In Vitro Screening of Plant Materials to Reduce Ruminal Protozoal Population and Mitigate Ammonia and Methane Emissions

• Main Authors: Pichad Khejornsart, Anusorn Cherdthong, Metha Wanapat
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Fermentation
• Subjects: phytochemical; protozoa; ruminal fermentation; tannins; methanogenesis; ammonia
• Online Access: https://www.mdpi.com/2311-5637/7/3/166

Alternative feed sources can be utilized to reduce enteric methane (CH₄) emissions, a major greenhouse gas that contributes to global warming. This study aimed to evaluate the potential use of tropical plants to improve digestibility, reduce protozoal populations, improve rumen fermentation, and minimize methane emissions from ruminants. The plants considered herein grow in tropical climates, are easily accessible in large quantities, and are directly related to human food production. Nine plants that grow naturally in tropical climates were assessed. Plant supplementation substantially enhanced accumulative gas production at 24 h (<i>p</i> < 0.05). The apparent organic matter digestibility (AOMDvt) of the diet was not affected by five of the nine plants. With the addition of the plant material, ammonia nitrogen concentrations were reduced by up to 47% and methane concentrations were reduced by 54%. Five of the nine plant materials reduced methane production in terms of CH₄/dry matter and CH₄/digestibility of the organic matter by 15–35% and 8–24%, respectively. In conclusion, supplementation with plants with high tannin contents was shown to be a viable strategy for improving rumen fermentation, reducing protozoal populations, and limiting methane emissions. In this regard, the leaves of <i>Piper sarmentosum</i>, <i>Acmella oleracea</i>, <i>Careya arborea</i>, and <i>Anacardium occidentale</i> were especially promising.