Natural Products as Manipulators of Rumen Fermentation

Abstract

There is increasing interest in exploiting natural products as feed additives to solve problems in animal nutrition and livestock production. Essential oils and saponins are two types of plant secondary compounds that hold promise as natural feed additives for ruminants. This paper describes recent advances in research into these additives. The research has generally concentrated on protein metabolism. Dietary essential oils caused rates of NH 3 production from amino acids in ruminal fluid taken from sheep and cattle receiving the oils to decrease, yet proteinase and peptidase activities were unchanged. Hyper-ammonia-producing (HAP) bacteria were the most sensitive of ruminal bacteria to essential oils in pure culture. Essential oils also slowed colonisation and digestion of some feedstuffs. Ruminobacter amylophilus may be a key organism in mediating these effects. Saponin-containing plants and their extracts appear to be useful as a means of suppressing the bacteriolytic activity of rumen ciliate protozoa and thereby enhancing total microbial protein flow from the rumen. The effects of some saponins seems to be transient, which may stem from the hydrolysis of saponins to their corresponding sapogenin aglycones, which are much less toxic to protozoa. Saponins also have selective antibacterial effects which may prove useful in, for example, controlling starch digestion. These studies illustrate that plant secondary compounds, of which essential oils and saponins comprise a small proportion, have great potential as 'natural' manipulators of rumen fermentation, to the potential benefit of the farmer and the environment.

Bioactivity of phytochemicals in some lesser-known plants and their effects and potential applications in livestock and aquaculture production systems

“…Saponins may kill or inactivate protozoa , resulting in a lower predation of bacteria by protozoa and a larger bacterial population, slowing protein turnover in the rumen. The slower protein turnover should lead to an increase in bacterial nitrogen flow to the duodenum and increase in productivity Wallace et al, 2002;Hess et al, 2004). As mentioned above, yucca, quillaja and acacia saponins enhanced both microbial mass production and efficiency of microbial protein synthesis, measured using both purine as a marker and 15 N incorporation in rumen microbes (Makkar, 2005).…”

Associative effects between forages on feed intake and digestion in ruminants

“…Saponins also cause a decrease in the proportion of protozoa in the rumen (Ivan et al, 2004). Thus, saponins could contribute to reducing methane emissions (Wallace et al, 2002;Hess et al, 2003;Pen et al, 2006). Indeed, protozoa contribute to methane production by hydrogen production.…”

Using juniper berry ( Juniperus communis ) as a supplement in Japanese quail diets

“…Positive impacts of medicinal and aromatic plants on appetite, digestive system, and weight gain and feed conversion ratios of broilers were also reported by Adiyaman and Ayhan (2010). Although there are limited studies about the effects of essential oils of aromatic plants on poultry traits, many studies focused on positive impacts of such additives to poultry diets (Jamroz and Kamel, 2002;Wallace et al, 2002). In recent years, decreased feed intake and mortality rates and improved FCR and carcass quality have been reported with the use of aromatic plants in broiler diets.…”

“…Plant extracts are considered as an effective solution for feed additives (Wallace et al, 2002;Adiyaman and Ayhan, 2010). Medicinal and aromatic plants are commonly used in various sectors, especially in the food industry from past to present because of their several benefits (Adiyaman and Ayhan, 2010).…”