SPAH-PBU-480

NUMBER 14

THE EIMERIA GENOME PROJECT: WHAT YOU NEED TO KNOW

VLA’S DR. RALPH MARSHALL ON HIS FASCINATION WITH COCCIDIOSIS — AND ITS CONTROL

SPECIAL REPORT FROM VENICE:NEW CHALLENGES IN INTESTINAL HEALTH

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FEATURES

NUMBER 14 www.ThePoultrySite.com/CocciForum

2 COVER STORYIN THE EYE OF THE BEHOLDEREimeria is the object of Dr. Ralph Marshall’s fascination

5 SPECIAL REPORT: COCCIFORUM VENICENew challenges in intestinal health management

17 PASSING THE ‘SO WHAT?’ TESTGenetic studies of Eimeria could lead to big breakthroughs in coccidiosis control

20 EUROPEAN POULTRY CONFERENCENecrotic enteritis outbreaks stop after vaccination

22 COCCI PEOPLERenowned parasitologist Peter Long remembered by poultry industry

23 COCCI NEWSNew developments affecting the poultry industry

25 COCCI VIEWSAsking tough questions

Paracox is a registered trademark and SprayCox is a trademark of Schering-Plough Animal Health Corporation.

Cover: Dr. Ralph Marshall of Veterinary Laboratories Agencies,Weybridge, England, finds Eimeria organisms — the ones thatcause coccidiosis — attractive, mysterious, clever and challenging.For more on his work and fascination, see page 2.Photo by Joseph Feeks.

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To an outsider, studying Eimeriafor a living is a far-from-glam-orous job, but parasitologist Dr.

Ralph Marshall considers the object ofhis work attractive, mysterious, cleverand challenging.

He even has a favorite coccidialspecies — Eimeria tenella.

“Under the microscope, it has themost beautiful shape of all the Eimeriaoocysts and a beautiful blue halo. It’s assimple as that. I just love it,” he says.

The scientist heads up coccidiosisresearch at the Veterinary LaboratoriesAgencies (VLA), an entity initiated over100 years ago in a small London office.Today, VLA is located in Weybridge,England, and is an internationally recognized veterinary research center.It is a reference laboratory for manyfarm animal diseases and conducts

important studies for pharmaceuticalcompanies.

Marshall came to VLA in 1971 andcompares his work studying Eimeriato his favorite hobby — bird-watching.“There are a lot of analogies betweenthe two,” he says. “I love walking outin the field and being able to identify a bird. And I love being able to look down a microscope and identifya parasite. Both have taught me theskill of observation, which is key toparasitology.”

Observation has also enabled himto witness an array of interesting devel-opments over the years in the field ofcoccidial research.

‘Brave new world’ When anticoccidial chemicals weredeveloped and marketed, it appearedto herald a “brave new world,” he says.Then the problem of Eimeria resistanceto anticoccidials started to develop.Marshall spent several years studyingthe problem.

“Slowly we realized that these littleparasites were winning. It was goodfun working out the mechanisms ofhow the parasites were getting resistantto drugs,” he says.

“We managed to develop lots ofresistant strains here in the lab. Weactually had one that got hooked on ananticoccidial. If we gave this particularEimeria strain to chickens that were feda particular anticoccidial, the parasiteslived. If we withdrew the drug, the par-asites died. The drug seemed to keepthe parasites alive,” Marshall says.

Recalling the advent of ionophores,he says, “The idea behind thesedrugs was not to wipe out the parasitescompletely.”

IN THE EYE OF THE BEHOLDEREimeria is the object of Dr. Ralph Marshall’s fascination

Marshall: ‘Slowly we realized that these little parasites were winning.’

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Around that time, however, Marshallexperienced a time warp when hemoved to another department withinVLA and temporarily lost track of coc-cidiosis research. He returned to hisbeloved field in the 1990s to find anewcomer on the scene: the attenuatedcoccidiosis vaccine Paracox, which hasdominated his life for the past decade.

The poultry industry had difficultyadjusting to the notion of vaccinatingpoultry to control coccidiosis. “Therewas a total change in mindset frombeing told you have to get a drug to killthis parasite to then being told that youdon’t want to use a drug, you can usea vaccine instead,” he says. “That was adifficult concept for producers tograsp.”

Today, coccidiosis vaccines arewidely accepted in the breeder sectorand in several countries, their use isgrowing in other segments of the mar-ket, including broilers and free-rangelaying hens, Marshall says.

Testing sprayed vaccine Marshall has also been involved in test-ing new methods of administering coc-cidiosis vaccines. About 6 years ago, heheaded up VLA’s assessment ofSchering-Plough Animal Health’sSprayCox II, a spray cabinet technolo-gy for application of Paracox-5 to broil-ers.

“We set up a cabinet that was like agiant sort of construction kit,” he says.“We had about 700 or 800 birds thatwere vaccinated in large groups atonce. Then we challenged them withfield strains of Eimeria given at timesranging from about 2 to 7 weeks aftervaccination. It was very successful andwe published the results.”

More recently, Marshall has beeninvolved in testing the efficacy of thespray cabinet for administration ofParacox-8 for broiler breeders as wellas free-range egg layers, a developmentthat would bring added convenience tofarmers vaccinating birds in this seg-ment of the market.

For the study, birds were challengedwith seven Eimeria species. The out-come is being determined by perform-ance results such as weight gain as wellas oocyst output and lesion scores. Atthis writing, the preliminary resultslooked good, he says.

Another important aspect ofMarshall’s work with coccidiosis hasbeen development of an anticoccidialsensitivity test to determine the level ofresistance among Eimeria parasitesrecovered from the field. Birds on vari-ous anticoccidials are challenged withEimeria field isolates and, again, per-formance and oocyst output and lesionscores will be used to reveal the sensi-tivity of each Eimeria species to the var-ious anticoccidials tested.

Studies in other countries, he notes,have demonstrated that resistant fieldstrains of Eimeria can be replaced withthe strains of Eimeria in the vaccine,which are still sensitive to anticoccidi-als. In other words, the vaccine can beused to revitalize a producer’s anti-coccidial program or it can replace the

‘Eimeria tenella ‘has the most beautiful shape of all Eimeria oocysts,’ saysMarshall, ‘but it’s also regarded as one of the most difficult strains to manage.’

Eimeria photo courtesy of Dr. Ralph Marshall.

use of anticoccidials, which is especial-ly important for growers raising antibi-otic- or drug-free birds.

At this writing, Marshall planned toinitiate sensitivity testing soon. Similartesting has been conducted elsewherein Europe and the United States, butnever before in the UK, he says.

“Our studies will demonstrate if theexperience in the UK is likely to be thesame as it has been elsewhere,” hesays.

Eimeria’s economic impactThroughout the interesting twists andturns that have occurred during hiscareer, Marshall never forgets the eco-nomic importance of his work.

Eimeria and resulting coccidiosishas been estimated to cost the UKalone £35 million (51.5 million Euros or$66.2 million) a year considering pro-duction losses and the cost of anti-coccidial control, he says. “With infla-tion, it’s probably a lot more since thatfigure was established. The diseasecauses a huge, huge cost to poultry dis-tributors.”

Eimeria, Marshall points out, is tena-cious. If you leave coccidia lying on the

ground in a chicken house, particularlyin the UK where it’s often cool anddamp, it can survive for weeks andmay resist normal cleaning and disin-fection processes. With short turn-around times, this can present a prob-lem for subsequent flocks. “It can be avery difficult bug to get rid of. Theindustry has found ways to containEimeria, but it comes with a price.

“We’ll never know all there is toknow about coccidia. These parasitesare just too clever for us,” he says.

There are also hidden costs fromcoccidiosis that aren’t even readilyapparent, Marshall says. Anticoccidialresistance has resulted in a subclinicalchallenge that knocks the edge off per-formance. Trials in the UK have shownthat when broilers are vaccinated forcoccidiosis with Paracox-5 and thatchallenge from resistant coccidia iseliminated, growth appears to blossomand there’s an increase in live weight.“Considering that we grow 800 millionbroilers in the UK annually, better con-trol of coccidiosis through vaccinationcould have a huge impact, but produc-ers here, understandably, want harddata,” he says.

Marshall’s work with vaccines hastaken on new importance due to themovement toward drug-free poultryproduction. The arsenal of anticoccidi-als is shrinking and, he predicts,ionophore use may be reconsidered inthe future.

