NEW STRATEGIES FOR COCCIDIOSIS MANAGEMENT

SPAH-PBU-460

DEANS FOODSGood training ensures success with coccidiosis vaccination

[ Innovative Solutions in Poultry Health ]

Paracox is a registered trademark of Schering-Plough Animal Health Corporation.Copyright© 2006, Schering-Plough Animal Health Corporation. All rights reserved.

[ Innovative Solutions in Poultry Health ]

Control Coccidiosiswith Flexibility and Peace of Mind

Control Coccidiosiswith Flexibility and Peace of Mind

Intestinal Health

For additional information, visit us at www.intestinalhealthpoultry.com

• Lifelong protection in a single application

• Compatible with drug-free programs

• Restores sensitivity to worn-out anticoccidial drugs

• Allows flexibility to optimize feeding programs

• Birds are ready to market at any time - no concerns for residues or withdrawal periods

FEATURES

NUMBER 12 www.ThePoultrySite.com/CocciForum

2 COCCI PROFILE SIMPLE MATHVaccinating layers for coccidiosis was an easy decision for UK’s Deans Foods

6 THINNING FLOCKS TO FATTEN PROFITSVaccination for coccidiosis complements thinning, increases flexibility for producers

10 BUILDING ON A GOOD IDEAFine-tuning wheat-based rations together with coccidiosis vaccination gives producers in Northern Europe more flexibility

14 TECHNICALLY SPEAKING: ESSENTIAL ELEMENTSDr. David Chapman presents new guidelines for coccidiosis vaccines

16 INDEPENDENT ANALYSISDr. Marco Tamba finds that coccidiosis vaccination reduces need for treatment

20 COCCI NEWSTrends and research affecting coccidiosis management

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

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Cover: One of nearly 4 billion eggs produced each year byDeans Foods in the UK. To learn more about their lateststrategy for managing coccidiosis in layers, see page 2.

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COCCI PROFILE

When you market nearly 4 bil-lion eggs from 13 millionhens every year, it’s only

natural to get preoccupied with num-bers and analyze statistical trends.

The decision by Deans Foods — thelargest egg marketer in the UK — toeliminate in-feed anticoccidials from itscompany-owned layer operations infavor of vaccination is one recentexample.

In this case, however, managementdidn’t need high-performance comput-ers or elaborate spreadsheets to maketheir decision. It was a matter of simplemath.

“Our decision to vaccinate was driv-en by two things,” explains AndrewJoret, operations director-agriculture forDeans Foods.

“One, we were seeing a growingnumber of birds with coccidiosisbreaks, even though they had beentreated with in-feed anticoccidials. Thatsuggested resistance problems,” heexplains.

“The second is that the number ofin-feed drugs available to us is dimin-ishing rapidly. We know it’s a goodpractice to rotate anticoccidials, butbetween resistance and residue issues,there’s not going to be anything left to

SIMPLE MATHVaccinating layers for coccidiosis was an easy decision for UK’s Deans FoodsSIMPLE MATHVaccinating layers for coccidiosis was an easy decision for UK’s Deans Foods

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rotate in the future. It was clear that weneeded to look at vaccination moreclosely.”

Getting it rightVaccinating layers for coccidiosis withParacox (also known as Paracox-8 insome markets) is not entirely new toDeans. The company tinkered with thepractice in previous years but theresults were sometimes inconsistent, anoutcome they now realize was due tothe error of their ways.

“A lot of the problems we had earli-er resulted from us trying to cut cornersa wee bit and save money by not usingthe full dose of the vaccine,” he says.“But closer scrutiny provided a solu-tion, which is that Paracox at fullstrength is the only way to go.”

According to Dr. Charlie Broussard,director of global technical services forSchering-Plough Animal Health, thecompany that makes Paracox, using thecorrect dose is particularly importantwith coccidiosis vaccines because theyprovide a controlled and carefully bal-anced dose of oocysts, or eggs, of theEimeria pathogens that cause coccidio-sis. These in turn stimulate the bird’simmune system, providing lifelong pro-tection against coccidiosis withoutresorting to resistance-prone drugs.

“If you use anything less than thefull dose of the vaccine, you cannotachieve optimum uptake of theoocysts, nor can you expect there to beadequate protection,” he adds.

Good training essentialGood training is also critical to the vac-cine’s success.

“With vaccines, whether it’s Paracoxor anything else, it’s all about howthey’re applied on the farm,” Joretinsists. “If your farm managers aren’tproperly trained, you can’t expect tohave good results. Since committing tothis program, we have not had anycocci problems to speak of. I thinktraining has been the key.”

To make sure all farm managerswere in sync with the new program,which involves administering the vac-cine through the drinking water at 5days, Joret sought assistance from localSchering-Plough representatives.

Besides dispatching technical per-sonnel to the farms, Schering-Ploughworked with Deans to produce Eggstra,an in-house publication that reviewedvaccine protocols and provided handyworksheets, checklists and remindersto help ensure successful vaccination.

Wanting to provide even moreincentive for farm managers to learnproper and successful vaccination pro-cedures, Deans and Schering-Ploughalso developed a contest to see whichoperations could administer the vac-cine most effectively.

According to Schering-Plough poultry business man-ager Iain Brown, this involvedgetting managers to collect 10individual fecal droppingsfrom each shed so a labora-tory could determine thelevel of vaccine uptake bythe flock.

Counting oocystsWhy fecal testing?

“We know that thelaboratory-produced vac-cine strains have ashorter life cycle insidethe bird than the wildstrains that occur inthe field,” says Dr.Sarah Rennie, tech-nical business man-ager at Schering-Plough.

“By testing 5days after vaccination,any oocysts found in the sample aremore likely to have come from the vac-cine than any wild strain, which cantake 6 to 7 days to appear in the feces.”

One thing fecal tests don’t show is

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the immune status of the bird. Vac-cinated birds do not become immune

to coccidiosis until 2 weeksafter vaccination, but theeffect lasts a lifetime.

“But if the vaccine hastaken hold, immunity islikely to follow unless someother factor on the farmprevents vaccinated birdsfrom developing immunity.For example, stress, immuno-suppressive diseases or poorquality nutrients in the feedcan all have an effect onthe development of theimmune response in vacci-nated birds,” she says.

Knowing the scoreOocyst counts from thesamples are rated on ascale of 1 to 5, with 5 beingthe highest. She explainsthat the aim of the program

is to have no birds test negative for vac-

cinal oocysts and to have the birdsscore from 1 to 3 (1 to 1,000 oocystsper sample).

