Repeated acidosis challenges and live yeast supplementation shape rumen microbiota and fermentations and modulate inflammatory status in sheep

• Published in: Animal (Cambridge, England) England), 2013-12, Vol.7 (12), p.1910-1920
• Main Authors: Silberberg, M., Chaucheyras-Durand, F., Commun, L., Mialon, M. M., Monteils, V., Mosoni, P., Morgavi, D. P., Martin, C.
• Format: Article
• Language: English
• Subjects: acidosis; Acidosis - metabolism; Acidosis - veterinary; acute phase proteins; Animals; bacteria; butyrates; Computer Science; diet; Dietary Supplements; experimental design; Fermentation; hay; histamine; Humanities and Social Sciences; inflammation; inflammatory status; Life Sciences; lipopolysaccharides; Male; microbial ecology; Nutrition; propionic acid; Real-Time Polymerase Chain Reaction; resting periods; rumen; Rumen - microbiology; rumen acidosis; rumen fermentation; rumen fermentations; rumen microbiota; rumen microorganisms; Saccharomyces cerevisiae; sheep; Sheep - physiology; wethers; yeasts; Yeasts - physiology
• ISSN: 1751-7311; 1751-732X; 1751-732X
• DOI: 10.1017/S1751731113001705

This study aimed to investigate the impact of repeated acidosis challenges (ACs) and the effect of live yeast supplementation (Saccharomyces cerevisiae I-1077, SC) on rumen fermentation, microbial ecosystem and inflammatory response. The experimental design involved two groups (SC, n=6; Control, n=6) of rumen fistulated wethers that were successively exposed to three ACs of 5 days each, preceded and followed by resting periods (RPs) of 23 days. AC diets consisted of 60% wheat-based concentrate and 40% hay, whereas RPs diets consisted of 20% concentrate and 80% hay. ACs induced changes in rumen fermentative parameters (pH, lactate and volatile fatty-acid concentrations and proportions) as well as in microbiota composition and diversity. The first challenge drove the fermentation pattern towards propionate. During successive challenges, rumen pH measures worsened in the control group and the fermentation profile was characterised by a higher butyrate proportion and changes in the microbiota. The first AC induced a strong release of rumen histamine and lipopolysaccharide that triggered the increase of acute-phase proteins in the plasma. This inflammatory status was maintained during all AC repetitions. Our study suggests that the response of sheep to an acidosis diet is greatly influenced by the feeding history of individuals. In live yeast-supplemented animals, the first AC was as drastic as in control sheep. However, during subsequent challenges, yeast supplementation contributed to stabilise fermentative parameters, promoted protozoal numbers and decreased lactate producing bacteria. At the systemic level, yeast helped normalising the inflammatory status of the animals.