Effect of dietary concentrate to forage ratio on growth performance, rumen fermentation and bacterial diversity of Tibetan sheep under barn feeding on the Qinghai-Tibetan plateau

Abstract

This study aimed to research the effects of different dietary concentrate to forage (C:F) ratio on growth performance, rumen fermentation and bacteria diversity of barn feeding Tibetan sheep. The experiment contains fiver treatments (HS1, HS2 HS3, HS4 and HS5; n = 8, respectively) based on dietary C:F ratios 0:100, 15:85, 30:70, 45:55, and 60:40, respectively. The ruminal bacterial community structure was investigated through high-throughput sequencing of 16S rRNA genes in V4 hypervariable region. The results showed that increasing dietary concentrate feed level from 0% to 60% exerted a positive effect on DMI, BW gain, gain rate and feed conversation ratio (FCR) in Tibetan sheep. The increases dietary concentrate feed level elevatedNH3-N, propionate and valerate concentrations, whereas, reduced molar ratio of acetate to propionate (A/P ratio) (P < 0.05). For rumen bacterial diversity, increases in dietary concentrate content contributed to lower alpha diversity indexes including Shannon wiener, Chao1 and observed species, meanwhile, significantly increased the abundances of the phylum Bacteroidetes and the genus Prevotella_1 (P < 0.05). In conclusion, increases dietary concentrate content improved the growth performance and Tibetan sheep fed diets of 45% concentrate obtained a better performance; the inclusion of concentrate in feed changed rumen fermentation from acetate fermentation to propionate fermentation, and improved the energy utilization efficiency of Tibetan sheep; the increased in concentrate content significantly reduced rumen bacteria diversity and changed the abundance of some core bacteria.

Tibetan Sheep Adapt to Plant Phenology in Alpine Meadows by Changing Rumen Microbial Community Structure and Function

“…In our study, the predominant phyla in the TS rumen were Bacteroidetes and Firmicutes, with average proportions of 59.69 and 22.34%, respectively. The distribution of the main phyla in the rumen were similar to those found in other research into the QTP (Liu et al, 2019;Ma et al, 2019). Kim et al (2011) have summarized the rumen bacterial distribution of the major domesticated livestock through a meta-analysis of all curated 16S rRNA sequences deposited in the RDP and found the proportion of Bacteroidetes and Firmicutes was about 31 and 56%, respectively.…”

“…Research has shown that Bacteroidetes plays an important role in forge nutrition utilization and host disease immunity (Huo et al, 2014;Zhang et al, 2018). Prevotella appears to be associated with propionic acid production and plays a pivotal role in degrading and utilizing plant noncellulosic polysaccharides, protein, starch and xylans (Strobel, 1992;Liu et al, 2019). In our study, the relative abundance of Bacteroidetes and Prevotella in the grassy stage provided significant advantages over the regreen and grassy periods.…”

“…The rumen fluid collected methods were similar to those report by Liu et al (2019). An esophageal tube with a vacuum pump was inserted through the mouth into the rumen for sampling.…”

“…The NH 3 -N content was quantified using a continuous flow analyzer (SEAL Auto Analyzer3, Germany), as described by Russell and Diezgonzalez (1998). The measurement of short volatile fatty acids (SVFAs) was same to that reported by Liu et al (2019).…”

“…Although rumen microorganisms are relatively stable, they are highly responsive to changes in host genetics (Huang et al, 2017), feeding paradigms (Xue et al, 2017) and diet (Lin et al, 2018;Liu et al, 2019), age (Jami et al, 2013) and environmental factors (Uyeno et al, 2010). Of these, diet was the key factor in determining microbial community structure (Tajima et al, 2001).…”