Ruminal metagenomic analyses of goat data reveals potential functional microbiota by supplementation with essential oil-cobalt complexes

Zhaomin Lei,Jianping Wu,Chao Li,Defu Tang,Ke Zhang,Jianfu Wang,Chong Li,Delmer I Davis,David P Casper,Yubing Wei,Xiaolong Wang,Kechuan Tian,Ting Jiao,Hui Jiang

doi:10.1186/s12866-019-1400-3

Abstract

BackgroundEssential Oils (EO) are complex mixtures of plant secondary metabolites that have been proposed as promising feed additives for mitigating methane and ammonia emissions. We have previously demonstrated that Essential Oil-Cobalt (EOC) supplementation resulted in increased average daily gain and improved phenotypes (cashmere fiber traits, carcass weight, and meat quality) when cashmere goats received supplementation at approximately 2 mg/kg of body weight. However, the ruminal microbiological effects of EO remain poorly understood with regard to the extent to which ruminal populations can adapt to EO presence as feed ingredients. The effects of varying levels of EO require additional study.ResultsIn this study, we conducted metagenomic analyses using ruminal fluid samples from three groups (addition of 0, 52, and 91 mg) to evaluate the influence of dietary EOC supplementation on goat rumen bacterial community dynamics. EOC addition resulted in changes of ruminal fermentation types and the EOC dose strongly impacted the stability of ruminal microbiota. The Bacteroides sp. and Succinivibrio sp. type bacterial community was positively associated with improved volatile fatty acid production when the diet was supplemented with EOC.ConclusionsA clear pattern was found that reflected rapid fermentative improvement in the rumen, subsequent to butyrate metabolism and EOC based feed additives may affect rumen microbes to further improve feed conversion. This observation indicates that EOC can be safely used to enhance animal productivity and to reduce ammonia and waste gas emissions, thus positively impacting the environment.

Highlights

Essential Oils (EO) are complex mixtures of plant secondary metabolites that have been proposed as promising feed additives for mitigating methane and ammonia emissions
The average daily gain (ADG) were significant increased with diet addition Essential Oil-Cobalt (EOC) (P < 0.05; Fig. 1a)
It is worth mentioning that the addition of EOC can significantly reduce the production of ammonia (NH3-N) in the rumen (P < 0.05; Fig. 1c)

Summary

Introduction

Essential Oils (EO) are complex mixtures of plant secondary metabolites that have been proposed as promising feed additives for mitigating methane and ammonia emissions. The ruminal microbiological effects of EO remain poorly understood with regard to the extent to which ruminal populations can adapt to EO presence as feed ingredients. Microbial communities of ruminants are vital for ruminants to access low-quality plant feed, while still producing high-quality protein [1]. The host and its microbiota are two major components that have evolved over millions of years, while ensuring both increased health and opportunities for mutual survival. Essential oils (EO) are volatile aromatic compounds that are produced by plants as complex mixtures of secondary metabolites. EOs do not exceed a molecular weight of 300, and can be physically distinguished from other plant components or membranous tissue [6].

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Discussion

Conclusion