The Effect of Dietary Replacement of Ordinary Rice with Red Yeast Rice on Nutrient Utilization, Enteric Methane Emission and Rumen Archaeal Diversity in Goats

L Z Wang,J W Wang,T Yan,D Wu,M L Zhou,Christos A Ouzounis

doi:10.1371/journal.pone.0160198

L Z Wang, J W Wang + Show 4 more

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https://doi.org/10.1371/journal.pone.0160198

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Abstract

Twenty castrated Boer crossbred goats were used in the present study with two treatments to examine the effect of dietary replacement of ordinary rice with red yeast rice on nutrient utilization, enteric methane emission and ruminal archaea structure and composition. Two treatment diets contained (DM basis) 70.0% of forage, 21.8% of concentrates and 8.2% of either ordinary rice (control) or red yeast rice (RYR). Nutrient utilization was measured and enteric methane emissions were determined in respiration chambers. Results showed that RYR had significantly lower digestibility of N and organic matter compared to control group. However, feeding red yeast rice did not affect N retention as g/d or a proportion of N intake, and reduced heat production as MJ/d or as a proportion of metabolizable energy intake, thus leading to a higher proportion of metabolizable energy intake to be retained in body tissue. RYR also had significantly lower methane emissions either as g/d, or as a proportion of feed intake. Although feeding red yeast rice had no negative effect on any rumen fermentation variables, it decreased serum contents of total cholesterol, triglycerides, HDL-cholesterol and LDL-cholesterol. In the present study, 75616 archaeal sequences were generated and clustered into 2364 Operational Taxonomic Units. At the genus level, the predominant archaea in the rumen of goats was Methanobrevibacter, which was significantly inhibited with the supplementation of red yeast rice. In conclusion, red yeast rice is a potential feed ingredient for mitigation of enteric methane emissions of goats. However, caution should be taken when it is used because it may inhibit the digestibility of some nutrients. Further studies are required to evaluate its potential with different diets and animal species, as well as its effects on animal health and food safety.

Highlights

Methane (CH4) is a greenhouse gas and about 25 times effective than carbon dioxide (CO2) in the global warming potential [1]
The lovastatin in the commercial market contains only 2% of active beta-hydroxy acid open ring form (H-form), and the remainder 98% is the inactive gamma-lactone closed ring form (L-form) which has no ability to inhibit the HMG-CoA reductase unless it is hydrolyzed by carboxylesterases in vivo to H-form [7]
There were no significant differences in DM intake, apparent digestibility of Neutral detergent fiber (NDF) or acid detergent fiber (ADF) between the two treatments

Summary

Introduction

Methane (CH4) is a greenhouse gas and about 25 times effective than carbon dioxide (CO2) in the global warming potential [1]. It is expected that use of inhibitor of HMG-CoA reductase can restrict the growth and proliferation of archaea and reduce CH4 production in the rumen. The previous in vitro experiments have indicated that lovastatin can inhibit archaea growth and mitigate the CH4 production [5,6,7,8]. The commercial lovastatin is a prescription medication for human and the approved use as a feed additive for animals has not been published. The lovastatin in the commercial market contains only 2% of active beta-hydroxy acid open ring form (H-form), and the remainder 98% is the inactive gamma-lactone closed ring form (L-form) which has no ability to inhibit the HMG-CoA reductase unless it is hydrolyzed by carboxylesterases in vivo to H-form [7]

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