The effects of dietary supplementation with 3-nitrooxypropanol on enteric methane emissions, rumen fermentation, and production performance in ruminants: a meta-analysis

RESEARCH ARTICLE J Anim Sci Technol 2020;62(1):31-42 https://doi.org/10.5187/jast.2020.62.1.31 Journal of Animal Science and Technology pISSN 2672-0191 eISSN 2055-0391 The effects of dietary supplementation with 3-nitrooxypropanol on enteric methane emissions, rumen fermentation, and production performance in ruminants: a meta-analysis Hanbeen Kim1#, Hyo Gun Lee1#, Youl-Chang Baek2, Seyoung Lee3 and Jakyeom Seo1* Received: Oct 31, 2019 Revised: Nov 13, 2019 Accepted: Dec 2, 2019 #These authors contributed equally to this work. *Corresponding author Jakyeom Seo Department of Animal Science, Life and Industry Convergence Research Institute, Pusan National University, Miryang 50463, Korea. Tel: +82-55-350-5513 E-mail: Copyright © 2020 Korean Society of Animal Sciences and Technology. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/bync/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ORCID Hanbeen Kim https://orcid.org/0000-0003-2803-7318 Hyo Gun Lee http://orcid.org/0000-0002-3286-7368 Youl-Chang Baek https://orcid.org/0000-0003-4454-5339 Seyoung Lee https://orcid.org/0000-0001-7991-0565 Jakyeom Seo https://orcid.org/0000-0002-9176-5206 Competing interests No potential conflict of interest relevant https://www.ejast.org 1 Department of Animal Science, Life and Industry Convergence Research Institute, Pusan National University, Miryang 50463, Korea 2 National Institute of Animal Science, Rural Development Administration, Wanju 55365, Korea 3 Division of Animal Husbandry, Yonam College, Cheonan 31005, Korea Abstract The aim of this study was to investigate the effects of 3-nitrooxypropanol (NOP) on gas production, rumen fermentation, and animal performances depending on animal type using a meta-analysis approach. A database consisted of data from 14 studies, 18 experiments and 55 treatments. The supplementation of NOP linearly decreased methane (CH4) emissions [g/kg dry matter intake (DMI)] regardless of animal type and length of experimental period (beef, p < 0.0001, R2 = 0.797; dairy, p = 0.0003, R2 = 0.916; and long term, p < 0.0001, R2 = 0.910). The total volatile fatty acids (VFA) concentration and the proportion of acetate, based on beef cattle database, were significantly decreased with increasing NOP supplementation (p = 0.0015, R2 = 0.804 and p = 0.0003, R2 = 0.918), whereas other individual VFAs was increased. Based on the dairy database, increasing levels of NOP supplementation linearly decreased proportion of acetate (p = 0.0284, R2 = 0.769) and increased that of valerate (p = 0.0340, R2 = 0.522), regardless of significant change on other individual VFAs. In animal performances, the DMI, from beef cattle database, tended to decrease when the levels of NOP supplementation increased (p = 0.0574, R2 = 0.170), whereas there was no significant change on DMI from dairy cattle database. The NOP supplementation tended to decrease milk yield (p = 0.0606, R2 = 0.381) and increase milk fat and milk protein (p = 0.0861, R2 = 0.321, p = 0.0838, R2 = 0.322). NOP is a viable candidate as a feed additive because of its CH4 mitigation effects, regardless of animal type and experiment period, without adverse effects on animal performances. Keywords: Animal performance, Feed additive, Methane mitigation, 3-Nitrooxypropanol, Rumen fermentation 31 3-Nitrooxypropanol supplementation on methane mitigation and animal performance: meta-analysis to this article was reported. INTRODUCTION Funding sources This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2019R1F1A1056904). Reducing methane (CH4) emissions in rumen is a critical challenge to ruminant nutritionists. This is because CH4 is a substantial anthropogenic greenhouse gas, possessing a global warming potential 28–34 times greater than carbon dioxide (CO2) [1], and makes up 2%–12% of the loss of dietary gross energy (GE) intake to the ruminants [2]. Thus, there have been numerous global efforts to mitigate ruminal CH4 emissions, using various feed additives such as tannin [3,4], dietary fats containing polyunsaturated fatty acids [5], plant essential oils [6,7], and phytochemicals [8,9]. 3-Nitrooxypropanol (NOP) is a chemical compound, designed by Duval and Kindermann [10], which reduces CH4 emissions produced by the rumen from microbial fermentation. The NOP is a structural analogue of methyl coenzyme-M, which inhibits the activity of methyl coenzyme-M reductase related to the final step of methanogenesis [11]. Until now, total 14 in vivo studies using NOP supplementation were performed on various domestic ruminants, including sheep [12], beef cattle [13–19], and dairy cattle [20–25]. According to the results of previous studies using NOP in vivo, the CH4 emissions and proportion of acetate (% total volatile fatty acids, VFA) clearly decreased, whilst the proportion of propionate (% total VFA) significantly increased, but any adverse effects were not detected. In a recent meta-analysis, Jayanegara et al. [26] observed that increasing NOP supplementation linearly decreased CH4 emissions regardless of type of CH4 unit, when a meta-analysis was investigated on 10 in vivo studies [12,16–24]. Dijkstra et al. [27] revealed that NOP supplementation has stronger CH4 mitigation effects in dairy cattle than in beef cattle, and those effects were decreased in increasing dietary fiber content, when a meta-analysis was conducted using 9 in vivo studies [16– 24]. With our knowledge, there is no meta-analysis study investigating the effects of supplementation of NOP on CH4 reduction in a long term experiment, and the changes of rumen fermentation by NOP supplementation in a related with ruminant types was not analyzed as well. In the present meta-analysis, therefore, we hypothesized that NOP supplementation might be affected differently on rumen fermentation characteristics depending upon animal type adding recent in vivo studies which was not included in previous meta-analysis studies [13–15,25]. The aim of this study was to investigate the effects of NOP on enteric gas production, rumen fermentation, and animal performances depending on animal type using a meta-analysis approach. Acknowledgements Not applicable. Availability of data and material Upon reasonable request, the datasets of this study can be available from the corresponding author. Authors’ contributions Conceptualization: Kim HB, Lee HG, Seo JK. Data curation: Kim HB, Lee HG, Baek YC, Seo JK. Formal analysis: Kim HB. Methodology: Kim HB, Lee HG, Seo JK. Software: Kim HB, Lee HG. Validation: Lee SY, Baek YC. Investigation: Kim HB, Lee HG. Writing - original draft: Kim HB, Lee HG, Seo JK. Writing - review & editing: Lee SY, Baek YC. Ethics approval and consent to participate This article does n (...truncated)