For the first time this year, the annual WPSA UK Spring meeting was held in collaboration with the British Veterinary Poultry Association, bringing together researchers and practitioners from a range of different disciplines and backgrounds. This led to a varied and interesting programme, highlights of which we have summarised for you below.
Dr de Jong started her presentation with a short history of the move towards lower density and slower growing production systems in mainland Europe, and the Netherlands in particular. Pressure on the industry from retailers started in 2007, soon after the implementation of the ban on antibiotic growth promoters.
By 2023, all fresh retail meat was sold under the Beter Leven brand. Beter Leven (which translates roughly as “better living”) has several different tiers, but the baseline production conditions for broilers is now a stocking density of 25 kg/m2, in-house enrichment and access to covered runs or verandas.
Last year, 50% of all broilers in the Netherlands were slow-growing breeds, but the total population of broilers has declined by 100M birds since 2015, due to a lack of housing space at the low densities. Consumption has remained steady across the same time period, driving increased imports and fewer exports. The price of retail chicken has also substantially increased, as the costs of production for these Beter Leven systems are approximately 142% of the costs of conventional systems.
Dr de Jong shared summaries of several of her published research studies on the behaviour and welfare of different breeds in low stocking density and enriched environments. She focused on a comparison between two particular broiler breeds, the JA787 (a faster-growing breed) and the S757N (a slow-growing breed), both from Hubbard. Her studies highlighted behavioural differences between the breeds, with the fast-growing line more inactive in all stocking densities. Slower growing birds, by contrast, had better gait, footpad and hock burn scores under all environments. As stocking density decreased, the welfare indicators increased for both genetic lines at a similar rate. However, the footpad scores of fast-growing broilers responded particularly well to lower stocking densities.
Dr de Jong concluded that reducing stocking or the use of slower-growing broilers (whether growth is controlled by breed or diet density) improved welfare, but that the best welfare outcomes were seen when both were combined. However, these systems have substantial implications for both economic and environmental costs of production, with producing under the ECC conditions estimated to cost 120% of production in conventional systems. Similarly, slow-growing broilers generate 19% more CO2 equivalent/kg BW than conventional broilers, due to higher FCR and longer growing cycles.
Throughout the WPSA conference, several shorter presentations focused on alternative breeds, housing or raw material assessment:
The second invited presentation was from Dr Bushra Schutiemaker, whose infectious enthusiasm for her subject carried the room through her in-depth presentation on the faecal microbiome profile of commercial broilers.
As part of her BBSRC and Aviagen funded PhD at the prestigious Quadram Institute, Dr Schuitemaker followed the faecal microbiome of three commercial broiler flocks. The flocks were placed in March 2020, March 2022 and September 2022.
Across the flocks, bacterial microbiome diversity – often considered a sign of maturity and stability of a microbial community, as well as indicating resilience and the ability to fight off opportunistic pathogens – was greater at day 40 than at day 7, 18 or 27. In particular, Dr Schuitemaker found the presence of two specific genera – Akkermansia and Alistipes – were indicators of maturity and stability. This matches previous research, which shows that Alistipes, a butyrate producer, is an indicator of a healthy, functioning microbiome.
There were no significant differences in overall microbiome composition between flocks at any time point of her study, which was unexpected, as farm, diet and weather factors are all expected to have substantial impacts on the microbial community. There were also no overall differences in the microbiome of high or low performing birds – in contrast to many scientific studies, which have associated different microbiome profiles with increased performance. However, there were differences at the species level and also in the intestinal levels of the short-chain fatty acids acetate and lactate. The SCFAs are considered indicators of a healthy and robust microbiome, and one that is less likely to lead to blooms of pathogenic bacterial strains.
Dr Schuitemaker also presented data on the fungal microbiome of the broiler flocks, which is not often considered in microbiological studies. Here, as the birds aged, the fungal microbiome becomes more similar between birds.
Associating the fungal microbiome with performance was clearer than for the bacterial results, with higher levels of the yeast Diutina associated with better bird and flock performance. In external studies, Diutina is known to affect phosphorus utilization, and in Dr Schuitemaker’s research was correlated with higher degradation of phytate in the intestinal contents and higher levels of inositol in diets fed without exogenous phytase.
Dr Schuitemaker concluded by exploring the future uses of microbiome research – from finetuning diets to feed specific genera, to developing new feed additives and therapeutics from the metabolites of beneficial microbiota.
Following Dr Schuitemaker’s expertise on the microbiome, several shorter presentations focused on the use of feed additives to influence microbial diversity and bird performance:
The Gordon Memorial talk, an annual highlight of the WPSA conference, was also focused on bird health and immunity. The talk was given this year by the highly respected Belgian scientist Professor Richard Ducatelle, whose long career has resulted in the publication of more than 300 scientific papers across a range of species.
