Effect of Grape Pomace Intake on the Rumen Bacterial Community of Sheep

Abstract

The performance of ruminants is affected mainly by the rumen bacterial community. The composition and properties of the rumen bacterial community depend largely on the diet components that are fed to the ruminant. The aim of this study was to determine the effect of grape pomace intake on the rumen bacterial community of sheep. Four different diets, two of which contained dried grape pomace (DGP), were used in this study. Rumen fluid samples from 12 wethers were used for 16S rRNA gene sequencing and subsequent bacterial identification. At the phylum level, Bacteroidetes and Firmicutes; at the family level, Prevotellaceae and Porphyromonadaeceae; and at the genera level, Prevotella and Verrucomicrobia_Subdivision5_genera_incertae_sedis were the most common regardless of the diet the animals were fed. After the addition of DGP to the diet, the relative abundance of Methanobrevibacter, Butytirivibrio, Fretibacterium, and Verrucomicrobia _Subdivision3 _genera_incertae_sedis significantly increased, whereas that of Succiniclasticum and Selenomonas significantly decreased. The upregulated pathway of methanogenesis from H2 and CO2 was supported by a significant increase in Methanobacteriaceae after the diet was supplemented with DGP. The rumen bacterial community diversity indices (Richness and Shannon) were significantly affected by diet composition as well as by the change of housing location. The addition of DGP into the wethers’ diet increased the richness of the rumen bacterial community, which is good for maintaining rumen bacterial homeostasis. No adverse effect of the addition of DPG on the rumen bacterial community was noted.

Keywords

• wine industry by-products
• grape pomace
• sheep
• rumen bacteria
• abundance
• diversity