Boosting beneficial microbial diversity in poultry

Selected yeast fraction is well known to improve the gut morphology, reduce pathogen pressure, and enhance the immune system of poultry. A new study has investigated whether this solution can also modulate intestinal microbiota.

A healthy functioning intestine is heavily reliant on a balanced gut microbiota, which is essential for the metabolism and absorption of consumed nutrients and other compounds. A flourishing microbiota is characterised by diverse microbial genera which increases intestinal metabolic capacity. Population dynamics of the intestinal microbiota can be altered according to age, nutrition, stress, bacterial infectious diseases, probiotics, and antimicrobials, all of which can affect animal health and performance. Probiotics are effective moderators of the symbiotic relationship between the host and its gastrointestinal tract microbiota, and one recent study demonstrated that yeast probiotic modified piglet microbiota and enhanced animal growth. Safmannan is a premium selected yeast fraction (SYF) rich in mannan-oligosaccharides (MOS) and ß-glucans (1,3 and 1,6) and is obtained from the primary culture and purification of selected proprietary S. cerevisiae strain (Phileo by Lesaffre). Multiple in vitro and in vivo studies worldwide have consistently demonstrated the positive effects of SYF on pathogen pressure reduction, gut integrity preservation, and immunity enhancement.

Boosting beneficial bacteria while limiting pathogens is key to obtaining a balanced microbiota. Photo: Phileo
Boosting beneficial bacteria while limiting pathogens is key to obtaining a balanced microbiota. Photo: Phileo

Comprehensive studies

During a 2015 in vivo study conducted at Shandong Agricultural University, China, layers were subjected to a density challenge (333 cm²/hen) and were fed with 250 g/t SYF from 12 until 29 weeks of age. SYF maintained a healthy balanced gut microflora by binding to and decreasing harmful E.coli populations while concomitantly increasing beneficial Lactobacillus populations (Shandong Agricultural University, 2015). Within this same study, it was found that SYF also improved gut morphology and integrity by maintaining villi height and reducing crypt depth due to decreased gut inflammation. Thus with the simple addition of this postbiotic, animals are likely to absorb nutrients more readily and have greater resistance to challenging environmental conditions (Shandong Agricultural University, 2015).

To investigate whether SYF could also modulate the microbiome of broilers, a recent in vivo trial was undertaken by Imunova Análises Biológicas in Brazil. Using cutting-edge metagenomic next-generation sequencing (NGS) techniques, they examined whether supplementing feed with SYF could improve microbial diversity and benefit the animals. These NGS methods generate vast quantities of data on the microbes comprising the gut microflora, and also enable the identification of novel bacterial genera that were previously undetectable with classical microbiology techniques.

For this study, 1-day-old Cobb 500 chickens were obtained from a commercial hatchery and divided into 2 treatment groups with 30 birds per pen and 8 pens per treatment. Chickens underwent feed restriction for the first 34 hours, and were then fed ad lib for 28 days with a wheat and barley-based diet supplemented with or without 250 g/t SYF. Faeces samples were collected for DNA extraction and analysis at D21. The resulting data was taxonomically classified to identify bacteria, and relative bacterial proportions were established.

It was found that SYF was responsible for 44.5% of differences in mean microbial proportions via bi-directional principle component analysis (Figure 1), indicating a more diverse caecal microbiota.

Figure 1 – SYF promotes poultry microbiota diversity (Principal component analysis (PCA)).

Boosting beneficial microbial diversity in poultry

Upon closer investigation, 7 genera differed significantly in abundance between the 2 treatment groups, as observed with Anova statistical analysis (p<0.05). further anova analyses with tukey-kramer post-hoc tests revealed significant increases in the>Roseburia, Ruminococcus torques, Eubacterium hallii, and Shuttleworthia genera in the SYF group when compared to controls (p<0.05).>

Promising results

These results were particularly promising, as R. torques is an active commensal, abundant in the intestinal microbiota of healthy animals. A study which anaerobically cultivated caecal content samples from laying hens at 12 weeks observed that 10% of recovered bacterial colonies belonged to R. torques. Ruminococcus sequences were also identified in broiler caecums at 42 days of age. This bacterial group has the potential to degrade and convert complex polysaccharides into valuable nutrients, thus broilers treated with SYF could have more efficient nutrient uptake. The intestinal bacteria E. hallii and Roseburia also utilise a wide spectrum of substrates, where acetate and lactate are metabolised into butyric and propionic acids. These metabolites positively impact intestinal microbiota balance and gut cell development, consequently improving host health.

In addition to the aforementioned increases, birds in the SYF group also demonstrated significant decreases in the Erysipelotrichaceae family linked to inflammation-related gastrointestinal disorders and Eubacterium genus bacteria (p<0.05).>Enterobacteria were also significantly reduced (p=0.026), and reductions in pathogenic Escherichia-Shigella bacteria were observed. Several E. coli strains can cause damaging local and systemic infections which negatively impact bird health, thus their reduction should lead to improved bird performance.

Dietary solution with significant benefits

Safmannan is already proven to produce consistent beneficial effects on poultry gut health by reducing pathogens and enhancing natural defences. In vivo and in-field experiences have clearly demonstrated that birds fed with SYF are more resilient to pathogens and environmental stressors, and also exhibit enhanced performance with improved growth and egg production.

In the study conducted by Imunova Análises Biológicas , SYF supplementation led to significant changes in the composition of intestinal microbiota of broiler birds under controlled conditions. Not only was the microbiota more diverse in SYF-treated animals, but beneficial bacteria were significantly increased, with a corresponding significant decrease in pathogenic species. When considered all together, studies on laying hens and broilers provide concrete evidence that SYF modulates gut microbiota in poultry with a beneficial impact on animal health. Thus, SYF supplementation significantly improves overall animal health, enabling the industry to reduce the likelihood and subsequent cost of managing potential pathogenic outbreaks.

Dr Alain Riggi, Global Species Manager, Poultry &
Dr Tadele Kiros, R&D Manager at Phileo by Lesaffre