Producers still using anticoccidialsneed to make the most of the ones thatare still available or they need to findalternatives. If they know they can suc-cessfully revitalize or replace their anti-coccidial program with vaccination,“that would be great,” Marshall says.

In addition to changes prompted bythe drug-free movement, animal wel-fare trends are also affecting poultryproducers. More birds will be free-range and the sizes of cages and thenumber of birds reared on floors aregrowing, which could increase the coc-

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Marshall has been involved in testing new methods of administering coccidiosis vaccine, including the SprayCox II spray cabinet.

continued on page 22

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SPECIAL REPORT

Growing flocks without in-feed antibiotic growthpromoters (AGPs) has had its consequences.One is an adverse impact on intestinal health,

which has contributed to the multifactorial diseaseknown as necrotic enteritis (NE). Until their use wasdiscontinued, the contribution of AGPs to the controlof NE was not fully appreciated.

The ban on AGPs was implemented due to concernthat subtherapeutic antibiotics given in poultry andlivestock feed may contribute to antibiotic resistantinfections in people, but it has resulted in more infec-tions and, ironically, has increased use of therapeuticantibiotics, underscoring the need to find non-antibiot-ic alternatives.

The importance of NE cannot be underestimated.As nutritionist Bill Dudley-Cash recently wrote inFeedstuffs, an internationally read trade publication,“The successful commercial production of [poultry], inthe absence of antibiotics, is dependent on the controlof necrotic enteritis.” An increasing number of poultryconsumers worldwide are demanding that their broil-ers be grown without in-feed antibiotics and “under-standing, controlling and/or managing necrotic enteri-tis are the keys to growing chickens without antibi-otics,” he said.

Dr. Luciano Gobbi, technical service manager for

Schering-Plough Animal Health in Italy, says that NEcan be controlled without routine, subtherapeuticantibiotics, enabling producers to move a huge steptoward meeting consumer demand for truly antibiotic-free poultry.

Gobbi points out, however, that NE goes hand-in-hand with another enteric disease — coccidiosis —which damages the intestinal lining, setting the stagefor the overgrowth of Clostridium perfringens — thecause of NE. “Good control of necrotic enteritisrequires good coccidiosis control,” he says.

The quest for antibiotic alternatives for control ofnecrotic enteritis as well as coccidiosis has focusedlargely on nutrition, management and vaccination.

To further knowledge in the poultry industry onthese topics, Schering-Plough Animal Health recentlyorganized a seminar near Venice. More than 100 rep-resentatives of leading poultry companies fromEurope, the Middle East and Africa gathered to hearfrom experts on non-antibiotic control of intestinal dis-ease. Participants also had the opportunity to hearfrom several producers who are successfully control-ling coccidiosis with vaccination and from a marketingexpert about how to succeed in today’s climate.

CocciForum magazine is pleased to present high-lights from the seminar in the articles that follow.

New Challenges in Intestinal Health Management

CocciForumVenice

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Necrotic enteritis has become a leadingproblem for broiler chicken producers,but control of the disease is possiblewith a combination of vaccines andmicroflora modulation, predicted Dr.Steve Davis, president of ColoradoQuality Research, Inc., a US-basedpoultry research company.

In recent poultry industry surveys,necrotic enteritis was one of the topfive health problems affecting broilerflocks, said Davis. “It’s very much a hottopic... and it did not become a prob-lem until we started trying to raisebroilers without in-feed antibioticgrowth promoters.”

Varies widelyDavis’s organization has conductedbetween 30 and 40 studies of necroticenteritis and made several interestingobservations. One is that the cause ofnecrotic enteritis — the alpha toxinproduced by Clostridium perfringens —varies widely.

“There’s a real difference in the C.perfringens out there,” he said. Withsome isolates, just a little administeredin feed will rapidly kill birds. Other C.perfringens isolates tend not to cause

mortality, but adversely affect weightgain and feed conversion.

“When we talk about necroticenteritis, we have to talk about coc-cidiosis control,” he continued. It’smuch easier to induce necrotic enteritisif birds have coccidiosis, particularlythe Eimeria maxima variety. Coccidiosisdamages the intestines, providing theright environment for C. perfringens toproliferate and for NE to develop.

Ionophore anticoccidials such aslasalocid, monensin and salinomycinhave antibacterial properties — morethan people realize, he added. “We feelvery strongly that ionophores havehelped prevent necrotic enteritis not bycontrol of coccidiosis, but because theyhave actual [antibacterial] efficacyagainst C. perfringens,” Davis said.

Ionophores, however, are probablyon their way out due to public pressureto eliminate the use of all antibiotics infood animals. Chemical anticoccidialshave no antibacterial effects and there-fore would do little to control NE, saidDavis.

Considering the current situation,vaccines are the direction of the futurefor coccidiosis control and may be usedalone or in rotation with any anti-coccidial to help prevent drug resist-ance, he said.

Besides coccidiosis, other factorsthat appear to predispose flocks to NEare poor chicken quality and uniformi-ty. “We’ve noticed if chicks are of poorquality, we have more necrotic enteritismortality and more early mortality,” hereported. “The more uneven the birdsare, the easier they succumb to a C.perfringens challenge. It’s always thesmallest chicks that end up being thefirst to die.”

In addition, faster growing birdsalso tend to break with necrotic enteri-tis sooner than slower-growing birds,he said.

Davis: ‘When we talk aboutnecrotic enteritis, we have to

talk about coccidiosis control.’

SPECIAL REPORT

Future approaches for necrotic enteritis control

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“When you get an ideal flock, it’svery difficult to produce necroticenteritis,” Davis said, adding that it’spossible that some breeds of birds aremore resistant to the disease.

New toxoidControl of NE in the future may dependlargely on vaccines, partly because theC. perfringens bacterium has excellentpotential for use as a vaccine antigen,he said.

Schering-Plough Animal Health hasdeveloped a C. perfringens type A tox-oid vaccine for NE that is currentlybeing used in the United States. (Seewww.netvaxforpoultry.com.) In 2008, itis expected to be approved for use inEurope.

Davis pointed out that while thenew C. perfringens type A toxoid maybe new for poultry, the technology isnot new among sheep, cattle andswine. Because injecting individualbroilers would be impractical and cost-ly, the toxoid is given to breeder hens,which then convey passive immunity totheir broiler progeny, he said.

Davis’s company tested the toxoidin broilers that also received a coc-cidiosis vaccine for coccidiosis control.Birds with passive immunity from hensthat had received the NE toxoid had asignificant decrease in NE lesions and anumerical decrease in mortality com-pared to birds not from hens thatreceived the toxoid. (Figure 1.)

“Passive immunity through vaccina-tion definitely shows that it has excel-lent potential” for control of NE, Davissaid.

To further prevent and control thedisease, “We have to avoid placingknown poor quality chicks on farmsthat we know have a high C. perfrin-gens challenge or repeat necroticenteritis farms,” he advised.

Improved cleaning and disinfectionprograms may help control NE if wayscan be found to kill C. perfringensspores but not the “good bugs” in thehouse, Davis added.

Davis has found that diet definitelycan influence NE. The more wheat, ryeand barley fed to chicks, the greater thetoll of NE. High protein levels havebeen associated with NE outbreaks.Animal byproducts, particularly fish-meal, may be contaminated withclostridium. Consider that successfulantibiotic-free poultry producers in theUnited States tend to use all vegetablediets, he said.

“I’m not saying we have all theanswers, but it’s quite obvious that wecan play with these diets and createnecrotic enteritis,” he said.

Davis has also studied feed addi-tives including enzymes, probiotics and organic acids. “We have not foundanything that I would say is a magicbullet.”

Nevertheless, “as we learn moreabout the natural microflora of the gut,we’re going to get better and betterwith these types of products. Whencombined with vaccine technology,we’re going to find that it may be pos-sible to prevent NE without antibiotics,”he said.

Figure 1. Necrotic enteritis mortality — vaccinates vs. challenged andnon-challenged controls.

A = Challenged control

B = Non-challenged control

C = Chicks from hens not given clostridium toxoid and vaccinated day 1 for coccidiosis

D =Chicks from hens given clostridium toxoid and vaccinated day 1 for coccidiosis

30%

25%

20%

15%

10%

5%

0%%

Mor

talit

y

24.1%

12.5%

16.1%

0.9%

A B C D

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Nutrition can maximize intestinal healthand help prevent enteric disease, butdeciding which ingredients to use andfinding the right balance of each canrequire as much finesse as a high wireact.

