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POULTRY HEALTH HIGHLIGHTS OF A ROUNDTABLE DISCUSSION T ODAY Optimizing immunity fin ‘no antibiotics ever’ and‘reduced use’ broiler flocks july 2017 • INDIANAPOlIS, INDIANA P O U - 0 0 0 9 4 POULTRY HEALTH HIGHLIGHTS OF A ROUNDTABLE DISCUSSION T ODAY Jon Schaeffer, DVM, PHD Director, Poultry Veterinary Services, Zoetis Inc. [email protected] • zoetisus.com/foodsafety WELCOME The growing trend toward “no antibiotics ever” and “reduced use” production systems has prompted poultry companies to rethink their traditional disease-management practices. When flocks are raised with few or no antibiotics, they’re naturally more susceptible to diseases caused by primary or secondary infections. This has presented a huge challenge for poultry veterinarians. alternative therapies have shown potential, but reports from the field — both scientific and anecdotal — show they’ve also been inconsistent. Making refinements in nutrition, stocking rates and housing may help to reduce disease pressure. But in the end, finding ways to optimize immunity and give broilers more “staying power” could be the best strategy for maintaining the health and welfare of these birds. To help the poultry industry meet this goal, we brought together an all-star team of experts with expertise in three diseases affecting the broiler’s immune system — IBD, Marek’s and reovirus — to talk about what producers can do now to raise the bar for protection and flock welfare. This booklet presents highlights from that lively and informative discussion. Special thanks to the participants for sharing their insights and expertise. Sponsored by f Optimizing immunity in ‘no antibiotics ever’ and‘reduced use’ broiler flocks TABLE OF CONTENTS 4 PANELISTS 6 BUILDING A STRONGER BIRD 9 INFECTIOUS BURSAL DISEASE 20 REOVIRUS 26 MAREK’S DISEASE 29 WRAPPING UP POULTRY HEALTH HIGHLIGHTS OF A ROUNDTABLE DISCUSSION T ODAY MARK BURLESON, DVM KALEN COOKSON, DVM ELIZABETH DALE, DVM DARAL JACKWOOD, PHD JEAN SANDER HOLLY SELLERS, DVM JOHN SMITH, DVM GUILLERMO ZAVALA, DVM 4 f Optimizing immunity in ‘no antibiotics ever’ and‘reduced use’ broiler flocks PANELISTS Mark BUrlesOn, DVM Wayne Farms kalen COOksOn, DVM Zoetis elizaBeth Dale, DVM Pilgrim’s Daral JaCkwOOD, PhD Ohio State University hOlly sellers, DVM University of Georgia JOhn sMith, DVM Alectryon, LLC GUillerMO zaVala, DVM Avian Health International, LLC MODERATOR: Jean sanDer Zoetis 5 POULTRY HEALTH T ODAY BUILDING A STRONGER BIRD 6 f Optimizing immunity in ‘no antibiotics ever’ and‘reduced use’ broiler flocks IBD is one of those diseases that will be here long after “ all of us are gone. It’s never going to go away. GUillerMO zaVala , D V M ” SANDER reovirus is a little bit more inconsistent — control of these viruses is therefore ? Dr. Zavala, would you tell us a bit about some strains are immunosuppressive critical — and we have the tools we need how control of immunosuppressive and some are not. Immunosuppressive to protect against the immunosuppressive reoviruses, like IBD, may affect B cells. diseases they cause. We don’t always diseases such as infectious bursal They cause bursal atrophy, for example, protect birds against them 100% the way disease (IBD), reovirus and Marek’s can and reduce the ability of the bird to we’d like to, but for the most part, the help us produce a more resilient bird produce immunoglobulins against vaccines we have for use in the field are with a stronger immune system? specific disease agents. good tools. ZAVALA Marek’s disease also affects B cells, IBD is one of those diseases that will be impairing the bird’s ability to produce SANDER here long after all of us are gone. It’s never sufficient antibodies to a number of ? Can vaccination against viral going to go away. It affects B cells and different infectious disease agents. It can diseases help reduce the incidence impairs their ability to produce specific impair the ability of T cells to function of secondary bacterial infections antibodies that have high affinity for very properly, which help coordinate the bird’s and, in that way, reduce the need specific disease agents. immune responses. for antibiotics? Protecting birds against Marek’s disease is a fourth very, very critical immuno- JACKWOOD absolutely critical if, for example, we’re to suppressive agent is chicken infectious When we’re talking about vaccines for reduce condemnations due to neoplasia in anemia virus (caV). It can interact immunosuppressive diseases like IBD, the processing plant. It’s also critical for with any or all of these other viruses reovirus and Marek’s, I think we can do protecting the immune system. and predispose birds to secondary a better job than what we’re doing now. opportunistic infections. It can infect If we can prevent birds from becoming and destroy bone marrow cells. immune-suppressed