Professor Ducatelle began by explaining that nutritional anatomy is highly conserved, with strong similarities in structure and function between the gastrointestinal tracts (GIT) of species. He also took the time to correct a common oversimplification – many people consider the intestine a tube with one opening at the mouth and the other at the anus, but Professor Ducatelle stressed that understanding the different sections and compartments within the GIT are of the highest importance when attempting to understand intestinal function.
With every mouthful of feed, chickens take up 1x106 cfu/g – or one million bacterial cells per gram. In faecal content, this has increased to 1x1011 cfu/g – equivalent to one hundred billion cells per gram. This multiplication of microbial populations in the intestine is actually batch fermentation, the same process that fuels the production of beer or wine or silage, and should be considered as such.
Prof Ducatelle then switched to a discussion of the increases in growth and efficiency over the past hundred years, with the days needed for a broiler to reach 2.5 kg BW reducing from 120 days in 1925 to 28 in 2019. And yet, are we always hitting the genetic potential of birds in commercial production?
The gap between potential and field results, Prof Ducatelle suggested, is not always due to clinical disease. Often, this gap is due to inefficiencies caused by dysbiosis, or dysregulation of the intestinal microbiome. Prof Ducatelle highlighted the presence of foamy small intestinal content as a sign of bacterial overgrowth and therefore competition for nutrients with the bird. This dysregulation can lead to single-strain dominance in the intestine, with dominant strains subsequently breaking down the mucin layer protecting the gut surface through the production of enzymes including sialidase. Sialidase production can therefore be a very good marker for the potential virulence of a particular strain in the bird.
Another marker of good intestinal health, Prof Ducatelle explained, is the presence of hypoxanthine. Hypoxanthine works as an antimicrobial agent, but production mechanisms seem to be downregulated in high feed intake birds, leaving these high performers vulnerable to pathogenic blooms and dysbiosis. Prof Ducatelle suggested that hypoxanthine could be replaced in these birds by careful supplementation of probiotic bacterial strains.
As his key take home messages for his extensive and highly scientific explanation of his unifying theory of gut health, Professor Ductaelle proposed the following:
One of the regular features of the spring BVPA meeting is The Keith Gooderham Waterfowl Lecture. This year, the speaker was Jim Jurgielewicz, a duck vet and farmer, from the United States of America. Jim works for the family firms of Joe Jurgielewicz & Son and Culver Duck Co, who between them process 14m ducks annually from their own genetic lines. The companies’ main domestic clients are the Asian restaurant trades in large Chinatowns in New York and Philadelphia.
For this market, the main target is to maximise the meat:fat ratio, and optimising this ratio takes priority over traditional measures of productivity, including FCR and growth rate. While increasing costs of production, this approach is essential for taste and consumer acceptance. However, despite this priority, the ducks have a very high growth rate – achieving 3.4 kg BW in 35 days, an average daily gain of 95 g/day.
Dr Jurgielewicz also gave a brief history of duck production in the north eastern United States, highlighting the regional differences in shed design and labour practices, with 95% of producing farms in Indiana run by Amish families. These farms are often very traditional, with limited access to mains electricity or water, meaning sheds rely on solar panels for lighting and have no ventilation. Birds on these farms are hand-fed, and laying birds use wooden nest boxes built onto the floor of the sheds. In Pennsylvania, by contrast, all farms use modern barns with automatic systems, but often struggle to reach the performance levels achieved in Indiana.
The breeding operation runs on a 28-day cycle, using two separate rooms in the same barn. Birds are placed in the first “starter” room for 14 days, after which they are moved to a grower room, in which they stay for a further 24 days. This means that birds in the starter room are ten days old when the growers go for slaughter, and the grower room has a 4-day cleaning/disinfection period before transfer.
As a qualified veterinarian, Dr Jurgielewicz gave an in depth run down of the disease issues facing his operation, and highlighted how the prevalence of the diseases has changed over time. The number one non-infectious issue facing the operation is tibial dischondropasia, driven in part by the fast growth rates. Rimerella anatipestifer, a duck specific pathogen, effects birds from d18, and can cause up to 30% mortality in the first five days of an outbreak. The issue is particularly prevalent in areas of high concentration of traditional barns and is less of concern in modern barns with high biosecurity measures in place. Dr Jurgielewicz explained how rapid testing and preventative treatment was key to managing RA outbreaks, and how his operation has developed an autogenous vaccine.
The operation, like much of the poultry industry in the US, is also struggling with the appearance of HPAI. In breeders, Dr Jurgielewicz explained that HPAI causes low mortality and that birds seem to recover from an infection. Whereas, in meat birds, HPAI causes high mortality.
This was an extremely interesting insight into production and health management “across the pond”, with lots of insights ranging from the importance of stockmanship, the potential of data to understand how diseases are transmitted between farms, the need to understand your consumer market, and the differences and similarities in production systems in different countries.
If you would like any further information or guidance on any of the papers or subjects covered, please do not hesitate to contact our Poultry nutrition team.