Broilers in a shed© Tim Scrivener

Consumers in the US are increasingly demanding poultry free from antibiotics, which is causing considerable angst across the sector.

Steve Bolden, director of world technical services for Cobb-Vantress, said a clear definition of antibiotics-free production was hard to find in the US, with definitions changing all the time.

See also: Biomass boiler maintenance for poultry farmers

Companies were using a wide range of labels, including “no antibiotics ever” (NAE) and “raised without antibiotics” (RWA) on their labelling.

Such wording meant no gram-positive feed or other product, no gram-negative spectrum feed or water antibiotics, no ionophores, although coccidiostats that control protozoal parasites can be used as can cocci vaccines as long as they are not organic-certified birds.

UK view

William Garton, poultry specialist at Minster Veterinary Practice, touched on the antibiotics resistance issues facing producers.

“I do see more bacteria resistant to antibiotics than five years ago – it is becoming more common.

“Some producers are withdrawing antibiotics altogether… while others are using other supplements, sometimes pulling in a number of non-veterinary products,” he said.

Mr Garton added that some producers now selected birds on the basis of disease resistance and robustness rather than liveweight.

Dr Bolden said US legislation meant the restaurant sector could use different language to market their poultry to the retail sector with some using the “no antibiotics used that impact human health” label, thereby permitting the use of ionophores.

Consumer groups have kept up pressure on food companies producing “ever-changing” score sheets that are published on a weekly basis.

Indeed, US integrator Perdue Farms has announced it is the first poultry processor to completely end the use of all antimicrobial treatments – including ionophores found in coccidiostats.

Consumer pressure

Dr Bolden said the situation in the US had developed due to direct pressure from consumers, the opportunity of achieving a price premium, social responsibility issues and the lack of a government mandate on the issue.

The drive towards antibiotics-free production is causing concern among vets in poultry companies even within companies that have embraced it.

Dr Bolden quoted a range of leading US experts on their thoughts about ABF production.

Randy Mitchell, Perdue Farms vice-president of technical services, said recently veterinary and nutritional issues, such as downtime between flocks, stocking densities, litter quality and dryness should dictate the timetable for change rather than the marketing drive for NAE or RWA products.

Husbandry methods

David Wicker, vice-president of live operations for Fieldale Farms, has said the transition to ABF production could not take place overnight, as it would take time for farmers to learn the proper husbandry methods needed.

“Stocking densities must be lower in ABF operations,” he added.

And Don Rittner, chicken vet at Mountaire Farms, said NAE was not the best route for farmers as birds suffered higher mortality rates.

Amy Batal, corporate nutritionist at Sanderson Farms, which has bucked the trend and is refusing to reduce its use of antibiotics, believes the sector is not helping itself.

“Let’s really take a look at it scientifically and work together,” she said.

See also: Sanderson Farms says antibiotics-free chicken is a ‘gimmick’

Dr Bolden said he felt it was likely public opposition to antibiotics would eventually drive Sanderson Farms from their current stance.

Disease prevention

But he stressed poultry breeders could do more to prevent disease, including improved management of floor eggs, cleaning or replacing nest pads between flocks keeping floors and slats dry and installing farm fumigation area for eggs.

The hatchery sector needed to ensure all contact surfaces were kept clean and sanitised and broiler growers needed to reduce stocking densities, increase downtime, clean out for each batch of birds, ensure there was good water sanitation, look at the use of litter acidification products and consider boosting bird health through cocci-vaccines.

Other issues to consider, he added, included use of coarse ground corn to help with digestibility, the use of probiotics, essential oils and plant extracts to enhance nutrition.

Commenting on Cobb’s position, Dr Bolden said the company no longer use ionophores or growth promoting antibiotics and the firm was exploring new technologies to capture better efficiencies, liveability and thriftiness which it would share with its customers in the near future.

Tackling social and environmental issues the Uber way

Sourcing, integrating and analysing data are key to combating challenges affecting the poultry sector.