“It is theoretically possible to score4 or 5 (1,001 to 10,001 oocysts), but thiswould be exceptional and would prob-ably indicate the presence of wildstrain oocysts,” she says.

For example:

• Farm A reports that 7 of 10 sampleswere negative and the other threescored 1 (1 to 10 oocysts). This indi-cates very poor vaccination.

• Farm B reports that all birds testedpositive, but the oocyst count scorewas low. This suggests “reasonablevaccination,” according to Rennie.

• Farm C has all birds testing posi-tive with scores from 1 to 3 (1 to1,000 oocysts), which suggests thebirds are uniformly immune tococcidiosis.

Joret says the contest, which awardsprizes to managers with the best scores,

Deans Foods has only one company-owned farm withcage-reared layer pullets. All other birds are reared onfloors, a setup that puts the company in good position tomeet new EC regulations, which prohibited the installationof any conventional wire layer cages after Jan. 1, 2003,and eliminates them in 2012.

Floor-reared birds are generally more susceptible to coc-cidiosis, which is routinely spread when infected birdsshed oocysts, or eggs, of Eimeria pathogens in their drop-pings, which contaminate feed, dust, water, litter and soil.Even so, Deans’ Joret says coccidiosis is still an issue incaged birds and all flocks need to be protected.

“The market is definitely moving toward free-range birds,so we’re lucky in that respect because most of our rearingwas on the floor anyway,” he adds. “We’re well aware ofthe threat that coccidiosis presents in these situations.”

Research by Mintel, a UK-based market research firm,confirms this trend.

According to a 2003 report, free-range eggs accounted for30% of egg sales by volume in the UK compared to just24% in 1998, representing a 38% rise in sales.

Producers also need to be extra careful about drugresidues. In January 2004, EU legislation was put in placerequiring that every egg be stamped with a home address,producer code, country of origin and “best before” date.

While beneficial to consumers, this has proved challeng-ing for egg producers. Fortunately, Joret says, the use ofcoccidiosis vaccination and better nutrition has allowedDeans to sharply decrease usage of in-feed medicinaladditives without compromising performance.

More on the floor

Joret: ‘The program has been very successful.’

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is repeated periodically to “provide arefresher” and ensure diligence in thefield.

“The competition serves as a remind-er for everyone involved in rearing toget it right consistently, whether rearingfor our company laying farms or forexternal pullet sales,” Joret says. “Theprogram has been very successful.”

‘Proved to be effective’John Simpson, area production manag-er for Deans’ North Region, whichencompasses 20 farms in Scotland andthe north of England, has also beenpleased with the results of the coc-cidiosis vaccination program.

“We haven’t had a problem withcoccidiosis, and we’ve never had to usea disinfectant on any of the floors,” hesays. “I was apprehensive at first, butthen it’s human nature to be apprehen-sive about change, isn’t it? For us, vac-cination has proved to be effective andvery simple to use.”

He notes that in the past birds on in-feed anticoccidials sometimes brokewith the disease after 6 weeks, whichrequired Deans to use additional antibi-otics, which added to the overall costof the treatment.

Furthermore, the in-feed treatmenthad to be pulled from the feed at 12weeks to avoid residue concerns. “Thatleft the birds without any coccidiosisprotection from 12 weeks until theystarted laying eggs at 18 weeks,”Simpson says. “The vaccine providesmuch longer protection, and you don’thave to worry about resistance orresidues.”

To help make up for the loss of anygrowth promotion effects of in-feedanticoccidials, Deans has also beenplacing more emphasis on promotinggood intestinal health through betternutrition. According to Joret, thisinvolved making a few changes to thelayer pullets’ feed rations.

“We didn’t change the diets them-selves,” he says. “We only changed theschedules at which they were fed.

Without having drugs in the feed, wecould be a lot more flexible and focusmore on the nutritional needs of thebirds.”

For example, Deans used to pullbirds off the starter feed at 3 weeks andoff the rearing feed at 6. Now, the com-pany keeps layer pullets on the starterfeed for 4 weeks and extends the rear-ing feed to 8.

“And that seems to have done thetrick,” he says.

You can’t keep a good oocyst downCoccidiosis, a ubiquitous protozoan disease common in standard broilersand other floor-raised birds, is routinely spread when infected birds shedoocysts of Eimeria pathogens in their droppings, which contaminate feed,dust, water, litter and soil.

Fresh oocysts are not infective until they sporulate, usually in 1 to 2 daysunder optimal conditions — 21°-32°C (70°-90°F) with adequate moistureand oxygen. Oocysts are resistant to most disinfectants commonly usedaround livestock.

They have also shown resistance to in-feed anticoccidials when thosemedications are used for extended periods.

Simpson: ‘Effective and very simple to use.’

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It’s easy to see why thinning broilerflocks has become a popular prac-tice throughout Europe. Thinning

lets poultry farmers satisfy marketdemand for light or heavier birds and,at the same time, capitalize on theeconomies of scale and enjoy increasedprofits.

But when traditional in-feed drugsare used to control coccidiosis, thin-ning has a down side. The requiredwithdrawal times for anticoccidials hin-der market flexibility and complicatefeed management. With anticoccidials,there is always concern that residues ofthe drugs could end up in poultry meatat a time when public demand for foodsafety is at an all-time high.

Farmers can, however, optimize thebenefits of thinning and eliminate theproblems inherent to anticoccidial useby vaccinating against coccidiosis atday-of-age.

“Vaccination fine tunes the practice

of thinning,” says Dr. Paolo Sani, a vet-erinarian and poultry business managerfor Schering-Plough Animal Health inItaly.

“It not only provides lifelong pro-tection against coccidiosis, it increasesmarket flexibility, dramatically simpli-fies feed management and completelyeliminates worries about anticoccidialresidues.

“In fact, we are finding that coc-cidiosis vaccination has evolved from adisease-control method into a manage-ment tool that enhances the practice ofthinning,” he says.

How thinning worksWhen flocks are thinned, Sani explains,lighter, less efficient females are sold.The weight at which females arethinned out varies among companiesand with market needs. Some compa-nies may start female thinning at aboutdays 35 to 37 (Figure 1), when the birdsare 1.7 kg (3.75 lbs). Occasionally,

THINNING FLOCKS TO FATTEN PROFITSVaccination for coccidiosis complements thinning,increases flexibility for producers

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there is a thinning of heavy females orlight males about days 44 to 46, whenbirds are 2.4 to 2.6 kg (5.29 to 5.73 lbs).After each thinning, space is freed upfor a greater number of faster-growing,large-breasted males that are sold laterin the production cycle for chickenparts and high-volume commercialsales, Sani says.