The trend toward growing broilerswith fewer or no in-feed antibiotics isforcing producers to consider an arrayof dietary approaches that may or maynot improve intestinal health and pre-vent “dysbacteriosis” — an overgrowthof “bad” gut bacteria, said Dr. Rob tenDoeschate, a poultry nutritionist withAbnatech Global, Peterborough,England, a consulting and research firmserving the poultry industry.

“We used to have antibiotic growthpromoters (AGPs). They’re gone. We’restill using anticoccidials in the feed andone by one the list of available anticoc-cidials gets shorter, so vaccines willneed to be used,” he said.

To help ensure good intestinalhealth in light of current trends, it’smore important than ever to begin bymaking sure broiler chicks get off to agood start, ten Doeschate said.

“Chicks need to develop a healthy,well-functioning gut early in life, so forthe first week, feed very high nutrientand mineral levels,” he said. Thedigestible levels of amino acids may be

above breed standards. Sodium is key,“but don’t forget calcium and phospho-rous,” he added.

The diet should also have a goodphysical quality to ensure intake andstimulate gut development. “Nowadayswe use good quality fat and oil almostexclusively,” he said. Too much fat,however, is bad because lipid digestionis still underdeveloped.

Young birds need highly digestibleprotein. “I don’t think that’s soy, so Ilike to see a bit of fish meal and, if youcan’t use fish meal, use some otherpurified protein to help the bird thefirst couple of days,” ten Doeschatesaid.

The nutritionist believes that betterintestinal health can be promoted byencouraging gizzard development,which can be accomplished by incor-porating some coarse material, such aswhole wheat, into the diet.

In the United Kingdom, wholewheat is widely used in broiler feeding.Wheat has been linked to an increasedrisk for some intestinal problems but,according to ten Doeschate, the key isfinding the right amount, which can bechallenging.

Feed trials comparing no whole-wheat dilution with medium and highlevels of added wheat showed that ahigh level of wheat resulted indecreased live weight and poor feedconversion, but it also resulted in alower water intake and fewer hocklesions. Medium amounts of wholewheat addition can be positive, tenDoeschate has found.

Wheat-based diets do result inincreased gut viscosity, “and we use NSP (non-starch polysaccharide)enzymes to get over that,” tenDoeschate said.

‘Pronutrients’Besides enzymes, there are severalother “pronutrients” or additives to

ten Doeschate: ‘Chicks need to develop a healthy, well-

functioning gut early in life.’

SPECIAL REPORT

Maximizing intestinal health with nutrition

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consider for broilers raised withoutAGPs, he said.

One option is acid salts or organicacids, which have been used extensive-ly in breeder feeds to eliminate or con-trol salmonella. In broiler chicks, theirbenefits are not as clear. Trials atAbnatech have shown that birds tendto drink more if there’s a lot of acid inthe feed, complicating litter manage-ment. “In addition, free acids are corro-sive and therefore are not popular atfeed mills; acid salts are probably lesseffective and aren’t really the productfor poultry either,” he said.

Plant extracts such as essential oilshave been touted as an alternative toantibiotic growth promoters, but ques-tions remain about their active ingredi-ents and quality. “If you get a level inthe diet that will work, it might be sohigh that we can’t afford it, so it’s notone we’ve used,” ten Doeschate said.

PrebioticsPrebiotics are another option andwould include complex carbohydratessuch as mannan oligosaccharides fromyeast cell walls. Yeast products, he said,have performed well in trials. They arenot digested by the bird and improvegut health. Mannoproteins preventattachment of Escherichia coli andother bacterium to the gut wall andstimulate the immune response, hesaid.

The nutritionist is also big onbetaine, which is an “osmoprotectant”that helps maintain cell integrity.Studies show that in chickens with coc-cidiosis, where the ratio between cryptdepth and villi length decreases,betaine allows villi to lengthen, result-ing in better nutrient absorption.“There’s an interaction between thecoccidial challenge and betaine in thetissue. Putting more betaine in the dietis positive, he said.

Betaine also prevents dehydrationand maintains ionic balance, especiallyduring times of stress such as transport,

high heat or pathogen challenges. It iscompatible with enzyme function, pro-tects enzymes and membranes fromosmotic inactivation and improveswater balance, ten Doeschate said.

“Nutrition,” he said in conclusion,“can effect changes in intestinal healththat may be positive or negative. Ofcourse, it’s important to establish ahealthy, good functioning gut duringthe starter period. There are more pos-

itive actions we can make in feeddesign. Use the right enzyme. We canminimize changes during the bird’s life.Look at food structure — I’m talkingabout coarse grinding. And then last,but not least, use some pronutrients,”he concluded.

‘The trend toward growing broilers withfewer or no in-feed antibiotics is forcingproducers to consider an array of dietaryapproaches that may or may not improveintestinal health’

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W hether they are smaller niche-

market operations or top industry

players, European poultry produc-

ers are finding that coccidiosis vaccination is

proving to be a problem solver. Vaccination is

allowing them to meet market demand for

antibiotic-free broilers, combat anticoccidial

resistance in conventional flocks, further

enhance food safety and simplify flock thinning.

Following are success stories from four progres-

sive EU producers.

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At Lloyd Maunder Ltd, afully integrated, family-run company that’sbeen producing broilersin England since the1950s, coccidiosis vacci-nation has become“fundamental to coc-cidiosis control,” sayshatchery manager MikeTanton.

As a relatively smallcompany, when com-petition with largercompanies in the con-ventional broiler marketbecame difficult, LloydMaunder looked to the

high-value, niche market. In 2000, the company startedgrowing organic, free-range broilers and now produces80,000 of them weekly, which it sells in 15 companyshops and to retail outlets, he said.

As part of its new venture, the company developed itsown robust breed of bird, the Devonshire Red, which isreared to 4 weeks of age in brood houses with high stan-dards of biosecurity. These high-health birds are thentransferred to mobile houses on the range areas.

Frequently farms have birds of three different age groupsat any one time, presenting tough coccidiosis controlchallenges, Tanton said.

The sole method of managing coccidiosis in its organ-ic chickens is vaccinating with Paracox-5. Chicks aresprayed at the hatchery when they are one day old. Redfood dye included in the vaccine not only encouragespreening and ingestion of Paracox-5, it marks the chicks,which lets hatchery staff and farmers receiving the chicksknow that birds are protected against coccidiosis. “Theapplication is very easy,” Tanton said.

Lloyd Maunder Ltd, UKVaccination ‘fundamental’ to coccidiosis control

Tanton: ‘Primary disease agentscause a reduction in the birds’immune status.’

Red food dye added to Paracox-5 encourages preening andmarks chicks, making it obvious they have been vaccinated.

SPECIAL REPORT

Amadori Group, ItalyBoth ‘green’ and standard broilers benefit from coccidiosis vaccination

Paracox-5 has helpedone of Italy’s poultrygiants, Amadori Group,launch its “green andhealthy” Amadori 10+product, developed inresponse to growingconsumer demand fordrug-free products.

Amadori, a fullyintegrated companythat produces about

110 million broilers annually, found that after gainingexperience with Paracox-5, it had “very satisfactory tech-nical results” in its green birds and began using the vac-cine in standard broilers too, said Dr. Tonino Toscani,director of health and nutrition for Amadori’s poultrybusiness.

In its drug-free birds, use of the vaccine coupled withgood management practices enable birds to maintainperformance similar to birds receiving traditional in-feedanticoccidials, “which we have demonstrated in manyinternal trials,” Toscani said.

In standard broilers, the vaccine is used primarily tocombat rising coccidial resistance to anticoccidial drugsand chemicals. “We hope to ensure greater choice ofeffective anticoccidial products for the future by rotatingthe vaccine with medicated feed,” he said.

Toscani showed data demonstrating that after threecycles of using the same ionophore anticoccidial, thenumber of resistant Eimeria coccidia rises. WhenParacox-5 is rotated with anticoccidials, ionophore resist-

ance decreases because the vaccine’s live, attenuatedEimeria oocysts replace resistant oocysts.

Isolates of European field coccidia, including sometaken from it’s own poultry units, have shown that com-

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“In round terms we vaccinate with Paracox-5 and thebirds don’t get coccidiosis. Performance data backs thisup with good levels of production performance” he said.

