection, but also influenced the ability to recover from the clinical symptoms caused by the pathogen. The incubation conditions, on the other hand, appeared to have more influence on stress-related parameters. This may explain the occurrence of problem behaviours such as feather pecking in later life.

Animal Breeding & Genomics (nr. 10 Dec. 2008) newsletter published by the Animal Sciences Group
Animal Breeding and Genomics Centre – Wageningen University

There is growing concern that land application of poultry litter will contribute to phosphorus and nitrogen contamination of rivers and estuaries in areas with large poultry industries. Land-applied poultry litter has a special problem because its phosphorus content is generally higher than plants need.

In 1997, environmentalists’ efforts to control water pollution due to run-off from poultry and livestock farms resulted in legislation being introduced into the 105th US Congress (SB 1323- Animal Agriculture Reform Act and HR 3232- Farm Sustainability and Animal Feedlot Enforcement Act) that would have set national standards on pollution from poultry and livestock farms. These bills did not become law, but new legislative initiatives undoubtedly will be submitted in the 106th Congress and at the state level.

Similar legislation was proposed and passed by the Maryland General Assembly (Water Quality Improvement Act of 1998 and the Nutrient Management Practices Act of 1998) mandating that by the end of the year 2000, all feeds for monogastric animals must be supplemented with a phytase enzyme or other additives that reduce phosphorus in poultry and livestock wastes to the maximum extent that is commercially and biologically feasible. In 1995 there was a legislative mandate in The Netherlands that called for a 30% reduction in phosphorus content in manure. This goal was partially attained in the poultry sector by reducing dietary inorganic phosphorus and supplementing the diets with a microbial phytase (Simons et al., 1990; 1992; Van der Klis and Versteegh, 1994).
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For the production of eggs and meat, highly specialised breeds of chicken are used. Because the male chicks of laying breeds neither lay eggs nor are they profitable as a source of meat, they are killed as day-old chicks. In the Netherlands, 30 million male chicks are killed at hatch, every year. The Animal Sciences Group in Lelystad, in collaboration with the Rathenau Institute and the Agricultural Economics Institute (LEI) have conducted research to find out what ’the public’ thinks about possible alternatives for killing day-old male chicks. Information was gained by holding discussions with focal groups, in combination with a wider public survey. The outcome of this research was published in a report headed ’Killing day-old male chicks: isn’t there an alternative?’ presented in October to the Lower Chamber of the Dutch Parliament.

A clear majority of those who responded rated the killing of day-old male chicks ’unpleasant’, ’bad’, or ’very bad’ and almost 60% were in favour of trying to find an alternative. From this result, three technological alternatives for killing day-old chicks, that would gain reasonable acceptance and support from society, have been identified, and will be the subject of further research. These are:

• 1. To pick out the ’male’ eggs by looking inside freshly laid eggs.Another alternative i.e. to select the male eggs at a later stage of embryonic development was considered much less favourable.

• 2. To influence sex determination by manipulating the environmental factors that affect sex determination in chickens. However, before following this route, it would be important first to ensure that such changes would not harm the well-being of chickens.

• 3. The third alternative is the same as the first one, except that it would be facilitated by genetic modification, by using a gene for green fluorescent protein. However, this method was considered less favourable in the public survey than the method without genetic modification.

The additional option of ’combination chickens’ also received a high score, but, because of the current specialisation into laying or meat chickens, it would be too expensive, i.e. feed costs per egg or per kg meat would at least double. However, it might be a feasible option for a niche market, but it could not be considered as a structural solution for the mass killing of day-old male chicks. Although the option of ’accepting the current method of killing the chicks’ was viewed as undesirable, it was nevertheless regarded as a possible realistic option.

Follow-up research will now be started to assess the ’technical’ principles of the alternatives, as listed above, for killing day-old chicks, and to amass the knowledge needed for developing these alternatives. Initially, efforts will be focused on the first two alternatives.

Animal Breeding & Genomics (nr. 10 Dec. 2008) newsletter published by the Animal Sciences Group
Animal Breeding and Genomics Centre – Wageningen University

Researchers at the Johns Hopkins Bloomberg School of Public Health have found evidence of a novel pathway for potential human exposure to antibiotic-resistant bacteria from intensively raised poultry—driving behind the trucks transporting broiler chickens from farm to slaughterhouse. A study by the Hopkins researchers found increased levels of pathogenic bacteria, both susceptible and drug-resistant, on surfaces and in the air inside cars traveling behind trucks that carry broiler chickens. The study is the first to look at exposure to antibiotic-resistant bacteria from the transportation of poultry. The findings are published in the first issue of the Journal of Infection and Public Health.