Thinning can be practiced withinthe limits of European Union welfarelaws, which dictate a maximum of 30kg (66.14 lbs) meat production persquare meter in buildings with naturalventilation systems and 38 kg (83.78lbs) of meat produced per square meterin buildings with artificial ventilationsystems, he notes.

Generally, the same house is usedfor all birds in flocks to be thinned, butmales and females are divided byremovable fences. After the first thin-ning, the remaining birds occupy thefull space, he says. Additional thinningscan be made based on market demand,in contrast to “mono” systems that startall birds at the same time and sendthem to market at the same time.

Thinning provides farmers with the

best balance of light and heavy birds. Itsignificantly improves space utilizationand the kilos of meat pro-duced per square meter,reduces fixed costs andimproves performance amongheavy birds, Sani says.

“Farmers have increasedincome and better return perkg of meat, while the integra-tor optimizes the logistics ofbroiler production,” he notes.

Cost savingsFor instance, since thinningenables more birds to beraised in the same house, thecosts for transporting feed andchicks to the house as well aschicks to market declines, hesays.

Economic analysis demon-strates that transport of feedalone, determined by examin-ing the results among severalproducers in Italy, can bereduced from 10% to 20% by thinning,although the savings would vary bycountry and among different produc-ers. The estimated cost reductions

Figure 1. Flock-thinning concept, typical scheme

Starter Grower Finisher 1 Finisher 2

Density(kg/m )2

Limit of bird density*

*As per the new EU Animal Welfare Directive – 30 kg/m to 38 kg/m

Flock thinning

Improved

Slaughterhouse

Conventional

Age

Extra Production(at lower fixed cost)

2 2

continued on page 8

Sani: ‘Fine tunes the practice of thinning.’

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among several Italian producers fortransporting chicks to farms and to theslaughterhouse ranged from 20% to

30%, Sani says.Dr. Luciano Gobbi,

technical service manag-er for Schering-PloughAnimal Health, Italy, saysthere’s another addedbenefit from thinning. “Itbecomes easier to raiseheavier birds in the heatof summer.”

As the chicks age,heat can be detrimentalto their health, but thin-ning gives heavier birdsmore space and they canremain cooler, he says.

Thinning, however,definitely complicatescoccidiosis control whentraditional in-feed antic-occidials are used, Dr.Gobbi agrees.

“ A n t i c o c c i d i a l srequire at least a 5-day withdrawal time(see Figure 2), so birds marketed earlyhave to receive a withdrawal feed

before they are sent to slaughter. Greatcare must be taken to assure that theright birds within a flock get the correctfeed,” he says.

When anticoccidials are removed toadhere with withdrawal requirements,birds intended for early marketing areat risk for a costly coccidiosis outbreak,he says.

“The overriding concern about theuse of in-feed anticoccidials, however,is that residues of the drugs will unin-tentionally end up in poultry meat,which could be immensely damagingto a poultry producer in light of thepublic focus on food safety. All it takesis an error at the feed mill or a farm-hand giving the wrong feed to thewrong group of birds within a flock,”Gobbi says.

All the potential complications asso-ciated with anticoccidial use can beeliminated simply by vaccinating birdsagainst coccidiosis once at 1 day ofage, Gobbi says. In return, farmers whothin their flocks will find that manage-ment of feed and of the birds will bedramatically simplified, he says.

Starter Grower Withdrawal Withdrawal

Density(kg/m )2

Limit of bird density*

Flock thinning Slaughterhouse

HIGH RISK OF COCCIDIOSIS OUTBREAKS AND

ANTICOCCIDIAL RESIDUES

*As per the new EU Animal Welfare Directive – 30 kg/m to 38 kg/m2 2

Figure 2. Flock thinning, feed management with in-feed anticoccidials

Gobbi: ‘Vaccination is a real problem solver.’

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Case in pointAs a case in point, Gobbi points toMartini Alimentare, one of Italy’s majorpoultry companies, which has coupledParacox-5 vaccination against coccidio-sis with the practice of thinning(CocciForum, No. 10). Males andfemales are kept in the same house butin separate areas. Females are usuallythinned out at days 35 and 42, somemales are thinned out at 46 days andthe remaining males are slaughtered at54 to 56 days.

Dr. Corrado Longoni, poultry veteri-narian for Martini, says, “If we used ananticoccidial in the feed, it would meanhaving two or three withdrawal peri-ods, which would be very difficult tomanage.”

Feed mill contamination would alsobe a very real concern for Longoni ifthe company used in-feed anticoccidi-als. The feed mill does not make feedjust for broilers, he says, and the linesat the mill would have to be flushedafter every use to insure that anti-

coccidial residues did not get into feedfor non-target species.

“We can’t take that risk, nor do wewant traces of drugs in our withdrawalfeed for broilers,” Longonisays.

“Martini as well as othercompanies that practice thin-ning,” says Gobbi, “are dis-covering that vaccination is areal problem solver and thatit provides excellent controlagainst coccidiosis. Whencoupled with good nutrition,the performance among vac-cinated birds at the very leastmeets performance amongbirds raised with in-feedanticoccidials.”

Vaccination also yieldsindirect savings for poultryfarmers by reducing thelabor it takes to manage thefeed and the birds in thinnedflocks. “It’s an excellent com-plement to the practice ofthinning,” he says.

Starter Grower Finisher 1 Finisher 2

Density(kg/m )2

Limit of bird density*

*As per the new EU Animal Welfare Directive – 30 kg/m to 38 kg/m

Flock thinning Slaughterhouse

NO RISK OF COCCIDIOSIS

OUTBREAKS AND ANTICOCCIDIAL

RESIDUES

2 2

Figure 3. Flock thinning, feed management with Paracox-5

Longoni: ‘We can’t take that risk.’

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Progressive poultry operationshave discovered that puttingmore emphasis on intestinal

health can help broiler chicks combatenteric challenges and reduce or elimi-nate the need for in-feed antibiotics.

In most cases, improving intestinalhealth usually means pouring moreresources into the starter and growerdiets to build immunity and optimizedigestibility. The payoff comes at theback end of the feed program, whenbroiler operations can either start birdson low-cost final feed at an earlier ageor possibly introduce a second finalfeed without compromising perform-ance and returns.

This four-pronged strategy — fre-quently called the IDEA concept forImpulse, Digestibility, Economy andAdvance (see accompanying story) —makes good sense for almost any oper-ation trying to wean itself from anti-biotic growth promoters, which helpedkeep some enteric problems in check.

