Ruminal fermentation parameters and microbial community at phylum level differently influenced by forage types in Bulls

Abstract

The current research aimed to evaluate the changes in the rumen ecosystem at phylum level and ruminal fermentation products by using whole crop corn silage (WCS), whole rice crop silage (WRS), or rice straw (RS) as forage sources in beef cattle ration. Ruminal digesta samples from 10 bulls per treatment were collected on days 60 of the experimental period. Ruminal fermentation pattern revealed that ruminal pH and acetate to propionate concentration was increased in RS fed animals as compared to WCS and WRS fed animals. However, ruminal NH3-N, isovalerate and valerate concentration was decreased in RS fed animals as compared to other treatments. Results of High-throughput Illumina sequencing of the bacterial 16S rRNA gene revealed distinct ruminal microbiota abundance at the phyla level. Among these phyla, Firmicutes was the most abundant phyla with a relative abundance of 48.65% ± 5.99%. The second most abundant phyla was Bacteroidetes, with an average abundance of 41.66% ± 4.24%. Furthermore, Firmicutes were higher in WRS as compared to WCS and RS treatments, while Bacteroidetes were higher in WCS treatment. Proteobacteria, Tenericutes, Spirochaetes, and Cyanobacteria were found to be more in RS treatment as compared to other treatments. Actinobacteria and Chloroflexi were higher in WRS and WCS treatment as compared to RS. Based on the findings of the current study, it is concluded that the microbial community was highly altered by RS. In contrast, it remained mostly similar for the other silages in bulls.