Typically, broiler chickens are transported in open crates on the back of flatbed trucks with no effective barrier to prevent release of pathogens into the environment. Previous studies have reported that these crates become contaminated with feces and bacteria.

The new study was conducted on the Delmarva Peninsula—a coastal region shared by Maryland, Delaware and Virginia, which has one of the highest densities of broiler chickens per acre in the United States. Ana M. Rule, PhD, a research associate in the Bloomberg School’s Department of Environmental Health Sciences, along with professor Ellen K. Silbergeld, PhD, and Sean L. Evans collected air and surface samples from cars driving two to three car lengths behind the poultry trucks for a distance of 17 miles. The cars were driven with both air conditioners and fans turned off and with the windows fully opened. Air samples collected inside the cars, showed increased concentrations of bacteria (including antibiotic-resistant strains) that could be inhaled. The same bacteria were also found deposited on a soda can inside the car and on the outside door handle, where they could potentially be touched.

“We were expecting to find some antibiotic-resistant organisms since it’s pretty clear that the transportation conditions for these chickens are not closed or contained,” Rule said. “Our study shows that there is a real exposure potential, especially during the summer months, when people are driving with the windows down; the summer is also a time of very heavy traffic in Delmarva by vacationers driving to the shore resorts.”

The strains of bacteria collected were found to be resistant to three antimicrobial drugs widely used to treat bacterial infections in people. These drugs are approved by the U.S. Food and Drug Administration for use as feed additives for broiler poultry. The study findings were also consistent with other studies on antibiotic resistance in poultry flocks and poultry products.

According to the authors, the findings support the need for further exposure characterization, and attention to improving methods of biosecurity in poultry production, especially for regions of high density farming such as the Delmarva Peninsula.

Support for the study came via the Johns Hopkins Center for a Livable Future’s Innovation Grant Program.

How does early growth rate alter the response to the crude protein level in roaster diets? How is the mortality of birds kept to roaster weight affected by early body weight gain? A study was conducted by Hank Classen and Carlyle Bennett at the University of Saskatchewan to answer these questions.

A total of 1440 broiler cockerels, 720 each of two different broiler strains, were placed at one day of age in 48 pens, 30 birds per pen. The two broiler strains were housed in separate pens. All birds were reared under an increasing lighting program. Feed formulation was changed at 0 to 15 days, 15 to 29 days, 29 to 43 days, 43 to 57 days, and 57 to 64 days (Tables 1 and 2). Up to 43 days of age, half of the birds of each strain were fed either high (Trt 1 to 3) or low protein diets (Trt 4 to 6). After 43 days of age, the birds in the low and high protein feeding programs were divided between high, medium or low protein feeding regimes. While the birds reared on low and high protein feeding programs for the first 6 weeks were both split between three levels of protein, the birds reared on the lower protein rations were fed slightly lower levels of protein from 6 to 9 weeks than those reared on high protein rations. The combination of the two early feeding regimes and three different protein levels after 6 weeks of age, resulted in a total of six dietary treatments in the trial.

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What is avian influenza?

Influenza is an ancient disease that has plagued humans throughout recorded history. There are three types of influenza virus, A, B and C (CDC, 2005b). All three types of influenza have been found circulating in the human population. However, influenza type A is the influenza virus that mainly infects wild birds. Avian influenza occurs naturally in the intestines of wild birds worldwide, and although most wild birds are asymptomatic, bird flu is very contagious and, if transmitted to domesticated birds, including chickens, ducks (Fig. 1) and turkeys, can make them very sick (CDC, 2005a; 2007a).

Figure 1.

Domesticated birds, including chickens, ducks, and turkeys, can become very sick from avian influenza virus.

The terminology "Avian influenza virus" usually refers to the influenza A viruses found mainly in birds but occasionally found infecting humans. "Human influenza virus" refers to the avian influenza virus subtypes that are wide spread among humans. The three previously known influenza A viruses circulating among humans are H1N1, H1N2, and H3N2. Recently a new virus subtype, H5N1, crossed into humans and has caused the largest number of detected cases of severe disease and death attributed to avian flu viruses in humans (CDC, 2007a, b).

Influenza virus is shed in saliva, nasal secretions and feces of infected birds. Other birds may become infected by contact with contaminated secretions or excretions or with contaminated surfaces. Domesticated birds can become infected through direct contact with wild birds or from contact with surfaces, like cages or dirt, or materials, like feed or water, that have been contaminated.

