Effects of dietary energy levels on rumen bacterial community composition in Holstein heifers under the same forage to concentrate ratio condition

Abstract

BackgroundThe rumen bacterial community plays a critical role in feeds degradation and productivity. The effects of different forage to concentrate ratios on the ruminal microbial population structure have been studied extensively; however, research into changes in the ruminal bacterial community composition in heifers fed different energy level diets, with the same forage to concentrate ratio, has been very limited. The purpose of this study was to investigate the effects of different dietary energy levels, with the same forage to concentrate ratio, on ruminal bacterial community composition of heifers. Furthermore, we also determine the relationship between rumen bacteria and ruminal fermentation parameters.ResultsThe 16S rRNA gene sequencing showed that, under the same forage to concentrate ratio of 50:50, an 8% difference in dietary energy level had no significant impact on the alpha diversity and the relative abundance of the major phyla and most of the major genera in heifers. In all the treatments groups, Firmicutes, Bacteroidetes, and Proteobacteria were the dominant phyla. Spearman correlation analysis between the relative abundances of the rumen bacteria at the genus level and the fermentation parameters showed that the relative abundances of Prevotella and BF311 were positively correlated with the ammonia nitrogen and butyrate concentrations, and these two genera were negatively correlated with the propionate and isovalerate concentrations, respectively, and the genus Bifidobacterium was positively correlated with the butyrate concentration and was negatively correlated with propionate and isovalerate concentration. The total volatile fatty acid concentration was positively correlated with BF311 abundances, and was negatively correlated with Trichococcus and Facklamia abundances.ConclusionsUnder the same forage to concentrate ratio condition of 50:50, an 8% difference in dietary energy levels had little impact on rumen bacterial community composition in heifers. The correlations between some genera of ruminal bacteria and the concentrations of volatile fatty acids and ammonia nitrogen might be indicative that the ruminal fermentation parameters are strongly influenced by the rumen bacterial community composition.

Ruminal microbiota composition associated with ruminal fermentation parameters and milk yield in lactating buffalo in Guangxi, China—A preliminary study

“…The study shows that phyla Proteobacteria ( R = 0.53; p = 0.04) were positively correlated with butyrate content. The genus Prevotella ( R = 0.52; p = 0.05) were also positively correlated with butyrate content, which is similar to a previous study (Bi et al, ). In contrast, Ruminococcus was negatively correlated with butyrate content ( R = −0.61; p = 0.02).…”

“…In the present study, the phyla Proteobacteria ( R = −0.56; p = 0.03) were negatively correlated with ruminal NH 3 ‐N, while genera BF311 ( R = 0.54; p = 0.04) were positively correlated with ruminal NH 3 ‐N. Bi et al () also found that genera BF311 were positively correlated with ruminal NH 3 ‐N.…”

“…The present study also shows that Acinetobacter was positively correlated with average milk protein yield ( R = 0.56; p = 0.03), average milk total solid yield ( R = 0.60; p = 0.02) and standard milk yield ( R = 0.57; p = 0.03). According to the Bi, Zeng, Zhang, Diao, and Tu ()’s results, the genera BF311 have similar metabolic ability with Prevotella, and Jami et al () and Benchaar et al () found Prevotella may influence the milk performance. Interestingly, the present study shows that the genera BF311 were negatively correlated with average milk yield ( R = −0.51; p = 0.05).…”

Dynamic alterations in rumen bacterial community and metabolome characteristics in response to feed nutrient levels of cashmere goats

“…The rumen is a complex microbial ecosystem in ruminants. It can ferment feedstuffs to volatile fatty acids (VFAs), microbial proteins and vitamins, which play important roles in animal health and production [4][5][6]. Among the microbiota, bacteria are the most abundant, diverse and metabolically active species in the rumen [7,8].…”

“…Previous studies have reported that dietary energy can promote protein to synthesize MCP [20][21][22]. The effective way to improve average daily weight gain (ADG) and production performance in cattle is increasing dietary energy levels under the same concentration of forage ratio [5].…”