and getting second- The result is increased bacterial ary bacterial infections, we may be able to infection and increased severity of get away with using fewer antibiotics. any infectious disease. continued 7 POULTRY HEALTH HIGHLIGHTS OF A ROUNDTABLE DISCUSSION T ODAY BUILDING A STRONGER BIRD ...it’s important to manage our secondary bacterial levels, “ and even bronchitis. kalen COOksOn, DVM ” SANDER broiler flock we knew had low reovirus SANDER ? Should efforts to build immunity titers and challenged half of them with ? Dr. Dale, according to published in broilers start with the breeder reovirus at 3 days of age and then IBD reports, Pilgrim is the second program? virus and caV at 7 days. and the results of largest producer in the uS, and that, from a viral standpoint, is that we got about 24% of your production is now SMITH about 10% weight suppression, probably “no antibiotics ever.” Have you Absolutely. The key to controlling diseases from the reovirus challenge, and 50% of seen a relationship between the like IBD or reovirus, at least under US the birds were infected with aL-2 by 2 management of these three diseases weeks of age. So IBD virus was also conditions, is hyper-immunization of the and the staying power of your flocks, probably a factor. hen using strains that are as close as and does it differ in antibiotic-free possible to your resident challenge strains. production systems versus on top of that, we challenged all the birds conventional production systems? DALE with a pathogenic Escherichia coli using If the bird is immune-compromised or either a high dose of about 8 logs or a low overwhelmed by conditions in the dose of 5 logs. Well, there wasn’t much DALE difference in the high-dose E. coli birds — environment, you can use the best The management of those three diseases as if even the immune-intact birds were vaccines in the world but they’re not is just as important in our conventional just as overwhelmed by the high E. coli going to elicit an appropriate response, systems. These problems lead to morbidity challenge. But in the low-dose E. coli and a bacterial challenge will break and mortality in both types of systems. birds, we still had significant levels of through pretty easily. however, it’s not as easy to prevent E. coli disease in the virally challenged secondary bacterial issues due to birds and no E. coli in the birds that immunosuppression in antibiotic-free COOKSON weren’t immune suppressed. So I think production systems. I’ll just share a study we performed a there’s information in that, that can kind of fit into our paradigms that we’re few years ago at auburn University careful management throughout the facing today. You know, how it’s important because I think it illustrates the interaction entire production process is needed to to manage our secondary bacterial between virally induced immune ensure we get the vaccine reaction we levels, and even bronchitis. It’s still very suppression and susceptibility to bacterial need to elicit adequate immunity, whether 1 important that we manage our immune challenge. In this study, we picked a that’s in breeders, at the hatchery or in health programs, as well. the broiler house. 8 INFECTIOUS BURSAL DISEASE 9 POULTRY HEALTH HIGHLIGHTS OF A ROUNDTABLE DISCUSSION T ODAY INFECTIOUS BURSAL DISEASE SANDER you don’t have B cells reaching the sec- The key to successful breeder vaccination ? Dr. jackwood, can you expand on ondary lymphoid organs yet. They’re con- is having breeder birds that aren’t IBD and tell us more about how it centrated in the bursa, and if they’re immune-suppressed to begin with and contributes to immune suppression? destroyed, you don’t have any more cells that have a fully functioning immune to repopulate — resulting in permanent system so they can respond to vaccines. JACKWOOD immune suppression where antibodies You need to get the titers of antibodies The virus infects immature B cells in the can’t be produced. very high so breeders pass those bursa of fabricius. Ultimately, what you antibodies on to broiler chicks through end up with is a bird with a diminished It’s important to note that the T-cell the yolk. ability to produce antibodies. population is also affected by IBD so you also see some cellular immune It’s been shown fairly well that if you have however, the severity of compromise suppression in these birds. (T cells are high serum antibodies in your breeders, depends on the timing of infection. Let’s critical for fighting bacterial infections) . you will have high antibodies in the say the bird is 14 days or older. You’ll broilers when they hatch. The issue with get a depopulation of bursa B cells and vaccination of breeders, as Dr. Smith you’ll get immune suppression, but it’s a SANDER mentioned, is that you want to make sure transient suppression.

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