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Archive for April, 2009

Factors Causing Poor Pigmentation of Brown-Shelled Eggs

Senin, 27 April 2009 9 komentar

The first documented report of shell pigment loss in brown-shelled eggs was in 1944 when Steggerda and Hollander, while removing dirt from eggshells produced from a small flock of Rhode Island Red hens, made the surprising discovery that some of the brown pigment also rubbed off. This effect was even more evident when the eggs were rubbed vigorously. Most of the eggs gave up their pigment fairly easily except those possessing a glossy surface.

It is well established that no single factor is responsible for the loss of shell pigment in brown-shelled eggs. Variation in pigmentation among brown-shelled eggs is more pronounced in broiler breeders than in commercial brown egg-type layers. In flocks of broiler breeders, it is common to have a variation in eggshell pigmentation, resulting in hues ranging from dark brown to almost bleached white. This contrast occurs because genetic selection for uniform brown-colored eggs in broiler breeder flocks is of little importance compared to eggshells of commercial brown egg-type birds. Most commercial producers and university personnel serving the poultry industry understand that the loss of shell pigment from brown-shelled eggs can be caused by numerous factors. Many individuals, however, still prematurely jump to conclusions and blame shell pigment loss and variability on only a single factor. The most common scapegoat is bronchitis. Statements such as “I know my hens had bronchitis because their shells are pale” or “All you have to do to determine if your hens had bronchitis is to look at their eggshell color — if the shells are pale they had a bronchitis challenge” are still often heard in the field. Such statements are made even without knowledge of the flock’s bronchitis antibody titer, bronchitis vaccination schedule, or supporting necropsy findings.

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Scientists Identify Lab-Made Proteins That Neutralize Multiple Strains of Seasonal and Pandemic Flu Viruses

Senin, 27 April 2009 2 komentar

Scientists have identified a small family of lab-made proteins that neutralize a broad range of influenza A viruses, including the H5N1 avian virus, the 1918 pandemic influenza virus and seasonal H1N1 flu viruses. These human monoclonal antibodies, identical infection-fighting proteins derived from the same cell lineage, also were found to protect mice from illness caused by H5N1 and other influenza A viruses. Because large quantities of monoclonal antibodies can be made relatively quickly, after more testing, these influenza-specific monoclonal antibodies potentially could be used in combination with antiviral drugs to prevent or treat the flu during an influenza outbreak or pandemic.

A report describing the research, supported by the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of

Health as well as the Centers for Disease Control and Prevention, appears online today in Nature Structural & Molecular Biology. Wayne Marasco, M.D., Ph.D., associate professor of medicine at the Dana-Farber Cancer Institute and Harvard Medical School in Boston led the research team, which included collaborators from the Burnham Institute for Medical Research in La Jolla, Calif., and the CDC in Atlanta.

“This is an elegant research finding that holds considerable promise for further development into a medical tool to treat and prevent seasonal as well as pandemic influenza,” notes NIAID Director Anthony S. Fauci, M.D. “In the event of an influenza pandemic, human monoclonal antibodies could be an important adjunct to antiviral drugs to contain the outbreak until a vaccine becomes available.”

Using standard methods of production, initial doses of a new influenza vaccine to fight pandemic influenza would be expected to take four to six months to produce.

Key to their research, Dr. Marasco and his colleagues discovered and described the atomic structure of an obscure but genetically stable region of the influenza virus to which their monoclonal antibodies bind. The hidden part of the influenza virus is in the neck below the peanut-shaped head of the hemagglutinin (HA) protein. HA and neuraminidase are the two main surface proteins on the influenza virus.

The scientists also identified a new mechanism of antibody action against influenza: Once the antibody binds, the virus cannot change its shape, a step required before it can fuse with and enter the cell it is attempting to infect.

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A Few Basic Points About Protein

Senin, 27 April 2009 3 komentar

Everyone is familiar with the word “protein”, because it turns up so frequently in everything from food to shampoo. Whether we are dealing with commercial or backyard flocks, all poultry need protein in the feed. Because of its tremendous importance, it is worthwhile to gain a basic understanding of this important nutrient.

