Characterization of the Core Rumen Microbiome in Cattle during Transition from Forage to Concentrate as Well as during and after an Acidotic Challenge

Abstract

This study investigated the effect of diet and host on the rumen bacterial microbiome and the impact of an acidotic challenge on its composition. Using parallel pyrosequencing of the V3 hypervariable region of 16S rRNA gene, solid and liquid associated bacterial communities of 8 heifers were profiled. Heifers were exclusively fed forage, before being transitioned to a concentrate diet, subjected to an acidotic challenge and allowed to recover. Samples of rumen digesta were collected when heifers were fed forage, mixed forage, high grain, during challenge (4 h and 12 h) and recovery. A total of 560,994 high-quality bacterial sequences were obtained from the solid and liquid digesta. Using cluster analysis, prominent bacterial populations differed (P≤0.10) in solid and liquid fractions between forage and grain diets. Differences among hosts and diets were not revealed by DGGE, but real time qPCR showed that several bacteria taxon were impacted by changes in diet, with the exception of Streptococcus bovis. Analysis of the core rumen microbiome identified 32 OTU's representing 10 distinct bacterial taxa including Bacteroidetes (32.8%), Firmicutes (43.2%) and Proteobacteria (14.3%). Diversity of OTUs was highest with forage with 38 unique OTUs identified as compared to only 11 with the high grain diet. Comparison of the microbial profiles of clincial vs. subclinical acidotic heifers found a increases in the relative abundances of Acetitomaculum, Lactobacillus, Prevotella, and Streptococcus. Increases in Streptococcus and Lactobacillus likely reflect the tolerance of these species to low pH and their ability to proliferate on surplus fermentable carbohydrate. The acetogen, Acetitomaculum may thereforeplay a role in the conversion of lactate to acetate in acidotic animals. Further profiling of the bacterial populations associated with subclinical and clinical acidosis could establish a microbial fingerprint for these disorders and provide insight into whether there are causative microbial populations that could potentially be therapeutically manipulated.

Rumen prokaryotic communities of ruminants under different feeding paradigms on the Qinghai-Tibetan Plateau

“…The relative abundance of the phyla Bacteroidetes and Proteobacteria was also found to be higher in TMR yak than in NG yak, but Firmicutes in TMR yak was significantly lower than NG yak. Similar to the findings of Petri et al [58], Proteobacteria was as much as 20.1% of the population in cattle feed concentrate, whereas Firmicutes, a Gram-positive group, was as low as 10%. An et al [3] analyzed the prokaryote diversity in the rumen of yaks (full-grazing style with grasses as the only feed) and Jinnan cattle (high concentrate diets), and only detected Proteobacteria in the rumen of cattle.…”

“…This microbial distribution of the major phyla was similar to other research results on the QTP [11]. However, the core rumen microbiome was found to consist of the phyla Bacteroidetes (32.8%) and Firmicutes (43.2%) in cattle during transition from forage to concentrate [58]. The composition of the core rumen microbiome did not change, but the relative abundance of these two phyla showed great variation, since the percentage of Bacteroidetes was less than Firmicutes.…”

“…Although rumen microbial community composition varies with diet and host, a 'core microbiome' is found across a wide geographical range [25,31,58]. Ruminants depend on these rumen microorganisms to digest nutritional components in feedstuffs and to convert them into proteins, carbohydrates, VFAs and gases [52].…”

Uso de monensina e óleos funcionais de mamona e caju em dietas com elevada proporção de concentrado fornecidas de forma abrupta para bovinos Nelore confinados

“…Streptococcus bovis predominam sob condições de acidose, o que comprova a tolerância desta espécie em se proliferar mesmo em condições de baixo pH do rúmen (PETRI et al, 2013). Com isso, esperava-se crescimento na população ao longo dos dias após transição abrupta, embora fosse observada uma redução desta.…”

Nutritional strategies to control ruminal acidosis in feedlot cattle

“…Inconsistences in the response to malate and S. ruminantium supplementation may be explained by variations in the dose, growth rate and age of the animal, diet composition and farming conditions, among other factors (Yoon and Stern, 1995;Carro and Ungerfeld, 2015). Our hypothesis was that dietary supplementation with malate or S. ruminantium may be effective at increasing ruminal pH and improving performance in beef cattle fed high-grain diets, as animals fed these diets usually have ruminal abundance of S. ruminantium and M. elsdenii (Petri et al, 2013). This study was designed to assess the effects of malate salts and S. cerevisiae culture on growth performance, carcass quality, ruminal fermentation products and blood metabolites in heifers raised under commercial farming conditions in southern Europe.…”