Gut decisions

Managing Nutrition to optimise intestinal health programs

As consumers grow more concerned about drugs in poultry feed and regulators tighten the screws on the range of therapeutics available, major poultry companies worldwide are placing more emphasis on vaccination for managing coccidiosis.

This is particularly evident in Europe, where an estimated 9% of broilers are now vaccinated for this costly and ubiquitous protozoan disease, a 700% increase over the past 3 years.

The switch from feed additives to vaccination has gone relatively smoothly, particularly with the development of a special spray cabinet that ensures uniform distribution of the vaccine to day-old chicks in the hatchery.

According to Dr. Fabio Paganini of Schering-Plough Animal Health Corporation, the increasing popularity of vaccination goes hand-in-hand with another emerging paradigm "that nutrition can and will play an even bigger role in managing health challenges.

"As the use of in-feed antibiotics or anticoccidials declines, producers will no longer be able to depend on these drugs to suppress the effects of poorly managed environmental conditions in poultry houses," Paganini says. "Nutrition therefore needs to be designed to guarantee the development of the immune system while minimizing the availability of nutrients for harmful bacteria's growth."

To address this emerging topic, Schering-Plough Animal Health Corporation recently brought 41 international poultry producers to New York City for a technical seminar focusing on the role of nutrition management in meeting the contemporary health challenges of the global poultry industry.

Conducted in the midst of a blustery coastal snowstorm that surprised New Yorkers with more than a foot of snow, the symposium featured technical presentations by international experts and a panel discussion in which speakers shared front-line experiences from around the world.

The gathering was an excellent opportunity for poultry producers to compare notes on the best strategies for managing nutritional programs of birds vaccinated for coccidiosis. More importantly, it offered new insights into future directions.

"There were some very enlightening presentations and discussions during the 2-day meeting," Paganini says. "This is relevant to poultry producers worldwide."

CocciForum is pleased to present this special report with highlights from the seminar. To request the full set of seminar papers, contact [email protected].

Broiler nutrient and energy need as influenced by genetics, nutritional and pharmaceutical environments

Robert G. Teeter, PhD Department of Animal Science Oklahoma State University Stillwater

Achieving optimal performance in commercial broilers requires specialists in animal health, nutrition and husbandry to work effectively together, especially given the move away from in-feed anticoccidial drugs.

Genetic progress in the past 50 years has been impressive. A typical 1950s broiler reached 1.5 kg (3.30 lbs) with a feed conversion ratio (FCR) of 3.2 and took 11 weeks to get there. Its descendant in the 2000s can make it to 2.3 kg (5.07 lbs) in just 5.5 weeks and an FCR of 1.66. Despite these gains, and despite the success of medication to keep it under control, coccidiosis remains the poultry industry's most expensive parasite, levying the world's producers about US$2 billion annually.

Impact of vaccination

Vaccination of birds against coccidiosis, while effective, is not without cost in terms of immune challenge and subse- quent energetic cost "manifested in greater feed consumption. The impact of immune stimulation on growth can be exacerbated by management issues such as drafts, temperature fluctuations, crowding and air quality.

Mistakes in these areas can open the way for infectious agents to overwhelm the immune system. This could lead to altered management recommendations to protect vaccinated birds during brief yet critical times in the production cycle.

Impacts of drugs

Anticoccidials and ionophores can also have negative effects. For example, nicarbazin has been shown to increase mortality during high humidity-high temperature stress periods. Ionophores can also have undesirable consequences. Drugs such as monensin, salinomycin and lasalocid affect translocation of ions (hence the name) across membranes. They can affect birds' mineral balance and thus water consumption, which can lead to problems with wet litter.

The impact of ionophores needs to be managed within the overall electrolyte nutrition of broilers. When moving from an ionophore-based cocci-control program to vaccination, the feed formulation needs to be altered for the absence of ionophores as well as the enhanced immune system activity.


Nutrition management requires a juggling of priorities for optimizing profit while catering for the energy costs associated with variables such as stocking density, hygiene, lighting and watering systems.

Setting goals

Any formulization program should be driven by principle goals. These are some principle goals "and some considerations if they are to be the focus:

Live body weight and FCR. Without correct adjustments to protein levels, birds will develop an over-fat carcass.

Lean mass production plus breast and/or specific parts yield. By slowing growth of offal protein and carcass and offal lipids, live bird mass and FCR will not be optimized. Tight management of non-nutritive factors is important to control energy demands.

