Subclinical infections with bacteria are a sinister problem for pig production, sapping animals of their productivity and rendering them more vulnerable to opportunistic diseases without ever manifesting clinical signs which would make farmers aware of the disease’s presence. Moreover, these are not obscure, uncommon issues, but are in fact widespread in the most important animal production markets globally.
Feed additives can provide the industry with an opportunity to mitigate some of the damage caused by bacteria such as Lawsonia intracellularis. As explained by Phileo by Lesaffre, its Safglucan product, made from yeast, can both stimulate the immune system to better protect against the pathogen and promote a healthier microbial environment in the gut. In the Industry Perspectives piece below, Edita Zandee, Global Species Manager for Swine and Olivier Merdy, Global Program Manager for Swine, elaborate on the damage Lawsonia intracellularis is causing the industry and the evidence for how Safglucan can improve the outcomes for pigs challenged with this extremely common issue, supporting farmers’ bottom lines.
[Feedinfo] Why is Lawsonia intracellularis an issue on a pig farm?
[Olivier Merdy] Lawsonia intracellularis, or Lawsonia for short, is a bacterium that is the cause of a group of enteric diseases grouped under the name of ileitis. This common name covers 3 clinically different diseases. The acute form, which is also known as proliferative haemorrhagic enteropathy, is characterized by bloody diarrhoea, emaciation, and sudden death. The chronic form, named Porcine Intestinal Adenomatosis, is characterized by weight loss, and chronic greyish diarrhoea.
In addition to these clinical presentations of ileitis, the subclinical form of infection must also be considered. As the name implies, subclinical disease is characterized by no obvious clinical signs such as diarrhoea. It is nevertheless associated with significant impacts on growth, feed conversion efficiency, and health of the pigs resulting in huge economic losses to the farmer.
[Feedinfo] Can you talk about the damage these diseases cause to the animals themselves, particularly at intestinal level?
[Olivier Merdy] Lawsonia infects the intestine epithelium cells, particularly in the ileum part. It induces a proliferation of immature enterocytes resulting in a thickening of the intestinal mucosa. An altered gut function due to reduced expression of nutrient absorptive and transporting capacities of intestinal cells, as well as an impaired mucosal integrity and barrier function due to the down regulation of mucin are the main reasons for the compromised intestinal health. Furthermore, Lawsonia infection alters microbial communities which may expose the pigs to coinfection by other enteric pathogens further complicating the disease.
[Feedinfo] What kind of data exist about the prevalence of Lawsonia in different areas? Should we conclude from these studies that at least subclinical infection with Lawsonia is basically a problem for nearly all pig producers?
[Edita Zandee] Lawsonia is highly prevalent in pig production sites worldwide. Recent studies have reported a detection rate of more than 90% on farms in Western Europe, 77%-90% in the United States, 88.5% in Russia, and 100% in China and Brazil. Interestingly, a study done in Western Europe indicates how within-herd (pig) seroprevalence is 31.6%, and ranges from 5% in nursery piglets to 64.5% in finisher pig, where bacteria can be detected in the faeces of 33% of growers and 27.8% of finishers. Therefore, although the infection can be detected within different swine categories, the active infection or peak of seroconversion is occurring at the growing-finishing stage.
So, indeed, even in the absence of clinical signs, almost all pig producers should consider paying attention to the control of Lawsonia.
[Feedinfo] Thus, ileitis is understood to be extensive even in pigs without clinical signs of disease. How much is this believed to cost the industry?
[Edita Zandee] Ileitis is globally among the most common and economically important enteric diseases that affect pigs of all age groups and under different management systems. However, very little attention is given to the disease by pig producers in many regions of the world as it usually occurs subclinically with little or no differentiating clinical signs. The economic impact can be enormous, particularly in grow-finish pigs, due to reduced weight gain, impaired feed conversion and weight variation at slaughter. In general, the economic cost of ileitis is estimated to be around $2.00 to $3.00 per pig in mild and subclinical cases.
[Feedinfo] Phileo argues that Safglucan can assist in mitigating the damage of Lawsonia. How does this work?
[Olivier Merdy] Safglucan® is a yeast postbiotic that positively influences intestinal health. First, it boosts the capacity of innate immune cells to react to pathogen molecular recognition patterns that are present on the bacteria surface. The capacity of innate immunity to react more strongly and rapidly is called trained immunity. This is thought to rely on the enrichment in the specific 1.3/1.6 beta-glucans present in the specific yeast strain selected.
Beyond this, our first results indicate that Safglucan also helps to modulate the microbiome by increasing the presence of beneficial bacteria and decreasing the abundance of biomarkers of susceptibility to ileitis caused by Lawsonia.
[Feedinfo] What evidence do you have about Safglucan’s impact on bacterial shedding of Lawsonia, improvement in growth performance in cases of active Lawsonia infection, and other metrics?
[Edita Zandee] Our research teams conducted a trial on a Spanish commercial farm suffering from subclinical ileitis. Pigs were supplemented during the whole growing-finishing phase and monitored for growth performance and Lawsonia fecal shedding. An active infection was evidenced from 19 weeks and up to the end of the trial at 24 weeks of age. As a whole, the Safglucan-supplemented pigs grew an additional 84 g per day between 19 and 24 weeks of age compared to the controls, yielding an extra 4.2 kg on final bodyweight. Ultimately, supplemented pigs showed significantly reduced fecal shedding as the load of Lawsonia in the faeces of Safglucan-supplemented animals decreased significantly compared to the control group (3.7 versus 5.1 log10 copy/g of faeces) as well indicating better intestinal health, correlating with better growth performance. These results are the cornerstone of a patent application and are undergoing the scientific publication process as well.
[Feedinfo] Can you help explain how Safglucan should be applied to help the swine industry mitigate the damage of Lawsonia? Is it a question of feeding the postbiotic basically throughout the pig’s life, or only at certain times when the pig is most susceptible to infection?
[Edita Zandee] To mitigate damage caused by Lawsonia, Safglucan can be effectively used in dosage of 250g per ton of feed. Our present results are based on feeding Safglucan throughout the whole growth/fattening period, from week 10 to 24. In addition, in an ongoing study we are also analyzing if the application of Safglucan during an active infection window in growing pigs, when they are most susceptible to infection, can obtain the same results.
[Feedinfo] Beyond mitigating the impacts of Lawsonia, what other role might Safglucan play in helping to promote animal health and productivity?
[Olivier Merdy] Safglucan showed beneficial effects on intestinal health, thus offering pig producers, nutritionists and veterinarians an innovative solution to mitigate the impact of Lawsonia. While it has been proven successful in the control of intestinal disorders, it could be a promising tool in the context of respiratory challenges due to the so-called gut-lung axis. Indeed, we also observed positive results of Safglucan in animals infected by respiratory pathogens.
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Published in association with Phileo by Lesaffre