The range of different substances that are composed of proteins is so varied it is difficult to remember we are talking about the same basic thing. To illustrate, animal tissues as different from each other as meat, hair, hooves and nails, egg white, cells in the blood, leather and skin, and feathers are almost all solid protein. Plants, and especially seeds like corn and soybeans, contain protein, but are mixed with carbohydrates like sugars, starch, and fiber.

The reason proteins can be so different from each other is that they are assembled out of 20 different building blocks, called amino acids. If we think about it, we can probably come up with a list of 20 different construction materials such as red bricks, cement blocks, concrete slabs, wooden beams, steel rods, and the like. While all are what we would call “building materials”, they can be used to construct an astonishing variety of structures. The same is true with the 20 amino acids…there is no end to the different types of proteins that can be made from them. Here we should mention that all acids are not like the fuming flasks in Dr. Frankenstein’s laboratory, and amino acids are not like that at all. They are simply white powders. The two most common that we add to poultry feeds are lysine and methionine.

The protein in poultry feeds comes mainly from plant sources, such as soybean meal. Oil is extracted from the soybean for human use, with the remaining solid portion having almost 50% protein after the fibrous hull is removed. Many by-products of animal processing, such as meat and bone meal from cattle and swine, and poultry and feather meal from chickens and turkeys, have 50% or more protein (i.e., amino acids, which collectively are called protein). Grains are mostly made up of starch and fiber, but are about 10% protein.

At this point a very reasonable question might be asked: “If the protein in poultry feeds comes from the ingredients mentioned in the above paragraph, and if all proteins are composed of amino acids, then why do we have to add to the feed extra synthetic amino acids like lysine and methionine, which are extremely expensive? If the feed needs additional amino acids, why not simply add more soybean meal?”.

The answer lies in the fact that in the diverse proteins, such as those mentioned above, the 20 amino acids are present in wildly different concentrations. It should not be a surprise that the proteins in plants have a very different combination of amino acids than do those in tissues of animals. Thus, when the chicken converts soybean protein into meat and eggs, it is reasonable to find that the concentrations of the 20 amino acids don’t exactly match up. Research has found that the animal needs more lysine and methionine than is present in a feed made mostly of corn and soybean meal.

While expensive, it is more economical to provide the birds with these amino acids in synthetic form. This is logical…if we only need to top off the levels of lysine and methionine to reach the bird’s requirement. Therefore, there is no reason to add all 20 amino acids which is what would happen if we simply added more of a high-protein ingredient. Synthetic amino acids allow us to more precisely meet the birds nutritional needs, and do so more economically.

By Nicholas M. Dale, Extension Poultry Scientist
Poultry Tips – College of Agricultural and Environmental Sciences
The University of Georgia Cooperative Extension Service

PUBLICATION DATE: 03/27/2009
SOURCE: Univ. of Georgia Cooperative Extension Service

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Ratite: Emu Reproduction

Senin, 27 April 2009 3 komentar

Managing egg production

Emus begin breeding at about 20-24 months. Young adults and other unpaired adults should be run in groups in large pens allowing each emu to choose its own mate thus forming compatible pairs; this increases egg fertility. (Selective pairing will begin to take place from December/January each year.) If each pen has only one pair of emus, they may be incompatible and poor matings will result, so decreasing egg fertility and possible bird injury.

When pairs form, they can then be separated into individual breeding pens. If the pair performs well, they can be left as a pair or, if you wish to split them, they can be put into the large group pen after the breeding season has finished.

Alternatively, breeding emus can be left as a group in a large pen and not segregated into individual breeding pens. If this option is chosen it is important to give them sufficient space to avoid fighting and to sex the birds so that the male:female sex ratio is about equal.

Hens will begin to lay from mid to late April each year, and most females will have finished laying by October/November.

Most adults are not physically aggressive to farm personnel when they are collecting the eggs. The few that get ‘too close for comfort’ can be bluffed by facing them and holding up an arm or other object to make you taller than the bird. Walking towards them will usually make them turn away.

However, as a basic safety rule, do not stand in front of an emu within range of its feet; keep at least 1 m away. Emus kick and strike forwards if they feel threatened or are caught but can’t kick sideways or backwards. The beak can pinch but generally causes little damage. Keep an eye on the feet.