The virus

Influenza viruses are segmented negative-strand RNA viruses that belong to the Orthomyxoviridae family of viruses (IFPMA, 2007a). The segmented genome of influenza viruses enables gene re-assortment. Gene rearrangement (antigenic shift) as well as nucleic acid changes in the genes encoding the main surface proteins (antigenic drift) results in modifications in viral surface proteins, thus enabling evasion of host immune mechanisms. While influenza A viruses can infect a wide range of hosts, including humans, swine and birds, B type viruses only infect humans, while type C infects humans and swine (IFPMA, 2007a).

Influenza A can be further categorized into subtypes based on different combinations of two of the viral surface proteins, hemagglutinin (HA) and neuraminidase (NA) (CDC, 2007a). There are 16 HA subtypes and 9 NA subtypes and each combination has been found in the wild bird population. All 16 HA subtypes, including H5, coexist in wild bird populations, with minimal disease outbreaks or changes to the viral genome (CDC, 2007a; IFPMA, 2007b). Once the virus infects a new host, the influenza virus rapidly evolves by changing the HA or NA surface proteins. Type A influenza virus of subtypes H5 and H7 include the viruses that are highly pathogenic. Infections of humans with these subtypes can result in mild disease (H7N3, H7N7) to severe and fatal disease (H7N7, H5N1) (CDC, 2005a; Webster et al., 2006).

Figure 2.

Colorized transmission electron micrograph of Avian influenza A H5N1 viruses (seen in gold) grown in MDCK cells (seen in green).

What are the symptoms?

In domestic birds, chickens, turkeys and ducks, low pathogenic strains of influenza A virus can cause mild symptoms, which include ruffled feathers and a drop in egg production. Most avian influenza A viruses can be classified as low pathogenicity (CDC, 2005a, b). The more pathogenic form of the virus spreads more rapidly through flocks. It may cause a disease that affects multiple organs and may result in 90-100% mortality within 48 hrs (IFPMA, 2007b).

Symptoms of low pathogenic avian influenza virus in humans may be similar to symptoms of human influenza disease, including fever, cough, sore throat and muscle aches. Additional symptoms are eye infections, pneumonia, severe respiratory disease, and include other severe, life-threatening complications. Highly pathogenic strains of the influenza A virus can cause severe and fatal illness in humans (CDC, 2007a, b).

How is it transmitted to humans?

Human cases of avian influenza A infection have resulted from contact with infected poultry or surfaces contaminated with secretions/ excretions from infected birds. Person to person transmission is rare, inefficient and un-sustained (CDC, 2007a, b).

How is it diagnosed?

Avian influenza viruses mainly infect the lower respiratory tracts. Therefore, specimens for identification can be collected by swabs of the throat and nasal-cavity, and from bronchioalveolar lavage and endo-tracheal aspirates. A serological sample can also be used to determine influenza virus infection status. The laboratory diagnosis of avian influenza A virus can detect the virus itself or the viral antigens, and antibodies to the virus. Direct detection methods include the following: 1) virus isolation; 2) detection of viral nucleic acid by polymerase chain reaction (PCR); or 3) the detection of viral antigens by either immunofluorescence (IFA) tests or rapid antigen detection kit. The serological methods for detecting the viral antibodies include the hemagglutination inhibition test (HAI) and the micro-neutralization tests (MT) (WHO, 2007).

What is the cure?

Laboratory studies suggest that avian influenza may be effectively treated with some medicines approved for human influenza virus. In Asia, the H5NI virus that causes sever human illness and death was resistant to amantadine and rimantadine, two commonly used influenza medications (Webster et al., 2006). The antiviral agent, oseltamivir, has also been recommended for treatment and prevention of human influenza A by the Centers for Disease Control and the World Health Organization. However, some evidence of resistance to oseltamivir has been reported. Other influenza antiviral medications have yet to be tested. Increased anti-viral resistance suggests a need for new treatments for avian influenza A (IFPMA 2007a, b).

Where does it occur?

Influenza A viruses occur in wild birds, world wide. Avian H5N1 has been detected since 2003 in poultry in the Republic of Korea, Vietnam, Japan, Thailand, Cambodia, Lao Peoples Democratic Republic, Indonesia, and China. Additionally, outbreaks have been reported in Malaysia, Russia, Kazakhstan and Mongolia. By late 2005, H5N1 outbreaks had spread to Turkey and Romania (IFPMA, 2007b).