The IDEA concept has proved to beparticularly beneficial where a vaccineis used instead of an in-feed coccidio-stat to control coccidiosis because pro-ducers don’t have to work around thecoccidiostats in the feed.

“In traditional anticoccidial pro-grams, you have to build your nutritionprogram around the rotation schedulesand withdrawal times,” explains Dr.John Radu, a veterinarian and world-wide technical service manager forSchering-Plough Animal Health.

“When you vaccinate for coccidio-sis, you don’t have those restrictions.You can tailor the nutrition program tomeet the needs of the birds at a specif-ic age, not the timetable for the coc-cidiostat program. The result is often abetter nourished and healthier flock,one that might get by on lower costrations in the final phases.”

Comparing nutritional requirementsDr. Rob ten Doeschate, a poultry nutri-tionist at Abnatech Global, Peter-borough, England, believes the nutri-tional requirements of vaccinated andmedicated birds shouldn’t have to beany different. They’re the same birdswith the same nutritional requirements,he argues. They also have similar chal-lenges from coccidiosis.

“Because at the end of the day, bothtypes of birds should have a minimalcoccidiosis challenge,” he says. “We doknow that a vaccinated bird at certainstages has to cope with a bit of a con-trolled challenge caused by the oocystsin the vaccine. But at the same time,birds on a standard in-feed anti-coccidial program are often faced witha similar and perhaps less predictablechallenge because the coccidiostatsdon’t provide 100% control. Lesion

BUILDING ON A GOOD IDEAFine-tuning wheat-based rations together with coccidiosis vaccination gives producers in Northern Europe more flexibility

Rennie and ten Doeschate: ‘Pretty unique challenges.’

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scoring tends to be about the same forboth groups.”

He notes that field strains of Eimeriaorganisms that cause coccidiosis aredeveloping resistance to in-feed anti-coccidials. “And we’re seeing a lotmore of that in recent years becausethere are even fewer in-feed productsavailable to rotate,” he says. “Whenevery poultry company is on the samerotation, there’s nothing to compare itto and no one knows if one company’sprogram is doing better than the other.The reality is that this background chal-lenge could be quite high even in birdson coccidiostats and we just don’t real-ize it.”

Ten Doeschate agrees with the prin-ciples of IDEA. However, in NorthernEurope and other areas with cooler,damper environments, he thinks pro-ducers might actually have an easiertime embracing the IDEA concept —for the simple reason that they’ve hadto practice it all along.

“We have some pretty unique chal-lenges in the UK,” he says. “We’re rais-ing birds in less than ideal economicconditions, where investment is diffi-cult, land prices are high and buildingis expensive.

“Then you have the issue of ourweather, which is legendary,” he con-tinues. “It’s generally much cooler herethan in southern Europe. And as every-one knows, we get a lot of rain. Thatcreates more problems maintaining thelitter, which can become a fertile breed-ing ground for coccidial oocysts.”

Working around wheatFeedstuffs also present a challenge.Like their counterparts in other areas ofNorthern Europe, producers in the UKfeed 100% wheat-based diets. Besidesbeing coarser in texture and rougheron the intestinal wall than diets incor-porating maize, the resulting digestaalso have high viscosity, which favorsthe growth of the undesirable bacteriathat cause enteritis.

“We use enzymes to combat that,but even with enzymes we have higherviscosity than you would have withmaize-based diets,” he explains.

The absence of antibiotic growthpromoters, which in the past had someeffect on enteric disease and helped tomake up for any shortcomings in man-agement, presents another chal-

lenge to produc-ers. While manypoultry operations inthe EU are still adapting tothe January 1 ban on suchproducts, ten Doeschate saysUK producers have pretty muchdone without them since 1998, whenall the major UK supermarket chainsinstituted a ban of their own.

Overcoming adversity His point is that UK poultry producers

continued on page 13

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Schering-Plough Animal Health devised the IDEA conceptto help birds vaccinated against coccidiosis achieve theirperformance potential.

For the UK and other northern markets, however, the IDEAconcept needs some refining because some aspects of theconcept are already routine practice in this market.

“The majority of the market is already using very highspecification starter diets, at or above breed standards,”notes Dr. Sarah Rennie, technical business manager forSchering-Plough Animal Health in the UK.

Working with Dr. Rob ten Doeschate at Abnatech Global,Rennie set up a trial to investigate the Digestibility andEconomy phases of the IDEA concept.

Good gut integrity“During the grower period, maintain-ing good gut integrity and efficientdigestion is not easy to achieve,especially in the absence of antibi-otic growth promoters and in-feedanticoccidials,” she explains.

“We wanted to investigate whetheradding betaine and adjusting theamino acid profile during the grower phase would have animpact on performance. We also wanted to see if notchanging the diet during the critical 13- to 27-day periodhelps maintain gut integrity.”

According to the IDEA concept, vaccinated birds should beable to utilize lower cost final diets better than medicatedbirds, which was the last factor to be investigated in thistrial.

In their 64-pen trial, they had 25 male and 25 female Ross308 broilers per pen. Basal diets were formulated to cur-rent UK nutritional standards. Trial diets were supplement-ed with up to 10% whole wheat, reflecting current on-farmpractice in the UK.

Coccidiosis was controlled by either vaccinating day-oldchicks with Paracox-5 or with a combination of in-feedanticoccidials — nicarbazin and narasin from 1 to 12 days,and monensin in the grower (13 to 27 days) and finisher (28to 35 days).

They wanted to determine whether the following wouldimpact performance:

• Adding nutrients thought to be beneficial to gut health— methionine, threonine and betaine — to the starter,grower and finisher rations.

• Avoiding a feed change during the peak vaccinal oocystmultiplication (around day 20). Birds were fed grower dietA from 13 to 20 days followed by grower diet B (reducednutrient level) from 21 to 27 days. Other birds receivedgrower diet B from 13 to 27 days.

• Using a lower-spec final feed (-5% digestible aminoacids) from 36 to 42 days without reducing bird performance.

At 42 days, they found no statistically significant (P>0.05)interactions between methods of coccidiosis control andfeed treatments, nor were there any significant differences

in live weight or feed conversion in any ofthe birds.

Cutting costs possibleThe results suggest that in Northern

Europe, there is no performance benefitfrom enhancing the starter diets or

cutting the number of grower diets from two to one in vaccinated birds. Furthermore, using a lower spec finalfeed in vaccinated birds did not affect liveweight or feed conversion.