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Cooling Broiler Chickens by Direct Sprinkling

Senin, 27 April 2009 18 komentar

Modern broilers grow at an extremely rapid rate and convert feed to meat with exceptional efficiency. However, this rapid growth rate and conversion efficiency have been associated with an increased susceptibility to heat stress. While a variety of genetic, nutritional, feeding and environmental strategies have been examined, much of the burden for dealing with the effects of heat falls to the producer and, in turn, the housing environment (Linn et al., 2006).

Evaporative pads, fogger pads and fogger nozzles are commonly used to control heat and its effects in broiler houses (Weaver, 2002). Except in extreme conditions poultry production personnel have tended to avoid systems that deposit moisture directly on the birds. Yet, cattle and hogs are often cooled in hot weather by sprinkling with water and many poultry producers have occasionally cooled chickens by sprinkling with water hoses during extremely hot periods to avoid catastrophic mortality. In practice, the effectiveness of conventional, low-pressure misting systems in broiler houses partially depends on the deposition of much of the released water onto the chickens and their immediate surroundings. Pad systems require large volumes of water to cool birds and many producers are concerned about the availability and cost of water to operate cool cell systems. An alternative sprinkling system for cooling broiler chickens was investigated at the Applied Broiler Research Farm (ABRF).

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Chlorine is Still the Most Popular Sanitizer in the Poultry Industry (Part 1)

Senin, 27 April 2009 2 komentar

Chlorine in the form of sodium hypochlorite, calcium hypochlorite tablets or chlorine gas is by-far the most commonly used carcass and equipment disinfectant in the U.S. poultry industry. The USDA, Food Safety and Inspection Service (FSIS) allows for addition of chlorine to processing waters at levels up to 50 ppm in carcass wash applications and chiller make-up water. The FSIS also requires that chlorinated water containing a minimum of 20 ppm available chlorine be applied to all surfaces of carcasses when the inner surfaces have been reprocessed (due to carcass contamination) other than solely by trimming.

With recent emphasis by USDA-FSIS on further reducing Salmonella, poultry plants have increased their reliance on the water chlorination program in the processing plant including pre-scald bird brushes, equipment rinses, inside/outside bird washers, carcass washes, and as a disinfectant during chilling. However, there remains a limited understanding of water chlorination and proper management of water chlorination in the poultry industry. Thus, a review of chlorination is needed.

At recommended levels, hypochlorite (chlorine derivative) based sanitizers reduce enveloped and non-enveloped viruses. Chlorine is also effective against fungi, bacteria, and algae. However, under traditional conditions of use, chlorine does not affect bacterial spores.

Chlorine was first used in water treatment by the municipal water treatment facilities in Chicago and Jersey City in 1908. Chlorine is used in three common forms for water treatment: elemental chlorine (chlorine gas), sodium hypochlorite (bleach) solution and dry calcium hypochlorite pellets. The amount of hypochlorite (OCl-) varies depending on the type of chlorine used. One pound of Cl2 generates an amount equal to one gallon of 12.5% NaOCl, and 1.5 pounds of Ca(OCl)2 (65%).


Types of chlorine used in the poultry industry

Chlorine gas

Chlorine in its elemental state is a halogen gas (Cl2) which is highly toxic and corrosive. Because of safety concerns with chlorine gas, many food processing facilities have changed to either sodium hypochlorite or calcium hypochlorite for water treatment.

Chlorine gas and sodium hypochlorite (NaOCl) can be produced in an electrochemical process depending on the process conditions (Equation 1). For NaOCl production, Cl2 gas is passed through sodium hydroxide solution (NaOH). The NaOH reacts with the Cl2 to produce NaCl, NaOCl and water as shown below.

Equation 1: 2 NaOH + Cl2 (g) º NaCl + NaOCl + H2O


Sodium hypochlorite

In most food plant applications, chlorine is purchased as sodium hypochlorite (NaOCl) solution. Sodium hypochlorite solutions used in poultry processing contain between 5 and 12% pure sodium hypochlorite. Household bleach typically contains 5.25% NaOCl.