Although avian influenza A viruses rarely infects humans, infections have been reported in humans since 1996. By 2003, 330 confirmed infections with the highly pathogenic H5N1 strain had been reported in 12 countries. Outbreaks of avian influenza A virus have been reported in the United Kingdom, Hong Kong, China, United States of America, Netherlands, Canada, Thailand, Vietnam, Cambodia, Egypt, Azerbaijan, Djibouti, Indonesia, Iraq, Turkey, Lao People’s Democratic Republic, Nigeria, Pakistan, and Myanmar. These confirmed instances include infections with high and low pathogenicity viruses (CDC, 2007b; IFPMA 2007b).

References

Center for Disease Control (CDC) (2005a) Avian Influenza A Viruses in Avian Influenza (Flu). CDC, Fact Sheet. http://www.cdc.gov/flu/avian/

Center for Disease Control (2005b) Influenza Viruses in Avian Influenza (Flu). CDC, Fact Sheet. http://www.cdc.gov/flu/avian/

Center for Disease Control (2007a) Key Facts About Avian Influenza (Bird Flu) And Avian Influenza A (H5N1) in Avian Influenza (Flu). CDC, Fact Sheet. http://www.cdc.gov/flu/avian/

Center for Disease Control (2007b) Avian Influenza A Virus Infections in Humans in Avian Influenza (Flu). CDC, Fact Sheet. http://www.cdc.gov/flu/avian/

International Federation of Pharmaceutical Manufacturers and Associations (IFPMA) (2007a) The Influenza Virus. IFPMA IVS Influenza Vaccines. http://www.ifpma.org/influenza/index.aspx?1

International Federation of Pharmaceutical Manufacturers and Associations (IFPMA) (2007b) Avian Influenza. IFPMA IVS Influenza Vaccines. http://www.ifpma.org/influenza/index.aspx?1

Webster, R.G., Peiris, M., Chen, H. and Guan, Y. (2006) H5N1 Outbreaks and Enzootic Influenza. Emerging Infectious Diseases. 12: 3-8.

World Health Organization (2007) Guidelines on Laboratory Diagnosis of Avian Influenza. WHO Regional Office for South-East Asia. http://www.searo.who.int/LinkFiles/CDS_CDS-Guidelines-Laboratory.pdf

Footnotes

1. Chelsea T. Smartt and C. Roxanne Connelly are assistant and associate professors in the Department of Entomology and Nematology.

PUBLICATION DATE: 19/12/2008

RATING

AUTHOR: Chelsea T. Smartt and C. Roxanne Connelly – University of Florida Cooperative Extension Service – Institute of Food and Agricultural Sciences (IFAS) publication

Clearly hatchability is important to both small flock and commercial poultry breeder flock owners. Maintaining hatching egg shell quality is important because of its connection with hatchability. The major factors that influence egg shell quality are genetics, diet, climate, housing and age of the hens. While the average poultry operation has limited control over most of these factors, the crucial significance of hatchability makes it is important to recognize and control egg shell quality where possible.

Obviously, eggs with thin shells are more likely to break, producing ’leakers.’ While leakers are not usually set in the incubator, thin shelled eggs crack easily in the hen house, during collection and transportation, resulting in poor hatches due to contamination. In addition to the increased likelihood of shell breakage, thin shelled eggs that do not suffer breakage allow for higher water vapor loss during the entire incubation process resulting in dehydration and higher embryonic mortality. Those chicks that do hatch from thin shelled eggs have decreased livability during the first few days of life and poor overall performance because they get off to a slow start.

Egg shell color has also been questioned in regards to its affects on hatchability. While the scientific literature contains conflicting data regarding the relationship between egg color and hatchability, poultry producers have long held the belief that in typical brown egg laying breeds, light colored eggs will not hatch as well as those that are darker in color. Indeed, it is interesting to note that in certain songbird species (flycatchers) experimental evidence suggests that healthier more wellfed females lay more intensely colored eggs (Moreno et al., 2006). Thus, there is some evidence to substantiate the assumption that darker eggs hatch better than lighter colored eggs. Eggshell color may also be associated with egg shell quality. Therefore, producers have been trained to eliminate light colored eggs from consideration as hatching eggs due to their poorer hatching expectations.

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Reoviruses are widespread in nature and have been isolated from a variety of animals. These viruses have also been isolated from humans and in fact the name reovirus is a mnemonic for respiratory (r) enteric (e) orphan (o) since the virus was isolated from the human respiratory and enteric tract, but was not associated with disease. In some species of mammals (primarily mice) these viruses have caused liver, pancreatic, lung, and heart disease and central nervous system symptoms.