Coping with environmental challenges that elevate mortality. The approach is to keep up carcass growth while downsizing metabolic demand. It may take longer for birds to reach market weight.

Least cost for live weight "lowering the ration cost. While FCR will fall, the approach is to provide enough nutrition for growth to occur, given enough time. Nutrition standards shouldn't be lowered to the point that birds are over fat.

The importance of nutrition in the initial phase - developing the intestinal tract and immune capacity

Antonio Mario Penz, Jr., PhD Universidade Federal do Rio Grande do Sul Brazil

There is still considerable room for improvement in feed conversion ratios, which means that every year, broilers must eat less to achieve the same weights. In terms of nutrition, this puts broilers on something of a knife's edge when it comes to achieving their potential. This is especially so in the first few days of life. Because broilers are being selected for lower feed consumption, their immune systems and very survival face greater challenges than before.

The digestive tract undergoes major anatomical changes during the first few days of life. The passage of feed during this phase has a big impact on this development and the way nutrients are absorbed later in life.

The immune system starts to develop during the embryonic phase and continues for the first week after hatching. A delay in water and feed consumption suppresses the immune system.

While the yolk sac sustains the newly hatched chick in the first few hours, it needs the stimulation of solid feed to get the digestive system developing properly. Delaying water and feed during this crucial period reduces the use of available nutrients in the yolk sac.

Under practical conditions, chicks arrive at the farm 24-36 hours after hatching. Delays in feeding during transport, sexing and vaccination can affect later development. Conversely, the benefits of early feeding give an advantage that is maintained through to market age (Table 1). It is important, therefore, to put chicks in contact with feed as soon as possible in the first day of life.

Other tips and observations

  • The use of lipids in pre-starter diets should be restricted, as animal fat digestibility is very low at this stage. Furthermore, undigested fat could become an energy source for bacteria in the intestine.
  • Sodium intake is another important consideration for the first week. Increasing levels of sodium are associated with increased weights due to higher water retention.
  • Average particle size in pre-starter diets can affect performance, having an impact on metabolizable energy, nitrogen retention and dry matter retention.
  • Addition of protein and fat to prestarter diets can affect abdominal fat percentages by slaughter.
  • Restricting water consumption directly affects feed consumption and thus the broiler's performance.

Increasing digestibility using vegetable- and drug-free feed

Antonio Mario Penz, Jr., PhD Universidade Federal do Rio Grande do Sul Brazil

A series of high-profile food scares in Europe "mad cow disease, antibiotic resistance and dioxin contamination, to name a few "has led to tighter regulations to help restore consumer confidence in the food sector.

Antibiotics in animal feed and antimicrobial growth promoters are being phased out to help reduce the risk of resistance to antibiotics used in human medicine.

Banning antimicrobial growth promoters (AGP) will improve consumer perceptions but has the potential to create animal health problems, including:

  • Reduced efficiency of feed utilization, especially where management or hygiene standards are poor.
  • Increased disease related to Clostridium perfringens, e.g., necrotic enteritis (NE), chronic hepatitis.
  • More wet litter problems because of increased NE.

Given the high use of wheat and barley in European poultry diets, feeding programs and feed composition may be important factors in disease when AGP are withdrawn. The soluble non-starchpolysaccharides (NSP) in these cereals can cause a range of digestive problems, especially in rye-based diets where elevated numbers of C. perfringens are reported. NSP-degrading enzymes are used to mitigate this problem.

Diet is also an important factor in coccidiosis, and Spain's department of animal nutrition has been studying the relationship between feed components and coccidiosis vaccination with Schering-Plough Animal Health.

The study compared performance of vaccinated birds on US-type corn-based diets with European wheat- or rye-based diets (with or without the NSP-degrading enzymes). Different nutritional strategies to improve performance of birds vaccinated against coccidiosis were also studied.

Performance issues relating to the age in vaccinated birds and their feed programs have been identified, but it appears that improving the digestibility of European broiler diets (e.g., through enzymes) could enhance the performance of vaccinated birds. Better digestibility will also help reduce the impact of C. perfringens and others.

Control of necrotic enteritis in drug-free birds

Magne Kaldhusdal, PhD National Veterinary Institute Norway

Research and development for the production system is based on in-feed antibiotics used for managing necrotic enteritis (NE). Their eventual abolition will require a more multidisciplinary approach, especially for dealing with NE associated with Clostridium perfringens. Many factors directly and indirectly affect the severity of C. perfringens-associated problems. Understanding and learning how to manage them is the key. It is clear that much more research is needed to understand the mechanisms and efficacy of alternative methods for NE control.

