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Chickens with bigger gizzard more efficient

Chickens with bigger gizzard more efficient

POULTRY researchers in France have determined that breeding chickens with larger digestive organs could improve production efficiency while reducing excess nutrient excretion into the environment.

Study co-author Dr. Agnes Narcy and colleagues from the French National Institute For Agricultural Research and France's Center of Agricultural Research for Development bred chickens to test whether selecting for a larger digestive organ size could reduce the amount of waste the chicken excreted.

The researchers studied the proventriculus — a stomach-like organ that softens food using acids and digestive enzymes — and the gizzard, which has thick, muscular walls that grind food. Together, these organs prepare foods for digestion in the small intestine.

The researchers hypothesized that chickens with larger, better-functioning digestive organs would absorb more nutrients from their feed and, therefore, produce less waste. To test this hypothesis, the researchers selected chickens and raised three lines with differing abilities to digest feed.

After rearing nine generations of each line, the researchers found that chickens with larger digestive organs ate less feed and produced less waste.

The researchers concluded that selecting specifically for this trait could make poultry production more environmentally and economically sustainable.

"Furthermore, such selection would not affect body composition and meat and bone quality traits at slaughter age," Narcy said.

Narcy said the next step is for animal scientists to identify the genes that control digestive efficiency in chickens. By pinpointing the right genes, researchers could help select the most efficient chickens for breeding.

The study, "Reducing the Environmental Impact of Poultry Breeding by Genetic Selection," was recently published in the Journal of Animal Science.


Helpful virus

A study conducted at the Virginia-Maryland Regional College of Veterinary Medicine has determined that a virus known to cause illness and death in poultry is also a promising treatment for prostate cancer in people.

Researchers have discovered that a genetically engineered Newcastle disease virus kills prostate cancer cells of all kinds, including hormone-resistant cancer cells.

The work of associate professor of virology Dr. Elankumaran Subbiah, graduate student Shobana Raghunath and Dr. Siba Samal, associate dean and chairman of the University of Maryland's department of veterinary medicine, was published in the April issue of the Journal of Virology.

About one in six men will develop prostate cancer. Patients typically receive hormone treatments or chemotherapy, both of which have adverse side effects. Subbiah hopes that the development of new treatment methodologies will not only better fight prostate cancer but also lessen the side effects commonly associated with hormone treatments and chemotherapy.

"This potential treatment is available for immediate preclinical and clinical trials, but these are typically not done at the university level," Subbiah said. "We are looking for commercial entities that are interested in licensing the technology for human clinical trials and treatment. Newcastle disease virus has yet to be tested as a treatment for prostate cancer in patients."

Newcastle disease virus affects domestic and wild bird species, especially chickens, and is one of the most economically important viruses to the poultry industry.

Scientists first documented the cancer-fighting properties of Newcastle disease virus in the 1950s, but it is only with recent advances in reverse genetics technology that they have turned to the genetically engineered virus as a possible treatment.


Appetite regulation

Researchers at The Roslin Institute at the University of Edinburgh in Scotland have identified how a chicken's genetic makeup can affect the signals sent from its stomach to its brain that tell a chicken when it has had enough to eat.

Poultry producers often have to restrict food for chickens because some birds are not sensitive to feelings of fullness and can overeat, an announcement said.

The study could make it easier to develop methods for formulating diets that more naturally reduce excess growth in these birds.

The researchers said genetic differences that affect when chickens realize when they have had enough to eat could date back thousands of years, when chickens were first domesticated and breeds were selected for their size.

Dr. Ian Dunn, who led the study, said, "The findings shed greater light on food intake in birds and help us understand why some breeds — in general, the faster-growing types of chickens — are more insensitive to feelings of fullness than others."

The study, published in the American Journal of Physiology, Endocrinology & Metabolism, focused on a protein called cholecystokinin that plays a key role in sending signals linked to being full from the gut to the brain.

The researchers, backed by funding by the U.K.'s Biotechnology & Biological Sciences Research Council (BBSRC), found that some birds were better equipped than others at recognizing the protein, making them more effective at triggering signals of feeling full.

The study involved crossbreeding a fast-growing meat production strain of chicken with a relatively slow-growing chicken.

The researchers looked at how the protein was processed in both types of chickens and in the new genetic line.

They showed that reduced levels of cholecystokinin also affected the chicken's natural bodyweight.

The study could also help inform research on appetite regulation in other animals.

"All species regulate their appetites to make sure the amount of food taken in is just right to maintain bodyweight and fat content," Dunn said. "Our research has shown that there is genetic variation in the interpretation of biological signals sent relating to being full. This also affects what would be considered to be the natural bodyweight of chickens."



A strain of probiotic bacteria that can fight harmful bacterial infections in poultry has the ability to change its coat, according to new findings from the BBSRC-funded Institute of Food Research (IFR) in the U.K.

The probiotic is currently being evaluated in farm-scale trials to see how well it combats Clostridium perfringens, a bacterium that can cause necrotic enteritis in poultry and foodborne illness in people.

The IFR researchers previously found that the probiotic Lactobacillus johnsonsii, when given to young chicks, prevented the colonization of C. perfringens.

Now, in research published in the journal PLOS ONE, they have found that the probiotic bacteria have the ability to alter their coat. They speculated that this could be one way in which the probiotic outcompetes C. perfringens.

The researchers noticed, when examining the bacteria, that a small number of them appeared smooth. They identified the genes responsible for making a special coat, or slime capsule, in which the bacteria surround themselves. This coat protects the bacteria from stomach acids and bile salts and helps them come together to form biofilms.

"The next step is to understand the regulation of the genes involved in making the coat," said Dr. Arjan Narbad, who led the studies. "We want to find out whether changing the coat affects the probiotic's fitness to colonize and inhabit the gut."

This could prevent C. perfringens from colonizing the gut. This competitive exclusion could be one reason why L. johnsonsii prevents the growth of other harmful bacteria.

Understanding the role of the slime capsule coat will help guide the commercial development of this strain of L. johnsonsii as a preventative treatment for C. perfringens infection in poultry, especially in regard to how the probiotic is stored and produced. In the U.K., technology transfer company Plant Bioscience Ltd. has patented the strain, which is now in large-scale farm trials to assess its efficacy.

Volume:85 Issue:18

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