“This indicates that cutting costs at this phase may bepossible,” Rennie adds.

They concluded that using Paracox-5 in broilers fed goodquality basal rations is not associated with a drop in per-formance and dietary enhancement is not needed.

Further work is needed to determine how much producerscan take advantage of the vaccinated birds’ improved sta-tus, which in this case allowed a reduction in concentra-tion of certain essential amino acids in the final feed with-out hurting performance.

The full scope of the study and additional insights on the resultswill be presented at the European Poultry Conference inVerona, Italy, September 10-14.

Adapting IDEA to Northern Europe

are used to facing all sorts of econom-ic, environmental and political adversi-ty. As a result, they’ve had to becomehighly resourceful and more cognizantof maintaining good intestinal health tofight disease and enhance perform-ance, he says.

The principles of IDEA are alreadyin place. With more operations turningto coccidiosis vaccination and pullinganticoccidials from their feed, tenDoeschate is hoping to take advantageof this newfound flexibility and makefurther refinements to their programs.

“When I first saw the IDEA concept,it wasn’t really new to me because wewere already following most of its prin-ciples,” he says. “My challenge is opti-mizing feed conversion, health and ulti-mately on the amount of money thegrower makes.”

“We don’t mind spending a bit ofmoney on the starter diet because youonly feed a small amount to the birds,”

he continues. “The grower is quitehappy to pay £5 a tonne more (over a£160 per tonne average) if he can see apenny a bird more profit. We’re alreadyin the habit of getting birds off to agood start. If you’re already using ahigh-spec starter diet, you can’t reallyimprove much on it.”

He notes that in some parts ofEurope, producers have used sodiumto boost feed intake in the starter. “Butthat’s not an option here because sodi-um also encourages birds to drinkmore water,” he says. “And when theydrink more water, you get more watercoming out the other end — and thatcreates problems for litter quality andbird welfare.”

Making good rations betterTen Doeschate initially targeted theDigestibility phase of the IDEA concept— approximately 13 to 27 days — tosee if further improvements could be

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What’s the big IDEA?By adapting nutrition programs to the physiological situa-tion in the intestine of vaccinated birds and matchingnutrient needs to the building of immu-nity in each period, vaccinated birdswill perform better. This is spelled out inthe IDEA concept:

I: Impulse phase. Prepare the immunesystem and intestinal cells for thedevelopment of immunity against coc-cidiosis; at the same time, get the birdsoff to a good start.

D: Digestibility phase. Help the immunesystem and intestinal cells build immu-nity. This is important not only for coc-cidiosis, but also because most intes-tinal infectious problems and disturb-ances occur in this period.

E: Economy phase. Take advantage ofbirds’ immunity against coccidiosis withgood intestinal health.

A: IDEA enables an Advance in poultry farming and is agood alternative for the new era when in-feed additiveswill no longer be available.

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continued on page 19

Increased recognition that live vac-cines provide a valuable alternativeto chemotherapy for coccidiosis

control has encouraged researchersaround the world to consider develop-ment of coccidiosis vaccines for localuse. As with all products developed forthe poultry industry, it is essential thatvaccine development be carried outusing rigorous procedures and highprofessional standards that also complywith any official regulations that maybe applicable.

Guidelines have long been availableto help researchers satisfy standards fordrugs and many viral and bacterial vac-cines — but none have been producedfor vaccines against coccidiosis. Con-sequently, the author recently assem-bled a group of experts to participate ina joint project aimed at finding a reme-dy to this deficiency. The team includ-ed myself and the following esteemedexperts:

• Professor Martin Shirley, deputydirector of the Institute for AnimalHealth, United Kingdom, lead the

research team in the 1980s that devel-oped the world’s first attenuated coc-cidiosis vaccine. More recently, he wasinstrumental in organizing a successfulproject to sequence the entire genomeof E. tenella, the most widespread,pathogenic species of Eimeria thatinfects the chicken.

• Dr. Ray Williams, of the UK, is oneof the world’s leading coccidiosisresearchers with vast experience in thepoultry industry. Dr. Williams has pub-lished numerous papers about aviancoccidiosis and vaccination.

• Dr. Brian Roberts, also of the UK, isan international authority with detailedknowledge of the registration require-ments necessary for obtaining market-ing authorization for poultry vaccines.

The project group’s goal was todevelop guidelines to assist scientistsand others in the design, implementa-tion and interpretation of studies forassessing the efficacy and safety of livecoccidiosis vaccines and to suggeststandards for manufacture and qualitycontrol. The resulting guidelines areintended to help researchers obtainspecific information for those involvedin the decision making process and tofacilitate the worldwide adoption ofconsistent, standard procedures.

The team received advice from vet-erinarians, researchers and those withpractical knowledge of poultry produc-tion. Scientists working in government,academia and industry around theworld were consulted, but the some-times controversial opinions expressedin the guidelines are the group’s own.A leading poultry veterinary journal,Avian Pathology, published the guide-lines1, which are shown below.

ESSENTIAL ELEMENTSIndependent project group develops guidelines for coccidiosis vaccines

By H.D. Chapman, Ph.D.Department of Poultry Science,University of Arkansas, USA

KEY POINTS

■ Rigorous procedures and high professional standards arenecessary to ensure safe and effective poultry products.

■ Standards for evaluating coccidiosis vaccines have beenlacking.

■ To remedy the deficiency, several top coccidiosis expertsrecently developed guidelines to facilitate the worldwideadoption of consistent standards for evaluating the efficacy,safety, manufacture and quality control of coccidiosis vac-cines for poultry.

14

TECHNICALLY SPEAKING

15

ProceduresBirds in vaccine development studiesshould be vaccinated under conditionsthat duplicate as closely as possible themanner in which vaccination will becarried out in the field. Subsequently,birds should be intentionally chal-lenged with the parasite to seewhether they have acquired protectiveimmunity.

An important aspect of experimen-tal design is that vaccinated birds mustbe reared in floor-pens to allow ade-quate exposure to infection followingvaccination; the challenge phase ofexperiments can be carried out in wire-floored cages or pens. The guidelinesas published in Avian Pathology providedetailed information about conductingthese studies.

Once satisfactory results have beenobtained from experimental studies,large-scale field tests can then be car-ried out; this is important to establishthat a vaccine is safe for use in thefield. Preferably, such trials should becarried out in all geographical regionswhere a vaccine is intended for use.

