Plant components with specific activities against rumen methanogens

Abstract

A wide range of plant bioactive components (phytochemicals) have been identified as having potential to modulate the processes of fermentation in the rumen. The use of plants or plant extracts as natural feed additives has become a subject of interest not only among nutritionists but also other scientists. Although a large number of phytochemicals (e.g. saponins, tannins and essential oils) have recently been investigated for their methane reduction potential, there have not yet been major breakthroughs that could be applied in practice. A key tenet of this paper is the need for studies on the influence of plant components on methane production to be performed with standardized samples. Where there are consistent effects, the literature suggests that saponins mitigate methanogenesis mainly by reducing the number of protozoa, condensed tannins both by reducing the number of protozoa and by a direct toxic effect on methanogens, whereas essential oils act mostly by a direct toxic effect on methanogens. However, because the rumen is a complex ecosystem, analysis of the influence of plant components on the populations of methanogens should take into account not only the total population of methanogens but also individual orders or species. Although a number of plants and plant extracts have shown potential in studies in vitro, these effects must be confirmed in vivo.Keywords: ruminants, methane, tannins, saponins, essential oils ImplicationsThis review demonstrates that plant phytochemicals can have important effects on rumen methanogens, either by affecting methanogens directly and/or indirectly by affecting rumen protozoa. Modulation of the rumen microbiota, including methanogens and protozoa, with plant extracts such as saponins, tannins and essential oils has implications in improvement of animal nutrition through decreased dietary energy loss, and in limitation of the negative impact on the environment through mitigation of methane production.

<i>In vitro</i> fermentation, digestibility and methane production as influenced by <i>Delonix regia</i> seed meal containing tannins and saponins

“…Guo et al (2008) demonstrated that saponins inhibited the expression of the methylcoenzyme M reductase (mcrA) gene which takes part in the final step of methanogenesis. In addition, the CH 4 -suppressing effects of saponins were presumably a direct action against the rumen microbes involved in CH 4 formation, including methanogens and protozoa (Cieslak et al, 2013(Cieslak et al, , 2016Anantasook et al, 2016). Similar findings were found in this study: the protozoal population was also linearly reduced with increased DR seed meal levels Table 3.…”

“…Plant secondary compounds have been reported to suppress CH 4 concentration, reduce rumen protozoa counts and modulate rumen fermentation patterns (Cieslak et al, 2013). Many studies have shown that forages containing condensed tannins reduce CH 4 emissions from ruminants (Guo et al, 2008;Cieslak et al, 2016).…”

Fontes proteicas alternativas oriundas da cadeia produtiva do biodiesel para alimentação de ruminantes

“…Isso pode ser explicado pelo maior conteúdo de proteína desse alimento, como mostra a Tab. 1, o que resultaria na formação de bicarbonato de amônio, a partir de CO 2 , reduzindo a sua contribuição para a produção de gás (Cieslak et al, 2013). Além disso, as sementes da moringa têm demonstrado efeito bactericida contra algumas cepas Grampositivas e Gram-negativas, sugerindo o uso das sementes como fontes de agentes antibacterianos (Costa et al, 2009).…”

“…Em relação aos demais, demonstra melhor disponibilidade de nutrientes para os microrganismos ruminais in vitro. Esse tempo é considerado limite para a permanência de grãos no rúmen para vacas em lactação com taxa de passagem de 4 a 6,5% h -1 e, dessa maneira, promoveria maior disponibilidade de energia fermentável no rúmen agindo em sincronia com a proteína degradável (Cieslak et al, 2013), o que resultaria em maiores produções de leite.…”

Developing a conceptual model of possible benefits of condensed tannins for ruminant production

“…fat and fatty acids) and proteins may naturally restrict the production of CH 4 in the rumen if their relative proportion is increased and daily DMI is kept the same. Literature review of experimental research (Tedeschi et al, 2003 and2011b;Cieslak et al, 2013) has indicated that in current production systems such mitigation might be attained with feed additives and feeding strategies used alone or combined. Regardless of limitations in measuring CT and the generally unknown fate and transformations of the CT molecule through the ruminant digestive system (Terrill et al, 1994), CT are thought to reduce CH 4 production in two ways.…”