Lloyd Maunder strives to grow birds slowly and keepsweight to about 2.25 kilograms (4.9 pounds) as dictatedby market requirements. Slower growth not only helpsproduce birds that taste good, it also has reduced mor-tality, Tanton said. In organic systems often the maincauses of loss are as a consequence of the more chal-lenging environment the birds grow in and the effects ofpredation.

Where coccidiosis is seen it is usually associated withother diseases such as Marek’s disease or Gumboro forexample.

“We think that these primary disease agents cause areduction in the birds’ immune status and coccidiosisoccurs as a secondary infection. Suboptimal managementcan also be a significant factor” Tanton said.

“In our experience on farms with good standards ofmanagement, Paracox-5 is highly effective and it doesexactly what it says on the box,” he said.

Toscani: ‘Performance results arebetter than expected.’

Figure 1. Number of resistant EEiimmeerriiaa strains (red dots)after three cycles of ionophore usage.

Figure 2. Number of resistant EEiimmeerriiaa strains (red dots)after three cycles of Paracox-5 usage.

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plete coccidial resistance and reduced sensitivity to thein-feed anticoccidials monensin and diclazuril are wide-spread on farms that strictly use in-feed anticoccidials forcoccidiosis control, Toscani added.

In contrast, “our experience suggests that a rotationprogram that includes at least two or three consecutivevaccinated flocks followed by two or three medicatedflocks on the same premises restores sensitivity to stan-dard anticoccidial drugs,” he said. In standard flocks,Amadori now usually uses in-feed anticoccidials duringwinter, which helps reduce the impact of wet litter, andthe coccidiosis vaccine in late spring and summer.

No acute disease outbreaks“Performance results are better than expected,” Toscanisaid, yielding not only good coccidiosis control with nocases of acute disease, but improved feed conversion.

He attributes some of Amadori’s success with the vac-cine to genetic improvement and feed management.Energy and protein in the diets have been reduced tocontrol enteric problems. In the future, enteric disease inbirds vaccinated against coccidiosis may require a dedi-

cated control strategy; medication may be occasionallyneeded in vaccinated birds as well as in those receivinganticoccidials.

Necrotic enteritis control will also require new strate-gies in brooding management, diet manipulation andvaccination when it becomes available. Bird density andwater quality are other factors that need to be consid-ered, Toscani said. Note: For more about Amadori’s experiences with coccidiosisvaccination, see CocciForum No. 8 or go towww.ThePoultrySite.com/CocciForum.

One of the major Italianpoultry producers —Martini Alimentare —has found that Paracox-5 significantly simplifiesmanagement in flocksthat are thinned, a pop-ular practice in Europe.

Martini, an integrat-ed company with sixfeed mills and threes l a u g h t e r h o u s e sthroughout Italy, pro-duces 15 million broil-ers annually.

Dr. Corrado Longoni,a poultry field veterinar-

ian with Martini, explained that males and females areplaced in the same house but are divided by a fence.Females are usually thinned at ages of 35 to 37 days

because they have less efficient feed conversion rates.Another thinning might be done for heavy females orlight males, usually at 44 to 46 days of age.

After each thinning, practiced in accordance with ani-mal welfare regulations, the fence is moved to give morespace to a greater number of faster-growing, large-breast-ed males that are processed at weights of 3.3 or 3.4 kilo-grams (7.2 or 7.4 pounds) and, sometimes as high as 4.5or 4.6 kilograms (9.9 or 10.14 pounds), he said.

Thinning makes it possible to send birds from eachgroup for processing at different ages, depending onmarket demand. Thinning makes it easier to raise veryheavy birds throughout the year, especially during sum-mer months when there is heat stress and higher densi-ty could be detrimental. In addition, thinning enablesproducers to capitalize on economies of scale, sincehouse space is used more efficiently and more kilos ofmeat per square meter can be produced. All players inthe production chain benefit from increased profits,Longoni said.

Martini Alimentare, ItalyCoccidiosis vaccination simplifiesfeed management, saves money

Longoni: ‘We can’t take the riskof residues.’

SPECIAL REPORT

Medication omplicates thinningThe use of in-feed synthetic or ionophore anticoccidialsand their required withdrawal time, which is usually 5days, seriously complicates thinning, he said. (Figure 1.)

Anticoccidials have to be withdrawn from feed soonenough to ensure that meat has no residues, and puts theflock at risk for a coccidiosis outbreak. Keeping anticoc-cidials in the feed increases the risk that residues couldmistakenly end up in meat at a time when consumerconcern about residues is at an all time high. Market flex-ibility is hindered and feed management becomes alogistical nightmare since two or three withdrawal peri-ods would be needed in thinned flocks, he said.

In addition, “feed mill contamination is a real con-cern,” since Martini makes feed for poultry other thanbroilers. “We can’t take the risk of residues either in feedfor non-target species or in our withdrawal feed for broil-ers,” Longoni said.

Vaccinating for coccidiosis eliminates these problems.It protects against coccidiosis, makes it easier and saferto thin flocks and enables Martini to be flexible inresponse to market needs. Feed management is simpli-fied since no withdrawal diet is needed, and there are noheadaches about anticoccidial residues in meat or aboutcross-contamination, he said. (Figure 2.)

Reduced costs Paracox-5 has not only improved disease and feed man-agement, it has saved money in several ways, Longoniadded. Since it enables thinning to be practiced andhouse space is used more efficiently, transportation costsfor moving day-old chicks and for transporting live birdsto slaughterhouses are each down by 20% to 30%.

The cost of transporting feed is reduced by 10% to20% because there is no need for withdrawal feed or forlarger quantities of other feed, although this savingswould vary among producers, he said.

Integrators pay farmers based on the kilograms ofmeat per square meter and flock performance, includingthe feed conversion ration, the culling rate and meatquality.

“Increased volume per square meter provides farmerswith reduced fixed costs and provides integrators withreduced variable costs,” Longoni said. Note: For more about Martini Alimentare’s experiences withcoccidiosis vaccination, see CocciForum No. 10 or go towww.ThePoultrySite.com/CocciForum.

Figure 1. The required withdrawal of anticoccidials toensure there are no residues in meat put the thinnedflock at risk for a coccidiosis outbreak.

Figure 2. In thinned flocks, Paracox-5 simplifies feedmanagement as well as eliminates concerns aboutresidues in meat.

13

14

At Spain’s leadingpoultry producer SADAp.a., a vertically inte-grated company withnine hatcheries and 10processing plants, over3 million chicks areplaced with contractfarmers weekly.

SADA consumerswant poultry meat thatis safe to eat fromhealthy birds raisedwith the environmentand animal welfare inmind, according tointegration manager Dr.

Santiago Bellés Medall of SADA, a subsidiary of theNetherlands-based Nutreco, one of the world’s leadinganimal nutrition companies.

Potential hazards in food include biological hazardssuch as bacteria, viruses and parasites, physical hazardssuch as bones or plastics, and chemical hazards, whichinclude pesticides, antibiotics and anticoccidial residues.Each risk must be identified and separate measures takento deal with each one. Consequently, SADA has strictprocedures in place to ensure that all potential hazardsare controlled and prevented, he said.

SADA has found that one way to prevent the risk ofanticoccidial residues in poultry meat is by usingParacox-5, which is administered to about 25% of thecompany’s flocks. Use of the vaccine especially comple-ments the practice of thinning flocks, Bellés said.

Thinning, he explained, is practiced on farms withmedium and high density — about 14 and 18 birds persquare meter (10.76 square feet), respectively — and isbased on live weight, not age. About 20% of its birds aregrown to about 1.8 kilograms (3.9 pounds) and the restto more than 2.5 kilograms (5.5 pounds).

When anticoccidials are used, managing withdrawaldiets in flocks that each have their own growth raterequires making several different feeds in small quanti-ties. Logistics at the feed mill become complicated, asdoes the transport of feed and feed management on thefarm because several different feeds have to be juggled,increasing the risk for errors or cross-contamination, hesaid.

It becomes “nearly impossible” to abide by legalrequirements intended to prevent anticoccidial residues,Bellés added.

With coccidiosis vaccination, the need for a with-drawal diet is eliminated, which simplifies feed manage-ment and, perhaps best of all, enables SADA to guaran-tee that its poultry is free of residues from ionophoreanticoccidials, he said.

SADA, SpainVaccination helps ensure food safety

Bellés: ‘Complements the practiceof thinning flocks’

Figure 1. Vaccination to control coccidiosis eliminatesthe need for a withdrawal diet.

