Correlations between the Composition of the Bovine Microbiota and Vitamin B ₁₂ Abundance

Abstract

Vitamin B 12 is synthesized by prokaryotes in the rumens of dairy cows-and this has implications in human nutrition since humans rely on consumption of dairy products for vitamin B 12 acquisition. However, the concentration of vitamin B 12 in milk is highly variable, and there is interest in determining what causes vitamin B 12 variability. We collected 92 temporally linked rumen, fecal, blood, and milk sample sets from Holstein cows at various stages of lactation fitted with rumen cannula and attempted to define which bacterial genera correlated well with vitamin B 12 abundance. The level of vitamin B 12 present in each sample was measured, and the bacterial population of each rumen, fecal, and milk sample (n ϭ 263) was analyzed by 16S rRNA-targeted amplicon sequencing of the V4 region. The bacterial populations present in the rumen, small intestine, and milk were highly dissimilar. Combined diet and lactation status had significant effects on the composition of the microbiota in the rumen and in the feces. A high ruminal concentration of vitamin B 12 was correlated with the increased abundance of Prevotella, while a low ruminal concentration of vitamin B 12 was correlated with increased abundance of Bacteroidetes, Ruminiclostridium, and Butyrivibrio. The ultimate concentration of vitamin B 12 is controlled by the complex interaction of several factors, including the composition of the microbiota. Bacterial consumption of vitamin B 12 in the rumen may be more important in determining overall levels than bacterial production. IMPORTANCE In this paper, we examined the microbiome of the bovine rumen, feces, and milk and attempted to understand how the bacterial communities at each site affected the production and movement of vitamin B 12 around the animal's body. It was determined that the composition of the bovine rumen microbiome correlates well with vitamin B 12 concentration, indicating that the rumen microbiota may be a good target for manipulation to improve production of this important vitamin.

Relationship between Vitamin B12 and Cobalt Metabolism in Domestic Ruminant: An Update

“…It is highly probable that the efficacy of the bacterial use of cobalt for the synthesis of cobalamin is influenced by multiple factors. These include the adequate contribution of cobalt [ 11 , 15 , 37 ], the ingredients and composition of the diet and their effects on fermentation and the composition of the ruminal microbiome [ 9 , 15 , 17 , 37 ].…”

“…Other factors, such as initial body reserves, the genetic selection of animals [ 40 , 41 ], the supplementation of different vitamins (alone or in combination) and even the adequacy or deficiency of other nutrients, play an important role in the production and use of vitamin B12, causing variable responses [ 12 , 17 , 22 , 30 , 37 , 40 , 42 ].…”

“…By examining the microbiome of the bovine rumen, feces and milk and trying to understand how the ruminal population affected the production and status of vitamin B12, it was determined that the composition of the microbiome of the bovine rumen correlates well with the concentration of vitamin B12. Therefore, manipulating the rumen microbiota can be a good technique to improve the production of this important vitamin [ 37 ]. Although Brito et al reported that only four species of 21 studied species of microorganisms present in the rumen ( Selenomonas ruminantium, Megasphaera elsdenii, Butyrivibrio fibrisolvens and an unnamed species) were able to synthesize corrinoids, with the first two species producing the highest amounts of vitamin B12 and analogs [ 17 , 21 ].…”

“…However, neither feed differences nor heritability nor herd management practices fully explain the variations of vitamin B12 in milk [ 40 , 41 , 45 ], and given that vitamin B12 is synthesized exclusively by bacteria and archaea, it is likely that the composition of the bovine microbiota plays a determining role in the variability observed in the production of vitamin B12 in the rumen [ 37 ].…”

“…Within these, the IF is degraded, and vitamin B12 is released into the bloodstream from the basolateral side. In blood, transcobalamin binds to vitamin B12 and is responsible for the transport of the vitamin to the tissues [ 37 , 52 ].…”