Criteria for efficacyThe criteria conventionally used toevaluate drug efficacy, such as weightgain, mortality, feed conversion and thepresence of intestinal lesions, may sim-ilarly be used to determine the extentof immunity development followingvaccination and subsequent challenge.However, in the opinion of the projectgroup, lesion scores are of question-able value. Lesion scoring requires con-siderable expertise. It is inherently sub-jective and, unfortunately, does notnecessarily correlate with protectionbecause lesions may be present in thegut of partially or completely immunebirds, even though their weight gain isnot depressed.

In some countries, guidelines foravian vaccines have been produced byregistration authorities, but specificstandards for anticoccidial vaccines in

poultry apparently have not been pub-lished so far. Detailed knowledge ofany local requirements is essential toobtain product approval.

The guidelines drafted by the proj-ect group provide information on thegeneral requirements of regulatoryauthorities based on regulations cur-rently applicable in the EU and the US.Topics covered in the guidelinesinclude efficacy requirements, safetyand environmental considerations,quality control in terms of purity, phar-

Guidelines for coccidiosis vaccines Ideally, any live anticoccidial vaccine should have the following 13characteristics:

✓ Induce protective immunity against economically important species of Eimeria

✓ Be safe for the target host, non-target animals and humans

✓ Not represent an environmental hazard

✓ Comprise parasites of normal or low virulence

✓ Comprise parasites that remain viable during storage for a reasonable period of time

✓ Protect against field strains in geographical areas where the vaccine is used

✓ Be administered by a commer-cially practical method to ensurethat as many birds as possiblereceive an immunizing dose

✓ Have no adverse effects on finalperformance or other production criteria

✓ Be compatible with other poultryvaccines

✓ Be free from viral, bacterial,mycoplasmal, fungal and chemi-cal contaminants

✓ Be cost effective compared withother methods of coccidiosis control

✓ Include drug-sensitive lines that may reduce drug resistance in field populations

✓ Raise no problems with residues or impose a need for mandatory withdrawal periods

continued on page 19

Good biosecurity helps ensure thatcoccidiosis vaccines are free fromcontaminants.

Vaccination of broilers againstcoccidiosis dramatically reducedthe need for coccidiosis treat-

ment, according to the results of anindependent analysis conducted inItaly.

The purpose of the analysis was toinvestigate current coccidiosis controlprograms in Italy from 2001 to 2004.The analysis was conducted by theIstituto Zooprofilattico Sperimentaledella Lombardia e Emilia Romagna andencompassed over 840 million broilers,which represented 55% to 60% ofItalian broiler production during thestudy period.

For nearly 80% of the birds, monoor solitary programs rather than combi-nation programs were used for coc-cidiosis control. The number of dualprograms declined and mono programsincreased during the study periodbecause nicarbazin was banned by theEU in June 2002.

From 2001 to 2004, the most popu-lar mono control method was vaccina-tion, which was used in over 45% ofbroilers during the study period. Thenext most popular mono control pro-gram was monensin, used in 19.1%, fol-lowed by salinomycin, used in 13.3%.

Of the approximately 20% of broil-ers that received a dual coccidiosis con-trol program from 2001 to 2004, theleading method used was nicarbazinplus narasin and monensin (8.6%), fol-lowed by nicarbazin plus monensin(4.2%).

By 2004, vaccination was used inover 54% of broilers. The next mostoften used mono coccidiosis controlmethod in 2004 was monensin, used in19.4%, followed by salinomycin, usedin 19.2% (see Figure 1). A dual programconsisting of nicarbazin, narasin plusmonensin was used in only 6.8% ofbroilers.

16

INDEPENDENT ANALYSISVaccination reduces need for coccidiosis treatment in broilers

By Marco Tamba, DVM, MPVMIstituto Zooprofilattico

Sperimentale della Lombardia e Emilia Romagna

Centro Emiliano Romagnolo di Epidemiologia Veterinaria

Bologna

Figure 1. In 2004, vaccination was the most popular monomethod of controlling coccidiosis in Italian broilers

Vaccination54.6%

Saliomycin19.2%

Monensin19.4%

Nicarbazin/Narasin+Monensin

6.8%

206,300 Million

Table 1. Data from the European Animal Health Study Centre indicate that antibiotic usage in the Italian poultry marketdeclined during the time that vaccination against coccidiosis trended upward.

Antibiotic Antibiotics used Antibiotics used Birds vaccinated Birds vaccinated 7/04 – 6/05 vs 4/05 – 6/05 vs 7/04 – 6/05 vs 4/05 – 6/05 vs

7/03 – 6/04 4/04 – 6/04 7/03 – 6/04 4/04 – 6/04

Betalactamics 1.20% -5.00% 12.00% 23.00%

Macrolides -8.10% -16.50% 12.00% 23.00%

Oxytetracyclines -13.70% -25.00% 12.00% 23.00%

Table 2. Recently acquired data from the European Animal Health Study Centre show that in the Italian poultry market, the trend toward less antibiotic use with increased coccidiosis vaccination continued.

Antibiotic Antibiotics used Antibiotics used Birds vaccinated Birds vaccinated 10/04 – 9/05 vs 7/05 – 9/05 vs 9/05 – 10/05 vs 7/05 – 9/05 vs

10/03 – 9/04 7/04 – 9/04 9/04 – 10/04 7/04 – 9/04

Betalactamics -7.10% -11.00% 25.00% 15.10%

Macrolides -15.20% -28.10% 25.00% 15.10%

Oxytetracyclines -15.40% -21.40% 25.00% 15.10%

17

Information from the European Animal Health Study Centre(CEESA) about trends in antibiotic use in the Italian poultrymarket for treatment of dysbacteriosis has demonstratedthat during the time vaccination for coccidiosis increased,the use of three antibiotics used to treat dysbacteriosisdeclined (see Table 1). More recently acquired CEESAdata (Table 2) show that the trend has continued, says Dr.Paolo Sani, poultry manager for Schering-Plough AnimalHealth, Italy.

The information from CEESA, coupled with the findingsfrom Italy that amprolium and amoxicillin use declinedwhen birds were vaccinated against coccidiosis, indicatesthat vaccination can provide excellent control of coccidio-sis and that it does not increase the risk for intestinalhealth problems such as dysbacteriosis, including necroticenteritis, Sani says.

CEESA data show antibiotic use declined when coccidiosis vaccination increased

There are two commercial coccidio-sis vaccines for broilers available inEurope. Of the two, Paracox-5 is themost widely used in Italy and was thevaccine administered to nearly 100% ofvaccinated birds in the analysis.

Paracox-5 is an attenuated vaccine thatincludes all precocious strains ofEimeria affecting broilers. The Eimeriastrains in Paracox-5 are sensitive to allanticoccidials, including antibioticionophores.

continued on page 18

Note: Dates are presented as month/year.