Anticoccidials Withdrawal days

Chemical

Robenidine 5

Halofuginone 5

Diclazuril 5

Ionophore

Lasalocid 5

Monensin 3

Narasin 5

Salinomycin 5

Maduramycin 5

Vaccine

Paracox-5 None

SPECIAL REPORT

Disease-control methods such as vacci-nation and other tools that reduceantibiotic usage and nurture the con-sumer’s view of poultry meat as a safe,high quality and socially consciousproduct will contribute to the successof European poultry companies in thefuture, according to a leading poultryconsultant and strategist.

“Today’s consumer wants to knowwhat he eats, from where it came andhow it was produced. He wants assur-ance that what he eats is safe for hishealth and the environment, that it isfair to the manpower that produced itand that the meat comes from animalsthat are well cared for and healthy,” saidDr. Osler Desouzart, a Brazil-basedfood-industry analyst who helps poul-try companies with marketing andplanning through his company ODConsulting.

Desouzart noted that this trend isparticularly gaining strength in Europe.“European producers should concen-trate in differentiated quality and newvalues of the consumer, among which Iwould say that regional and local val-ues are important. More and more, theissue of ‘landen,’ ‘paeso,’ ‘terroir,’ ‘fromhome’ is perceived by the consumer asa value,” Desouzart added.

These trends are initiating changesranging from the use of more “natural”diets in poultry feed to reduced hous-ing density for birds, he added, empha-sizing that poultry companies thatignore “His Almighty Excellency, TheConsumer” will be doomed to fail.

Traits of successful companiesDuring the course of his work,Desouzart has found that the successfulpoultry companies of today considerquality an intrinsic value of the wholecompany. They have a permanentimprovement system in place and are

never happy with the status quo. Theirstrategy reflects where they want to bein 10 years and provides a detailed,quantified and dated plan for the next3 years. They base decisions on dataand facts.

The primary focus of successfulpoultry companies is on the consumerrather than production. They have“win-win” relationships with theirclients and suppliers, he said.

Granted, cutting costs is important,but “creating value is essential,” hesaid. A lower price does not necessari-ly mean better value. Value goes hand-in-hand with quality, which must startat the beginning.

“A premium chicken sold at a pre-mium price cannot be made... with sec-ond-grade feed, with the lots managed

15

Future success for EU poultry companiesrequires focus on consumer trends, quality

Desouzart: ‘European produc-ers should concentrate on differentiated quality and new values.’

‘Today’s consumer wants to know whathe eats, from where it came and how itwas produced. He wants assurance thatwhat he eats is safe for his health and the environment’

16

by untrained people and with the ‘costdictatorship’ determining that the leastexpensive ingredients should alwaysbe used,” he said.

“Quality begins at the beginning,but has to go all the way to the end.There is no ‘partial’ quality, or qualityjust in parts of the process, by part ofthe departments and part of the time,”Desouzart said.

“My point is that if European pro-ducers try to fight the imports with theirunbeatable prices and tailor-made bul-letproof productions that resist anyquality assurance audit, they shall fail.If they think that they can entrenchbehind protectionism, they aredoomed.”

Desouzart said that marketing“fresh” poultry might be one way tocompete, but he warned producers thatthey should be prepared to fight againin 20 years because it’s only a matter oftime before technology makes it possi-ble for foreign suppliers to sell freshpoultry as well.

“The only thing that the invaderscannot obtain is the level of marketingknowledge and understanding that canonly come from working in that mar-ket,” he said. “Furthermore, foreignproducers can’t claim that their productis locally produced.”

Branding denotes confidenceAnother trait common among success-ful poultry companies is branding.“There are no leaders without a brand,”and to consumers, a brand denotesconfidence, assurance, reliability,recognition, comfort, feeling at homeand safety, he said.

The basis for branding is “definedand established quality.” Consumersare prepared to pay for this personalreassurance, “provided you do not for-get that ‘accessibility’ is a component ofquality,” Desouzart continued.

“A French consumer will argue fordays that a “poulet de Bresse” is supe-rior to any other broiler in the world,even if you can induce him to error ina blind test,” Desouzart explained. “Butwhy does he pay up to CHF 24,00 perkg for the chicken produced in Bresse?Because of its reputation, which datesback to Louis XIV.

“So sell uniqueness and reputation,”he added, “because wealthy consumersare not buying meat or protein. Aboveall, they are buying pleasure.”

Desouzart emphasized that whilepositive connotations of a brand cantake decades to build, they can takenanoseconds to be lost. “His Majestythe consumer seldom forgets or for-gives,” he quipped.

Desouzart warned mainstreamEuropean poultry producers to aban-don any notions they may have aboutfeeding the world’s hungry with low-cost meat, which could lead to defeatas underdeveloped countries increas-ingly supply inexpensive poultry forconsumers in their countries.Mainstream producers, Desouzart said,need to stay focused on producingquality meat with added value for localmarkets.

In fact, “Your local market knowl-edge, its idiosyncrasies and consumervalues may be the best ally that youhave to survive,” he said.

SPECIAL REPORT

17

Professor Martin Shirley gets frus-trated at times. His research intothe genetics and genomes of

Eimeria could lead to major advances incoccidiosis control. But to anyone out-side his field, Shirley’s work seemscomplicated, futuristic and, well — bor-ing to those involved with poultry pro-duction. And talk of it often falls upondeaf ears.

“This is not science fiction,” Shirleysays. “I want producers and veterinari-ans to understand that this research willpass the ‘so what’ test. It has hugepotential significance for controllingcoccidiosis, which remains one of theeconomically important diseases inpoultry.”

Shirley is director of the Institute forAnimal Health (IAH), the largestresearch institute focused on livestockdiseases in the United Kingdom. In the1980s, he led the team that developedthe world’s first attenuated coccidiosisvaccine, which set the stage for what isnow known in Europe as the Paracoxline.

Today, his focus is nailing down thegenetics of E. tenella, the most wide-spread and problematic of the Eimeriaspecies affecting poultry. Shirley initiat-ed the project and is working jointlywith Fiona Tomley, also of IAH, as wellas researchers at the Sanger Institute ofthe UK, the Malaysia Genome Institute,the University of Sao Paolo, Brazil andthe Laboratory for Molecular Biology ofthe UK Medical Research Council.

Benefits for poultry producersStudying the genetics of the ever-evolv-ing Eimeria, Shirley predicts, will leadto simpler but more effective methodsof protecting poultry from coccidiosis.It’s the only way the poultry industry

will be able to meet demand, performup to par and reap better profits,Shirley says.

Consider that Eimeria has evolvedover tens of thousands of years. It hasbecome adept at subverting the biologyof its host — the chicken — to its ownadvantage, and it’s likely to keep evolv-ing. “We’re trying to untangle that rela-tionship so we can intervene and comeup with new control measures as theyare needed. It’s a tough challenge,” hesays.

Toward that goal, the researchersare ‘mapping’ E. tenella’s genome.Genome is another word for geneticinformation. In short, Shirley and col-leagues are deciphering the parasite’sgenetic makeup.

“When we started the work, thegenetic information of E. tenella was abit like having a book that has no chap-ters, paragraphs, sentences or punctua-tion and you have to figure out where

PASSING THE ‘SO WHAT?’ TESTGenetic studies of Eimeria could lead to big breakthroughs in coccidiosis control

Shirley and IAH associate Fiona Tomley: ‘This is not science fiction.’

18

each strand of words belongs and fitstogether,” he says.

Until recently, virtually nothing wasknown about the chromosomes ofEimeria, Shirley says. Chromosomes arethe rod-shaped structures in the nucle-us, or center, of the cell and they carrythe genes which determine the charac-teristics that an organism inherits fromits parents.

E. tenella has a sequence of 14 chro-mosomes. “When we finish our map-ping project, we will have 14 sets ofinformation — one set of informationfor each chromosome. But keep inmind that these 14 chromosomes com-prise millions of pieces of data,” Shirleysays.

Unique chromosomesThe project to map E. tenella’s geneticstructure has already proved interestingbecause the chromosomes of thisspecies are unique compared to most ifnot all other organisms that have everbeen studied. In fact, they are amongthe most complex organisms in all ofveterinary medicine, he says.

Shirley likens the study of E. tenella

chromosomes to discovering the pat-terns along strings with four differentcolored beads. “Imagine the 14 chro-mosomes of E. tenella as 14 strings eachcontaining between 1 million and 14million of the four differently coloredbeads,” he says.