Coccidiosis control. Coccidiosis predisposes birds to NE. Commercially, vaccinated birds are protected from coccidiosis and perform on par with medicated birds. However, additional measures to protect against NE are needed in vaccinated (non-medicated) birds.

Digestibility for young birds. Digestibility is not very relevant for young birds protected by in-feed medication, but it becomes significant when the antibiotics are removed. High digestibility is important to prevent the accumulation of a substrate that favors development of C. perfringens.

Dietary fat. Young birds digest some fats better than others and this can affect levels of C. perfringens.

Cereal type. Wheat- and barley-based diets appear to encourage greater proliferation of C. perfringens than corn-based feed. The action of dietary enzymes on the cereals may be implicated. Plant breeding might be used to optimize performance of different cereals in this respect. However, more research is needed into the mechanisms of this relationship between cereal type and NE risk.

Cereal storage. The length of storage (longer is better for wheat and barley) and the method of storage (air-tight for barley and oats), seem to have a positive effect on digestibility.

Dietary protein source. Diets high in protein, especially non-digestible protein, favor growth of C. perfringens.

Feed processing. Many factors in feed processing affect vulnerability to NE. These include use of pelleting, which appears to have both positive and negative effects. Heat affects digestibility and could open the door for C. perfringens by killing less-resilient competitors. Particle size can be a factor in digestibility for some ingredients.

Whole grain feeding. Whole grain wheat can reduce C. perfringens counts, but it is not known why.

Microbial cultures. These may help resist the onset of NE by quickly establishing healthy cultures of gut flora in young birds. Microbial cultures can also encompass probiotics which include microorganisms and some of their products.

Prebiotics. These are food ingredients that encourage the development of beneficial bacteria in the hindgut.

Supplementary enzymes. These are used to optimize digestive function. It is not clear whether these are directly useful for preventing NE.

Plant products. Some plant products such as essential oils appear to reduce counts of C. perfringens, but more work is needed to support their use against NE.

Immunity. Maternal antibodies against C. perfringens seem to protect birds from NE for the first 2-3 weeks. On the strength of this, there could be potential for a vaccine to stimulate maternal or active immunity and contribute to NE control.

Management. The "farm effect" of stocking density, lighting programs, feeding methods and the state of litter all contribute to the NE status of a poultry operation.

Infection sources. C. perfringens spores are very difficult to kill, and survive disinfectant treatments between grow-outs. It can be carried in feed, but there are numerous environmental sources.

Economic advantage of managing nutrition in coccidiosis-vaccinated broilers

Phillip Hargis, PhD Hargis Associates USA

In terms of economy, coccidiosis vaccination is competitive with using in-feed anticoccidials, but a few changes must be made to feed formulation, feeding program and broiler-house management to ensure success.

Do not expect performance of vaccinated broilers to exceed performance in programs using ionophores and/or chemical drugs. The cost of production will be the same for either option.

The most economically feasible strategy is to use conventional drug programs with lighter birds (1.7 kg "� 1.9 kg/3.75 "� 4.19 lbs) and coccidiosis vaccination programs along with conventional programs for birds taken through the heavier weights.

There is only so much a feed program can do to enhance the effectiveness of vaccination. In addition to nutrition, there are several other key factors in the success of a coccidiosis vaccination program:

Time of year. It's best to introduce vaccination between April 1 and November 1, when houses are dry and challenge low. Year-round use can be phased in later.

House management. Litter condition is crucial; so is the ability to control environmental conditions.

Lighting. No dark periods to limit feed intake and no continuous bright lights to overstimulate activity and utilization of nutrients, thus over-taxing the coccidiosischallenged gut.

Genetics. Birds that feed well in early life do better under vaccination programs. Where regular drug programs also involve vaccination, there are critical "companion drugs." Likewise, there are important companion ingredients such as sodium bicarb, phytase and betaine.

Feed formulations to support vaccination programs

Vaccinated birds need time to overcome the early coccidiosis challenge. Once the second challenge is passed, the formulation should maximize growth from day 30 on. Before this, there are two critical periods: 17-21 days and 27-30 days. Feed for mulation must be closely controlled with no changes at these times.

Some other important tips for nutrition programs are:

  • Use high-digestibility ingredients
  • Use ingredients low in peroxides and gut-corrosive properties
  • Minimize mycotoxin exposure
  • Minimize bird stress via ingredient quality
  • Minimize ingredients that promote intestinal fermentation
  • Avoid feed reformulations or switching to cheaper ingredients.