Avian reoviruses, in the past, have been associated with viral arthritis/tenosynovitis, malabsorption syndrome, stunting/runting syndromes, enteric disease, immunosuppression, and respiratory disease. Recently, there have been reports from the field and isolations of reoviruses from chickens exhibiting neurological signs.

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Before poultry meat quality is addressed, the term quality should be clearly defined as it relates to poultry. This is a difficult task, because quality is “in the eye of the beholder.” For example, someone trying to sell a product might view its quality in terms of how well it sells and how much people are willing to pay for it. However, this definition is incomplete, because it does not consider the product’s character. Since people only buy what they like, the consumer’s perspective of quality is more appropriate. When consumers buy a poultry product, cook and serve it to their families, they expect it to look, taste, and feel good in their mouth. If these characteristics do not meet the consumer’s expectation, the product is considered to be of lower quality.

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Previous research has shown that quality hatching eggs improve the likelihood of optimum hatchability as well as result in good chick quality (Yoho et al., 2008, Moyle et al., 2008). Pathogens can penetrate, contaminating the egg shell, its membranes and the embryo (Berrang et al., 1999). Improperly handled eggs can also explode contaminating the surrounding eggs in the setter. While proper sanitation of eggs can be beneficial to overall hatchability, failure to follow recommended sanitation procedures often has negative consequence on hatchability and chick quality (Funk et al., 1949, Scott and Swetnan., 1993).

Within the poultry industry it is understood that only clean and good quality broiler breeder hatching eggs should be sent to the hatchery for incubation. Breeder managers routinely discuss this topic with contract producers with varied success. However, increased production costs dictate that every possible hatching egg be sent to the hatchery and it would seem advantageous to have some practical method for dirt removal. Producers commonly use paper towels, rags or sanding blocks to remove dirt from eggs. If the dirt is gone then the problem should be solved, right? But, do these cleaning methods affect hatchability or chick quality? With these questions in mind, this study was undertaken to evaluate the effect poor hatching egg selection, improper egg handling techniques and “cleaning” procedures on hatchability, hatch of fertile and egg contamination rates.

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Chick quality is still a term than many breeder, hatchery and broiler people still have a hard time defining. Most everyone can identify poor quality chicks from good quality chicks. However, when three people are asked to define chick quality, three different descriptions would be received. Currently chick quality is mainly based on observations such as whether or not the chick is alert, dry or wet, whether the navel is completed sealed, and deformities. While these are a good start, there are chicks than can be dry, have completely sealed navels, no deformities but still do not perform well. Researchers will continue to search for an objective measurement (one that will not vary from person to person) but in the mean time the best measurement is to use a combination of observations. Most people working to evaluate chick quality agree that first week mortality may be the best measure available. However, the information if after the fact and growers and broiler flock supervisors need the information as soon as possible to make management decisions need to optimize that flock’s performance.

There are several factors that can affect chick quality. These are listed in Table 1. Since there is no objective way to measure chick quality at this time, it is important to define how chick quality is determined. One group in Belgium has been evaluated chick quality from three different broiler breeder lines. In order to report and compare chick quality they have come up with a system that has been successful in their observations. It should be noted that there is still a possibility that the information will differ from person to person, but this appears to be a good start. Table 2 describes the parameters they used for determining chick quality and Table 3 demonstrates the scoring system. The score level for each parameter was determined based on the importance to chick survival and the severity of any anomaly it may carry.

While this system was useful to this project, some alterations could be made to fit a companies needs. The important thing to remember is consistency when evaluating each parameter. Other methods for determining chick quality have been developed and tried and are quite similar to the one described above. The common feature is that each method used multiple parameters to assess chick quality.

References:

Tona, K. F., Bamelis, B. De ketelaere, V. Bruggeman, V. M. B. Moraes, J. buyse, O. Onagbesan, and E. Decuypere, 2003. Effects of egg storage time on spread of hatch, chick quality, and chick juvenile growth. Poultry Sci 82:736-741.

Tona, K., O. Onagbesan, Y. Jego, B. Kamers, E. Decuypere, and V. Bruggeman 2004. Comparison of embryo physiological parameters during incubation, chick quality, and growth performance of three lines of broiler breeders differing in genetic composition and growth rate. Poultry Sci 83:507-513.

Table 1. Factors that can affect chick quality

Table 2. Parameters used to assess chick quality

Table 3. Scoring system used in chick quality determination

By Brian D. Fairchild, Extension Poultry Scientist
Poultry Tips – College of Agricultural and Environmental Sciences
The University of Georgia Cooperative Extension Service