18

2001

Nic

arba

zin +

Mon

ensi

n

Othe

r An

ticoc

cidi

als

Othe

r An

ticoc

cidi

als

Vacc

inat

ion

Vacc

inat

ion

Othe

r An

ticoc

cidi

als

Nic

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zin +

Mon

ensi

n

2002 2003 2004

Amoxicillin (kg)Amprolium (l)

Note: The “other anticoccidials” group included metilchlorpidole+metilbenzoquate and salinomycin, monensin and nicar-bazin+narasin and monensin alone. Nicarbazin was a good method of controlling both coccidiosis and necrotic enteritisbut was banned from use in the EU as of 2002.

Amprolium treatment declinedOne of the most significant findings inthe analysis was that amprolium fortreatment of coccidiosis declined dra-matically when broilers were vaccinat-ed for coccidiosis compared to use ofamprolium when other anticoccidialswere used. This finding indicates thatvaccination is resulting in good coc-cidiosis control.

Figure 2 shows an example of oneItalian producer’s preventive programwhere amprolium was administered tocontrol clinical coccidiosis and amoxi-cillin was used to treat necrotic enteri-tis. Use of amprolium is a good indica-tor of clinical coccidiosis occurrence:Every peak in amprolium use due to

anticoccidial resistance is followed by achange in the control program, thenthe use of amprolium decreases untilthere is an increase in new resistance.

After vaccination was implementedin September 2003, there was a dra-matic drop in the use of amprolium,which is evident in the graph.

In contrast, the use of amoxicillinadministered for treatment of necroticenteritis progressively increasedthroughout the study period. Certainly,problems with bacterial enteritis stillexist when broilers are vaccinated forcoccidiosis control, but this clinicalproblem does not appear directlylinked to the vaccination.

Figure 2. Liters of amprolium for treatment of coccidiosis dropped dramatically and kilograms of amoxicillin for treatment of necrotic enteritis did not change significantly when birds were vac-cinated against coccidiosis.

made there and whether changing feedingredients would have any negativeimpact on the performance of vaccinat-ed birds during the period of highoocyst replication. (See accompanyingstory.)

His next focus is the Economicphase, or about 28 days to marketweight. Because vaccinated birdsgrown on the principles of IDEAshould have better immunity and guthealth, there’s room to economize onthe diets in the final phase withoutcompromising performance or returns.

“Going from 28 or 30 days to a mar-ket age of around 50 days for the malesis quite a long period in the lifetime ofthe birds,” he says. “Is it desirable tokeep birds on the same feed for 20days? From a nutritional standpoint, itmight be possible in that period tohave more than one feed. As the birdsget older, you could reduce the aminoacid levels and improve profitability. Ifyou were feeding 45-day-old pullets onthe final feed we use in the broilerswe’re using at the moment, you wouldargue that you’re overfeeding protein.”

Not having a coccidiostat in the feedalso helps operations remain more flex-ible when thinning females from theirflocks, usually somewhere between 33to 40 days. The vaccine provides life-long protection, so producers don’thave to worry about withdrawal timesor leaving the males unprotected forlonger periods.

“To be fair, all of the nutritionalknowledge we have was developed inmedicated birds,” ten Doeschate con-cludes. “I look back on our trial data-base, and it’s all birds that had anticoc-cidials in their feed. When producersare vaccinating for coccidiosis, there’sso much more to look at and hopeful-ly new opportunities at hand. We haveto keep the end goal in sight, which ismaintaining litter quality and profitableproduction.”

“But every country is different,” headds. “Every country has different chal-lenges and different economics. Wecan’t make a blueprint, but the princi-ples are universal.”

19

macopoeial sterility, potency, quantifi-cation and stability etc., manufacturingpractice and, last but not least, neces-sary documentation.

PurposeIn the foreseeable future, new vaccinesare likely to be introduced for protect-ing poultry against coccidiosis. Some ofthese vaccines will be produced bycompanies with an established trackrecord in providing high quality vac-cines to the poultry industry but, aspointed out at the 2005 InternationalCoccidiosis Conference held in Brazil,many smaller companies lacking suchexperience are also likely to beinvolved. It is important that all com-mercial vaccines, whatever theirsource, be produced to the same highstandards. For example, in the US,

source flocks used to produce poultryvaccines must be serologically tested toensure freedom from at least 11 kindsof virus, not to mention Mycoplasmaand Salmonella species.

To reiterate, the purpose of the proj-ect group’s guidelines is to facilitate theworldwide adoption of consistent, stan-dard procedures for evaluating the effi-cacy, safety, manufacture and qualitycontrol of coccidiosis vaccines for poul-try. The poultry industry deserves noless.

Reference1 Chapman, HD, Shirley, MW, Williams,

RB. Guidelines for evaluating the efficacy

and safety of live anticoccidial vaccines,

and obtaining approval for their use in

chickens and turkeys. Avian Pathology

2005;34: 279-290.

ESSENTIAL ELEMENTS continued from page 15

GOOD IDEA continued from page 13

20

COCCI NEWS

Editor’s note: The following news items are from the IX International Coccidiosis Conference in Iguasu Falls, Brazil.

Late production E. maxima problemslinked to anticoccidial resistanceProblems with Eimeria maxima infections late in the pro-duction cycle appear to be linked to extensive use ofionophore antibiotics and resulting ionophore-resistant E. acervulina, says Dr. Greg F. Mathis of Southern PoultryResearch, Inc.

An earlier study suggested that E. acervulina can interferewith E. maxima colonization. Consequently, Dr. Mathisdesigned a battery cage study to examine the relationship of E. acervulina sensitivity to the ionophore salinomycin andsubsequent infection levels with E. maxima.

Birds were fed nonmedicated feed or salinomycin at therate of 60 grams/ton and were then challenged with either asalinomycin sensitive strain of E. acervulina, a resistant strainof E. acervulina and/or an E. maxima field isolate.

The oocyst per bird challenge levels were as follows:

• None (control)

• E. acervulina (sensitive strain) 50,000

• E. acervulina (resistant strain) 50,000

• E. acervulina (sensitive strain ) 50,000 plus E. maxima 5,000

• E. acervulina (resistant strain) 50,000 plus E. maxima 5,000

• E. maxima 5,000

E. maxima alone caused a 20% weight reduction and 2.70lesion score, said Mathis.

Salinomycin controlled the sensitive strain with 5% weightreduction and 1.25 lesion score. It did not control the resist-

ant strain, resulting in a 22% weight reduction and 2.75lesion score.