Jeff Wilson, president of Novemetrix Research, told the conference producers needed to understand the power of data analysis and its value to retailers, processors and animal welfare advocates.

The sector then needed to enter into an authentic dialogue with the “value chain”, including consumer and advocacy groups to help deal with environmental and social challenges, such as antimicrobial resistance and the changing regulatory environment.

By doing this, creating solutions that satisfied the interests of everyone would be possible.

Dr Wilson cited the taxi company Uber as an example of one of the first businesses to understand and deliver the “collaborative economy” as it had successfully integrated  component network parts into a functional business.

Getting to the guts of poultry health 

The impact of antibiotics on poultry guts can have a surprising long-term effect on bird health.

Professor Martin Woodward, of the University of Reading, said it was important to stress scientists did not know all the bugs in the gut and what their function is.

But they were beginning to understand the metabolic consequences of interactions with birds and the industry needed to act in “a more holistic way”.

DNA analysis

DNA coding of poultry is helping scientists analyse microbial activity in the gut.

Unsurprisingly, the status of the gut is markedly different for diseased birds, suffering from salmonella, E coli or campylobacter compared to healthy birds.

But studies at Reading University have shown alternatives to antibiotics can, for a time, boost the health of broiler gut.

These include bedding materials, such as woodchips, wood shavings, distillers’ dried grains and enzymes.

Generally, at the end of the study the level of bacteria and pathogens are similar in birds, which have had bulking agents to those that haven’t.

“Age rather than intervention is a powerful driver of development of microflora,” he added.

Tiamulin

Prof Woodward spoke of an experiment using 18-week-old birds which were dosed with the pleuromutilin antibiotic Tiamulin at three different levels to control Brachyspira pilosicoli-induced avian intestinal spirochaetosis, which can lead to high morbidity levels in broilers.

The control birds suffered loose faeces, low weight gains and poor egg production. Tiamulin reduced the amount of brachyspira quickly but there were still pathogens floating around.

“You think you have controlled the pathogen but there is a danger it will come back again with a vengeance. So the antibiotic is effective but it doesn’t remove the pathogen completely.

“But if you do nothing, the gut gets back to normal, although the birds are not so heavy having not put on so much weight,” he said.

Investigations showed that Tiamulin changed the gut microbiota quite considerably with a significant drop in bacteria diversity in treated birds.

Prof Woodward’s work at Reading has involved integrated analyses of the use of current interventions such as antibiotics usage with dietary modification through the use of pre- and probiotics to alter gut flora and its metabolism.

Using the “in vitro” gut model systems developed at Reading, these analyses are making use of contemporary metagenomics (the study of genetic material recovered directly from environmental samples) and metabonomic (the study of metabolites – substances necessary for metabolism) approaches to assess and refine potential interventions.

A key tool is the development of genome-scale metabolic models of the pathogens to help understand metabolic interactions between them with a view to altering metabolic activity as a method of pathogen control.

Metabolic atlas

He spoke of the latest work around establishing a proton nuclear magnetic resonance (NMR)-based metabolic atlas of chicken.

Metabolic extractions were performed prior to 1H-NMR and 2D NMR spectra acquisition on 12 biological matrices – liver, kidney, spleen, plasma, egg yolk and white, colon, caecum, faecal water, ileum, pectoral muscle and brain of six chickens.

The metabolic profiles were then exhaustively characterised, resulting in the identification of nearly 80 metabolites.

A cross-comparison of the matrices was performed to determine metabolic variations between and within each section and this highlighted that only eight metabolites were systematically found in every matrix.

It also found antibiotics shifted the metabolism in the birds with Tiamulin detected in the liver, which triggered a cascade of activities across the bird leading to the production of more fat but less quality meat.

“Here, you are getting wonderful weight gain. but more fat,” he added.

He said the work constituted a database for future NMR-based metabolomic investigations in relation to avian production and health.