Saccharomyces cerevisiae fermentation product improves robustness of equine gut microbiome upon stress

Abstract

IntroductionNutritional and environmental stressors can disturb the gut microbiome of horses which may ultimately decrease their health and performance. We hypothesized that supplementation with a yeast-derived postbiotic (Saccharomyces cerevisiae fermentation product-SCFP) would benefit horses undergoing an established model of stress due to prolonged transportation.MethodsQuarter horses (n = 20) were blocked based on sex, age (22 ± 3 mo) and body weight (439 ± 3 kg) and randomized to receive either a basal diet of 60% hay and 40% concentrate (CON) or the basal diet supplemented with 21 g/d Diamond V TruEquine C (SCFP; Diamond V, Cedar Rapids, IA) for 60 days. On day 57, horses were tethered with their heads elevated 35cm above wither height for 12 h to induce mild upper respiratory tract inflammation. Fecal samples were collected at days 0, 28, and 56 before induction of stress, and at 0, 12, 24, and 72 h post-stress and subjected to DNA extraction and Nanopore shotgun metagenomics. Within sample (alpha) diversity was evaluated by fitting a linear model and between sample (beta) diversity was tested with permutational ANOVA.ResultsThe SCFP stabilized alpha diversity across all time points, whereas CON horses had more fluctuation (P < 0.05) at 12, 24, and 72 h post-challenge compared to d 56. A significant difference between CON and SCFP was observed at 0 and 12 h. There was no difference in beta-diversity between SCFP and CON on d 56.DiscussionTaken together, these observations led us to conclude that treatment with SCFP resulted in more robust and stable microbial profiles in horses after stress challenge.

Postbiotics from Saccharomyces cerevisiae fermentation stabilize microbiota in rumen liquid digesta during grain-based subacute ruminal acidosis (SARA) in lactating dairy cows

“…Robustness is de ned as the capacity of a microbial community to resist changes caused by the dietary, metabolic or pathogenic stressors. As such, the degree of microbiome robustness is a key determinant of the microbiome-linked pathologies [10]. In the presence of excess starch content of the diet, insu cient dietary coarse ber, and a reduced pH, a less robust rumen microbiome rapidly loses its evenness and becomes dominated by a smaller number of taxa [11,12].…”

“…One strategy for the prevention of SARA might be supplementation with compounds that improve the robustness of digestive tract's microbiomes [10]. These compounds can be divided into two categories, including those with direct suppressive effects on other microorganisms, such as antibiotics and ionophores, and those with direct promotive effects, such as a sub set of probiotics and postbiotics [20].…”

“…However, the suppressive approach is accompanied with side effects, such as the development of a resistome against suppressor compounds, and reductions in the diversity of carbohydrate active enzymes (CAZyme) in the microbial community [20]. In contrast, the use of promotive supplements, such as the use of postbiotics, improves the robustness of microbiome by the provision of metabolites that stimulate a wide range of bacteria, including those with brolytic activity, with a competitive edge against faster grower species that allows them to maintain their populations within the microbial community [10,21,22]. As such, a postbiotic approach can promote the robustness of a microbiome without affecting its resistome and CAZyme capability [10,20].…”