Birds infected with E. maxima and the sensitive E.acervulina strain had E. maxima lesion scores of 2.25. Thebirds infected with E. maxima and the resistant E. acervuli-na strain had E. maxima lesion scores of 1.30. “From the results it can be inferred that E. acervulina inter-

fered with development of E. maxima. Higher anticoccidialresistance allows more E. acervulina colonization, whichappears to interfere with colonization of E. maxima, andthus indirectly slows E. maxima immunity development.

“This increases the chance for late problems with E. max-ima, possibly explaining an increase in field reports of lateE. maxima infections where salinomycin has been extensive-ly used,” Mathis said.

Organic meat sales up in US asAmericans follow European trend

Producing meat without antibiotics and other drugs haslong been advocated by European consumers and regulatorsand it appears that more Americans are following suit.

Consider the following preliminary findings from the 2006Manufacturer Survey of the Organic Trade Association (OTA),a US organization reporting on US food trends:

• Organic food sales totaled nearly $14 billion in 2005, repre-senting 2.5% of all retail sales for food.

• Organic food sales are expected to reach nearly $16 billionby the end of 2006.

• The fastest-growing organic food in 2005 was organicmeat, including poultry, with sales rising by over 55%.

“These findings show there is continued strong growth fororganic products, which means additional opportunities forfarmers and more choices for consumers,” according toCaren Wilcox, the OTA’s executive director.

The OTA has also forecasted that the fastest growing cate-gory of organic product sales would be poultry with an antic-ipated average annual growth of over 33% through 2008.

To meet this demand, many mainstream poultry opera-tions in the Americas and Europe have already discontinuedtheir use of growth-promoting antibiotics — either voluntari-ly or because of legislation — and are placing more empha-sis on intestinal health programs as a means of controllingdisease. Vaccination control has also helped operationsreduce or discontinue the use of chemicals or ionophores forcoccidiosis control.

Mathis

CocciForum is published by the Worldwide Poultry Business Unit ofSchering-Plough Animal Health Corporation, Union, NJ. The editors welcome your ideas and suggestions for news articles concerning coccidiosis management. Send correspondence to CocciForum, FeeksCommunications, PO Box 9000, PMB 239, Edgartown, MA 02539-9000,USA. E-fax: 928-569-2491, E-mail: JFeeks@prworks.net. Back issues areavailable online at www.thepoultrysite.com/cocciforum

© Copyright 2006, Schering-Plough Animal Health Corporation. Articlesmay be reprinted for educational purposes with written permission from the publisher.

Executive Editors: Stephen P. CollinsMarcelo Lang Fabio Paganini

Managing Editor: Joseph Feeks

Associate Editor: Diana Delmar

Design & Production: Deborah Sottile

Proofreader: Marisa Kane

21

Lesser known Eimeria species underestimatedTwo lesser-known Eimeria species in poultry may beunderestimated in importance.

One of the species is Eimeria mitis. “Mitis” means mildand the species is so namedbecause it has been consideredto be of minor significance inpoultry, said Dr. Luciano Gobbi,of Schering-Plough AnimalHealth, Italy.

However, a two-phase trial hasshown that, in contrast to itsname, E. mitis can impair chick-en performance and cause lossesjust like other, better knownEimeria species, the veterinariansaid.

In the first phase of the study,groups of 14-day-old Ross 508 chickens were infected witheither E. mitis or Eimeria acervulina, a species of coccidiaknown to have a significant adverse effect on chickens. A third group of birds received saline solution and servedas a control. The success of the challenge was confirmed by oocyst counting and shedding. Bird performance wasevaluated.

Compared to controls, birds that received either E. mitisor E. acervulina had significantly lower daily weight gain,feed intake and water consumption, as well as a higherfeed conversion ratio and lower final body weight, Gobbisaid.

In the second trial phase, three additional groups of 14-day-old Ross 508 birds were challenged with E. mitis and E.acervulina and were then injected with Pontamine SkyBlue dye to enable evaluation of intestinal mucosa, he said.

Eimeria-infected chickens exhibited color differences inthe mucosal surface compared to controls. In fact, only theinfected birds had dye leakage between 72 and 144 hourspost-infection. The leakage stained intestinal mucosa andgut contents, confirming cell damage and increased gut per-meability due to the multiplication of both Eimeria species.

In addition, infection with either Eimeria species causedsignificant gut wall thickening due to edema and inflamma-tion, he said.

“The results indicate that E. mitis can impair chicken per-formance and cause losses just like other, well-knownEimeria species, despite the name E. mitis,” Dr. Gobbi said.

Dr. Steve H. Fitz-Coy, also of Schering-Plough AnimalHealth, reported on E. mivati, a coccidial species that someresearchers have considered to be a variant of E. acervuli-na or a mixture of E. acervulina and E. mitis, but not aunique species.

Fitz-Coy identified several field isolates from Georgia andthe DelMarVa Peninsula that fit descriptions of E. mivati. Heselected three of the isolates and sent them with 10 otherEimeria species samples to an independent lab for poly-merase chain reaction (PCR) assay. The identity of eachsample was not known by the lab.

“The only isolates that could not be identified by PCRassay were the E. mivati samples,” he said. The currentprimers for identification of Eimeria species include E.acervulina and virtually all the other Eimeria speciesknown to affect chickens — except E. mivati, Fitz-Coy said.

The PCR test indicates that E. mivati is, in fact, a validand unique Eimeria species, he said.

E. mivati is also “moderately pathogenic” in chickensand, on some occasions, can cause mortality, according toFitz-Coy. In one study, mortality due to E. mivati was 40%in naive chickens, but there was no pathology in hyper-immunized hatch-mates.

Gobbi

Water potential carrier of coccidia to poultryDrinking water may be a potential carrier of coccidia tochickens, according to a new study.

The study focused on 24 farms that used forage or sur-face water and did not include farms supplied by treatedwater, said Reperant Jean-Michael, Le Du Maryse, of theFrench Agency for Food Safety, Zoopôle Les Croix,Ploufragan, France.

Fecal samples from the farms showed that 75% of theflocks were positive for coccidia. When filters were placedto capture oocysts where water entered the buildings, fourof the samples were positive for coccidia, he said.

The species of coccidia found in the water was Eimeriaacervulina, which was also present in litter from farms inthe study, the investigator said.

“These preliminary results suggest that water can be apotential carrier of coccidia for chickens,” he said, addingthat other forms of water supply could be considered infuture studies.

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