Integration with ionophore drugs

Coccidial vaccines "revive" over-used and abused ionophores. Take advantage of this by following a vaccination cycle with the weakest in the current drug program.

Nutritional programs to optimize performance in drug-free diets "the Brazilian experience

PRonei Gauer, PhD Nutrition Consultant Brazil

Each 1 kg (2.2 lbs) on a Boeing 767 consumes an extra 200 liters (52.8 gallons) of aviation fuel per year. In the broiler industry, the extra "weight" in a diet can also drag down productivity.

In Brazil, two factors are leading to the demise of coccidiostats and growth promoters in poultry feed: consumer resistance, and declining efficacy. Doses of anticoccidials have been increased to combat resistance to antibiotics.

The investment in drugs has diverted poultry industry investment from more productive lines of research, such as feed and water quality, and training of personnel.

In Brazil, a number of strategies have now been identified to help maximize performance in drug-free production systems that employ vaccination against coccidiosis:

Quality of ingredients. Higher quality raw material improves digestibility and leaves less substrate for bacterial development.

Particle size. Whole cereals can stimulate the gizzard and may help with digestion and suppression of salmonella.

Feed processing. Temperatures and pressure can affect feed absorption.

Organic acids. These can impede the invasion of birds by bacteria.

Protein/enzymes. Minimizing nonabsorption of protein denies bacteria such as Clostridium perfringens a substrate for development. Enzymes help maximize protein absorption.

Betaine. This helps decrease incidence and severity of intestinal lesions in vaccinated birds and could help improve feed conversion rates.

Differentiated diets. Weight gain, pigmentation and feed conversion can be issues in vaccinated birds if diets are not adjusted appropriately at crucial periods "for example, reducing protein levels in starter feed (10-20 days).

Pre-starter feed. This should be used until immunity builds up. High-quality ingredients are essential.

Starter feed. Lower levels of crude protein are required as the immunitybuilding process peaks. This helps control bacterial growth.

Variability. With more digestible feed and more consistent quality and other refinements such as enzymes, it will be possible to minimize bacterial challenge that was previously controlled with antimicrobial growth promoters. Work is also needed to improve management of the basics (e.g., water quality) among the poorest producers.

Taken together, the strategies are tipped to offer a cumulative FCR improvement of 0.18 g per kg of gain (0.0008 per lb).

PRESENTER: Amatzia Eyal, PhD Nutrition Consultant Israel

Nutritional programs to optimize performance in anticoccidial-free diets "the Israeli experience

Amatzia Eyal, PhD Nutrition Consultant Israel

Comparative trials in Israel have shown very similar performance results for coccidiostat- treated birds and birds vaccinated against coccidiosis.

The birds were split into male and female groups, with different feed regimes for the vaccinated and medicated birds. The vaccinated birds received diets designed to reduce mortality and feed cost without compromising performance. The feed for both groups was based on corn and wheat because of the Israeli market requirement for white skin.

In both the male and female groups, finished weights were very similar for vaccinated and medicated birds.

An interesting result for both the male (+42 g/+0.092 lb) and female (+30 g/ +0.066 lb) birds was that vaccinated animals yielded more breast meat than the medicated birds, but the reason has not been determined.

Alternative feed programs in broilers vaccinated for coccidiosis "the Spanish experience

José Ignacio Barragan, DVM Nutrition Consultant Spainl

Traditional feed programs in Spain are designed around the withdrawal period from a coccidiostat. Using a vaccine that provides lifelong immunity instead of an in-feed anticoccidial has allowed producers to focus on managing feed ingredients for optimum performance "without worrying about drug treatment or withdrawal times.

The added flexibility allows operations to:

  • Provide the right start for broilers with the highest possible feed digestibility during the crucial 14-28 day period.
  • Use lower-cost finishing rations for longer periods, without compromising production.
Trials were conducted at Nutreco Group's experiment station in Spain to compare the impacts of conventional and modified diets in drug-treated (nicarbarbazin/ monensin) and vaccinated birds.

Trial 1: Use of high-digestibility rations at an early age
The trial compared performance using the conventional starter (0-20 days), grower (21-42 days) and finisher (43-49 days) program with an alternative that split the 0-20 day program into two phases "a pre-starter and starter feed. The aim was to optimize the pre-starter period performance and to promote digestibility during the starter period with a less concentrated feed.

For the total study (0-49 days), the final weight of vaccinated broilers on the alternative feed program was clearly better than weights for medicated birds on a conventional diet. There were no significant differences in mortality or real feed conversion indexes.

