Effects of Phragmites australis Shoot Remainder Silage on Growth Performance, Blood Biochemical Parameters, and Rumen Microbiota of Beef Cattle

Abstract

The objective of the present study was to assess the effects of replacing corn silage with Phragmites australis shoot remainder (PSR) silage on intake, growth performance, serum biochemical parameters, and rumen microbial diversity of growing-finishing beef. Fifteen Angus beef cattle with an average body weight of 253 ± 2.94 kg were randomly divided into three groups (five replicas vs. each group vs. Angus beef cattle). The three treatments were group A fed 60% PSR silage + 40% concentrate, group B fed 30% PSR silage + 30% corn silage + 40% concentrate, and group C fed 60% corn silage + 40% concentrate. The adaptation period was 15 days, and the trial period lasted for 45 days. Results showed that the ADG was significantly higher, and FCR was significantly lower both in groups A and B compared with group C. The results of serum biochemical parameters showed that the concentration of GLU was significantly lower in group B than both groups A and C. Microbial diversity results showed that the OTUs, Shannon, Chao1, and ACE indices were significantly lower in group A compared with groups B and C. At the phyla level, the relative abundances of Tenericutes and Melainabacteria had significant differences among the three groups, and the relative abundances of Papillibacter, Anaeroplasma, and Anaerovorax had significant differences among the three groups at the genus level. Additionally, Rikenellaceae was the unique biomarker among the three groups. Furthermore, the results of function prediction showed that the gene families associated with metabolism of cofactors and vitamins, cellular processes and signaling, metabolism, biosynthesis of other secondary metabolites, infectious diseases, signaling molecules and interaction, nervous system, and digestive system were significantly decreased, while lipid metabolism was dramatically increased from groups A to C at KEGG level 2. At KEGG level 3, 11 metabolic pathways were significantly influenced among the three groups. In summary, these findings indicated that PSR silage substituted the corn silage totally or partially improved the growth performance, and altered the rumen microbial composition and diversity and the corresponding change in prediction function of rumen bacteria in Angus beef cattle.

Keywords: Phragmites australis feed; beef cattle; growth performance; rumen bacterial function; rumen microbiota.

Figure 1

Phragmites australis shoot remainder (PSR) silage totally or partially substituting the corn silage alters rumen microbiota composition in Angus beef cattle (N = 5). Group A, fed 60% PSR silage; Group B, fed 30% PSR silage + 30% corn silage; and Group C, fed 60% corn silage. (A) PCoA analysis of rumen microbiota based on operational taxonomic unit (OTU) abundance. (B) Assessment of alpha diversity. (C) Rumen microbiota taxonomic profiling at the phylum level. (D) Relative abundances of Bacteroidetes, Firmicutes, Proteobacteria, Tenericutes, and Melainabacteria. Bars with different letters (a, b) indicate significant differences (p < 0.05) among different groups (the same below). (E) Rumen microbiota taxonomic profiling at the genus level. (F) Relative abundances of representative and significant difference genera. (G) LDA score of rumen microbiota composition according to LEfSe analysis by three treatments.

Figure 2

Phylogenetic tree of genus level species among PSR silage totally or partially substituted the corn silage groups in Angus beef cattle (N = 5). Group A, fed 60% PSR silage; Group B, fed 30% PSR silage + 30% corn silage; and Group C, fed 60% corn silage. Branches and fan colors represent its corresponding phyla, the accumulation histogram outside the fan ring shows the relative abundance distribution information of the genus in different groups.

Figure 3

Effects of PSR silage totally or partially substituted the corn silage on the predicted functional composition of rumen bacterial community in Angus beef cattle (N = 5). Group A, fed 60% PSR silage; Group B, fed 30% PSR silage 30% corn silage; and Group C, fed 60% corn silage. (A) The majority of the gene sequences annotated to KEGG level 1. (B) The majority of the gene sequences annotated to KEGG level 2. (C) The gene families of significant differences at KEGG level 2. (D) The majority of the gene sequences annotated to KEGG level 3. (E) The relative abundant pathways with significant differences at KEGG level 3. Bars with different letters (a,b) indicate significant differences (p < 0.05) among different groups.