Interestingly, a study of the smallestchromosome has revealed that it con-tains distinct, alternating regions.Looking from left to right, the beads ini-tially appear as though the colors aredistributed randomly, then there aredistinct and repeating patterns of color,then seemingly random colors again,then the strong and repeating patternsof color and, finally, seemingly randomcolors again, Shirley says.

“Our mission is to identify similari-ties in the patterns of these ‘beads’ andthen link them to specific traits that willenhance our understanding of the par-asite and the best way to control it,”Shirley says.

E. tenella’s unique arrangement mayexplain parasitic mysteries such as whyEimeria has become increasingly resist-ant to drugs. Chromosomes from twoEimeria strains are known to cometogether during sexual reproduction, hesays, but that is all the detail known atpresent.

Although the genomic mapping ofE. tenella is an enormous undertaking,the project is already about 95% com-plete, Shirley says. Once done,researchers can “data mine,” produc-ing results that will be freely availableto anyone in the world who wants touse the information for research ordevelopment of commercially usefulproducts.

The IAH researchers want to discov-er what it is about the Eimeria parasitethat causes chickens to develop a pro-tective immune response. They are alsolooking at a technology known as“transfection,” which enables pieces ofDNA to be moved from one parasiteinto another. The technology mightmake it possible to develop a “piggy-

Shirley (right) reviews a report of the Eimeria genome project with Schering-Plough’s Iain Brown. ‘The industry is embracing vaccines.’

19

back” vaccine with one parasite thatwould protect against all species ofEimeria.

FlashbackAnyone who questions whether genet-ic studies of Eimeria are too futuristic tolead to something practical need onlyconsider the situation years ago whenscientists first grew Eimeria parasites inchicken embryos.

At the time, scientists were viewedwith skepticism as they tried to discov-er whether the life cycle of the parasitecould be modified, but they found theanswer was “yes.” Moreover, the para-sites defined by the life cycle changeswere attenuated and could be used aslive vaccines.” Soon after, the researchspawned other, better, approaches toattenuation, which led to the develop-ment of the breakthrough coccidiosisvaccine ‘Paracox’, Shirley says.

“When we started collecting preco-cious Eimeria parasites over 20 yearsago, we had no idea they were going tobecome the sort of global standard forcontrol of coccidiosis with a live atten-uated vaccine. No idea at all,” he says.“Today, there are a billion doses a yearof the vaccine helping poultry produc-ers control coccidiosis in their flocks.”

Vaccines are the futureEven though the coccidiosis vaccines oftoday work well, making them requiresgrowing all the different species ofEimeria that cause coccidiosis and thenharvesting them from chicken fecalmatter to make the vaccines. Birdsprobably are receiving many more geneproducts than they need.

In the future, it eventually may bepossible and more cost effective toidentify exactly which gene productsare relevant to immunity, then manu-facture — perhaps with genetic engi-neering — single parasite vaccines thatprotect against all types of Emeria.

New technology for controlling coc-cidiosis that arises from the genomic

data, Shirley says, is likely to be a vac-cine because the continuing use ofchemotherapy is under political andother pressures.

“The industry is embracing vaccinesand beginning to see that the future ofcoccidiosis control will depend on vac-cines. We’re already facing the prospectin the European Union that drugs maybe removed entirely from systembecause of consumer concerns. We arethen left with vaccines and, I believe, aslong as there is poultry, there will be aneed for Eimeria vaccines. That much isvery clear now,” he says.

“For poultry to remain the majormeat-producing animal in many partsof the world and remain of importanceto the UK, the United States and othercountries, there will have to be prod-ucts that effectively control coccidiosis.And these products will not be devel-oped in 5 minutes by somebody havinga ‘eureka’ moment. They will comefrom sophisticated scientific projectssuch as genome analyses and genomicmapping,” he says.

For now, Shirley hopes that thepoultry industry will take note of E.tenella genetic research, think about itspositive implications for the future andmeet the researchers with open ears.“Be prepared to support our work,which the industry will need,” he says.“It may not be for the people farmingnow, but for their sons and daughtersand grandsons and granddaughters.”

In turn, researchers have to do theirbit, he freely admits, by communicatingto the industry in understandable lan-guage. “We can be accused of notexpressing ourselves in ways that canbe properly understood,” he concedes.“I hope the industry is ready to listenand that it challenges us. We both needto meet halfway. There’s work to bedone.”

More information on the E. tenellagenome project can be found athttp://www.sanger.ac.uk/Projects/E_tenella.

Shirley: 'I hope the industry isready to listen'

20

Outbreaks of necrotic enteritis in conventionalbroiler flocks stopped after breeder hens werevaccinated with Netvax, a new clostridium tox-

oid vaccine, Dr. Neil Ambrose said at the EuropeanPoultry Conference held last fall in Verona, Italy.

The initial experience with the vaccine indicates that“passive immunity to Clostridium perfringens type A alphatoxin appears to be a viable strategy for the control ofnecrotic enteritis in broiler chickens,” said Ambrose,director of veterinary services for Sunrise Farms ofSurrey, British Columbia, Canada.

The Clostridium perfringens type A toxoid was devel-oped by Schering-Plough Animal Health and is the firstproduct of its kind for poultry, although clostridium tox-oids have been used in other species for many years.Two doses of the vaccine are administered to hens, initi-ating immunity to the alpha toxin produced by C. per-fringens, which is the most common cause of necrotic

enteritis in chickens. The hens pass on the immunity totheir broiler progeny.

Necrotic enteritis, Ambrose said, can be devastating,resulting in high mortality and reduced feed intake,weight gain and flock profitability. The problem is espe-cially difficult to control in birds on wheat-based rations,which are common in Canada.

With a trend in many parts of the world towards theproduction of broiler chicken meat without the aid ofantibiotics, including ionophore anticoccidials, Ambrosestarted trials for Sunrise Farms by using a live coccidiosisvaccine instead of an in-feed anticoccidial in wheat-fedbirds. However, in 2005, the company had six consecu-tive cycles of about 30,000 birds that experienced necrot-ic enteritis outbreaks. The birds had received a coccidio-sis vaccine, a nonattenuated coccidiosis vaccine based onlive Eimeria field strains, at day-of-age and the in-feedantibiotic-growth promoter bacitracin and/or virgini-amycin. Three of the flocks also received the anti-coccidial salinomycin, which was added to stem thenecrotic enteritis outbreak, but did not.

For each flock, there were two peaks in mortalityattributed to necrotic enteritis, which occurred at about19 and 27 days of age. Both roughly corresponded to expected peaks in coccidial cycling from the non-attenuated vaccine, he said.

“It is likely that the combination of intestinal viscosityassociated with the wheat ration and the mucosal dis-ruption caused by the normal cycling of the coccidialvaccine allowed the overgrowth of C. perfringens, trigger-ing the necrotic enteritis events,” he said. “There was noevidence of coccidial lesions outside of the normalexpected levels for the coccidial vaccine, which appearedto be performing normally, with adequate developmentof immunity to coccidiosis.”

Trial flocksSunrise Farms wanted to determine if passive immunityprovided by the new clostridium vaccine could replaceor augment in-feed antibacterial medication given tobroilers that are fed a wheat-based diet, which is com-mon in Canada, he said.

The company grew two broiler flocks from hens thathad received Clostridium perfringens type A toxoid. Both

XII EUROPEAN POULTRY CONFERENCE

Necrotic enteritis outbreaks in broilers stop after vaccinating hens with clostridium toxoid

Sunrise Farms modified diets to ensure a good start and reduce thenecrotic enteritis-causing bacterium in young chicks.

21

flocks were vaccinated for coccidiosis at day-of-age andthe broilers, which totaled about 24,000 in number,received only the growth promoter bacitracin in thestarter, grower and finisher rations. No in-feed anti-coccidial was provided (Table 1).

The results with these test birds were compared to thesix flocks that had experienced necrotic enteritis out-breaks and were from hens not vaccinated with Netvax.

All the birds had received the same, wheat-based diet.Among birds in the test group, “there was no evi-

dence of necrotic enteritis in random birds, culls or mor-tality upon post-mortem examination, which also verifiedcontinued cycling of the coccidiosis vaccine at acceptablelevels,” Ambrose said.

Better growth after toxoidGrowth performance in the flocks from hens vaccinatedwith the Clostridium perfringens type A toxoid met breedstandards and, in fact, surpassed growth in the controlgroup, he said. These results were achieved in the sec-ond flock despite severe heat stress at 27 days of age dueto unseasonably high environmental temperatures, hesaid.