It should be noted that household cleaners and sanitizers are not acceptable for USDA-FSIS inspected food plants unless accepted by USDA. Commercial forms of sodium hypochlorite are provided in a range of concentrations from 3-50%. The most commonly used form in poultry processing plants is commercial bleach which contains 12.5% NaOCl. This is the most common or popular form of chlorine used in poultry plants worldwide.


Calcium hypochlorite

Available in granular or pellet form, calcium hypochlorite is generally more expensive to use than other hypochlorite forms. Some companies use calcium hypochlorite because the concentration can be controlled more effectively than other forms of chlorine used.

Chlorine based sanitizers are low in cost and can control bacteria in food processing plants when used appropriately. The advantages and disadvantages to using chlorine sanitizers are listed in Table 1.


Table 1. The advantages and disadvantages of sodium hypochlorite use in poultry p
rocessing.

By Scott M. Russell, Ph.D., Extension Poultry Scientist
Poultry Tips – College of Agricultural and Environmental Sciences
The University of Georgia Cooperative Extension Service

PUBLICATION DATE: 04/20/2009
SOURCE: Univ. of Georgia Cooperative Extension Service
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Salmonella Strain’s Path to Virulence Uncovered

Senin, 27 April 2009 2 komentar

Agricultural Research Service (ARS) scientists have uncovered genetic evidence about the evolutionary path that transformed Salmonella enteritidis from an innocuous bacterium into a virulent pathogen.

S. enteritidis, like many bacteria, reproduces very quickly–every 20 minutes in optimal conditions, according to veterinary medical officer Jean Guard-Bouldin in the ARS Egg Safety and Quality Research Unit in Athens, Ga.

“To reduce current levels of infection, we’re studying how S. enteritidis evolves and infects hens on the farm,” says Guard-Bouldin. “Using mutational changes in the Salmonella genome as a sort of ‘breadcrumb trail,’ we’ve tried to determine the first time this bacterium became capable of getting inside the egg from hen reproductive organs.”

Such a fast reproductive pace allows the organism to accumulate genetic variations. Only healthy competitors go on to reproduce, survive and develop the mechanisms needed to infect the egg. Using DNA analysis, Guard-Bouldin is looking at evolutionary evidence to determine how some S. enteritidis strains became pathogenic. Studying how S. enteritidis evolves and infects hens on the farm may someday help reduce levels of infection.

Guard-Bouldin and her colleagues found S. enteritidis strains to be so similar genetically that they appear identical, yet they may behave differently inside the hen. To distinguish between the apparently identical genomes, researchers must use a technique called “whole-genome mutational mapping” to analyze multiple strains.

Through these analyses, the researchers developed a timeline of when S. enteritidis first became capable of getting inside the egg from hen reproductive organs–approximately 36 years ago. It appears that a large-scale swap of DNA between strains, in association with the emergence of egg contamination, created a hybrid strain of S. enteritidis.

This hybrid strain had the ability to contaminate the internal contents of eggs. Later, it also split very quickly into two lineages, each carrying one virus. Both of the newly split lineages continued to evolve and eventually began to vary in their ability to contaminate eggs and to survive on the farm.

The data from this research is being entered into a publicly available database by the National Center for Biotechnology Information, part of the National Institutes of Health.

“This information about differences between genomes could help streamline the process of finding out how human disease organisms evolve to become more virulent,” says Guard-Bouldin. “The main focus for us now is to continue sequencing entire genomes and searching for more genetic changes that help us understand the Salmonella organism.

“Up until recently, genomic techniques for delving this deeply into the genetic code of multiple Salmonella strains weren’t available or cost effective.

“If we can understand how Salmonella evolved to become pathogenic, perhaps we can apply the same principles to other foodborne pathogens and begin to study foodborne illness the way influenza is being monitored-with equal emphasis on the importance of small, as well as large, genetic changes.”

According to the Centers for Disease Control and Prevention, about 40,000 cases of salmonellosis are reported in the United States every year. Most result in diarrhea, fever, and abdominal cramps lasting 4 to 7 days, but severe cases caused about 70 deaths in 2000. Adequate cooking eliminates the risk of infection from eggs.

PUBLICATION DATE: 04/21/2009
SOURCE: USDA Agricultural Research Service
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