Trial 2: Use of different finisher diet periods
The trial split vaccinated birds into conventional and alternative starter programs as in the first trial, but also looked at the impact of varying the finisher feed periods. A medicated group was also tested.

The study concluded that it is practicable to prolong the use of finisher diets without impairing final performance - something that might reduce the cost of feeding programs for vaccinated broilers.

Trial 3: Combined studies 1 and 2
A trial at the IRTA experimental station revisited the impact of digestibility at earlier stages as well as using feeding finishing diets for longer periods with some refinements.

Once again, the trial confirmed that with correct husbandry and ambient conditions, performance of vaccinated broilers matches that of medicated birds. Interestingly, both vaccinated and medicated birds benefited from the alternative feed programs. It also demonstrated the benefits of using alternative diets in vaccinated birds.

In vaccinated chickens, longer finisher/ withdrawal diet periods at a lower cost did not compromise weights, mortality or feed conversion ratio (FCR), nor did it increase risk of late coccidiosis outbreaks. The results were consistent with practical experience in Spain.

Managing nutrition for coccidiosis-vaccinated birds - UK trial results and novel marketing concepts

Peter Woodward, BSc Poultry Nutrition Specialists Hereford, UK

Over the past several years, there has been a series of small-scale and commercial- scale trials to explore ways to maintain gut health in chickens vaccinated against coccidiosis in the UK and Ireland.

Small pen trials in the UK in 2000-01 aimed to develop a nutritional program for vaccinated birds that provided performance at least equal to conventionally raised chickens and at a comparable cost.

Despite increased mortality, the best economic performance was observed with vaccinated birds on high-density starter diets with high-quality proteins. Protein source (fishmeal or soya meal) was not a factor. Savings in feed cost offset the cost of vaccination.

Further trials in Ireland last year looked at the effects of raw materials and dietary additives in the diets of vaccinated birds.

In the first trial, some of the bioflavonoid additives showed potential synergistic responses. In trial 2, vaccinated birds were given either vegetable or fishmeal protein sources. As long as nutrients were balanced following removal of fishmeal from the diet, there were no nutritional factors interfering with the birds' response to vaccination.

Trials have also been held in a UK commercial environment over the past 2 years. The farm chosen had experienced a range of health problems including clinical coccidiosis. Performance of vaccinated birds was inconsistent, although improvements were noted with subsequent crops.

It was concluded that more needs to be known about the dynamics and factors critical for vaccination. It was also noted that successful and economic performance using vaccination against coccidiosis will be achieved through combinations of feed manipulations and modifying management standards.

A nutritional concept for vaccinated birds "IDEA program

César Carnicer, PhD Poultry Business Manager Schering-Plough Animal Health Spain

The research results from Spain presented by Dr. Barragan (page 15) indicated that nutrition programs for vaccinated birds are free from the constraints imposed by withdrawal times. As such, they can be adapted to better suit their nutritional needs and the producers' economic needs.

Dr. Carnicer developed this theme by proposing a good "IDEA" in the form of a nutrition program that fits the dynamics of Eimeria spp. during the production cycle of vaccinated birds.

The accompanying graph shows the classical oocyst-excretion curve of wellmanaged, vaccinated birds. There are three oocyst cycles, with peak production occurring typically during the third, at 21- 28 days.

Good uniform vaccine coverage is essential to ensure that all birds begin the cycling process together, which in turn leads to uniformity in oocyst cycling and immune development.

Equally important to the success of a coccidiosis vaccination program is the overall quality of poultry house management. This includes everything from cleanout before the introduction of a vaccinated flock, to bedding, temperature control, litter moisture, flock density and warmth.

By adapting nutrition programs to the physiological situation in the intestine of vaccinated birds and matching nutrient needs to the building of immunity in each period, vaccinated birds will perform better. This is spelled out in the IDEA concept:

I: Impulse phase (1-2 in graph). Prepare the immune system and intestinal cells to develop immunity against coccidiosis; at the same time an adequate start for the fattening period is provided.

D: Digestibility or Developing phase (2- 3) in graph). Help the immune system and intestinal cells build immunity. This is important not only for coccidiosis, but also because most intestinal infectious problems and disturbances occur in this period.

E: Economic advantage (4 in graph). Take advantage of birds' immunity against coccidiosis with good intestinal health.

A: An Advance in poultry farming and a good Alternative for the new era when in-feed additives will no longer be available.

Source: CocciForum Issue No.8, Schering-Plough Animal Health.

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