“Passive immunity against the C. perfringens type Aalpha toxin appeared to successfully augment in-feedmedication to prevent lesions of necrotic enteritis whena non-attenuated coccidiosis vaccine was used in concertwith a wheat-based ration,” Ambrose concluded.

Sunrise Farms, he added, was planning further testingto determine whether passive immunity provided byClostridium perfringens type A toxoid could controlnecrotic enteritis when reduced levels of in-feed medica-tion are given or in the complete absence of in-feed medication.

RationMedication Coccidiosis vaccine Salinomycin inregimen at day-of-age grower ration Starter Grower Finisher Withdrawal

Flocks with necrotic enteritis outbreaks that were not from hens receiving the clostridium vaccine

1 Yes No bacitracin bacitracin bacitracin

2 Yes No bacitracin virginiamycin virginiamycin virginiamycin

3 Yes No virginiamycin virginiamycin virginiamycin virginiamycin

4 Yes Yes virginiamycin virginiamycin/ virginiamycin virginiamycinsalinomycin

5 Yes Yes virginiamycin virginiamycin/ virginiamycin virginiamycinsalinomycin

6 Yes Yes virginiamycin virginiamycin/ virginiamycin virginiamycinsalinomycin

Flocks with no evidence of necrotic enteritis that were from hens that received the clostridium vaccine

1 Yes No bacitracin bacitracin bacitracin bacitracin

1 Yes No bacitracin bacitracin bacitracin bacitracin

Table 1. Medication regimens for flocks that did and did not experience necrotic enteritis outbreaks.

Ambrose: ‘There was no evidence of coccidial lesions outsideof the normal expected levels.’

22

COCCI PEOPLE

Eye of the Beholder Continued from page 4

cidial challenge. That’s why Marshallsays vigilance is needed not only tokeep up with coccidiosis disease pat-terns, but also to find improved controlstrategies that help producers minimizelosses due to Eimeria.

Apart from VLA, Marshall plans tobe vigilant about traveling with wifeJackie, adding to the list of 40 countriesthey’ve visited so far.

His most exciting trip was a safari inBotswana — hands down. “The ani-

mals, birds and ecology are fantastic,”he says.

Asked what observation in the birdworld compares to the excitement of E.tenella’s blue halo, though, andMarshall says it was finding a nestingpair of black stilts in New Zealand,probably the rarest shorebird wader inthe world.

“There are only about 80 of thesebirds left in the world, and I observeda breeding pair,” he says.

Last October, sad news slow-ly spread throughout theworld’s poultry industry.Renowned poultry parasitolo-gist Peter Leslie Long haddied at age 78 after a short illness.

“Peter Long is a giant inthe history of coccidiosisresearch,” says colleague Dr.Martin Shirley, of the Institutefor Animal Health, UnitedKingdom, who was mentoredby Long. According to Long’s col-

league Dr. Ray B. Williams, Long demonstrated a flair forinnovation early on when he served in the Royal ArmyMedical Corps and suggested using the erythrocyte fragilitytest as an aid to diagnosing Cooley’s anaemia in Maltesefamilies.

After his military service, Long worked in parasitologyresearch at the entity now known as the AgriculturalResearch Council, a British government body. Despite noformal academic qualifications at the time, he made steadyand impressive progress in his career and innumerable con-tributions to the field of coccidiosis research. Long studiedpart time and, in 1952, became a member of the Institute ofMedical Laboratory Technology by examination and, by1956 obtained Fellow status.

Long had many other accomplishments too numerous tolist here that included a steady stream of publications aswell as teaching positions and fellowships around theworld. In 1971, he received a PhD from Brunel Universityfor his work on avian coccidia and, in 1977, was awarded aDSc, says Shirley. Long was a recipient of the Tom NewmanMedal for Poultry Research from the British Poultry

Breeders and Hatcheries Association and an honorarymember of the British Veterinary Poultry Association. Heco-edited a book entitled The Coccidia, which became thefirst in a series of volumes that have stood the test of timeand continue to be useful reference texts.

In 1979, Long succeeded Prof. W. Malcolm Reid asProfessor in the Department of Poultry Science at theUniversity of Georgia. In 1983, Long was awarded the titleof D.W. Brooks Distinguished Professor of Poultry Science,which he held until 1990, when he returned to the UK forretirement.

Of Long’s many important contributions to the knowl-edge of coccidia, says Williams, one of the most significantwas his demonstration that Eimeria tenella can develop inchicken embryos.

Improved approaches to attenuation, such as the use ofspecific-pathogen-free birds, were initiated by Long, lead-ing to the creation of anticoccidial vaccines through the fullattenuation of all remaining poultry Eimeria. Long providedtools for other workers to explore the biology andchemotherapy of coccidia.

Adds Shirley: “[Long’s] later contributions to coccidiosisresearch continued to reflect his desire to improve andunderstand the control of disease and his early work inGeorgia was pivotal to the first understandings of the rela-tionship between pathological changes in the intestines andbody weight changes of vaccinated or naive chickens afterchallenge, findings that were to become important consid-erations in the evaluation of vaccines.”

Williams notes that Long was also highly respected forhis support and encouragement of younger researchers. Hisgenerosity in sharing ideas and authorship of publicationswas widely acknowledged, and the international scientificcommunity showed its appreciation with a dedication toLong at the Ninth International Coccidiosis Conference inBrazil, 2005.

Renowned parasitologist Peter Long remembered by poultry industry

Peter Long

23

A popular book on coccidiosis hasbeen updated to include a newchapter on anticoccidial drugs and vaccines.

The 165-page book, PoultryCoccidiosis: Diagnostic andTesting Procedures, is authored byveterinary parasitologists DonalConway and M. ElizabethMcKenzie. When it was firstreleased in 1979 and a second edi-tion was published in 1991, thebook was found to be very usefulfor poultry scientists, disease diagnosticians and veterinarians.

The most recent edition reflectssubstantial progress in knowledgeabout coccidiosis in poultry and agrowing body of critical informa-tion, Conway says.

The book includes an introduc-tion to coccidiosis, reviews diag-nostic procedures and collectionand counting of oocysts. It alsocontains basic procedures andexample protocols for testing anti-coccidial drugs.

There is a tutorial on scoringgross lesions caused by major species of Eimeria infectingchickens. The review is based on the Johnson and Reid lesionscoring procedure. For each species, lesions due to infectionsranging from light to severe are illustrated by high-qualityimages.

“Over the years, these images have been of significant valuein assessing the importance and severity of both controlled andnaturally occurring coccidial infections, and it is a specialdelight to us to review these images once again,” Conwaycomments.

Vaccines minimize resistanceIn a chapter on the epidemiology and control of coccidiosis,Conway and McKenzie state that the use of anticoccidial vac-cines in a rotational program with anticoccidial drugs is recom-mended to minimize the risk of anticoccidial drug tolerance orresistance problems over the long term.

“The use of anticoccidial vaccines in breeders and replace-ment birds is probably the optimum course in most situations,and the current ability to vaccinate chicks at the hatchery byspray cabinet... has made a big difference in making anti-coccidial vaccines a practical option for broiler chickens aswell,” say the authors, who also cover important topics such asenvironmental management and feed quality.

The book’s new chapter on anticoccidial drugs and vaccinesreviews various anticoccidials and provides a review of eachdrug’s chemical structure, safety and efficacy. It contains aninteresting history on the development of polyether

ionophorous antibiotics, reviews the advantages of these drugsand includes concerns such as ionophore toxicity.

Vaccines a ‘practical alternative’Vaccines, the authors state, “provide a very practical andimportant alternative to the exclusive use of anticoccidial drugsfor two excellent reasons.”

A number of studies have demonstrated that vaccines give acomparable level of coccidiosis protection to growing broilerchickens compared to anticoccidial drug programs and mostlive vaccines replace indigenous coccidial populations in thebroiler house with coccidia that are susceptible to anticoccidialdrugs, extending the usefulness of anticoccidials, they say.

Although initial application of live vaccines was limited tolayers and broiler breeders, there is currently a growing use oflive anticoccidial vaccines in broiler chickens due in large partto the ability to apply vaccines in an economically effectiveway at the hatchery, the authors say.

