Erforschung der molekularen Grundlagen des Pansen- und Dünndarmdysbiose-Komplexes bei Rindern
Zusammenfassung der Projektergebnisse
This project comprised two in vivo experiments with dairy cows (WP1) and another experiment with calves (WP2), investigating gut health during high-grain feeding with a focus on rumen and small intestinal acidosis and dysbiosis. The first trial (WP1) was conducted with firstlactating Holstein dairy cows that were rapidly transitioned from a moderate- to a high-grain diet (from 30 to 60% of DM) after calving. The trial was successfully conducted and samples and data are currently analyzed and prepared for publication. The high-grain challenge induced a strong SARA for around 2 weeks post-partum, whereas it is noteworthy that ruminal pH already began to drop around one day before calving. Moreover, not all cows reacted similar to the grain challenge, but we identified 1/3 of cows as SARA-susceptible and 2/3 as SARA- resistant. Our pending analyses will reveal whether this classification can also be transferred to the small intestine – hereby, the bile acid profiles in blood sera can provide valuable insights into small intestinal dysbiosis. As SARA-susceptible cows showed no differences in feed intake, rumination and eating behavior, we believe that SARA susceptibility is mainly determined by the host metabolism, such as absorptive capacity for SCFA in the rumen. In the trial of WP2, Hostein calves were fed either pure forage diets or forage with 70% concentrate from birth until week 14, while they were fully weaned on week 12. The trial was successfully conducted and samples and data are currently analyzed and in parts published or submitted for publication. We observed that the manifestation of the microbial structure was clearly driven by concentrate inclusion. Feeding concentrate generally decreased all bacterial diversity metrics, promoted the abundance of potential starch degraders and reduced the presence of key genera associated with fiber degradation in the rumen and hindgut. Therefore, evolvement of concentrate-related dysbiosis was indicated. Likewise, two fecal enterotypes separated by concentrate inclusion were found. Regarding the small intestine, microbiota analyses are currently performed and will help to clarify whether concentrate inclusion also triggered a dysbiotic microbiota in this gut segment. First results on SCFA concentrations in the duodenum and jejunum indicate no acidosis as SCFA concentrations were much lower compared to the rumen or hindgut. However, reference values are not available and coming results on tight junction gene expression, histomorphometry and microbiota composition will help to evaluate whether the concentrate-fed calves suffered from small intestinal acidosis. The WP3 comprised the dissemination of the project results and is not yet finished. In conclusion, this research opens avenues to understand cows’ susceptibility to acidotic insults in the gut, including the small intestine, and enabled the fellowship holder to improve his scientific qualifications immensely.
Projektbezogene Publikationen (Auswahl)
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Supplementing a Clay Mineral-Based Feed Additive Modulated Fecal Microbiota Composition, Liver Health, and Lipid Serum Metabolome in Dairy Cows Fed Starch-Rich Diets. Frontiers in Veterinary Science, 8.
Pacífico, Cátia; Hartinger, Thomas; Stauder, Alexander; Schwartz-Zimmermann, Heidi Elisabeth; Reisinger, Nicole; Faas, Johannes & Zebeli, Qendrim
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Effects of concentrate inclusion and hay quality on the intestinal microbiota in Holstein calves. 5th AMICI-Symposium 2022, Vienna, Austria
Hartinger, T.; Pacífico, C.; Poier, G.; Terler, G.; Klevenhusen, F. & Zebeli, Q.