They explain that Paracox vaccines were the first commer-cially available products of their kind containing attenuatedstrains of Eimeria spp, which are relatively nonpathogenic. Thevaccines, Paracox and Paracox-5, have several possible meth-ods of application; hatchery spray at day of age appears toprovide substantial benefit in stimulating early immune devel-opment in broilers.

The updated book will be available through BlackwellPublishing Professional, 2121 State Avenue, Ames, IA 50014-8300, USA, or through its website: www.blackwellprofession-al.com or www.blackwellvet.com.

COCCI NEWS

Updated coccidiosis book addresses value of coccidiosis vaccination

Oocyst-counting method ensures properadministration of Paracox-5 A practical method of counting oocysts after the first shed-ding in birds vaccinated with Paracox-5 has proved to be anexcellent method for assessing the effectiveness of vaccineadministration.

The method was developed for birds receiving Paracox-5 viaspray cabinet in the hatchery. It is the brainchild of Schering-Plough Animal Health’s technical service manager in Italy, Dr.Luciano Gobbi, and his associates in the company as well aspoultry field veterinarians.

“We devised the method after discovering that other, similarmethods requiring collection of individual droppings were timeconsuming and difficult to implement on a routine basis,”Gobbi explains. “They also resulted in failures monitoring theoocyst count in birds vaccinated with Paracox-5.”

The newer method, in use since 2005, indirectly evaluatesthe accuracy of vaccine hatchery spray by monitoring the firstoocyst shedding. “We now have enough experience with thismethod to conclude that it is effective and useful,” he says.

Fecal samples are usually collected by Schering-PloughAnimal Health employees, who work with poultry farm man-agers or their deputies. Diagnostic labs handle fecal sampleprocessing and oocyst counting because they have the neces-sary facilities and expertise, Gobbi says.

The oocyst-counting method provides data and figures thatenable judgments to be made about how effectively the spraycabinet has worked and whether uniform vaccine coverage hasoccurred. It helps determine whether chicken preening andvaccine swallow are adequate, he says.

The procedure starts with day-old chickens, when they arereleased from transport cages and placed on the floor. One

chicken per cage is caught ran-domly. The selected chickens areconfined in one or two wire-floored poultry cages with legsthat raise the cages from 40 to 50centimeters (16 to 20 inches)above the floor. This ensures thatbirds have no contact with the litter.

Starting at 96 to 97 hours afterParacox-5 vaccination by sprayadministration and until 148 to156 hours post-vaccination, stain-less steel trays are placed underthe poultry cages so that all fecescan be collected and pooled every20 to 24 hours.

This is the time when birds shed only Eimeria oocysts fromthe vaccine. The collection of oocysts and subsequent countingat a lab can demonstrate that a large amount of chickensingested the vaccine and, above all, that vaccinal oocysts have“multiplied” within the intestine epithelial cells, stimulatingimmunity, Gobbi says.

Studies have shown, Gobbi adds, that the litter oocyst pat-tern in birds that receive Paracox-5 for broilers differs frombirds that receive Paracox-8, which is designed for layers andbreeders. One of several possible reasons could be thatParacox-5 has three fewer Eimeria species compared toParacox-8, which may reduce the number of oocysts producedafter vaccination. In addition, Gobbi prefers fecal sample col-lections be taken after several hours of fecal deposition asopposed to collecting individual droppings at one specifictime, as previous methods required.

UK flu outbreak in turkeys posed no threat to Paracox vaccine safetyThe outbreak of H5N1 avian influenza in February at a farmbelonging to Britain’s largest poultry producer poses nothreat whatsoever to the safety of Paracox vaccines, saysPhilip Grose, plant director for Schering-Plough AnimalHealth’s manufacturing facilities in the United Kingdom.

Every step of production for Paracox vaccines is carefullycontrolled under strict biosecurity procedures to ensure thepurity of both Paracox-8 for breeders and layers andParacox-5 for broilers, he says.

For instance, Paracox vaccines are made with specific-pathogen-free (SPF) birds hatched from SPF eggs, which aretested to be doubly certain they are free of any pathogens,including avian influenza. Feed used during production isirradiated and water used for production is purified, he says.

The vaccines are chemically sterilized and, during this pro-cedure, are handled either in a biological safety cabinet orlaminar flow hood. The sterilization process has been testedto verify its effectiveness. “Specifically, our sterilizationprocess fully inactivates H5N1 avian influenza (Thailand ori-gin), which has been demonstrated by the Australian AnimalHealth Laboratory,” Grose says.

“In addition to all this, our quality control proceduresinclude testing of finished products to confirm the vaccinesare sterile and free of extraneous agents,” he adds.

Biosecurity procedures for manufacture of Paracox vac-cines include strict control of production facilities, he contin-ues. Positive pressure cascades are used to prevent entry ofextraneous agents into the facilities. Air is filtered and pro-duction areas and equipment are routinely sanitized. Theproduction facilities have pressurized airlocks for the transferof materials; raw materials and equipment are passedthrough the airlocks and are sanitized using approved disin-fectants.

During the secondary manufacturing stage, clean roomsare used and employees handling antigens before packagingwear full, sterile gowns. All materials in the clean rooms areautoclaved, Grose says.

Employees and contractors are screened before enteringthe plant to make sure they pose no risk. If they have beenanywhere that non-SPF birds are held or visit facilities whereinfectious avian agents are handled, they are forbidden fromentering Paracox vaccine manufacturing facilities for threedays.

“Both Paracox-8 and Paracox-5 customers can rest assuredthat our vaccines are completely safe for use,” he says.

COCCI NEWS

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Gobbi: ‘It is effective anduseful’

CocciForum is published by the Worldwide Poultry Business Unit ofSchering-Plough Animal Health Corporation, Summit, NJ. The editors welcome your ideas and suggestions for news articles concerning coccidiosismanagement. Send correspondence to CocciForum, PO Box 9000, PMB239, Edgartown, MA 02539-9000, USA. E-fax: 928-569-2491, E-mail:JFeeks@prworks.net. Back issues are available online atwww.ThePoultrySite.com/CocciForum

© Copyright 2007, Schering-Plough Animal Health Corporation.

Executive Editors: Stephen P. CollinsPaolo Sani, DVM

Technical Editor: Luciano Gobbi, DVM

Managing Editor: Joseph Feeks

Associate Editor: Diana Delmar

Design & Production: Deborah Sottile

Proofreader: Lori Cavanaugh

How should European poultry producers fight growingcompetition from inexpensive frozen imports? Shouldproducers seek more protectionist policies? Or shouldthey rethink their strategies to become more competitive?

What is the best way for European poultry companiesto deal with this new competition? Do they simply needto become bigger and more efficient? Or should theysteer consumers toward value-added, locally produced,branded products that command a premium price?

And how will your company meet these challenges?What does your operation do exceptionally well? Whatcould it do better? What opportunities have you ignored?Where will your operation be 10, 20 or even 50 yearsfrom now? What roadblocks stand in your way ofprogress?

These are among the many questions facing poultryproducers in and around Europe today. And they are noteasy to answer. No one poultry operation is the same interms of management, facilities, marketing or long-termgoals. We do know, however, that change is essential ifwe want to remain competitive.

As poultry industry trend-watcher Osler Desouzarttells us in the article beginning on page 15, “Today’s con-sumer wants to know what he eats, from where it cameand how it was produced. He wants assurance that whathe eats is safe for his health and the environment, that itis fair to the manpower that produced it and that themeat comes from animals that are well cared for andhealthy.”

Desouzart also warns against mistaking economy forprogress: “A premium chicken sold at a premium pricecannot be made... with second-grade feed, with the lots

managed by untrainedpeople and with the‘cost dictatorship’ deter-mining that the leastexpensive ingredientsshould always be used.Quality begins at thebeginning, but has togo all the way to theend. There is no ‘partial’quality, or quality just inparts of the process, by part of the departments and partof the time.”

At Schering-Plough Animal Health, we are makingefforts to partner with poultry producers to meet thesechallenges. A good example of this effort is the recentmeeting we hosted near Venice (see the Special Reportbeginning on page 5) to help producers focus on intes-tinal health and ways to produce wholesome, value-added, yet competitive poultry while meeting the grow-ing consumer demand for birds without in-feed antibiotics.

It is our hope that this special issue of CocciForum —the first one published specifically for Europe and theMiddle East — will provide inspiration and ideas formeeting the many challenges presented above.

Paolo Sani, DVMSchering-Plough Animal HealthRegional Manager-Europepaolo.sani@spcorp.com

COCCI VIEWS

Asking tough questions

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